WO2020154841A1

WO2020154841A1 - Measurement-based dual connectivity and carrier aggregation activation

Info

Publication number: WO2020154841A1
Application number: PCT/CN2019/073431
Authority: WO
Inventors: Peng Cheng; Huichun LIU
Original assignee: Qualcomm Incorporated
Priority date: 2019-01-28
Filing date: 2019-01-28
Publication date: 2020-08-06

Abstract

Methods, systems, and devices for wireless communications are described. One or more lower-layer configurations may be stored for use in re-establishing communications when a user equipment (UE) leaves an inactive communications state. For example, a UE may communicate with a network using a particular communications scheme and subsequently transition to the inactive communication state. The UE and the network may store a set of lower-layer configurations associated with the communications scheme, and the UE may also be configured to perform cell measurements while in the inactive communication state. Upon transitioning out of the inactive communication state, the UE may indicate, to the network, an availability of measurement reports generated while the UE was in the inactive state. Further, the UE may resume communications on one or more cells based on signaling from the network that indicates a difference between a current lower-layer configuration and the stored lower-layer configuration(s).

Description

MEASUREMENT-BASED DUAL CONNECTIVITY AND CARRIER AGGREGATION ACTIVATION

BACKGROUND

The following relates generally to wireless communications, and more specifically to measurement-based dual connectivity (DC) and carrier aggregation activation (CA) .

Wireless communications systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power) . Examples of such multiple-access systems include fourth generation (4G) systems such as Long Term Evolution (LTE) systems, LTE-Advanced (LTE-A) systems, or LTE-A Pro systems, and fifth generation (5G) systems which may be referred to as New Radio (NR) systems. These systems may employ technologies such as code division multiple access (CDMA) , time division multiple access (TDMA) , frequency division multiple access (FDMA) , orthogonal frequency division multiple access (OFDMA) , or discrete Fourier transform spread orthogonal frequency division multiplexing (DFT-S-OFDM) .

A wireless multiple-access communications system may include a number of base stations or network access nodes, each simultaneously supporting communication for multiple communication devices, which may be otherwise known as user equipment (UE) . A UE may be configured to simultaneously connect to and communicate with a network using multiple cells, such as in DC and CA operations. In some cases, the UE may resume communications with one or more of the cells after a period of inactivity. Techniques to efficiently resume communications between the UE and network are desired.

SUMMARY

The described techniques relate to improved methods, systems, devices, or apparatuses that support measurement-based dual connectivity (DC) and carrier aggregation (CA) activation. Generally, the described techniques provide for the storage of one or more lower-layer configurations for use in re-establishing communications when a user equipment (UE) transitions from an inactive communications state. For example, a UE may communicate with a network using a particular communications scheme (e.g., DC, CA, etc. ) and subsequently transition to the inactive communication state (e.g., a radio resource control (RRC) inactive state) . The UE and the network may store a set of lower-layer configurations that were used for the communications scheme. For instance, a lower-layer master cell group (MCG) configuration and/or a lower-layer secondary cell group (SCG) configuration of a DC deployment may be stored when the UE enters the inactive communication state. In other examples, lower-layer configurations for CA operations may be stored when the UE enters the inactive communication state. In any case, the UE may also perform one or more cell measurements while in the inactive communication state.

Upon performing a state transition from the inactive communication state (e.g., to a connected communications state) , the UE may indicate, to the network, an availability of measurement reports generated while the UE was in the inactive state. Further, the UE may resume communications on one or more cells based on signaling from the network that indicates a difference between a current lower-layer configuration and the stored lower-layer configuration (s) . In such cases, the difference signaled by the network may be based on measurement reports provided by the UE. Additionally, the network may efficiently modify the cells used, for example, in DC or CA operation, based on the measurement reports provided by the UE and through the use of the signaling of the changes from the stored lower-layer configuration. As a result, the UE may efficiently resume communications with the network with minimized signaling after exiting the inactive communication state (e.g., as compared to when lower-layer configurations are dropped upon entering the inactive communication state) .

A method of wireless communication at a UE is described. The method may include performing a state transition to an inactive communication state with a first cell and a second cell, storing, based on the state transition to the inactive communication state, a first lower-layer configuration for the first cell and a second lower-layer configuration for the second cell, determining that communications with at least one of the first cell or the second cell are to resume, transmitting, based on the determination, an indication of whether one or more measurement reports are available, and receiving a reconfiguration message that indicates a difference between a current lower-layer configuration and at least one of the stored first lower-layer configuration or the second lower-layer configuration.

An apparatus for wireless communication at a UE is described. The apparatus may include a processor, memory in electronic communication with the processor, and instructions stored in the memory. The instructions may be executable by the processor to cause the apparatus to perform a state transition to an inactive communication state with a first cell and a second cell, store, based on the state transition to the inactive communication state, a first lower-layer configuration for the first cell and a second lower-layer configuration for the second cell, determine that communications with at least one of the first cell or the second cell are to resume, transmit, based on the determination, an indication of whether one or more measurement reports are available, and receive a reconfiguration message that indicates a difference between a current lower-layer configuration and at least one of the stored first lower-layer configuration or the second lower-layer configuration.

Another apparatus for wireless communication at a UE is described. The apparatus may include means for performing a state transition to an inactive communication state with a first cell and a second cell, storing, based on the state transition to the inactive communication state, a first lower-layer configuration for the first cell and a second lower-layer configuration for the second cell, determining that communications with at least one of the first cell or the second cell are to resume, transmitting, based on the determination, an indication of whether one or more measurement reports are available, and receiving a reconfiguration message that indicates a difference between a current lower-layer configuration and at least one of the stored first lower-layer configuration or the second lower-layer configuration.

A non-transitory computer-readable medium storing code for wireless communication at a UE is described. The code may include instructions executable by a processor to perform a state transition to an inactive communication state with a first cell and a second cell, store, based on the state transition to the inactive communication state, a first lower-layer configuration for the first cell and a second lower-layer configuration for the second cell, determine that communications with at least one of the first cell or the second cell are to resume, transmit, based on the determination, an indication of whether one or more measurement reports are available, and receive a reconfiguration message that indicates a difference between a current lower-layer configuration and at least one of the stored first lower-layer configuration or the second lower-layer configuration.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, transmitting the indication of whether the one or more measurement reports may be available may include operations, features, means, or instructions for transmitting, via the first cell, an indication that a measurement report for the second cell may be available based on measurements performed by the UE while in the inactive communication state. Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for resuming communications on the second cell based at least in part on the reconfiguration message indicating a difference between a current lower-layer configuration for the second cell and the stored second lower-layer configuration for the second cell, the difference being based at least in part on the measurement report for the second cell.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for resuming communications on the first cell, where the first cell may be from a MCG associated with a master node of a DC deployment, and where the second cell may be from a SCG associated with a secondary node of the DC deployment.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for resuming communications on the first cell, where the first cell may be from a previously-serving SCG associated with a previously-serving secondary node of a DC deployment, and where the second cell may be from a previously-serving MCG associated with a previously-serving master node of the DC deployment.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, transmitting the indication of whether the one or more measurement reports may be available may include operations, features, means, or instructions for transmitting, via the first cell, an indication that a measurement report for a third cell may be available based on measurements performed by the UE while in the inactive communication state. Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for communicating on the third cell based at least in part on the reconfiguration message indicating a difference between a current lower-layer configuration for the third cell and the stored second lower-layer configuration for the second cell, the difference being based at least in part on the measurement report for the third cell.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for resuming communications on the first cell, where the first cell may be from a MCG associated with a master node of a DC deployment, and where the second cell may be from a previously-serving SCG associated with a previously-serving secondary node of the DC deployment, and communicating on the third cell as part of a currently-serving SCG associated with a currently-serving secondary node of the DC deployment.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for resuming communications on the first cell, where the first cell may be from a currently-serving MCG associated with a currently-serving master node of a DC deployment, and where the second cell may be from a previously-serving MCG associated with a previously-serving master node of the DC deployment, and communicating on the third cell as part of a currently-serving SCG associated with a secondary node of the DC deployment.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the indication that the measurement report for the third cell may be available may be transmitted via a signaling radio bearer associated with the second cell, and where the reconfiguration message may be received on the signaling radio bearer associated with the second cell.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for resuming communications on the first cell, where the first cell may be from a previously-serving SCG associated with a previously-serving secondary node of a DC deployment, and where the first cell may be from a previously-serving MCG associated with a previously-serving master node of the DC deployment, and communicating on the third cell as part of a currently-serving MCG of a currently-serving master node of the DC deployment.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, transmitting the indication of whether the one or more measurement reports may be available may include operations, features, means, or instructions for transmitting, to the first cell, an indication that measurement reports for one or more cells may be unavailable based on measurements performed by the UE while in the inactive communication state. Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for refraining from communicating with the second cell based at least in part on the reconfiguration message, wherein the reconfiguration message indicates that the second cell has been released based at least in part on the unavailability of the measurement reports.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for resuming communications on the first cell, where the first cell may be from a MCG associated with a master node of a DC deployment, and where the second cell may be from a previously-serving SCG associated with a previously-serving secondary node of the DC deployment.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for resuming communications on the first cell, where the first cell may be from a previously-serving SCG associated with a secondary node of a DC deployment, and where the second cell may be from a previously-serving MCG associated with a previously-serving master node of the DC deployment.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, transmitting the indication of whether the one or more measurement reports may be available may include operations, features, means, or instructions for transmitting, to the first cell and via a signaling radio bearer associated with the second cell, an indication that a measurement report for the first cell and the second cell may be available based on measurements performed by the UE while in the inactive communication state. Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for resuming communications with the second cell based at least in part on the reconfiguration message indicating a difference between a current lower-layer configuration for the second cell and the stored second lower-layer configuration for the second cell, the difference being based at least in part on the measurement report for the second cell.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the reconfiguration message may be received via the signaling radio bearer associated with the second cell. Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for resuming communications on the first cell, where the first cell may be from a MCG associated with a master node of a DC deployment, and where the second cell may be from a SCG associated with a secondary node of the DC deployment.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first cell includes a primary cell of a CA deployment and the second cell includes a secondary cell of the CA deployment.

A method of wireless communication at a base station is described. The method may include communicating with a UE using a first lower-layer configuration for a first cell of the base station, storing the first lower-layer configuration based on a determination that the UE has transitioned to an inactive communication state, receiving, from the UE, a request to resume communications, the request including an indication of whether one or more measurement reports are available at the UE, determining a current lower-layer configuration for at least one of the first cell or a second cell, and transmitting, to the UE, a reconfiguration message that indicates a difference between a current lower-layer configuration and at least one of the stored first lower-layer configuration or a second lower-layer configuration for the second cell.

An apparatus for wireless communication at a base station is described. The apparatus may include a processor, memory in electronic communication with the processor, and instructions stored in the memory. The instructions may be executable by the processor to cause the apparatus to communicate with a UE using a first lower-layer configuration for a first cell of the base station, store the first lower-layer configuration based on a determination that the UE has transitioned to an inactive communication state, receive, from the UE, a request to resume communications, the request including an indication of whether one or more measurement reports are available at the UE, determine a current lower-layer configuration for at least one of the first cell or a second cell, and transmit, to the UE, a reconfiguration message that indicates a difference between a current lower-layer configuration and at least one of the stored first lower-layer configuration or a second lower-layer configuration for the second cell.

Another apparatus for wireless communication at a base station is described. The apparatus may include means for communicating with a UE using a first lower-layer configuration for a first cell of the base station, storing the first lower-layer configuration based on a determination that the UE has transitioned to an inactive communication state, receiving, from the UE, a request to resume communications, the request including an indication of whether one or more measurement reports are available at the UE, determining a current lower-layer configuration for at least one of the first cell or a second cell, and transmitting, to the UE, a reconfiguration message that indicates a difference between a current lower-layer configuration and at least one of the stored first lower-layer configuration or a second lower-layer configuration for the second cell.

A non-transitory computer-readable medium storing code for wireless communication at a base station is described. The code may include instructions executable by a processor to communicate with a UE using a first lower-layer configuration for a first cell of the base station, store the first lower-layer configuration based on a determination that the UE has transitioned to an inactive communication state, receive, from the UE, a request to resume communications, the request including an indication of whether one or more measurement reports are available at the UE, determine a current lower-layer configuration for at least one of the first cell or a second cell, and transmit, to the UE, a reconfiguration message that indicates a difference between a current lower-layer configuration and at least one of the stored first lower-layer configuration or a second lower-layer configuration for the second cell.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, receiving the indication of whether the one or more measurement reports may be available may include operations, features, means, or instructions for receiving an indication that a measurement report for the second cell may be available based on measurements performed by the UE while in the inactive communication state. Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for activating the second cell based at least in part on the measurement report for the second cell.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the indication that the measurement report for the second cell may be received via a signaling radio bearer associated with the second cell, and where the reconfiguration message may be transmitted via the signaling radio bearer associated with the second cell.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the cell may be from a MCG of a DC deployment and the second cell may be from a previously-serving SCG of the DC deployment. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, receiving the indication of whether the one or more measurement reports may be available may include operations, features, means, or instructions for receiving an indication that a measurement report for a third cell may be available based on measurements performed by the UE while in the inactive communication state.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for transmitting, to a target base station providing the third cell, a secondary node addition request based at least in part on the measurement report for the third cell. Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for transmitting, to a second base station providing the second cell, a secondary node release request, wherein the second cell is from a previously-serving secondary cell group of a dual connectivity deployment.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving, from the second base station, an indication of the second lower-layer configuration for the second cell, where determining the current lower-layer configuration may be based on the received indication, and transmitting, as part of the secondary node addition request, an indication of the second lower-layer configuration to the target base station.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, receiving the indication of whether the one or more measurement reports may be available may include operations, features, means, or instructions for receiving, via a signaling radio bearer associated with the second cell, an indication that a measurement report for a third cell may be available based on measurements performed by the UE while in the inactive communication state, and transmitting, to a third base station providing the third cell, a handover request based on the measurement report for the third cell, where the handover request includes an indication of the stored first lower-layer configuration for the first cell.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the reconfiguration message may be transmitted via the signaling radio bearer associated with the second cell. In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, receiving the indication of whether the one or more measurement reports may be available may include operations, features, means, or instructions for receiving an indication that measurement reports for one or more other cells may be unavailable based on measurements performed by the UE while in the inactive communication state. Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for transmitting, to a second base station providing the second cell, a secondary node release request based at least in part on the unavailability of the measurement reports.

A method of wireless communication at a base station is described. The method may include communicating with a UE using a lower-layer configuration for a cell of the base station, where the cell is from a SCG of a DC deployment, storing the first lower-layer configuration based on a determination that the UE has transitioned to an inactive communication state, and receiving, from the UE, a request to resume communications, the request including an indication of whether one or more measurement reports are available at the UE.

An apparatus for wireless communication at a base station is described. The apparatus may include a processor, memory in electronic communication with the processor, and instructions stored in the memory. The instructions may be executable by the processor to cause the apparatus to communicate with a UE using a lower-layer configuration for a cell of the base station, where the cell is from a SCG of a DC deployment, store the first lower- layer configuration based on a determination that the UE has transitioned to an inactive communication state, and receive, from the UE, a request to resume communications, the request including an indication of whether one or more measurement reports are available at the UE.

Another apparatus for wireless communication at a base station is described. The apparatus may include means for communicating with a UE using a lower-layer configuration for a cell of the base station, where the cell is from a SCG of a DC deployment, storing the first lower-layer configuration based on a determination that the UE has transitioned to an inactive communication state, and receiving, from the UE, a request to resume communications, the request including an indication of whether one or more measurement reports are available at the UE.

A non-transitory computer-readable medium storing code for wireless communication at a base station is described. The code may include instructions executable by a processor to communicate with a UE using a lower-layer configuration for a cell of the base station, where the cell is from a SCG of a DC deployment, store the first lower-layer configuration based on a determination that the UE has transitioned to an inactive communication state, and receive, from the UE, a request to resume communications, the request including an indication of whether one or more measurement reports are available at the UE.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining a current lower-layer configuration for the cell, and transmitting, to the UE, a reconfiguration message that indicates a difference between the current lower-layer configuration and at least one of the stored lower-layer configuration or a second lower-layer configuration for a second cell provided by a second base station, where the second cell may be from a MCG of the DC deployment.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, receiving the indication of whether the one or more measurement reports may be available may include operations, features, means, or instructions for receiving an indication that a measurement report for the second cell may be available based on measurements performed by the UE while in the inactive communication state. Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for transmitting, based at least in part on the measurement report for the second cell, a context request to the second base station, the context request comprising an indication to exchange a master node and the secondary node.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving, from the second base station, an indication of the second lower-layer configuration, wherein the reconfiguration message indicates a difference between a current lower-layer configuration for the cell and the second lower-layer configuration for the second cell.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, receiving the indication of whether the one or more measurement reports may be available may include operations, features, means, or instructions for receiving an indication that a measurement report for a third cell may be available based on measurements performed by the UE while in the inactive communication state. Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for transmitting, to a third base station providing the third cell, an indication of the stored lower-layer configuration, wherein the reconfiguration message indicates a difference between a current lower-layer configuration for the cell and the second lower-layer configuration for the second cell.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, receiving the indication of whether the one or more measurement reports may be available may include operations, features, means, or instructions for receiving an indication that measurement reports for one or more other cells may be unavailable based on measurements performed by the UE while in the inactive communication state. Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for transmitting, to the second base station, a secondary node release request based at least in part on the unavailability of the measurement reports.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, receiving the indication of whether the one or more measurement reports may be available may include operations, features, means, or instructions for receiving an indication that measurement reports for one or more other cells may be unavailable based on measurements performed by the UE while in the inactive communication state. Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for transmitting, to the second base station, a handover request based at least in part on the unavailability of the measurement reports.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example of a system for wireless communications that supports measurement-based dual connectivity (DC) and carrier aggregation (CA) activation in accordance with aspects of the present disclosure.

FIG. 2 illustrates an example of a wireless communications system that supports measurement-based DC and CA activation in accordance with aspects of the present disclosure.

FIGs. 3 through 13 illustrate examples of a process flow in a system that supports measurement-based DC and CA activation in accordance with aspects of the present disclosure.

FIGs. 14 and 15 show block diagrams of devices that support measurement-based DC and CA activation in accordance with aspects of the present disclosure.

FIG. 16 shows a block diagram of a communications manager that supports measurement-based DC and CA activation in accordance with aspects of the present disclosure.

FIG. 17 shows a diagram of a system including a device that supports measurement-based DC and CA activation in accordance with aspects of the present disclosure.

FIGs. 18 and 19 show block diagrams of devices that support measurement-based DC and CA activation in accordance with aspects of the present disclosure.

FIG. 20 shows a block diagram of a communications manager that supports measurement-based DC and CA activation in accordance with aspects of the present disclosure.

FIG. 21 shows a diagram of a system including a device that supports measurement-based DC and CA activation in accordance with aspects of the present disclosure.

FIGs. 22 through 27 show flowcharts illustrating methods that support measurement-based DC and CA activation in accordance with aspects of the present disclosure.

DETAILED DESCRIPTION

In some wireless communications systems, a user equipment (UE) may communicate with a network using dual connectivity (DC) . In such cases, the UE may simultaneously communicate with different base stations, where a first base station may provide a first cell and be referred to as a master node. Likewise, a second base station providing a second cell of the DC deployment may be referred to as a secondary node, and the first and second cells may each be associated with a same or different radio access technology (RAT) . As such, various DC deployments may be referred to as evolved universal terrestrial radio access (E-UTRA) new radio (NR) -dual connectivity (EN-DC) , NR E-UTRA-DC (NE-DC) , NR NR-DC, LTE LTE-DC, or may include other types of multi-radio access technology-dual connectivity (MR-DC) deployments based on the RAT implemented by each cell. In any case, the different cells a UE communicates on for DC may use the same or different radio frequency (RF) spectrum bands.

Additionally or alternatively, a UE may communicate with a single base station using multiple carriers (e.g., component carriers (CCs) ) . In such cases, a CC may refer to each of the carriers used by a UE in carrier aggregation (CA) operations. Further, a serving cell of a base station may correspond to each CC used in CA operation, where each serving cell may be different (e.g., based on the path loss experienced by different CCs on different RF spectrum bands) . In some examples, one carrier may be designated as a primary carrier, or primary CC (PCC) , for the UE, which may be served by a primary cell (PCell) . Additional carriers may be designated as secondary carriers, or secondary CCs (SCCs) , which may be served by secondary cells (SCells) of the base station. CA operations may also use the same or different RF bands for communications.

A UE may not continuously communicate with one or more base stations, and the UE may accordingly operate in various communication states, for example, to save power when not transmitting or receiving data. For instance, the UE may operate in an idle communication state (e.g., a radio resource control (RRC) idle state) , where the UE may be “on standby” and thus, may not be assigned to a particular serving base station. Additionally, the UE may operate in a connected communication state (e.g., an RRC connected state) where the UE may be “active” and may transmit data to/receive data from a serving cell. The UE may accordingly transition from the RRC idle state to the RRC connected state, and vice versa, based on its activity.

In some systems, a UE may support additional communication states. For example, an inactive communication state (e.g., an RRC inactive state) between the connected communication state and the idle communication state may be used to enable transitions from the inactive communication state to the connected communication state more quickly (e.g., as compared to the transition from the idle communication state to the connected communication state) . When transitioning to the inactive communication state, a UE context (e.g., an access stratum (AS) context) may be retained at the UE and the network, and both the UE and network may further store higher-layer configurations (e.g., for respective cells of DC/CA deployments) while simultaneously releasing lower-layer configurations (as the lower-layer configurations may change, for example, due to the UE’s mobility) . Then, when resuming communications with the network and moving out of the inactive communication state, the UE may apply the stored higher-layer configurations.

However, due to the release of the lower-layer configurations, the UE may not be able to operate using the previously-established DC and/or CA schemes immediately after leaving the inactive communication state. For example, a UE in a DC deployment that enters the inactive communication state may later require multiple reconfiguration messages from the network to obtain a full configuration, including the lower-layer configurations, for different cells (and any updates thereto) to establish communication with multiple nodes of the DC deployment. Such signaling overhead may reduce efficiency in the system and may cause unnecessary delays in configuring a UE for CA/DC communications.

As described herein, techniques for storing lower-layer configurations may reduce latency and signaling overhead when the UE leaves the inactive communication state. For example, the stored lower-layer configurations may be used to efficiently re-establish communications with nodes of a DC deployment (or re-establish a CA configuration) with minimal signaling (e.g., as compared to multiple handshakes required when the lower-layer configurations are not stored) . In some cases, the UE may receive signaling, from the network, that indicates a difference between a current lower-layer configuration and the stored lower-layer configuration. In some aspects, the signaling indicating differences between the current and stored lower-layer configurations may be based on measurement reporting provided by the UE, where, for example, the measurements used to generate the measurement reporting may be performed while the UE is in the inactive communication state.

The storage of the lower-layer configurations and the use of signaling that indicates one or more parameters that may have changed since a lower-layer configuration was stored upon entering into an inactive communication state may reduce signaling overhead used to fully configure one or more cells for a UE. The described techniques may accordingly be applicable for DC configurations (e.g., NE-DC, EN-DC, and the like) and CA configurations when the UE resumes from an inactive communication state. Additionally or alternatively, the described techniques may be applicable to scenarios where a UE is connected to a single base station, and may be used to efficiently set up DC or CA when the UE resumes communications from the inactive communication state.

Aspects of the disclosure are initially described in the context of a wireless communications system. Additional aspects are then described with reference to process flows that illustrate techniques to reduce latency and signaling overhead when resuming DC and/or CA operations after leaving an inactive communication state in a system. Aspects of the disclosure are further illustrated by and described with reference to apparatus diagrams, system diagrams, and flowcharts that relate to measurement-based DC and CA activation.

FIG. 1 illustrates an example of a wireless communications system 100 that supports measurement-based DC and CA activation in accordance with aspects of the present disclosure. The wireless communications system 100 includes base stations 105, UEs 115, and a core network 130. In some examples, the wireless communications system 100 may be a Long Term Evolution (LTE) network, an LTE-Advanced (LTE-A) network, an LTE-A Pro network, or a New Radio (NR) network. In some cases, wireless communications system 100 may support enhanced broadband communications, ultra-reliable (e.g., mission critical) communications, low latency communications, or communications with low-cost and low-complexity devices. Wireless communications system 100 may support the storage of lower-layer configurations used in DC and/or CA deployments to enable the efficient transition from an RRC inactive state. Further, signaling that indicates a difference between the stored lower-layer configurations and updated lower-layer configurations (e.g., delta signaling) after exiting the RRC inactive state may reduce signaling overhead in the system.

Base stations 105 may wirelessly communicate with UEs 115 via one or more base station antennas. Base stations 105 described herein may include or may be referred to by those skilled in the art as a base transceiver station, a radio base station, an access point, a radio transceiver, a NodeB, an eNodeB (eNB) , a next-generation NodeB or giga-NodeB (either of which may be referred to as a gNB) , a Home NodeB, a Home eNodeB, or some other suitable terminology. Wireless communications system 100 may include base stations 105 of different types (e.g., macro or small cell base stations) . The UEs 115 described herein may be able to communicate with various types of base stations 105 and network equipment including macro eNBs, small cell eNBs, gNBs, relay base stations, and the like.

Each base station 105 may be associated with a particular geographic coverage area 110 in which communications with various UEs 115 is supported. Each base station 105 may provide communication coverage for a respective geographic coverage area 110 via communication links 125, and communication links 125 between a base station 105 and a UE 115 may utilize one or more carriers. Communication links 125 shown in wireless communications system 100 may include uplink transmissions from a UE 115 to a base station 105, or downlink transmissions from a base station 105 to a UE 115. Downlink transmissions may also be called forward link transmissions while uplink transmissions may also be called reverse link transmissions.

The geographic coverage area 110 for a base station 105 may be divided into sectors making up a portion of the geographic coverage area 110, and each sector may be associated with a cell. For example, each base station 105 may provide communication coverage for a macro cell, a small cell, a hot spot, or other types of cells, or various combinations thereof. In some examples, a base station 105 may be movable and therefore provide communication coverage for a moving geographic coverage area 110. In some examples, different geographic coverage areas 110 associated with different technologies may overlap, and overlapping geographic coverage areas 110 associated with different technologies may be supported by the same base station 105 or by different base stations 105. The wireless communications system 100 may include, for example, a heterogeneous LTE/LTE-A/LTE-A Pro or NR network in which different types of base stations 105 provide coverage for various geographic coverage areas 110.

The term “cell” refers to a logical communication entity used for communication with a base station 105 (e.g., over a carrier) , and may be associated with an identifier for distinguishing neighboring cells (e.g., a physical cell identifier (PCID) , a virtual cell identifier (VCID) ) operating via the same or a different carrier. In some examples, a carrier may support multiple cells, and different cells may be configured according to different protocol types (e.g., machine-type communication (MTC) , narrowband Internet-of-Things (NB-IoT) , enhanced mobile broadband (eMBB) , or others) that may provide access for different types of devices. In some cases, the term “cell” may refer to a portion of a geographic coverage area 110 (e.g., a sector) over which the logical entity operates.

UEs 115 may be dispersed throughout the wireless communications system 100, and each UE 115 may be stationary or mobile. A UE 115 may also be referred to as a mobile device, a wireless device, a remote device, a handheld device, or a subscriber device, or some other suitable terminology, where the “device” may also be referred to as a unit, a station, a terminal, or a client. A UE 115 may also be a personal electronic device such as a cellular phone, a personal digital assistant (PDA) , a tablet computer, a laptop computer, or a personal computer. In some examples, a UE 115 may also refer to a wireless local loop (WLL) station, an Internet of Things (IoT) device, an Internet of Everything (IoE) device, or an MTC device, or the like, which may be implemented in various articles such as appliances, vehicles, meters, or the like.

Some UEs 115, such as MTC or IoT devices, may be low cost or low complexity devices, and may provide for automated communication between machines (e.g., via Machine-to-Machine (M2M) communication) . M2M communication or MTC may refer to data communication technologies that allow devices to communicate with one another or a base station 105 without human intervention. In some examples, M2M communication or MTC may include communications from devices that integrate sensors or meters to measure or capture information and relay that information to a central server or application program that can make use of the information or present the information to humans interacting with the program or application. Some UEs 115 may be designed to collect information or enable automated behavior of machines. Examples of applications for MTC devices include smart metering, inventory monitoring, water level monitoring, equipment monitoring, healthcare monitoring, wildlife monitoring, weather and geological event monitoring, fleet management and tracking, remote security sensing, physical access control, and transaction-based business charging.

Some UEs 115 may be configured to employ operating modes that reduce power consumption, such as half-duplex communications (e.g., a mode that supports one-way communication via transmission or reception, but not transmission and reception simultaneously) . In some examples half-duplex communications may be performed at a reduced peak rate. Other power conservation techniques for UEs 115 include entering a power saving “deep sleep” mode when not engaging in active communications, or operating over a limited bandwidth (e.g., according to narrowband communications) . In some cases, UEs 115 may be designed to support critical functions (e.g., mission critical functions) , and a wireless communications system 100 may be configured to provide ultra-reliable communications for these functions.

In some cases, a UE 115 may also be able to communicate directly with other UEs 115 (e.g., using a peer-to-peer (P2P) or device-to-device (D2D) protocol) . One or more of a group of UEs 115 utilizing D2D communications may be within the geographic coverage area 110 of a base station 105. Other UEs 115 in such a group may be outside the geographic coverage area 110 of a base station 105, or be otherwise unable to receive transmissions from a base station 105. In some cases, groups of UEs 115 communicating via D2D communications may utilize a one-to-many (1: M) system in which each UE 115 transmits to every other UE 115 in the group. In some cases, a base station 105 facilitates the scheduling of resources for D2D communications. In other cases, D2D communications are carried out between UEs 115 without the involvement of a base station 105.

Base stations 105 may communicate with the core network 130 and with one another. For example, base stations 105 may interface with the core network 130 through backhaul links 132 (e.g., via an S1, N2, N3, or other interface) . Base stations 105 may communicate with one another over backhaul links 134 (e.g., via an X2, Xn, or other interface) either directly (e.g., directly between base stations 105) or indirectly (e.g., via core network 130) .

The core network 130 may provide user authentication, access authorization, tracking, Internet Protocol (IP) connectivity, and other access, routing, or mobility functions. The core network 130 may be an evolved packet core (EPC) , which may include at least one mobility management entity (MME) , at least one serving gateway (S-GW) , and at least one Packet Data Network (PDN) gateway (P-GW) . The MME may manage non-access stratum (e.g., control plane) functions such as mobility, authentication, and bearer management for UEs 115 served by base stations 105 associated with the EPC. User IP packets may be transferred through the S-GW, which itself may be connected to the P-GW. The P-GW may provide IP address allocation as well as other functions. The P-GW may be connected to the network operators IP services. The operators IP services may include access to the Internet, Intranet (s) , an IP Multimedia Subsystem (IMS) , or a Packet-Switched (PS) Streaming Service.

At least some of the network devices, such as a base station 105, may include subcomponents such as an access network entity, which may be an example of an access node controller (ANC) . Each access network entity may communicate with UEs 115 through a number of other access network transmission entities, which may be referred to as a radio head, a smart radio head, or a transmission/reception point (TRP) . In some configurations, various functions of each access network entity or base station 105 may be distributed across various network devices (e.g., radio heads and access network controllers) or consolidated into a single network device (e.g., a base station 105) .

Wireless communications system 100 may operate using one or more frequency bands, typically in the range of 300 megahertz (MHz) to 300 gigahertz (GHz) . Generally, the region from 300 MHz to 3 GHz is known as the ultra-high frequency (UHF) region or decimeter band, since the wavelengths range from approximately one decimeter to one meter in length. UHF waves may be blocked or redirected by buildings and environmental features. However, the waves may penetrate structures sufficiently for a macro cell to provide service to UEs 115 located indoors. Transmission of UHF waves may be associated with smaller antennas and shorter range (e.g., less than 100 km) compared to transmission using the smaller frequencies and longer waves of the high frequency (HF) or very high frequency (VHF) portion of the spectrum below 300 MHz.

Wireless communications system 100 may also operate in a super high frequency (SHF) region using frequency bands from 3 GHz to 30 GHz, also known as the centimeter band. The SHF region includes bands such as the 5 GHz industrial, scientific, and medical (ISM) bands, which may be used opportunistically by devices that may be capable of tolerating interference from other users.

Wireless communications system 100 may also operate in an extremely high frequency (EHF) region of the spectrum (e.g., from 30 GHz to 300 GHz) , also known as the millimeter band. In some examples, wireless communications system 100 may support millimeter wave (mmW) communications between UEs 115 and base stations 105, and EHF antennas of the respective devices may be even smaller and more closely spaced than UHF antennas. In some cases, this may facilitate use of antenna arrays within a UE 115. However, the propagation of EHF transmissions may be subject to even greater atmospheric attenuation and shorter range than SHF or UHF transmissions. Techniques disclosed herein may be employed across transmissions that use one or more different frequency regions, and designated use of bands across these frequency regions may differ by country or regulating body.

In some cases, wireless communications system 100 may utilize both licensed and unlicensed radio frequency spectrum bands. For example, wireless communications system 100 may employ License Assisted Access (LAA) , LTE-Unlicensed (LTE-U) radio access technology, or NR technology in an unlicensed band such as the 5 GHz ISM band. When operating in unlicensed radio frequency spectrum bands, wireless devices such as base stations 105 and UEs 115 may employ listen-before-talk (LBT) procedures to ensure a frequency channel is clear before transmitting data. In some cases, operations in unlicensed bands may be based on a carrier aggregation configuration in conjunction with component carriers operating in a licensed band (e.g., LAA) . Operations in unlicensed spectrum may include downlink transmissions, uplink transmissions, peer-to-peer transmissions, or a combination of these. Duplexing in unlicensed spectrum may be based on frequency division duplexing (FDD) , time division duplexing (TDD) , or a combination of both.

In some examples, base station 105 or UE 115 may be equipped with multiple antennas, which may be used to employ techniques such as transmit diversity, receive diversity, multiple-input multiple-output (MIMO) communications, or beamforming. For example, wireless communications system 100 may use a transmission scheme between a transmitting device (e.g., a base station 105) and a receiving device (e.g., a UE 115) , where the transmitting device is equipped with multiple antennas and the receiving device is equipped with one or more antennas. MIMO communications may employ multipath signal propagation to increase the spectral efficiency by transmitting or receiving multiple signals via different spatial layers, which may be referred to as spatial multiplexing. The multiple signals may, for example, be transmitted by the transmitting device via different antennas or different combinations of antennas. Likewise, the multiple signals may be received by the receiving device via different antennas or different combinations of antennas. Each of the multiple signals may be referred to as a separate spatial stream, and may carry bits associated with the same data stream (e.g., the same codeword) or different data streams. Different spatial layers may be associated with different antenna ports used for channel measurement and reporting. MIMO techniques include single-user MIMO (SU-MIMO) where multiple spatial layers are transmitted to the same receiving device, and multiple-user MIMO (MU-MIMO) where multiple spatial layers are transmitted to multiple devices.

Beamforming, which may also be referred to as spatial filtering, directional transmission, or directional reception, is a signal processing technique that may be used at a transmitting device or a receiving device (e.g., a base station 105 or a UE 115) to shape or steer an antenna beam (e.g., a transmit beam or receive beam) along a spatial path between the transmitting device and the receiving device. Beamforming may be achieved by combining the signals communicated via antenna elements of an antenna array such that signals propagating at particular orientations with respect to an antenna array experience constructive interference while others experience destructive interference. The adjustment of signals communicated via the antenna elements may include a transmitting device or a receiving device applying certain amplitude and phase offsets to signals carried via each of the antenna elements associated with the device. The adjustments associated with each of the antenna elements may be defined by a beamforming weight set associated with a particular orientation (e.g., with respect to the antenna array of the transmitting device or receiving device, or with respect to some other orientation) .

In one example, a base station 105 may use multiple antennas or antenna arrays to conduct beamforming operations for directional communications with a UE 115. For instance, some signals (e.g., synchronization signals, reference signals, beam selection signals, or other control signals) may be transmitted by a base station 105 multiple times in different directions, which may include a signal being transmitted according to different beamforming weight sets associated with different directions of transmission. Transmissions in different beam directions may be used to identify (e.g., by the base station 105 or a receiving device, such as a UE 115) a beam direction for subsequent transmission and/or reception by the base station 105.

Some signals, such as data signals associated with a particular receiving device, may be transmitted by a base station 105 in a single beam direction (e.g., a direction associated with the receiving device, such as a UE 115) . In some examples, the beam direction associated with transmissions along a single beam direction may be determined based at least in in part on a signal that was transmitted in different beam directions. For example, a UE 115 may receive one or more of the signals transmitted by the base station 105 in different directions, and the UE 115 may report to the base station 105 an indication of the signal it received with a highest signal quality, or an otherwise acceptable signal quality. Although these techniques are described with reference to signals transmitted in one or more directions by a base station 105, a UE 115 may employ similar techniques for transmitting signals multiple times in different directions (e.g., for identifying a beam direction for subsequent transmission or reception by the UE 115) , or transmitting a signal in a single direction (e.g., for transmitting data to a receiving device) .

A receiving device (e.g., a UE 115, which may be an example of a mmW receiving device) may try multiple receive beams when receiving various signals from the base station 105, such as synchronization signals, reference signals, beam selection signals, or other control signals. For example, a receiving device may try multiple receive directions by receiving via different antenna subarrays, by processing received signals according to different antenna subarrays, by receiving according to different receive beamforming weight sets applied to signals received at a plurality of antenna elements of an antenna array, or by processing received signals according to different receive beamforming weight sets applied to signals received at a plurality of antenna elements of an antenna array, any of which may be referred to as “listening” according to different receive beams or receive directions. In some examples a receiving device may use a single receive beam to receive along a single beam direction (e.g., when receiving a data signal) . The single receive beam may be aligned in a beam direction determined based at least in part on listening according to different receive beam directions (e.g., a beam direction determined to have a highest signal strength, highest signal-to-noise ratio, or otherwise acceptable signal quality based at least in part on listening according to multiple beam directions) .

In some cases, the antennas of a base station 105 or UE 115 may be located within one or more antenna arrays, which may support MIMO operations, or transmit or receive beamforming. For example, one or more base station antennas or antenna arrays may be co-located at an antenna assembly, such as an antenna tower. In some cases, antennas or antenna arrays associated with a base station 105 may be located in diverse geographic locations. A base station 105 may have an antenna array with a number of rows and columns of antenna ports that the base station 105 may use to support beamforming of communications with a UE 115. Likewise, a UE 115 may have one or more antenna arrays that may support various MIMO or beamforming operations.

In some cases, wireless communications system 100 may be a packet-based network that operate according to a layered protocol stack. In the user plane, communications at the bearer or Packet Data Convergence Protocol (PDCP) layer may be IP-based. A Radio Link Control (RLC) layer may perform packet segmentation and reassembly to communicate over logical channels. A Medium Access Control (MAC) layer may perform priority handling and multiplexing of logical channels into transport channels. The MAC layer may also use hybrid automatic repeat request (HARQ) to provide retransmission at the MAC layer to improve link efficiency. In the control plane, the Radio Resource Control (RRC) protocol layer may provide establishment, configuration, and maintenance of an RRC connection between a UE 115 and a base station 105 or core network 130 supporting radio bearers for user plane data. At the Physical layer, transport channels may be mapped to physical channels.

A service data application protocol (SDAP) protocol layer may be associated with mapping bearers of a network. For example, the SDAP may map radio bearers based on quality of service (QoS) requirements. In such cases, packets (e.g., IP packets) may be mapped to different radio bearers in accordance with a QoS of the packets. Following the mapping to a radio bearer, the packets may be passed to the PDCP protocol layer. In some examples, the SDAP protocol layer may indicate a QoS flow identifier for uplink and downlink packets.

In some cases, UEs 115 and base stations 105 may support retransmissions of data to increase the likelihood that data is received successfully. HARQ feedback is one technique of increasing the likelihood that data is received correctly over a communication link 125. HARQ may include a combination of error detection (e.g., using a cyclic redundancy check (CRC) ) , forward error correction (FEC) , and retransmission (e.g., automatic repeat request (ARQ) ) . HARQ may improve throughput at the MAC layer in poor radio conditions (e.g., signal-to-noise conditions) . In some cases, a wireless device may support same-slot HARQ feedback, where the device may provide HARQ feedback in a specific slot for data received in a previous symbol in the slot. In other cases, the device may provide HARQ feedback in a subsequent slot, or according to some other time interval.

Time intervals in LTE or NR may be expressed in multiples of a basic time unit, which may, for example, refer to a sampling period of T _s = 1/30,720,000 seconds. Time intervals of a communications resource may be organized according to radio frames each having a duration of 10 milliseconds (ms) , where the frame period may be expressed as T _f = 307,200 T _s. The radio frames may be identified by a system frame number (SFN) ranging from 0 to 1023. Each frame may include 10 subframes numbered from 0 to 9, and each subframe may have a duration of 1 ms. A subframe may be further divided into 2 slots each having a duration of 0.5 ms, and each slot may contain 6 or 7 modulation symbol periods (e.g., depending on the length of the cyclic prefix prepended to each symbol period) . Excluding the cyclic prefix, each symbol period may contain 2048 sampling periods. In some cases, a subframe may be the smallest scheduling unit of the wireless communications system 100, and may be referred to as a transmission time interval (TTI) . In other cases, a smallest scheduling unit of the wireless communications system 100 may be shorter than a subframe or may be dynamically selected (e.g., in bursts of shortened TTIs (sTTIs) or in selected component carriers using sTTIs) .

In some wireless communications systems, a slot may further be divided into multiple mini-slots containing one or more symbols. In some instances, a symbol of a mini-slot or a mini-slot may be the smallest unit of scheduling. Each symbol may vary in duration depending on the subcarrier spacing or frequency band of operation, for example. Further, some wireless communications systems may implement slot aggregation in which multiple slots or mini-slots are aggregated together and used for communication between a UE 115 and a base station 105.

The term “carrier” refers to a set of radio frequency spectrum resources having a defined physical layer structure for supporting communications over a communication link 125. For example, a carrier of a communication link 125 may include a portion of a radio frequency spectrum band that is operated according to physical layer channels for a given radio access technology. Each physical layer channel may carry user data, control information, or other signaling. A carrier may be associated with a pre-defined frequency channel (e.g., an evolved universal mobile telecommunication system terrestrial radio access (E-UTRA) absolute radio frequency channel number (EARFCN) ) , and may be positioned according to a channel raster for discovery by UEs 115. Carriers may be downlink or uplink (e.g., in an FDD mode) , or be configured to carry downlink and uplink communications (e.g., in a TDD mode) . In some examples, signal waveforms transmitted over a carrier may be made up of multiple sub-carriers (e.g., using multi-carrier modulation (MCM) techniques such as orthogonal frequency division multiplexing (OFDM) or discrete Fourier transform spread OFDM (DFT-S-OFDM) ) .

The organizational structure of the carriers may be different for different radio access technologies (e.g., LTE, LTE-A, LTE-A Pro, NR) . For example, communications over a carrier may be organized according to TTIs or slots, each of which may include user data as well as control information or signaling to support decoding the user data. A carrier may also include dedicated acquisition signaling (e.g., synchronization signals or system information, etc. ) and control signaling that coordinates operation for the carrier. In some examples (e.g., in a carrier aggregation configuration) , a carrier may also have acquisition signaling or control signaling that coordinates operations for other carriers.

Physical channels may be multiplexed on a carrier according to various techniques. A physical control channel and a physical data channel may be multiplexed on a downlink carrier, for example, using time division multiplexing (TDM) techniques, frequency division multiplexing (FDM) techniques, or hybrid TDM-FDM techniques. In some examples, control information transmitted in a physical control channel may be distributed between different control regions in a cascaded manner (e.g., between a common control region or common search space and one or more UE-specific control regions or UE-specific search spaces) .

A carrier may be associated with a particular bandwidth of the radio frequency spectrum, and in some examples the carrier bandwidth may be referred to as a “system bandwidth” of the carrier or the wireless communications system 100. For example, the carrier bandwidth may be one of a number of predetermined bandwidths for carriers of a particular radio access technology (e.g., 1.4, 3, 5, 10, 15, 20, 40, or 80 MHz) . In some examples, each served UE 115 may be configured for operating over portions or all of the carrier bandwidth. In other examples, some UEs 115 may be configured for operation using a narrowband protocol type that is associated with a predefined portion or range (e.g., set of subcarriers or RBs) within a carrier (e.g., “in-band” deployment of a narrowband protocol type) .

In a system employing MCM techniques, a resource element may consist of one symbol period (e.g., a duration of one modulation symbol) and one subcarrier, where the symbol period and subcarrier spacing are inversely related. The number of bits carried by each resource element may depend on the modulation scheme (e.g., the order of the modulation scheme) . Thus, the more resource elements that a UE 115 receives and the higher the order of the modulation scheme, the higher the data rate may be for the UE 115. In MIMO systems, a wireless communications resource may refer to a combination of a radio frequency spectrum resource, a time resource, and a spatial resource (e.g., spatial layers) , and the use of multiple spatial layers may further increase the data rate for communications with a UE 115.

Devices of the wireless communications system 100 (e.g., base stations 105 or UEs 115) may have a hardware configuration that supports communications over a particular carrier bandwidth, or may be configurable to support communications over one of a set of carrier bandwidths. In some examples, the wireless communications system 100 may include base stations 105 and/or UEs 115 that support simultaneous communications via carriers associated with more than one different carrier bandwidth.

Wireless communications system 100 may support communication with a UE 115 on multiple cells or carriers, a feature which may be referred to as carrier aggregation or multi-carrier operation. A UE 115 may be configured with multiple downlink component carriers and one or more uplink component carriers according to a carrier aggregation configuration. Carrier aggregation may be used with both FDD and TDD component carriers.

In some cases, wireless communications system 100 may utilize enhanced component carriers (eCCs) . An eCC may be characterized by one or more features including wider carrier or frequency channel bandwidth, shorter symbol duration, shorter TTI duration, or modified control channel configuration. In some cases, an eCC may be associated with a carrier aggregation configuration or a dual connectivity configuration (e.g., when multiple serving cells have a suboptimal or non-ideal backhaul link) . An eCC may also be configured for use in unlicensed spectrum or shared spectrum (e.g., where more than one operator is allowed to use the spectrum) . An eCC characterized by wide carrier bandwidth may include one or more segments that may be utilized by UEs 115 that are not capable of monitoring the whole carrier bandwidth or are otherwise configured to use a limited carrier bandwidth (e.g., to conserve power) .

In some cases, an eCC may utilize a different symbol duration than other component carriers, which may include use of a reduced symbol duration as compared with symbol durations of the other component carriers. A shorter symbol duration may be associated with increased spacing between adjacent subcarriers. A device, such as a UE 115 or base station 105, utilizing eCCs may transmit wideband signals (e.g., according to frequency channel or carrier bandwidths of 20, 40, 60, 80 MHz, etc. ) at reduced symbol durations (e.g., 16.67 microseconds) . A TTI in eCC may consist of one or multiple symbol periods. In some cases, the TTI duration (that is, the number of symbol periods in a TTI) may be variable.

Wireless communications system 100 may be an NR system that may utilize any combination of licensed, shared, and unlicensed spectrum bands, among others. The flexibility of eCC symbol duration and subcarrier spacing may allow for the use of eCC across multiple spectrums. In some examples, NR shared spectrum may increase spectrum utilization and spectral efficiency, specifically through dynamic vertical (e.g., across the frequency domain) and horizontal (e.g., across the time domain) sharing of resources.

A UE 115 attempting to access a wireless network may perform an initial cell search by detecting a primary synchronization signal (PSS) from a base station 105. The PSS may enable synchronization of slot timing and may indicate a physical layer identity value. The UE 115 may then receive a secondary synchronization signal (SSS) . The SSS may enable radio frame synchronization, and may provide a cell identity value, which may be combined with the physical layer identity value to identify the cell. The SSS may also enable detection of a duplexing mode and a cyclic prefix length. Some systems, such as TDD systems, may transmit an SSS but not a PSS. Both the PSS and the SSS may be located in the central 62 and 72 subcarriers of a carrier, respectively. In some cases, a base station 105 may transmit synchronization signals (e.g., PSS SSS, and the like) using multiple beams in a beam-sweeping manner through a cell coverage area. In some cases, PSS, SSS, and/or broadcast information (e.g., a physical broadcast channel (PBCH) ) may be transmitted within different synchronization signal (SS) blocks on respective directional beams, where one or more SS blocks may be included within an SS burst.

After receiving the PSS and SSS, the UE 115 may receive an MIB, which may be transmitted in the PBCH. The MIB may contain system bandwidth information, an SFN, and a PHICH configuration. After decoding the MIB, the UE 115 may receive one or more SIBs. For example, SIB1 may contain cell access parameters and scheduling information for other SIBs. Decoding SIB1 may enable the UE 115 to receive SIB2. SIB2 may contain RRC configuration information related to RACH procedures, paging, PUCCH, PUSCH, power control, SRS, and cell barring.

After completing initial cell synchronization, a UE 115 may decode the MIB, SIB1 and SIB2 prior to accessing the network. The MIB may be transmitted on PBCH and may utilize the first 4 OFDMA symbols of the second slot of the first subframe of each radio frame. It may use the middle 6 RBs (72 subcarriers) in the frequency domain. The MIB carries a few important pieces of information for UE initial access, including: DL channel bandwidth in term of RBs, PHICH configuration (duration and resource assignment) , and SFN. A new MIB may be broadcast every fourth radio frame (SFN mod 4 = 0) at and rebroadcast every frame (10ms) . Each repetition is scrambled with a different scrambling code.

After reading a MIB (either a new version or a copy) , the UE 115 may can try different phases of a scrambling code until it gets a successful CRC check. The phase of the scrambling code (0, 1, 2 or 3) may enable the UE 115 to identify which of the four repetitions has been received. Thus, the UE 115 may determine the current SFN by reading the SFN in the decoded transmission and adding the scrambling code phase. After receiving the MIB, a UE may receive one or more SIBs. Different SIBs may be defined according to the type of system information conveyed. A new SIB1 may be transmitted in the fifth subframe of every eighth frame (SFN mod 8 = 0) and rebroadcast every other frame (20ms) . SIB1 includes access information, including cell identity information, and it may indicate whether a UE is allowed to camp on a cell. SIB1 also includes cell selection information (or cell selection parameters) . Additionally, SIB1 includes scheduling information for other SIBs. SIB2 may be scheduled dynamically according to information in SIB1, and includes access information and parameters related to common and shared channels. The periodicity of SIB2 can be set to 8, 16, 32, 64, 128, 256 or 512 radio frames.

After the UE 115 decodes SIB2, it may transmit a RACH preamble to a base station 105. For example, the RACH preamble may be randomly selected from a set of 64 predetermined sequences. This may enable the base station 105 to distinguish between multiple UEs 115 trying to access the system simultaneously. The base station 105 may respond with a random access response that provides an uplink resource grant, a timing advance, and a temporary C-RNTI. The UE 115 may then transmit an RRC connection request along with a TMSI (if the UE 115 has previously been connected to the same wireless network) or a random identifier. The RRC connection request may also indicate the reason the UE 115 is connecting to the network (e.g., emergency, signaling, data exchange, etc. ) . The base station 105 may respond to the connection request with a contention resolution message addressed to the UE 115, which may provide a new C-RNTI. If the UE 115 receives a contention resolution message with the correct identification, it may proceed with RRC setup. If the UE 115 does not receive a contention resolution message (e.g., if there is a conflict with another UE 115) it may repeat the RACH process by transmitting a new RACH preamble. Such exchange of messages between the UE 115 and base station 105 for random access may be referred to as a four-step RACH procedure.

Wireless communications system 100 may support the storage of one or more lower-layer configurations for use in re-establishing communications when a UE 115 transitions from an inactive communications state. For example, a UE 115 may communicate with a network (e.g., via one or more base station 105) using a particular communications scheme (e.g., DC, CA, etc. ) and subsequently transition to the inactive communication state (e.g., an RRC inactive state) . The UE 115 and the network may store a set of lower-layer configurations that were used for the communications scheme. For instance, a lower-layer MCG configuration and/or a lower-layer SCG configuration of a DC deployment may be stored when the UE 115 enters the inactive communication state. Additionally or alternatively, lower-layer configurations for CA operations may be stored when the UE 115 enters the inactive communication state. In any case, the UE 115 may also be configured to perform one or more cell measurements while in the inactive communication state.

Upon performing a state transition from the inactive communication state (e.g., to a connected communications state) , the UE 115 may indicate, to a base station 105, an availability of measurement reports generated while the UE 115 was in the inactive state. Further, the UE 115 may resume communications on one or more cells based on signaling from the network that indicates a difference between a current lower-layer configuration and the stored lower-layer configuration (s) . In such cases, the difference indicated to the UE 115 may be based on measurement reports provided by the UE 115. Additionally, the network may efficiently modify the cells used, for example, in DC or CA operation, based on the measurement reports provided by the UE 115 and through the use of the signaling of the changes from the stored lower-layer configuration. As a result, the UE 115 may efficiently resume communications with the network (e.g., using the same communications scheme as before entering into the RRC inactive state) with minimized signaling after exiting the inactive communication state (e.g., as compared to when lower-layer configurations are dropped upon entering the inactive communication state) .

FIG. 2 illustrates an example of a wireless communications system 200 that supports measurement-based DC and CA activation in accordance with aspects of the present disclosure. In some examples, wireless communications system 200 may implement aspects of wireless communications system 100. For example, wireless communications system 200 includes a first base station 105-a, a second base station 105-b, and a UE 115-a, which may be examples of the corresponding devices described with reference to FIG. 1. Wireless communications system 200 may support the use of techniques that enhance the resumption of communications in CA and DC deployments after a UE leaves an RRC inactive state.

In wireless communications system 200, a UE 115-a may communicate with a network using a DC configuration. In such cases, UE 115-a may simultaneously communicate with different base stations 105 (e.g., first base station 105-a and second base station 105-b) . First base station 105-a may provide a first cell 205-a and first base station 105-a may be referred to as a master node. First cell 205-a may correspond to a PCell in the DC deployment. Additionally, second base station 105-b may provide a second cell 205-b of the DC configuration, and second base station 105-b may be referred to as a secondary node. In some cases, second cell 205-b may correspond to a PSCell in the DC deployment, which may be configured with time-frequency resources for PUCCH. Additional SCells may associated with each base station 105-a and 105-b, where a set of cells (e.g., SCells) associated with the master node may correspond to a master cell group (MCG) and another set of SCells associated with the secondary node may correspond to a secondary cell group (SCG) .

In some cases, the different base stations 105 and corresponding cells of the DC deployment may be associated with a same or different RAT. For instance, first base station 105-a and second base station 105-b may communicate using a first RAT and a second RAT, respectively. The first RAT and/or the second RAT may be the same or different and may include, for example, LTE, NR, or another RAT. As such, various DC deployments may sometimes be referred to as EN-DC, NE-DC, NR NR-DC, LTE LTE-DC, enhanced LTE (eLTE) eLTE-DC, or may include other types of MR-DC deployments based on the RAT that is used by each base station 105. In any case, the different cells of a DC deployment may use the same or different RF spectrum bands for communication with UE 115-a.

In some cases, DC deployments may use different radio bearers for transmitted messages for each cell. For instance, when first base station 105-a is configured as a master node that provides a set of serving cells corresponding to the MCG, first base station 105-a may use a first set of signaling radio bearers (SRBs) (e.g., SRB1, SRB2) to transport messages for the MCG, such as RRC messages. Additionally, when second base station 105-b is configured as a secondary node, second base station 105-b may provide another set of serving cells that correspond to the SCG and may use a second set of SRBs (e.g., SRB3) to transport messages for the SCG. In some examples, a split bearer configuration may be supported, where a particular protocol layer (e.g., a packet data convergence protocol (PDCP) layer) for both the master node and secondary node may be used to route data streams to/from UE 115-a. Here, an SRB (e.g., SRB1/SRB2) may be split between the master node and the secondary node, and downlink messages sent from the master node to UE 115-a may be routed via lower-layers (e.g., radio link control (RLC) , medium access control (MAC) , physical (PHY) , etc. ) of either first base station 105-a (e.g., the master node) or second base station 105-b (e.g., the secondary node) . In other cases, downlink messages may be routed via the lower-layers of both the master and secondary nodes. In the uplink, RRC messages from UE 115-a may be transmitted to the master node via the secondary node using the split bearer (e.g., via a “leg” associated with the secondary node) . For the signaling of data in the user plane, respective data radio bearers (DRBs) may be used by the MCG and SCG.

Additionally or alternatively, UE 115-a may communicate with a single base station 105 (e.g., first base station 105-a) using multiple carriers (e.g., CCs, which may also be referred to as layers, channels, etc. ) . In such cases, a CC may refer to each of the carriers used by UE 115-a in CA operations. Further, a serving cell of first base station 105-a may correspond to each CC used in CA operation, where each serving cell may be different (e.g., based on the path loss experienced by different CCs on different RF spectrum bands) . In some examples, one carrier may be designated as a primary carrier, or primary CC (PCC) , for UE 115-a, which may be served by a PCell of first base station 105-a. Additional carriers may be designated as secondary carriers, or secondary CCs (SCCs) , which may be served by SCells of first base station 105-a. CA operations may use the same or different RF bands for communications.

UE 115-a may operate in different RRC states when communicating with one or more base stations 105. For instance, and as illustrated by state diagram 210, UE 115-a may operate in an RRC connected state 215 where UE 115-a may be “active” and transmit data to/receive data from a serving cell. Additionally, UE 115-a may operate in an RRC idle state 220, in which case UE 115-a may be “on standby” and thus, may not be assigned to a particular serving base station 105 while saving power. In the RRC idle state 220, radio bearers for the system may be released (e.g., to avoid re-routing should UE 115-a move to another cell) , but UE 115-a may still perform various functions, such as cell reselection and discontinuous reception (DRX) for page messages, among other functions. UE 115-a may accordingly transition from the RRC idle state 220 to the RRC connected state 215, and vice versa, based on its activity. When transitioning to the RRC connected state 215 from the RRC idle state 220, UE 115-a may transmit, to a base station 105, a setup request message (e.g., RRCSetupRequest) . Alternatively, when transitioning from the RRC connected state 215 to the RRC idle state 220, UE 115-a may receive a release message (e.g., RRCRelease) .

In wireless communications system 200, UE 115-a may support an additional RRC state. For example, an RRC inactive state 225 between the RRC connected state 215 and the RRC idle state 220 may be used to enable a faster transition to the RRC connected state 215 (e.g., as compared to the state transition from the RRC idle state 220 to the RRC connected state 215) . When UE 115-a is in the RRC inactive state 225, it may receive system information, perform cell measurements, and perform other functions. UE 115-a may transition to the RRC connected state 215 from the RRC inactive state 225 when downlink data is available for UE 115-a, or UE 115-a has uplink data to transmit, or both, and UE 115-a may accordingly transmit a resume request message (e.g., RRCResumeRequest) to resume communications with a base station 105. When transitioning from the RRC connected state 215 to the RRC inactive state 225, UE 115-a may receive a release message (e.g., RRCRelease) from a base station 105. Likewise, when moving from the RRC inactive state 225 to the RRC idle state, UE 115-a may receive a release message from the base station 105.

When entering into the RRC inactive state 225, a UE context (e.g., an access stratum (AS) context) may be retained at UE 115-a and the network, and both UE 115-a and the network may store higher-layer configurations (e.g., for a DC/CA deployment) while simultaneously releasing lower-layer configurations (as the lower-layer configurations may change, for example, due to UE 115-a being mobile (i.e., non-stationary) ) . More specifically, UE 115-a, first base station 105-a (e.g., providing the MCG) , and second base station 105-b (e.g., providing the SCG) may store PDCP/SDAP configurations for both MCG and SCG when UE 115-a transitions to the RRC inactive state 225. Additionally, UE 115-a may release lower-layer configurations for both the MCG and SCG when in the RRC inactive state 225. When resuming communications with either first base station 105-a or second base station 105-b by transitioning to the RRC connected state 215 from the RRC inactive state 225, UE 115-a may apply the stored upper-layer (PDCP and/or SDAP) configurations of the MCG and SCG.

However, due to the release of the lower-layer configurations, UE 115-a may not be able to immediately operate using DC (or CA) communications after transitioning from the RRC inactive state 225. For example, when entering the RRC inactive state 225, UE 115-a may later require multiple reconfiguration messages (e.g., RRC reconfiguration messages) to obtain a full configuration, including the lower-layer configurations for the MCG and SCG (and any updates thereto) , to establish communication with first base station 105-a and/or second base station 105-b (or another, different, base station 105) of the DC deployment. This signaling overhead may reduce efficiency in the system through added delays in resuming and/or modifying the DC configuration that UE 115-a operated with prior to entering into the RRC inactive state 225. CA operations may be similarly affected when transitioning out of the RRC inactive state 225.

As described herein, techniques for storing lower-layer configurations (e.g., when UE 115-a transitions into the RRC inactive state 225) may reduce latency and signaling overhead when UE 115-a leaves the RRC inactive state 225. For example, the stored lower-layer configurations may be used to efficiently reestablish communications with the nodes that were previously serving as master node and secondary node (e.g., first base station 105-a, second base station 105-b) of a DC deployment. The stored lower-layer configurations may also enhance the resumption of CA operations with minimal signaling (e.g., as compared to multiple handshakes required when the lower-layer configurations are not stored) . In some cases, UE 115-a may receive signaling, from first base station 105-a or second base station 105-b, that indicates a difference between a current lower-layer configuration (e.g., a configuration based on present cell conditions after UE 115-a leaves the RRC inactive state 225) and the stored lower-layer configuration. As such, the differences in configurations signaled (e.g., via delta signaling) by a base station 105 may be based on the stored lower-layer configurations that are known by both UE 115-a and the network.

In some aspects, the delta signaling that indicates the difference between the lower-layer configurations may be based on measurement reporting provided by UE 115-a, where the corresponding measurements (e.g., of surrounding or nearby cells) are performed while UE 115-a is in the RRC inactive state 225. In such cases, and as described in further detail below, measurement reporting configurations may be signaled to UE 115-a via UE-specific RRC messaging (e.g., an RRC release message that includes a suspension configuration) or via system information (e.g., a common system information block (SIB) ) .

In wireless communications system 200, the storage of the lower-layer configurations and the use of signaling that indicates difference between current configurations and the stored MCG and/or SCG configurations may be used to reduce signaling overhead. Such overhead may be associated with multiple reconfiguration messages that each provide the full information for a configuration (as opposed to only the parts that have changed) , and may also result in latency in the system due to the time taken to decode and process the full configurations. As a result, the described techniques may provide for enhanced operation that enables UE 115-a to more quickly resume communications when exiting the RRC inactive state 225.

It is noted that aspects of the present disclosure are described in the context of DC deployments (e.g., NE-DC, EN-DC, or the like) when UE 115-a resumes communications from the RRC inactive state 225; however, the techniques may be applicable to other deployments and configurations not explicitly described herein. For example, the described techniques may also be applicable to CA configurations when UE 115-a transitions out of the RRC inactive state 225. Additionally or alternatively, the described techniques may be applicable to scenarios where UE 115-a is connected with a single base station to efficiently set up DC or CA when UE 115-a resumes communications from an RRC inactive state 225.

FIG. 3 illustrates an example of a process flow 300 in a system that supports measurement-based DC and CA activation in accordance with aspects of the present disclosure. In some examples, process flow 300 may implement aspects of wireless communications system 100. For instance, process flow 300 includes UE 115-b, which may be an example of a UE 115 described with reference to FIGs. 1 and 2. Further, process flow 300 includes a master node 302 and a secondary node 303 which may be configured for operation in a DC deployment with UE 115-b. Master node 302 and secondary node 303 may each be an example of a base station 105 as described with reference to FIGs. 1 and 2. Process flow 300 may illustrate a UE 115 transitioning from an inactive communication state (e.g., RRC inactive) and resuming communications within a DC deployment.

In process flow 300, UE 115-b may operate in a DC configuration with master node 302 providing an MCG and secondary node 303 providing an SCG. In some cases, UE 115-b may move into the RRC inactive state to save power, for example, based on communication activity with a network. In such cases, UE 115-b may transition into the RRC inactive state based on signaling received from the network. For instance, at 305, master node 302 may transmit a message that includes an indication of an RRC release to UE 115-b, and UE 115-b may move into the RRC inactive state (e.g., from an RRC connected state) based on the received signaling. In some cases, UE 115-b may obtain, from the RRC release message, a measurement configuration for potential frequencies of secondary node 303.

Upon transitioning to the RRC inactive state, UE 115-b may store upper-layer configurations used to communicate with master node 302 and secondary node 303 (e.g., upper-layer MCG configurations and upper-layer SCG configurations, respectively) while simultaneously releasing lower-layer configurations for master node 302 and secondary node 303. Similarly, master node 302 and secondary node 303 may store the upper-layer configurations and release the lower-layer configurations. That is, upper-layer MCG and SCG configurations may be stored while lower-layer MCG and SCG configurations may be released by both UE 115-b and the network. Additionally, an AS context for UE 115-b may be stored by both UE 115-b as well as master node 302 and/or secondary node 303.

At 310, UE 115-b may perform measurements of one or more cells. For instance, the measurements may include layer 3 (L3) measurements for one or more cells, which may be performed following reception of the RRC release message at 305. As such, the measurements at 310 may be performed while UE 115-b is in the RRC inactive state. UE 115-b may perform the measurements to determine a quality of each of the frequencies associated with secondary node 303 based on the information included in the RRC release message at 305. Additionally, UE 115-b may perform measurements of other cells, including measurements of frequencies associated with master node 302 and one or more additional cells that are near UE 115-b. For example, UE 115-b may be mobile while in the inactive communication state, and may move to a cell that is different from the respective cells provided by master node 302 and secondary node 303.

After operating in the RRC inactive state, UE 115-b may later transition to the RRC connected state to communicate uplink and/or downlink data with the network. As such, UE 115-b may perform a random access procedure (e.g., RACH procedure) to re-establish a connection with a cell that UE 115-b was previously communicating on (e.g., for either master node 302 or secondary node 303) . As an example, at 315, UE 115-b may transmit a first random access message (e.g., message 1, Msg1, or other like terminology) including a PRACH preamble to master node 302 when initiating the RACH procedure. Master node 302 may have been configured as a previously-serving master node 302 prior to UE 115-b operating in the inactive communication state, and at 320, master node 302 may transmit a second message (e.g., Msg2) to UE 115-b that may include a random access response.

At 325, UE 115-b may transmit a third message (e.g., Msg3) to master node 302 that may include an RRC resume request. In some cases, the resume request sent at 325 may include an indication of the availability of one or more measurement reports corresponding to measurements performed by UE 115-b while in the RRC inactive state. As an example, one (1) bit may be added in the RRC resume request to indicate whether measurement results are available for transmission to a base station 105. At 330, master node 302 may transmit a fourth message (e.g., Msg4) to UE 115-b that may include an indication of RRC resumption. In some examples, master node 302 may include a request for the measurement reporting in the RRC resume message, which may be based on UE 115-b indicating that the measurement reporting was available via the RRC resume request. In other examples, and as discussed below, UE 115-b may not have any available measurement reports and may indicate that no measurement reporting is available in the RRC resume request at 325. In such cases, master node 302 may refrain from requesting the measurement reports in the RRC resume request at 330. It is also noted that while UE 115-b may perform a four-step RACH procedure, as illustrated, other RACH procedures (such as two-step RACH procedures) may be performed by UE 115-b.

At 335, UE 115-b may acknowledge that the RACH procedure is completed by transmitting a message to master node 302 indicating that RRC resumption has been completed at UE 115-b. In some examples, the RRC resume complete message may include measurement reports (e.g., L3 measurement reports) requested by master node 302 and based on the measurements UE 115-b performed while in the RRC inactive state.

At 340, master node 302 may transmit a message to secondary node 303 that indicates a secondary node addition request. For instance, based on measurements provided by UE 115-b at 335, master node 302 may determine that secondary node 303 may still provide a secondary cell with a best signal quality for UE 115-b (e.g., as compared to measured signal quality for other nearby cells) for DC communications. Accordingly, master node 302 may signal to secondary node the addition of (or re-establishment of) secondary node in the DC deployment for UE 115-b. At 345, secondary node 303 may transmit a message that indicates a secondary node addition request acknowledgment (ACK) to master node 302.

At 350, master node 302 may transmit an RRC reconfiguration message to UE 115-b and, at 355, master node 302 may further signal to secondary node 303 that the secondary node reconfiguration is complete. Additionally, after processing the configuration (s) included in the RRC reconfiguration message at 350, UE 115-b may indicate that the RRC reconfiguration is complete at 360. As such, UE 115-b may perform a random access procedure with secondary node 303 at 365, and may proceed to communicate data at 370.

However, as mentioned above, the lower-layer configurations previously used to communicate with master node 302 and secondary node 303 in the DC deployment (e.g., the SCG lower-layer configuration and/or the MCG lower-layer configuration used prior to the suspension of communications for the RRC inactive state) may have been released. As a result, UE 115-b and the network may have no knowledge of the configurations in use prior to UE 115-b entering into the RRC inactive state. So, even when UE 115-b is configured with DC before entering the RRC inactive state, one or more RRC connection reconfiguration messages may be required to enable communications with master node 302 and for the addition of secondary node 303, which may result in signaling overhead in the system. In particular, at 350, master node 302 may transmit at least one RRC reconfiguration messages to UE 115-b that includes the full lower-layer configuration information for each of the nodes in the DC deployment. The RRC reconfiguration sent at 350 may include, for example, resource configurations, MAC configurations, and the like. But the signaling of the full lower-layer configurations may add delays in UE 115-b resuming communications in accordance with the previously-established DC scheme, for example, due to latency involved when decoding and processing the information received from the network in multiple RRC reconfiguration messages. Further, without the lower-layer configurations, UE 115-b may not be able to resume communications until the RRC reconfiguration messages are received.

As described herein, such signaling overhead and latency may be reduced or minimized by storing the lower-layer configurations at UE 115-b and the network when UE 115-b transitions into the RRC inactive state. Such techniques may enable UE 115-b to resume communications more quickly than having to wait for the lower-layer configurations to be provided. For instance, UE 115-b may store one or more MCG and SCG lower-layer configurations upon entering the RRC inactive state (e.g., when the RRC release message is received at 305) . Likewise, master node 302 and secondary node 303 may also store the lower-layer MCG and SCG configurations based on UE 115-b entering into the RRC inactive state. Then, upon UE 115-b leaving the RRC inactive state, the stored lower-layer configurations may be used for the resumption of communications, and to determine a difference between current MCG/SCG lower-layer configurations. As such, only the difference may be signaled to UE 115-b upon resuming from the RRC inactive state, for example, in an RRC reconfiguration message including delta signaling. Such delta signaling may provide a more efficient means for UE 115-b to resume communications with a cell in a DC deployment (or in a CA scheme) , which may reduce processing times, decrease signaling overhead, and enable UE 115-b to resume operations more quickly in the system.

FIG. 4 illustrates an example of a process flow 400 in a system that supports measurement-based DC and CA activation in accordance with aspects of the present disclosure. In some examples, process flow 400 may implement aspects of wireless communications system 100. For example, process flow 400 includes UE 115-c, which may be an example of a UE 115 described with reference to FIGs. 1 through 3. Further, process flow 400 includes a master node 402 and a secondary node 403 which may be configured for operation in a DC deployment with UE 115-c. Master node 402 and secondary node 403 may each be an example of a base station 105 as described with reference to FIGs. 1 and 2. Process flow 400 may illustrate the configuration of measurement reporting for UE 115-c for use when operating in an inactive communication state (e.g., RRC inactive) .

In process flow 400, UE 115-c may operate in a DC configuration with master node 402 providing an MCG and secondary node 403 providing an SCG. At 405, secondary node 403 may transmit a message to master node 402 that includes an activity notification. For instance, the activity notification may indicate an inactive status of communications with UE 115-c. At 410, master node 402 may transmit a message that may include a secondary node modification request to secondary node 403. The secondary node modification request message may suspend secondary node 403 as the network prepares for UE 115-b to move to an RRC inactive state. In some cases, the secondary node modification request may indicate an AS context for UE 115-c, which may be saved at secondary node 403.

At 415, secondary node 403 may transmit a message to master node 402 that may include a secondary node modification response and may indicate secondary node-configured measurements. For instance, secondary node 403 may configure measurements on master node 402 or another neighboring cell, and include such measurement configurations for use by UE 115-c in the secondary node modification response at 415. In such cases, UE 115-c may resume from an RRC inactive state using secondary node 403, indicate the availability of measurement reports, and secondary node 403 may know whether master node 402 may also be resumed based on the measurement reporting configurations (and received measurements) for master node 402. Likewise, master node 402 may configure measurements on secondary node 403 or one or more neighboring nodes. Should UE 115-c resume communications with master node 402 upon exiting the RRC inactive state and signal an availability of measurements for secondary node 403 (or the other nodes) , master node 402 may thus know whether secondary node 403 or the other node (s) may also be added or reconfigured within the DC deployment.

At 420, master node 402 may transmit a message to UE 115-c that includes the measurement configurations. In some cases, the message at 420 may be an RRC release message or a SIB, or a combination thereof. In some examples, an RRC release message may indicate a suspend configuration for UE 115-c, which may signal that UE 115-c may enter the RRC inactive state. Additionally, the RRC release message may include the measurement configurations for master node 402 and/or secondary node 403. Additionally or alternatively, a SIB sent at 420 may indicate the measurement configuration for master node 402 and secondary node 403.

In some cases, lower-layer configurations of MCG (e.g., corresponding to master node 402) and SCG (e.g., corresponding to secondary node 403) may be stored in the network and UE 115-c when UE 115-c is in the RRC inactive state. Additionally, depending on movement by UE 115-c during a time period when in the RRC inactive state, UE 115-c may be resumed in a cell provided by master node 402 or a cell provided by secondary node 403. The described configuration of the measurements UE 115-c may perform while in the RRC inactive state may serve to enhance operations when UE 115-c exits the RRC inactive state. For instance, an indication of whether measurement reporting is available when UE 115-c exits the RRC inactive state, based on the received measurement configuration at 420, may signal to the network how to most efficiently enable communication resumption with various nodes for UE 115-c. In particular, when UE 115-c indicates that measurement reports are available, the master node 402 and/or secondary node 403 (based on which node UE 115-c resumes in) may use the measurement reports to provide delta signaling that indicates a difference between a stored lower-layer configuration and a current lower-layer configuration. In such cases, the signaling may include changes between stored lower-layer configurations and current lower-layer configurations that may be based on the measurement reports provided by UE 115-c, as configured via the processes described herein. The described features of storing lower-layer configurations, and delta signaling, may also be applicable to resuming communications with a single base station 105, such as for CA.

FIG. 5 illustrates an example of a process flow 500 in a system that supports measurement-based DC and CA activation in accordance with aspects of the present disclosure. In some examples, process flow 500 may implement aspects of wireless communications system 100. For example, process flow 500 includes UE 115-d, which may be an example of a UE 115 described with reference to FIGs. 1 through 4. Further, process flow 500 includes a master node 502 and a secondary node 503 which may be configured for operation in a DC deployment with UE 115-d. Master node 502 and secondary node 503 may each be examples of a base station 105 as described with reference to FIGs. 1 and 2. Process flow 500 may illustrate the use of saved lower-layer configurations when UE 115-d resumes from an RRC inactive state. Additionally, process flow 500 may illustrate the modification of a secondary node configuration in a DC deployment through delta signaling, which may be based on measurements of the secondary node.

In process flow 500, UE 115-d may operate in a DC configuration with master node 502 providing an MCG (e.g., including a first cell) and secondary node providing an SCG (e.g., including a second cell) . In some examples, UE 115-d may further support operation in the RRC inactive state and may receive signaling that enables the transition to the RRC inactive state. For example, at 505, master node 502 may transmit, to UE 115-d, an RRC release message that enables the transition to the RRC inactive state. Further, master node 502 may also signal an indication of one or more measurement configurations (e.g., such as the measurement configurations described with reference to FIG. 4) . In some cases, the measurement configurations may be sent via the RRC release message, via a SIB, or a combination thereof.

UE 115-d may transition into the RRC inactive state (e.g., from an RRC connected state) based on the received signaling from master node 502. In some cases, at 510, UE 115-d, may perform one or more measurements of nearby cells after entering the RRC inactive state. For example, UE 115-d may perform measurements of secondary node 503 (e.g., including downlink received signal strength measurements, carrier-to-interference ratio measurements, etc. ) , which may be based on measurement configurations received via the message received at 505.

In some cases, the previously-establish DC scheme for communicating with master node 502 and secondary node 503 may remain unreleased while UE 115-d is in the RRC inactive state. Additionally, upon transitioning into the RRC inactive state, UE 115-d may store upper-layer configurations used to communicate with master node 502 and secondary node 503 (e.g., upper-layer MCG configurations and upper-layer SCG configurations, respectively) . Similarly, master node 502 and secondary node 503 may store the upper-layer configurations. An AS context for UE 115-b may be stored by UE 115-b as well as master node 302 and/or secondary node 303.

Further, UE 115-d may store a set of lower-layer configurations for communicating with master node 502 and secondary node 503. For example, a lower-layer MCG configuration and a lower-layer SCG configuration may be stored by UE 115-d. Master node 502 may likewise store the lower-layer MCG/SCG configuration used to communicate with UE 115-d prior to the transition by UE 115-d into the inactive state, and secondary node 503 may also store the lower-layer SCG/MCG configuration used to communicate with UE 115-d prior to the transition by UE 115-d into the inactive state. The storage of the lower-layer configurations may enable UE 115-d to resume from the RRC inactive state with reduced signaling overhead (e.g., as compared to when the lower-layer configurations are released) . In such cases, a full configuration of either master node 502 or secondary node 503, or both, may be obtained from stored lower-layer configurations and delta signaling received when UE 115-d resumes communications in the previously-established DC deployment.

As an example, UE 115-d may resume from the RRC inactive state in a cell of master node 502 (e.g., the last-serving master node in the DC deployment) . At 515, UE 115-d may transmit a message (e.g., Msg1) to master node 502 as part of a random access procedure. As such, master node 502 may respond with a random access response (e.g., Msg2) at 520, and UE 115-d may transmit, to master node 502, an RRC resume request (e.g., Msg3) . Based on the measurements performed at 510 (e.g., of secondary node 503) , UE 115-d may include, in the RRC resume request, an indication of measurements available for the network. For instance, UE 115-d may indicate that a measurement report for measurements performed for one or more cells of secondary node 503 is available, which may further signal that communications with secondary node 503 may be resumed (e.g., in addition to communications with master node 502) as part of the DC deployment.

In some examples, at 530, master node 502 may transmit a message to secondary node 503 that may include a data forwarding address indication, and secondary node 503 may respond at 535 with data to be forwarded to UE 115-d. In such cases, the forwarded data may be data buffered for UE 115-d at secondary node 503 while UE 115-d was in the RRC inactive state.

At 540, master node 502 may transmit, to UE 115-d, an RRC resume message (e.g., Msg4) that includes a request for the measurements indicated by UE 115-d at 525. In some cases, the RRC resume message at 540 may enable communications to be resumed between UE 115-d and master node 502. For example, based on the stored lower-layer MCG configurations at both UE 115-d and the network, and because master node 502 operates as both the previously-serving and currently-serving master node of the DC deployment, the stored lower-layer MCG configuration may enable UE 115-d to communicate with master node 502 without having to receive additional configuration signaling for resuming communications with master node 502. As such, at 545, UE 115-d and master node 502 may transmit and receive uplink and/or downlink data. In some examples, the data may include the data forwarded to master node 502 from secondary node 503.

At 550, UE 115-d may transmit an RRC resume complete message to master node 502. The RRC resume complete message may include a measurement report of secondary node 503, and may include the measurement reporting (in response to the request by master node 502) for the measurements performed by UE 115-d while in the RRC inactive state. Further, 555 to 570 illustrate the activation of secondary node 503 by master node 502. In such cases, master node 502 may initialize a secondary node modification procedure based on the received measurement reporting from UE 115-d. For instance, at 555, master node 502 may transmit a modification request to secondary node 503. The modification request may include a secondary node modification request and may be transmitted on a Xn interface between master node 502 and secondary node 503. In response, and at 560, secondary node 503 may transmit a modification response to master node 502 that may include a secondary node modification response. The response may be transmitted via the Xn interface to master node 502.

At 565, master node 502 may transmit an RRC reconfiguration message to UE 115-d that includes an indication of delta signaling of the lower-layer MCG configuration, the lower-layer SCG configuration, or a combination thereof. For example, the delta signaling may comprise a difference between the stored lower-layer MCG configuration and a current lower-layer MCG configuration. Additionally or alternatively, the delta signaling may comprise a difference between the stored lower-layer SCG configuration and a current lower-layer SCG configuration that is based on the measurements of secondary node 503. In such cases, the differences indicated by the delta signaling may include a change in one or more parameters of a current lower-layer configuration as compared to the stored lower-layer configuration. As an illustrative example, a current lower-layer SCG configuration may include a configuration of a set of time-frequency resources used to communicate with secondary node 503. The resource configuration may have changed from the stored lower-layer SCG configuration (e.g., the lower layer SCG configuration used before UE 115-d transitioned to the RRC inactive state) , and the delta signaling may indicate the differences or change in the resource configuration. Additionally, a MAC configuration may have remained the same between the current lower-layer SCG configuration and the stored lower-layer SCG configuration. As such, the delta signaling may not include an explicit indication of the MAC configuration, and UE 115-d may apply MAC configuration from the stored lower-layer configuration (as it may be determined that the MAC configuration remained unchanged and the resource configuration changed) . Accordingly, the delta signaling received by UE 115-d at 565 may indicate which parameters, fields, and/or aspects of a lower-layer configuration (e.g., MCG and/or SCG lower-layer configuration) have been added, modified, or changed from a previous lower-layer configuration.

At 570, UE 115-d may transmit an RRC reconfiguration complete message to master node, and may then resume communications with master node 502. For example, at 575, uplink and downlink data may be communicated between UE 115-d and master node 502 (e.g., based on the delta signaling) . Additionally, UE 115-d may resume communications with secondary node 503, where UE 115-d may perform a random access procedure with secondary node 503 at 580. In some cases, the random access procedure may be based on the delta signaling received from master node 502. Upon completion of the random access procedure, at 585, any buffered downlink packets at secondary node 503 may be transmitted to UE 115-d from secondary node 503. In any case, UE 115-d and secondary node 503 may resume communications in the DC deployment. Thus, the various aspects of process flow 500 may illustrate a case where both master node 502 and secondary node 503 remain unchanged after UE 115-d exits the RRC inactive state based on early measurement reporting by UE 115-d. However, such techniques may be applicable to other cases, including those not explicitly described herein.

FIG. 6 illustrates an example of a process flow 600 in a system that supports measurement-based DC and CA activation in accordance with aspects of the present disclosure. In some examples, process flow 600 may implement aspects of wireless communications system 100. As an example, process flow 600 includes UE 115-e, which may be an example of a UE 115 described with reference to FIGs. 1 through 5. Further, process flow 600 includes a master node 602, a previously-serving secondary node 603, and a target secondary node 604, each of which may be configured to operate in a DC deployment with UE 115-e. Master node 602, previously-serving secondary node 603, and target secondary node 604 may each be an example of a base station 105 as described with reference to FIGs. 1 and 2. Process flow 600 may also include an AMF 608 and UPF 609 associated with a core network, where AMF 608 and UPF 609 may communicate with one or more nodes. Process flow 600 may illustrate the use of stored lower-layer configurations when UE 115-e resumes from an RRC inactive state, where UE 115-e may resume in a previously-serving master node. Additionally, process flow 600 may illustrate the modification of secondary nodes in the DC deployment, which may be based on measurements of the target secondary node 604.

In some cases, UE 115-e may operate in an RRC inactive state. Prior to transitioning into the RRC inactive state, UE 115-e may have communicated with a network in a DC deployment including master node 602 and previously-serving secondary node 603. UE 115-e and the network (e.g., master node 602 and previously-serving secondary node 603) may save lower-layer MCG/SCG configurations when UE 115-e transitioned into the RRC inactive state. In some example, UE 115-e may perform one or more measurements of cells while in the RRC inactive state. For example, UE 115-e may be mobile (e.g., moving through different geographic regions or areas) while in the RRC inactive state, and may move near a cell provided by target secondary node 604 that is different from a cell provided by master node 602 and previously-serving secondary node 603. In such cases, based on the measurements of a target cell, UE 115-e may resume communications with master node 602 and target secondary node 604 upon exiting the RRC inactive state.

Upon resuming from the RRC inactive state, at 605, 610, 615, and 620, UE 115-e and master node 602 may perform a random access procedure. In such cases, an RRC resume request sent by UE 115-e at 615 may include an indication that a measurement report for target secondary node 604 is available based on the measurements UE 115-d completed while in the RRC inactive state. Accordingly, the RRC resume message transmitted by master node 602, and received by UE 115-e at 620, may include a request for the indicated measurement report for target secondary node 604. In such cases, when UE 115-e resumes communications of the DC deployment with master node 602, and using a measurement report for target secondary node 604, the secondary node of the DC deployment may change while the master node remains unchanged. Thus, a secondary node change procedure may be triggered. For example, master node 602 may initiate procedures to release previously-serving secondary node 603 from the DC deployment and add target secondary node 604 to the DC deployment. At 630, master node 602 may transmit a message to previously-serving secondary node 603 that may request the retrieval of an AS context for UE 115-e. Previously-serving secondary node 603 may respond with the requested information, including a stored lower-layer SCG configuration (e.g., stored at the time UE 115-e entered into the RRC inactive state) . Then, master node 602 may transmit, to target secondary node 604, a secondary node addition request. The secondary node addition request may include information that conveys the lower-layer SCG configuration received from previously-serving secondary node 603. In such cases, delta signaling may be used to configure UE 115-e for communication with target secondary node 604.

As an example, after transmitting a secondary node release request (e.g., optionally including a data forwarding address) to previously-serving secondary node 603 (at 650) and receiving a secondary node release ACK from previously-serving secondary node 603 (at 655) , master node 602 may receive an indication of a status transfer at 660. Master node 602 may also transmit, at 655, an RRC reconfiguration to UE 115-e, where the RRC reconfiguration may include delta signaling that indicates a difference between the stored lower-layer MCG/SCG configurations with respect to current lower-layer MCG/SCG configurations. In such cases, the delta signaling may be based on the measurement report for target secondary node 604 provided by UE 115-e (e.g., at 625) . As described herein, the delta signaling provided to UE 115-e may reduce signaling overhead (e.g., as compared to cases where an RRC connection reconfiguration includes a full configuration for target secondary node 604 and/or master node 602) .

In some cases, data forwarding may be performed, where a UPF 609 may trigger the forwarding of data by previously-serving secondary node 603 (e.g., at 675 and 680) . Additionally, master node 602 may transmit a secondary node reconfiguration complete message to target secondary node 604 at 685. Thereafter, target secondary node 604 and UE 115-e may perform a random access procedure (e.g., a RACH procedure) to enable communications with target secondary node 604 as a currently-serving secondary node of the DC deployment. For example, at 695, master node 602 may signal a secondary node status transfer to target secondary node 604, which may enable the switch from previously-serving secondary node 603 to target secondary node 604 for DC. Additional data forwarding may be performed by UPF 609, master node 602, and target secondary node 604 (e.g., at 697 and 698) . In some cases, a path update procedure may be performed at 699. Thus, the described techniques of process flow 600 may illustrate a case where, in a DC deployment, a master node is unchanged and secondary nodes change after UE 115-e exits the RRC inactive state based on early measurement reporting by UE 115-e. However, such techniques may be applicable in other examples, including those not explicitly described herein.

FIG. 7 illustrates an example of a process flow 700 in a system that supports measurement-based DC and CA activation in accordance with aspects of the present disclosure. In some examples, process flow 700 may implement aspects of wireless communications system 100. For example, process flow 700 includes UE 115-f, which may be an example of a UE 115 described with reference to FIGs. 1 through 6. Further, process flow 700 includes a master node 702 and a previously-serving secondary node 703, each of which may be configured for operation in a DC deployment with UE 115-f. Master node 702 and previously-serving secondary node 703 may each be examples of a base station 105 as described with reference to FIGs. 1 and 2. Process flow 700 may also include an AMF 708 and UPF 709 associated with a core network. Process flow 700 may illustrate the use of saved lower-layer configurations when UE 115-f resumes from an RRC inactive state, where UE 115-f may resume in a previously-serving master node (e.g., master node 702) . Additionally, process flow 700 may illustrate the release of a secondary node in the DC deployment, which may be based on a lack of measurements obtained by UE 115-f.

In some cases, UE 115-f may operate in an RRC inactive state. Prior to transitioning into the RRC inactive state, UE 115-f may have been configured to communicate with a network in a DC deployment with master node 702 and previously-serving secondary node 703. As described herein, UE 115-f and the network (e.g., master node 702 and previously-serving secondary node 703 may save a UE context and higher-layer MCG/SCG configurations when UE 115-f transitions into the RRC inactive state. Additionally, UE 115-f and the network may save lower-layer MCG/SCG configurations when UE 115-f transitions into the RRC inactive state.

UE 115-f may perform one or more cell measurements while in the RRC inactive state. For example, UE 115-f may be mobile (e.g., moving through different geographic regions or areas) while in the RRC inactive state, and may move into or near various cells. In some cases, UE 115-f may not be able to generate a measurement report for any cells while in the RRC inactive state. For instance, a signal quality for one or more nodes, including previously-serving secondary node 703, may not be sufficient for UE 115-f to generate a measurement report. In such cases, when UE 115-f resumes from the RRC inactive state, UE 115-f may indicate that no measurement reports are available, which may indicate to master node 702 that the previously-serving secondary node 703 may be released from the DC deployment.

When UE 115-f transitions out of the RRC inactive state, UE 115-f may perform a random access procedures (e.g., at 705 through 720) . In an RRC resume request message at 715, UE 115-f may transmit an indication to master node 702 that no measurement results are available. Accordingly, at 720, master node 502 may transmit, to UE 115-f, an RRC resume message that does not include a request for measurement reporting, based on the indication from UE 115-f of whether measurement reporting is available.

At 725, UE 115-f may transmit an RRC resume complete message to master node 702 that may not include a measurement report (e.g., because none are available to be reported) . Further, when UE 115-f resumes in master node 702 without a measurement report on previously-serving secondary node 703 (or another node) , a secondary node release procedure may be triggered. That is, the radio link quality with the previously-serving secondary node 703 and/or another node may not be adequate for the DC deployment, and communications with UE 115-f may resume under a single-connectivity configuration/deployment with master node 702.

As a result, at 730, master node 702 may transmit, to previously-serving secondary node 703 a message that indicates the secondary node release request. The message may optionally include a data forwarding address. At 735, previously-serving secondary node 703 may transmit a message including a secondary node release ACK to master node 702. At 740, master node 702 may transmit a message to UE 115-f that includes an RRC reconfiguration message, which may indicate the release of previously-serving secondary node 703 (e.g., through delta signaling) . In some examples, master node 702 may also indicate any changes in a lower-layer configuration used to communicate with UE 115-f via the RRC reconfiguration message at 740. In other cases, UE 115-f and master node 702 may rely on stored lower-layer configurations (e.g., used before UE 115-f operated in the RRC inactive state) for communications. At 745, UE 115-f may respond with an RRC reconfiguration complete message to master node 702.

At 750, previously-serving secondary node 703 may optionally transmit a secondary node status transfer message to master node 702. Additionally or alternatively, any buffered downlink data (e.g., for previously-serving secondary node 703) may be forwarded to master node 702, such as triggered by UPF 709. As an example, at 755, UPF may transmit a data forwarding indication to previously-serving secondary node 703, and previously-serving secondary node 703 may transmit a data forwarding message to master node 702 at 760.

In some examples, at 765, a path update procedure may be performed between master node 702 and AMF 708. Further, at 770, a UE context release procedure may be performed between master node 702 and previously-serving secondary node 703. The described techniques of process flow 700 may illustrate a case where, in a DC deployment, a master node is unchanged, and a secondary node is released based on measurement reporting by UE 115-f. However, such techniques may be applicable to other cases, including those not explicitly described herein.

FIG. 8 illustrates an example of a process flow 800 in a system that supports measurement-based DC and CA activation in accordance with aspects of the present disclosure. In some examples, process flow 800 may implement aspects of wireless communications system 100. For example, process flow 800 includes UE 115-g, which may be an example of a UE 115 described with reference to FIGs. 1 through 7. Process flow 800 also includes a previously-serving master node 802 and a previously-serving secondary node 803 which may be configured for operation in a DC deployment with UE 115-g (e.g., prior to UE 115-g entering into an inactive communication state) . Previously-serving master node 802 and previously-serving secondary node 803 may each be examples of a base station 105 as described with reference to FIGs. 1 and 2. Process flow 800 may further include an AMF 808, where the AMF 808 may communicate with one or both of previously-serving master node 802 and previously-serving secondary node 803. Process flow 800 may illustrate the use of stored lower-layer configurations when UE 115-g resumes communications from an RRC inactive state. Additionally, process flow 800 may illustrate the exchange of a secondary node and a master node in a DC deployment based on measurements of the master node.

In process flow 800, UE 115-g may initially operate in a DC configuration with previously-serving master node 802 providing an MCG (e.g., including a first cell) and previously-serving secondary node 803 providing an SCG (e.g., including a second cell) . UE 115-g may transition into the RRC inactive state (e.g., from an RRC connected state) based on the received signaling from previously-serving master node 802. In some cases, UE 115-g, may perform one or more measurements of nearby cells after entering the RRC inactive state. For example, UE 115-g may perform measurements of previously-serving master node 802 (e.g., downlink received signal strength measurements, carrier-to-interference ratio measurements, etc. ) , which may be based on measurement configurations received from previously-serving master node 802 or previously-serving secondary node 803 prior to transitioning to RRC inactive.

As described herein, UE 115-g, previously-serving master node 802, and previously-serving secondary node 803 may store a set of lower-layer configurations. For instance, UE 115-g and the network may store the lower-layer MCG configuration (e.g., associated with previously-serving master node 802) and the lower-layer SCG configuration (e.g., associated with previously-serving secondary node 803) . The storage of the lower-layer configurations may enable UE 115-g to resume from the RRC inactive state with reduced signaling overhead (e.g., as compared to when the lower-layer configurations are released) . In such cases, a full configuration of previously-serving master node 802, previously-serving secondary node 803, or both, may be obtained from stored lower-layer configurations and delta signaling (e.g., indicating changes to the stored lower-layer configurations, if any) when UE 115-g resumes communications with one of the nodes of the previously-established DC deployment.

UE 115-g may resume communications with at least one of previously-serving master node 802 or previously-serving secondary node 803. In some cases, UE 115-g UE 115-g may determine to resume communications with previously-serving secondary node 803 (e.g., instead of previously-serving master node 802) . In such cases, UE 115-g may perform a random access procedure, for example, transmitting, at 805, a random access message (e.g., including a RACH preamble) to previously-serving secondary node 803 and receiving, at 810, a random access response from previously-serving secondary node 803. Additionally, at 815, UE 115-g may transmit an RRC resume request to previously-serving secondary node 803. That is, UE 115-g may send a resume request message to the node that last served as a secondary node in a DC configuration prior to UE 115-g operating in the RRC inactive state, while the previously-serving master node 802 may remain suspended. In such cases, the RRC resume request may indicate whether measurement reports are available at UE 115-g. Here, UE 115-g may indicate that the measurement report for previously-serving master node 802 is available. The RRC resume request message may include information such as a resume-identity, a cause-value, a resumeMAC-I, or the like. In some examples, the ResumeMAC-I may be protected with a master key. In some cases, according to the resume-identity, previously-serving secondary node 803 may determine that UE 115-g was configured with DC (e.g., MR-DC) .

After receiving the indication of the available measurement report for previously-serving master node 802, at 820, previously-serving secondary node 803 may transmit a context request to previously-serving master node 802. The context request may include an indication that the master node and secondary node may be exchanged. For instance, based on UE 115-g resuming communications in previously-serving secondary node 803, previously-serving master node 802 and previously-serving secondary node 803 may exchange roles in the DC deployment. In some examples, the context retrieval request at 820 may be security protected with an updated key from an SRB (e.g., SRB1) of previously-serving secondary node 803 (e.g., operating as a currently-serving master node after UE 115-g move out of the RRC inactive state) . At 825, previously-serving master node 802 may respond with a configuration for the master node/secondary node exchange. If UE 115-g is verified successfully, previously-serving master node 802 may accept the exchange of the master node and secondary node. In such cases, previously-serving master node 802 may remain suspended until a measurement report is received (e.g., from UE 115-g via previously-serving secondary node 803) . In some examples, one or both of the context request (at 820) and the context response (at 825) may be transmitted over an Xn interface between previously-serving master node 802 and previously-serving secondary node 803. In some cases, at 830, AMF 808 may transmit an indication of a path switch based on the exchange of the master node and the secondary node.

At 835, previously-serving secondary node 803 may transmit, to UE 115-g, an RRC resume message (e.g., Msg4 of the random access procedure) . The RRC resume message may include the indication of the exchange of the secondary node and the master node in the DC deployment. Further, the RRC resume message may include a request for the measurement report (s) that UE 115-g indicated were available in the RRC resume request message received at previously-serving secondary node 803. UE 115-g may then transmit, at 840, an RRC resume complete message (e.g., a random access acknowledgment) that includes the request measurement report (s) for previously-serving master node 802.

At 845 and 850, previously-serving master node 802 may be activated (e.g., as a currently-serving secondary node) by previously-serving secondary node 803. For example, previously-serving secondary node 803 may initialize a secondary node modification procedure based on the received measurement reporting from UE 115-g. As such, at 845, previously-serving secondary node 803 may transmit a resume request to previously-serving master node 802. The resume request may be transmitted on an Xn interface between previously-serving master node 802 and previously-serving secondary node 803. In some cases, the request message may include an indication of the measurement report received from UE 115-g, which may enable previously-serving master node 802 to resume communications with UE 115-g as the currently-serving secondary node. In response, and at 850, previously-serving master node 802 may transmit a resume response to previously-serving secondary node 803. The response may be transmitted via the Xn interface. In some cases, previously-serving master node 802 may provide an indication of the stored lower-layer MCG configuration that was used before UE 115-g entered into the RRC inactive state.

At 855, previously-serving secondary node 803 may transmit an RRC reconfiguration message to UE 115-g that includes an indication of delta signaling of the lower-layer MCG configuration, the lower-layer SCG configuration, or a combination thereof. The delta signaling may be used by UE 115-g for the configuration of the lower-layer MCG/SCG based on a UE context received from previously-serving master node 802. In some cases, the delta signaling may comprise a difference between the stored lower-layer MCG configuration and a current lower-layer MCG configuration (e.g., where previously-serving secondary node 803 is currently associated with a current MCG) . Additionally or alternatively, the delta signaling may comprise a difference between the stored lower-layer SCG configuration and a current lower-layer SCG configuration that is based on the measurements of previously-serving master node 802. In such cases, the differences indicated by the delta signaling may include a change in one or more parameters of a current lower-layer configuration as compared to the stored lower-layer configuration.

At 860, UE 115-g may transmit an RRC reconfiguration complete message to previously-serving secondary node 803, and may then resume communications with previously-serving master node 802. For example, at 865 and 870, UE 115-g may perform a random access procedure (e.g., including the transmission of a PRACH preamble and subsequent exchange of messaging) with previously-serving master node 802, and may subsequently exchange data (e.g., uplink and downlink data) with previously-serving master node 802. Thus, the described techniques of process flow 800 may illustrate a case where, in a DC deployment, a master node and a secondary node are exchanged based on early measurement reporting by UE 115-g. However, such techniques may be applicable to other scenarios, including those not explicitly described herein.

FIG. 9 illustrates an example of a process flow 900 in a system that supports measurement-based DC and CA activation in accordance with aspects of the present disclosure. In some examples, process flow 900 may implement aspects of wireless communications system 100. For example, process flow 900 includes UE 115-h, which may be an example of a UE 115 described with reference to FIGs. 1 through 8. Process flow 900 also includes a previously-serving master node 902 and a previously-serving secondary node 903 which may be configured for operation in a DC deployment with UE 115-h (e.g., prior to UE 115-h entering into an inactive communication state) . Further, process flow 900 may include a target node 904. Previously-serving master node 902, previously-serving secondary node 903, and target node 904 may each be examples of a base station 105 as described with reference to FIGs. 1 and 2. Process flow 900 may further include an AMF 908, where the AMF 908 may communicate with one or both of previously-serving master node 902 and previously-serving secondary node 903. Process flow 900 may illustrate the use of stored lower-layer configurations when UE 115-h resumes communications from an RRC inactive state. Additionally, process flow 900 may illustrate the exchange of a secondary node and a master node in a DC deployment based on measurements of an additional node.

In process flow 900, UE 115-h may initially operate in a DC configuration with previously-serving master node 902 providing an MCG (e.g., including a first cell) and previously-serving secondary node 903 providing an SCG (e.g., including a second cell) . UE 115-h may transition into the RRC inactive state (e.g., from an RRC connected state) based on received signaling from previously-serving master node 902. In some cases, UE 115-h, may perform one or more measurements of nearby cells after entering the RRC inactive state. Additionally, UE 115-h may be mobile and may be located in or near another cell provided by a node that is different from previously-serving master node 902 and previously-serving secondary node 903. In such cases, UE 115-h may perform measurements (e.g., downlink received signal strength measurements, carrier-to-interference ratio measurements, etc. ) of target node 904, which may be based on measurement configurations received from previously-serving master node 902 or previously-serving secondary node 903 prior to transitioning to RRC inactive.

Upon UE 115-h performing a state transition into the RRC inactive state, UE 115-h, previously-serving master node 902, and previously-serving secondary node 903 may store lower-layer MCG configuration (e.g., associated with previously-serving master node 902) and the lower-layer SCG configuration (e.g., associated with previously-serving secondary node 903) . The storage of the lower-layer configurations may enable UE 115-h to resume from the RRC inactive state with reduced signaling overhead (e.g., as compared to when the lower-layer configurations are released) .

UE 115-h may determine to resume communications with at least one of previously-serving master node 902 or previously-serving secondary node 903. As mentioned above, UE 115-h may have moved since transitioning into the RRC inactive state, and UE 115-h may resume communications with previously-serving secondary node 903 based on the location of UE 115-h. In such cases, UE 115-h may perform a random access procedure by transmitting, at 905, a random access preamble (e.g., Msg1) to previously-serving secondary node 903 and receiving, at 910, a random access response (e.g., Msg2) from previously-serving secondary node 903. Additionally, at 915, UE 115-h may transmit an RRC resume request (e.g., Msg3) to previously-serving secondary node 903. In other words, UE 115-h may send a resume request message to the node that last served as a secondary node in a DC configuration prior to UE 115-h operating in the RRC inactive state, while the previously-serving master node 902 may be suspended. In such cases, the RRC resume request may indicate whether measurement reports are available at UE 115-h. For example, UE 115-h may indicate that the measurement report for target node 904 is available. The availability of the measurement report for target node 904 may signal to the network that target node 904 may serve as a new secondary node in the DC deployment.

As a result, after receiving the indication of the available measurement report for target node 904, at 920, previously-serving secondary node 903 may transmit a context request to previously-serving master node 902. The context request may include an indication that the master node and secondary node may be exchanged. For instance, based on UE 115-h resuming communications in previously-serving secondary node 903 (e.g., due to a new physical location of UE 115-h) , previously-serving master node 902 and previously-serving secondary node 903 may exchange roles in the DC deployment.

At 925, previously-serving master node 902 may respond with a configuration for the master node/secondary node exchange. If UE 115-h is verified successfully, previously-serving master node 902 may accept the exchange of the master node and secondary node. In some cases, at 930, AMF 908 may perform a path switch with previously-serving master node 902 based on the exchange of the master node and the secondary node.

At 935, previously-serving secondary node 903 may transmit, to UE 115-h, an RRC resume message (e.g., Msg4) . The RRC resume message may include the indication of the exchange of the secondary node and the master node in the DC deployment. Further, the RRC resume message may include a request for the measurement report (s) that UE 115-h indicated were available in the RRC resume request message received at previously-serving secondary node 903. UE 115-h may then transmit, at 940, an RRC resume complete message (e.g., a random access acknowledgment) that includes the request measurement report (s) for target node 904.

At 945 and 950, target node 904 may be activated (e.g., as a currently-serving secondary node) by previously-serving secondary node 903. For example, previously-serving secondary node 903 may initialize a secondary node addition procedure based on the received measurement reporting for target node 904 from UE 115-h. As a result, at 945, previously-serving secondary node 903 may transmit an addition request to target node 904. The addition request may include an indication of the SCG configuration stored at previously-serving secondary node 903. Further, at 950, target node 904 may transmit an addition request ACK to previously-serving secondary node 903.

Previously-serving secondary node 903 may initiate the release of previously-serving master node 902 from the DC deployment based on the addition request (and the measurement report for target node 904) . In such cases, at 955, previously-serving secondary node 903 may transmit a secondary node release request to previously-serving master node 902. At 960, previously-serving master node 902 may respond with a transmission of an ACK for the release request. In some examples, AMF 908 may perform a path switch for previously-serving master node 902 based on the addition of target node 904 and release of previously-serving master node 902.

At 970, previously-serving secondary node 903 may transmit an RRC reconfiguration message to UE 115-h that includes an indication of delta signaling of the lower-layer MCG configuration, the lower-layer SCG configuration, or a combination thereof. The delta signaling may be used by UE 115-h for the configuration of the lower-layer MCG/SCG based on a UE context received from previously-serving master node 902. In some cases, the delta signaling may include a difference between the stored lower-layer SCG configuration at previously-serving secondary node 903 and a current lower-layer MCG configuration (e.g., where previously-serving secondary node 903 is associated with a current MCG) . Additionally or alternatively, the delta signaling may comprise an indication of an SCG configuration associated with target node 904. In such cases, the differences indicated by the delta signaling may include a change in one or more parameters of lower-layer configurations as compared to the stored lower-layer configuration at UE 115-h.

At 975, UE 115-h may transmit an RRC reconfiguration complete message to previously-serving secondary node 903, and may subsequently initiate communications with target node 904. For example, at 980 and 985, UE 115-h may perform a random access procedure with target node 904, and may subsequently exchange data (e.g., uplink and downlink data) with target node 904. Thus, the described techniques of process flow 900 may illustrate a case where, in a DC deployment, a master node and a secondary node are exchanged, and an additional node operates as an updated secondary node (e.g., due to UE mobility) based on early measurement reporting by UE 115-h. However, such techniques may be applicable in other examples, including those not explicitly described herein.

FIG. 10 illustrates an example of a process flow 1000 in a system that supports measurement-based DC and CA activation in accordance with aspects of the present disclosure. In some examples, process flow 1000 may implement aspects of wireless communications system 100. For example, process flow 1000 includes UE 115-i, which may be an example of a UE 115 described with reference to FIGs. 1 through 9. Process flow 1000 also includes a previously-serving master node 1002 and a previously-serving secondary node 1003 which may be configured for operation in a DC deployment with UE 115-i (e.g., prior to UE 115-i entering into an inactive communication state) . Previously-serving master node 1002 and previously-serving secondary node 1003 may each be examples of a base station 105 as described with reference to FIGs. 1 and 2. Process flow 1000 may further include an AMF 1008, where the AMF 1008 may communicate with one or both of previously-serving master node 1002 and previously-serving secondary node 1003. Process flow 1000 may illustrate the use of stored lower-layer configurations when UE 115-i resumes communications from an RRC inactive state. Additionally, process flow 1000 may illustrate the exchange of a secondary node and a master node in a DC deployment based on measurements of the master node.

In process flow 1000, UE 115-i may operate in a DC configuration with previously-serving master node 1002 providing an MCG (e.g., including a first cell) and previously-serving secondary node 1003 providing an SCG (e.g., including a second cell) . UE 115-i may transition into the RRC inactive state (e.g., from an RRC connected state) , for example, based on signaling (e.g., an RRC release message) received from previously-serving master node 1002. In some cases, at 1010, UE 115-i, may perform one or more measurements of nearby cells after entering the RRC inactive state. However, in some examples, UE 115-i may be unable to generate a measurement report for any cells based on its measurements. For instance, a signal quality for one or more nodes, including previously-serving master node 702, may not be sufficient for UE 115-i to generate a measurement report. In such cases, when UE 115-i resumes from the RRC inactive state, UE 115-i may resume communications with previously-serving secondary node 1003 and indicate that no measurement reports are available. In such cases, the lack of measurement reporting for other nodes, such as previously-serving master node 1002, may indicate to previously-serving secondary node 1003 that previously-serving master node 1002 may be released from the DC deployment.

In some cases, UE 115-i may transition to the RRC inactive state, and UE 115-i, previously-serving master node 1002, and previously-serving secondary node 1003 may store lower-layer MCG configuration (e.g., associated with previously-serving master node 1002) and the lower-layer SCG configuration (e.g., associated with previously-serving secondary node 1003) . The storage of the lower-layer configurations may enable UE 115-i to resume from the RRC inactive state with reduced signaling overhead (e.g., as compared to when the lower-layer configurations are released) .

UE 115-i may determine to resume communications with at least one of previously-serving master node 1002 or previously-serving secondary node 1003. For example, and as mentioned above, UE 115-i may resume communications with previously-serving secondary node 1003. In such cases, UE 115-i may perform a random access procedure, for example, transmitting, at 1005, a random access message (e.g., Msg1) including a PRACH preamble to previously-serving secondary node 1003 and receiving, at 1010, a random access response (e.g., Msg2) from previously-serving secondary node 1003. Additionally, at 1015, UE 115-i may transmit an RRC resume request (e.g., Msg3) to previously-serving secondary node 1003. In such cases, previously-serving master node 1002 may be suspended. The RRC resume request from UE 115-i may indicate whether measurement reports are available at UE 115-i. As such, due to the lack of available measurement reports, UE 115-i may indicate that there are no measurement reports available. The unavailability of the measurement reports may signal to the network that UE 115-i may resume communications using single connectivity (e.g., instead of DC) .

In such cases, after receiving the indication of the unavailable measurement reporting, at 1020, previously-serving secondary node 1003 may transmit a context request to previously-serving master node 1002. The context request may include an indication that the master node and secondary node may be exchanged based on the absence of measurement reporting. At 1025, previously-serving master node 1002 may respond with a configuration for the master node/secondary node exchange. At 1030, AMF 1008 may perform a path switch for previously-serving master node 1002 based on the exchange of the master node and the secondary node.

At 1035, previously-serving secondary node 1003 may transmit, to UE 115-i, an RRC resume message (e.g., Msg4) . The RRC resume message may indicate, to UE 115-i, the exchange of the master node and the secondary node. Further, the RRC resume message may not include a request for the measurement report (s) based on the indication from UE 115-i at 1015 that measurement reports for other cells are unavailable. UE 115-i may then transmit, at 1040, an RRC resume complete message (e.g., a random access acknowledgment) to previously-serving secondary node 1003.

At 1045 and 1050, previously-serving secondary node 1003 may initiate the release of previously-serving master node 1002 (which may be suspended since UE 115-i entered the RRC inactive state) from the DC deployment based on the unavailability of the measurements. In such cases, at 1055, previously-serving secondary node 1003 may transmit a secondary node release request to previously-serving master node 1002. In response, at 1060, previously-serving master node 1002 may transmit an ACK of the release request. In some examples, AMF 1008 may perform a path switch for previously-serving master node 1002 based on the release of previously-serving master node 1002.

At 1070, previously-serving secondary node 1003 may transmit an RRC reconfiguration message to UE 115-i that includes an indication of signaling of the lower-layer MCG configuration, the lower-layer SCG configuration, or a combination thereof. In some cases, the lower-layer MCG configuration may be based on the lower-layer SCG configuration stored by previously-serving secondary node 1003. At 1075, UE 115-i may transmit an RRC reconfiguration ACK to previously-serving secondary node 1003. UE 115-I and previously-serving secondary node 1003 may communicate data (e.g., uplink and downlink data) in a single connectivity configuration. Thus, the described techniques of process flow 1000 may illustrate a case where, in a DC deployment, a master node and a secondary node are exchanged, and the former master node is released based on an unavailability of early measurement reporting by UE 115-i. However, such techniques may be applicable in other examples, including those not explicitly described herein.

FIG. 11 illustrates an example of a process flow 1100 in a system that supports measurement-based DC and CA activation in accordance with aspects of the present disclosure. In some examples, process flow 1100 may implement aspects of wireless communications system 100. For example, process flow 1100 includes UE 115-j, which may be an example of a UE 115 described with reference to FIGs. 1 through 10. Process flow 1100 also includes a previously-serving master node 1102 and a previously-serving secondary node 1103 which may be configured for operation in a DC deployment with UE 115-j (e.g., prior to UE 115-j entering into an inactive communication state) . Previously-serving master node 1102 and previously-serving secondary node 1103 may each be examples of a base station 105 as described with reference to FIGs. 1 and 2. Process flow 1100 may illustrate the use of stored lower-layer configurations when UE 115-j resumes communications from an RRC inactive state. Additionally, process flow 1100 may illustrate signaling using a split radio bearer configuration and the resumption of communications with a same master node and secondary node by UE 115-j.

In some cases, UE 115-j may be configured to operate using a split bearer configuration. For instance, SRBs of UE 115-j (e.g., SRB1/SRB2) may have been configured as split bearers prior to UE 115-j transitioning into the RRC inactive state. In such cases, downlink messages sent from the master node (e.g., from previously-serving master node 1102) to UE 115-j may be sent via lower-layers (e.g., RLC, MAC, PHY, etc. ) of either the master node or the secondary node. In other cases, downlink messages may be sent via the lower-layers of both the master and secondary nodes. In the uplink, RRC messages from UE 115-j may be transmitted to the master node via the secondary node (e.g., previously-serving secondary node 1103) using the split bearer (e.g., via a “leg” associated with the secondary node) . In such cases, UE 115-j may transmit messages (e.g., RRC signaling) to previously-serving master node 1102 via previously-serving secondary node 1103. As a result, and as described in further detail below, a role change between previously-serving master node 1102 and previously-serving secondary node 1103 may not be required.

In some cases, UE 115-j may initially operate in a DC configuration with previously-serving master node 1102 providing an MCG (e.g., including a first cell) and previously-serving secondary node 1103 providing an SCG (e.g., including a second cell) . UE 115-j may later transition into the RRC inactive state (e.g., from an RRC connected state) based on a level of communication with the network. In some cases, UE 115-j, may perform one or more measurements of nearby cells after entering the RRC inactive state. For example, UE 115-j may perform measurements of both previously-serving master node 1102 (e.g., downlink received signal strength measurements, carrier-to-interference ratio measurements, etc. ) and previously-serving secondary node 1103, which may be based on measurement configurations received from previously-serving master node 1102 or previously-serving secondary node 1103 prior to transitioning to RRC inactive. As such, UE 115-j may generate corresponding measurement reports for the measurements performed.

In some examples, UE 115-j, previously-serving master node 1102, and previously-serving secondary node 1103 may store a set of lower-layer configurations when UE 115-j transitions to the RRC inactive state. For instance, UE 115-j and the network may store the lower-layer MCG configuration (e.g., associated with previously-serving master node 1102) and the lower-layer SCG configuration (e.g., associated with previously-serving secondary node 1103) . Additionally or alternatively, previously-serving secondary node 1103 may store a resume identity of UE 115-j.

UE 115-j may determine to resume communications with at least one of previously-serving master node 1102 or previously-serving secondary node 1103. In some cases, UE 115-j may determine, after exiting the RRC inactive state, to resume communications with previously-serving secondary node 1103 (e.g., instead of previously-serving master node 1102) . In such cases, UE 115-j may perform a random access procedure, where UE 115-j may transmit, at 1105, a random access preamble to previously-serving secondary node 1103 and receive, at 1110, a random access response from previously-serving secondary node 1103. In such cases, previously-serving master node 1102 may be in a suspended state. At 1115, UE 115-j may transmit an RRC resume request to previously-serving secondary node 1103, and the RRC resume request may indicate whether measurement reports are available at UE 115-j. Here, UE 115-j may indicate that the measurement report for previously-serving master node 1102 and previously-serving secondary node 1103 are available. The RRC resume request message may include information such as a resume-identity, a cause-value, a resumeMAC-I, or the like. In some examples, the ResumeMAC-I may be protected with a master key. In some cases, according to the resume-identity, previously-serving secondary node 1103 may determine that UE 115-j was configured with DC (e.g., MR-DC) . In some examples, UE 115-j may expect to receive a response to the RRC resume request via a secondary node leg of an SRB (e.g., SRB1) , which may be based on the split bearer configuration.

After receiving the indication of the available measurement report for previously-serving master node 1102 and for previously-serving secondary node 1103, at 1120, previously-serving secondary node 1103 may transmit a context request to previously-serving master node 1102. The context request may include a secondary node resumption configuration. At 1125, previously-serving master node 1102 may respond with a configuration for the master node/secondary node resumption. If UE 115-j is verified successfully, previously-serving master node 1102 may send an RRC resume message (e.g., Msg4) over the secondary node leg of SRB1. More specifically, at 1125, previously-serving master node 1102 may transmit a context response that includes an RRC container over a leg of SRB1 that is associated with previously-serving secondary node 1103. The message may be routed, at 1130, through the lower-layers of previously-serving secondary node 1103 in accordance with the split bearer configuration and received at UE 115-j. As a result, a secondary node configuration of the DC deployment may be resumed after the transmission of the RRC resume message at 1130.

In some aspects, previously-serving master node 1102 may be activated upon receipt of the available measurement report from UE 115-j. For example, previously-serving master node 1102 may remain suspended until a measurement report is received. As such, UE 115-j may transmit an RRC resume complete message to previously-serving master node 1102. Thus, at 1140, the RRC resume complete message sent to previously-serving master node 1102 may include the measurement report for previously-serving master node 1102, and may be transmitted from UE 115-j via the leg of SRB1 that is associated with previously-serving secondary node 1103. Upon receiving the measurement report at 1140, previously-serving master node 1102 may transmit, to previously-serving secondary node 1103, a resume request at 1145. In response, and at 1150, previously-serving secondary node 1103 may transmit a resume response to previously-serving master node 1102. The resume request and the resume response may be transmitted over an Xn interface between previously-serving master node 1102 and previously-serving secondary node 1103. In some cases, a path switch may not be needed due to the established split bearer configuration used in the DC deployment.

At 1155, previously-serving master node 1102 may transmit, to UE 115-j, an RRC reconfiguration message to UE 115-j. Based on the split bearer configuration, the RRC reconfiguration message may be sent over the secondary node leg of the SRB. the RRC reconfiguration message may include delta signaling for the lower-layer MCG configuration, the lower-layer SCG configuration, or a combination thereof. In some cases, the delta signaling may indicate a difference between the stored lower-layer MCG configuration and a current lower-layer MCG configuration based on the measurements for previously-serving master node 1102 (e.g., where previously-serving master node 1102 remains associated with a current MCG configuration) . Additionally or alternatively, the delta signaling may indicate a difference between the stored lower-layer SCG configuration and a current lower-layer SCG configuration that is based on the measurements of previously-serving secondary node 1103 (where previously-serving secondary node 1103 remains associated with a current SCG of the DC deployment) . In such cases, the differences indicated by the delta signaling may include a change in one or more parameters of a current lower-layer configuration as compared to the stored lower-layer configurations.

At 1160, UE 115-j may transmit an RRC reconfiguration complete message to previously-serving secondary node 1103, and the RRC reconfiguration complete message may be transmitted to previously-serving master node 1102. The RRC reconfiguration complete message may serve as an ACK to previously-serving master node 1102 that DC configurations have been re-established using the delta signaling provided at 1155, where the delta signaling may serve to minimize signaling overhead in the system.

Communications may be resumed with previously-serving master node 1102. For example, at 1165 and 1170, UE 115-j may perform a random access procedure with previously-serving master node 1102, and data may be subsequently exchanged (e.g., uplink and downlink data) with previously-serving master node 1102. Thus, the described techniques of process flow 1100 may illustrate a case where, in a DC deployment, a master node and a secondary node remain the same based on early measurement reporting by UE 115-j and a split bearer configuration. That is, there may not be an exchange of master node and secondary node after a UE 115 resumes from an inactive communication state. However, such techniques may be applicable to other scenarios, including those not explicitly described herein.

FIG. 12 illustrates an example of a process flow 1200 in a system that supports measurement-based DC and CA activation in accordance with aspects of the present disclosure. In some examples, process flow 1200 may implement aspects of wireless communications system 100. For example, process flow 1200 includes UE 115-k, which may be an example of a UE 115 described with reference to FIGs. 1 through 11. Process flow 1200 also includes a previously-serving master node 1202 and a previously-serving secondary node 1203 which may be configured for operation in a DC deployment with UE 115-k (e.g., prior to UE 115-k entering into an inactive communication state) . In some cases, process flow 1200 may include a target master node 1204. Previously-serving master node 1202, previously-serving secondary node 1203, and target master node 1204 may each be examples of a base station 105 as described with reference to FIGs. 1 and 2. Process flow 1200 may illustrate the use of stored lower-layer configurations when UE 115-k resumes communications from an RRC inactive state. Additionally, process flow 1200 may illustrate signaling using a split radio bearer configuration and the resumption of communications with an updated master node.

In some cases, UE 115-k may be configured to operate using a split bearer configuration. For instance, SRBs of UE 115-k (e.g., SRB1/SRB2) and a master node-terminated DRB may have been configured as split bearers prior to UE 115-k transitioning into the RRC inactive state. Additionally, UE 115-k may initially operate in a DC configuration with previously-serving master node 1202 providing an MCG (e.g., including a first cell) and previously-serving secondary node 1203 providing an SCG (e.g., including a second cell) . UE 115-k may later transition into the RRC inactive state based on a level of communication with the network, for example, to save power. In some cases, UE 115-k, may perform one or more measurements of nearby cells after entering the RRC inactive state. For example, UE 115-k may perform measurements of one or more additional cells, which may include a cell provided by target master node 1204, which may be based on UE 115-k being mobile and moving near the cell of target master node 1204. As such, UE 115-k may generate a measurement reports for the measurements for target master node 1204.

In some examples, UE 115-k, previously-serving master node 1202, and previously-serving secondary node 1203 may store a set of lower-layer configurations when UE 115-k transitions to the RRC inactive state. For instance, UE 115-k and the network may store the lower-layer MCG configuration (e.g., associated with previously-serving master node 1202) and the lower-layer SCG configuration (e.g., associated with previously-serving secondary node 1203) . Additionally or alternatively, previously-serving secondary node 1203 may store a resume identity of UE 115-k.

UE 115-k may determine to resume communications with at least one of previously-serving master node 1202 or previously-serving secondary node 1203. In some cases, UE 115-k may determine, after exiting the RRC inactive state, to resume communications with previously-serving secondary node 1203 (e.g., instead of previously-serving master node 1202) . In such cases, UE 115-k may perform a random access procedure, where at 1205, UE 115-k may transmit a random access preamble (e.g., a PRACH preamble) to previously-serving secondary node 1203 and receive, at 1210, a random access response from previously-serving secondary node 1203. In such cases, previously-serving master node 1202 may be in a suspended state.

At 1215, UE 115-k may transmit an RRC resume request to previously-serving secondary node 1203, and the RRC resume request may indicate whether measurement reports are available at UE 115-k. In some examples, after transmitting the RRC resume request at 1215, UE 115-k may expect to receive a response to the RRC resume request via a secondary node leg of an SRB (e.g., SRB1) , which may be based on the split bearer configuration. Additionally, UE 115-k may indicate that the measurement report for target master node 1204 is available. In such cases, when UE 115-k resumes communications of the DC deployment with previously-serving secondary node 1203, and using a measurement report for target master node 1204, the master node of the DC deployment may change while the secondary node remains unchanged. For example, the measurement report for target master node 1204 may indicate an improved signal quality provided by target master node 1204 (e.g., as compared to previously-serving master node 1202) .

After receiving the indication of the available measurement report for target master node 1204, at 1220, previously-serving secondary node 1203 may transmit a context request to previously-serving master node 1202. The context request may include a secondary node resumption configuration. At 1225, previously-serving master node 1202 may respond with a configuration for the master node/secondary node resumption, and an RRC resume message (e.g., Msg4) may be sent over a secondary node leg of SRB1. More specifically, at 1225, previously-serving master node 1202 may transmit an RRC resume message over a leg of SRB1 that is associated with previously-serving secondary node 1203. The message may be routed, at 1230, through the lower-layers of previously-serving secondary node 1203 in accordance with the split bearer configuration, and thus received at UE 115-k.

In some aspects, a handover of previously-serving master node 1202 to target master node 1204 may be triggered upon receipt of the available measurement report for target master node 1240 from UE 115-k. As such, at 1240, UE 115-k may transmit an RRC resume complete message to previously-serving master node 1202, which may include the measurement report for target master node 1204. The RRC resume complete message may be transmitted from UE 115-k via the leg of SRB1 that is associated with previously-serving secondary node 1203. Upon receiving the measurement report at 1240, previously-serving master node 1202 may transmit, to previously-serving secondary node 1203, a handover request at 1245. The handover request may include the lower-layer MCG configuration that was stored by previously-serving master node 1202 when UE 115-k transitioned into the RRC inactive state. Thus, target master node 1204 may obtain the stored MCG configuration used by previously-serving master node 1202.

Further, at 1250, target master node 1204 may transmit, to previously-serving secondary node 1203, a secondary node addition request. In some examples, the addition request may enable previously-serving secondary node 1203 to resume operating as a secondary node for UE 115-k in the DC deployment. At 1255, previously-serving secondary node 1203 may transmit an ACK of the secondary node addition request received from target master node 1204. In some examples, at 1260, target master node 1204 may transmit a message including a handover request ACK to previously-serving master node 1202.

At 1265, in some examples, previously-serving master node 1202 may transmit a secondary node release request to previously-serving secondary node 1203. In response, previously-serving secondary node 1203 may respond, at 1270, with an acknowledgment of the secondary node release request.

Based on the received measurement report for target master node 1204 and the stored lower-layer configuration, previously-serving master node 1202 may transmit, to UE 115-k, an RRC reconfiguration message to UE 115-k that includes delta signaling for the lower-layer MCG configuration, the lower-layer SCG configuration, or a combination thereof. In some examples, and based on the split bearer configuration, the RRC reconfiguration message may be sent over the secondary node leg of the SRB and routed to UE 115-k. The differences, changes, or additions to the lower-layer configurations indicated by the delta signaling may indicate a modification of one or more parameters of a current lower-layer configuration as compared to the stored lower-layer configurations. Here, target master node 1204 may operate as a currently-serving master node associated with the MCG in the DC deployment, where previously-serving secondary node 1203 may continue to operate as the secondary node associated with the SCG. The delta signaling may accordingly reflect the changes in the current lower-layer configurations with respect to the stored lower-layer configurations.

At 1280, UE 115-k may transmit an RRC reconfiguration complete message to previously-serving secondary node 1203. Communications may then be resumed with target master node 1204. For example, at 1285, UE 115-k may perform a random access procedure with target master node 1204, and data may be subsequently exchanged (e.g., uplink and downlink data) with target master node 1204. Thus, the described techniques of process flow 1200 may illustrate a case where, in a DC deployment, a master node may change while a secondary node remains the same based on early measurement reporting by UE 115-k and a split bearer configuration. That is, there may not be an exchange of a secondary node after a UE 115 resumes from an inactive communication state with an early measurement report for another node/cell. However, such techniques may be applicable to other scenarios, including those not explicitly described herein.

FIG. 13 illustrates an example of a process flow 1300 in a system that supports measurement-based DC and CA activation in accordance with aspects of the present disclosure. In some examples, process flow 1300 may implement aspects of wireless communications system 100. For instance, process flow 1300 includes UE 115-m, which may be an example of a UE 115 described with reference to FIGs. 1 through 11. Process flow 1300 also includes a previously-serving master node 1302 and a previously-serving secondary node 1303 which may be configured for operation in a DC deployment with UE 115-m (e.g., prior to UE 115-m entering into an RRC inactive state) . Previously-serving master node 1302 and previously-serving secondary node 1303 may each be examples of a base station 105 as described with reference to FIGs. 1 and 2. Process flow 1300 may further include an AMF 1308, and AMF 1308 may communicate with one or both of previously-serving master node 1302 and previously-serving secondary node 1303. Process flow 1300 may illustrate the use of stored lower-layer configurations when UE 115-m resumes communications from an RRC inactive state. Process flow 1300 may illustrate resumption from the RRC inactive state using single connectivity with a secondary node.

In some cases, UE 115-m may be configured to operate using a split bearer configuration. For instance, SRBs of UE 115-m (e.g., SRB1/SRB2) may have been configured as split bearers prior to UE 115-m transitioning into the RRC inactive state. Additionally, UE 115-m may initially operate in a DC configuration with previously-serving master node 1302 providing an MCG (e.g., including a first cell) and previously-serving secondary node 1303 providing an SCG (e.g., including a second cell) . UE 115-m may later transition into the RRC inactive state upon receiving messaging from the network.

In some examples, UE 115-m, previously-serving master node 1302, and previously-serving secondary node 1303 may store a set of lower-layer configurations when UE 115-m transitions to the RRC inactive state. For instance, UE 115-m and the network may store the lower-layer MCG configuration (e.g., associated with previously-serving master node 1302) and the lower-layer SCG configuration (e.g., associated with previously-serving secondary node 1303) . Additionally or alternatively, previously-serving secondary node 1303 may store a resume identity of UE 115-m.

UE 115-m may determine to resume communications with at least one of previously-serving master node 1302 or previously-serving secondary node 1303. Additionally, UE 115-m may have performed one or more measurements of nearby cells after entering the RRC inactive state. However, in some examples, interference may affect the measurements performed by UE 115-m, and UE 115-m may determine that the signal quality of signaling transmitted by one or more nodes (e.g., including previously-serving master node 1302 and previously-serving secondary node 1303) may not be good enough for UE 115-m to generate a measurement report to be provided to the network.

As a result, upon transitioning out of the RRC inactive state and after initiating a random access procedure (e.g., transmitting a random access preamble (Msg1) at 1305 and receiving a random access response (Msg2) at 1310) , UE 115-m may indicate, at 1315, that no measurement reports are available in an RRC resume request (e.g., Msg3) . Upon receiving the RRC resume request from UE 115-m, previously-serving secondary node 1303, at 1320, previously-serving secondary node 1303 may transmit a context request to previously-serving master node 1302. The context request may include a secondary node resumption configuration. At 1325, previously-serving master node 1302 may respond with a configuration for secondary node resumption, and an RRC resume message (e.g., Msg4) may be sent to UE 115-m over a secondary node leg of SRB1. For example, at 1325, previously-serving master node 1302 may transmit an RRC resume message over a leg of SRB1 that is associated with previously-serving secondary node 1303. The message may be routed, at 1330, through the lower-layers of previously-serving secondary node 1303 in accordance with the split bearer configuration, and thus received at UE 115-m. In some examples, one or both of the context request (at 1320) and the context response (at 1325) may be transmitted over an Xn interface between previously-serving master node 1302 and previously-serving secondary node 1303.

At 1335, UE 115-m may transmit an acknowledgment to previously-serving secondary node 1303 in an RRC resume complete message. In such cases, the RRC resume complete message may not include a measurement report based, at least in part, on the signal quality affecting measurements performed by UE 115-m while in the RRC inactive state. At 1340, previously-serving secondary node 1303 may trigger a handover procedure (e.g., a forward handover procedure) by transmitting a handover notification to previously-serving master node 1302. For instance, due to the lack of measurement reporting from UE 115-m, previously-serving secondary node may determine that a handover is required so that UE 115-m may resume communications. Accordingly, the handover notification may indicate that previously-serving secondary node 1303 may continue communicating with UE 115-m based on UE 115-m resuming communications with previously-serving secondary node 1303 after exiting the RRC inactive state. Previously-serving master node 1302 may respond at 1345, and may transmit a handover notification to previously-serving secondary node 1303. Based on the handover request, previously-serving master node 1302 may be released.

In some examples, at 1350, AMF 1308 may perform a path switch procedure with previously-serving master node 1302 based on the completed handover with previously-serving secondary node 1303. At 1355, previously-serving secondary node 1303 may transmit an RRC reconfiguration message to UE 115-m. In some examples, the RRC reconfiguration message may include delta signaling for the lower-layer MCG configuration, the lower-layer SCG configuration, or a combination thereof. In some cases, the RRC reconfiguration message may enable UE 115-m to resume communications with previously-serving secondary node 1303 in a single connectivity configuration. After receiving the RRC reconfiguration message, UE 115-m may transmit a message, at 1360, that indicates that the RRC reconfiguration is complete. The described techniques of process flow 1300 may illustrate a case where, in a DC deployment, a master node may be released such that a UE 115 and base station resume communication in a single connectivity configuration after the UE 115 exits and RRC inactive state. However, such techniques may be applicable in other examples, including those not explicitly described herein.

It is noted that some aspects of signaling by a UE 115 and/or the various nodes may have been omitted from the above process flows for the sake of brevity and clarity of description. It is also understood that the described features, functions, and signaling of the above process flows may be combined or may be performed in a different order than the order shown.

FIG. 14 shows a block diagram 1400 of a device 1405 that supports measurement-based DC and CA activation in accordance with aspects of the present disclosure. The device 1405 may be an example of aspects of a UE 115 as described herein. The device 1405 may include a receiver 1410, a UE communications manager 1415, and a transmitter 1420. The device 1405 may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses) .

The receiver 1410 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to measurement-based DC and CA activation, etc. ) . Information may be passed on to other components of the device 1405. The receiver 1410 may be an example of aspects of the transceiver 1720 described with reference to FIG. 17. The receiver 1410 may utilize a single antenna or a set of antennas.

The UE communications manager 1415 may perform a state transition to an inactive communication state with a first cell and a second cell, determine that communications with at least one of the first cell or the second cell are to resume, store, based on the state transition to the inactive communication state, a first lower-layer configuration for the first cell and a second lower-layer configuration for the second cell, receive a reconfiguration message that indicates a difference between a current lower-layer configuration and at least one of the stored first lower-layer configuration or the second lower-layer configuration, and transmit, based on the determination, an indication of whether one or more measurement reports are available. The UE communications manager 1415 may be an example of aspects of the UE communications manager 1710 described herein.

The UE communications manager 1415, or its sub-components, may be implemented in hardware, code (e.g., software or firmware) executed by a processor, or any combination thereof. If implemented in code executed by a processor, the functions of the UE communications manager 1415, or its sub-components may be executed by a general-purpose processor, a DSP, an application-specific integrated circuit (ASIC) , a FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described in the present disclosure.

The UE communications manager 1415, or its sub-components, may be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations by one or more physical components. In some examples, the UE communications manager 1415, or its sub-components, may be a separate and distinct component in accordance with various aspects of the present disclosure. In some examples, the UE communications manager 1415, or its sub-components, may be combined with one or more other hardware components, including but not limited to an input/output (I/O) component, a transceiver, a network server, another computing device, one or more other components described in the present disclosure, or a combination thereof in accordance with various aspects of the present disclosure.

The transmitter 1420 may transmit signals generated by other components of the device 1405. In some examples, the transmitter 1420 may be collocated with a receiver 1410 in a transceiver module. For example, the transmitter 1420 may be an example of aspects of the transceiver 1720 described with reference to FIG. 17. The transmitter 1420 may utilize a single antenna or a set of antennas.

FIG. 15 shows a block diagram 1500 of a device 1505 that supports measurement-based DC and CA activation in accordance with aspects of the present disclosure. The device 1505 may be an example of aspects of a device 1405, or a UE 115 as described herein. The device 1505 may include a receiver 1510, a UE communications manager 1515, and a transmitter 1535. The device 1505 may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses) .

The receiver 1510 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to measurement-based DC and CA activation, etc. ) . Information may be passed on to other components of the device 1505. The receiver 1510 may be an example of aspects of the transceiver 1720 described with reference to FIG. 17. The receiver 1510 may utilize a single antenna or a set of antennas.

The UE communications manager 1515 may be an example of aspects of the UE communications manager 1415 as described herein. The UE communications manager 1515 may include a communication state manager 1520, a lower-layer configuration component 1525, and a measurement report manager 1530. The UE communications manager 1515 may be an example of aspects of the UE communications manager 1710 described herein.

The communication state manager 1520 may perform a state transition to an inactive communication state with a first cell and a second cell and determine that communications with at least one of the first cell or the second cell are to resume (e.g., in a connected communication state) . The lower-layer configuration component 1525 may store, based on the state transition to the inactive communication state, a first lower-layer configuration for the first cell and a second lower-layer configuration for the second cell and receive a reconfiguration message that indicates a difference between a current lower-layer configuration and at least one of the stored first lower-layer configuration or the second lower-layer configuration. The measurement report manager 1530 may transmit, based on the determination, an indication of whether one or more measurement reports are available.

The transmitter 1535 may transmit signals generated by other components of the device 1505. In some examples, the transmitter 1535 may be collocated with a receiver 1510 in a transceiver module. For example, the transmitter 1535 may be an example of aspects of the transceiver 1720 described with reference to FIG. 17. The transmitter 1535 may utilize a single antenna or a set of antennas.

FIG. 16 shows a block diagram 1600 of a UE communications manager 1605 that supports measurement-based DC and CA activation in accordance with aspects of the present disclosure. The UE communications manager 1605 may be an example of aspects of a UE communications manager 1415, a UE communications manager 1515, or a UE communications manager 1710 described herein. The UE communications manager 1605 may include a communication state manager 1610, a lower-layer configuration component 1615, a measurement report manager 1620, and a communications resumption component 1625. Each of these modules may communicate, directly or indirectly, with one another (e.g., via one or more buses) .

The communication state manager 1610 may perform a state transition to an inactive communication state with a first cell and a second cell. In some examples, the communication state manager 1610 may determine that communications with at least one of the first cell or the second cell are to resume. In some cases, the first cell includes a primary cell of a CA deployment and the second cell includes a secondary cell of the CA deployment.

The lower-layer configuration component 1615 may store, based on the state transition to the inactive communication state, a first lower-layer configuration for the first cell and a second lower-layer configuration for the second cell. In some examples, the lower-layer configuration component 1615 may receive a reconfiguration message that indicates a difference between a current lower-layer configuration and at least one of the stored first lower-layer configuration or the second lower-layer configuration. In some cases, the reconfiguration message is received via a signaling radio bearer associated with the second cell.

The measurement report manager 1620 may transmit, based on the determination, an indication of whether one or more measurement reports are available. In some examples, the measurement report manager 1620 may transmit, via the first cell, an indication that a measurement report for the second cell is available based on measurements performed by the UE 115 while in the inactive communication state, the method further including. In some cases, the measurement report manager 1620 may transmit, via the first cell, an indication that a measurement report for a third cell is available based on measurements performed by the UE 115 while in the inactive communication state, the method further including.

In some examples, the measurement report manager 1620 may transmit, to the first cell, an indication that measurement reports for one or more cells are unavailable based on measurements performed by the UE 115 while in the inactive communication state, the method further including. Additionally or alternatively, the measurement report manager 1620 may transmit, to the first cell and via a signaling radio bearer associated with the second cell, an indication that a measurement report for the first cell and the second cell is available based on measurements performed by the UE 115 while in the inactive communication state, the method further including. In some cases, the indication that the measurement report for the third cell is available may be transmitted via a signaling radio bearer associated with the second cell, and where the reconfiguration message is received on the signaling radio bearer associated with the second cell.

The communications resumption component 1625 may resume communications on the first cell, where the first cell is from an MCG associated with a master node of a DC deployment, and where the second cell is from an SCG associated with a secondary node of the DC deployment. In some examples, the communications resumption component 1625 may resume communications on the first cell, where the first cell is from a previously-serving SCG associated with a previously-serving secondary node of a DC deployment, and where the second cell is from a previously-serving MCG associated with a previously-serving master node of the DC deployment.

In some examples, the communications resumption component 1625 may resume communications on the first cell, where the first cell is from an MCG associated with a master node of a DC deployment, and where the second cell is from a previously-serving SCG associated with a previously-serving secondary node of the DC deployment. In some examples, the communications resumption component 1625 may communicate on the third cell as part of a currently-serving SCG associated with a currently-serving secondary node of the DC deployment.

In some examples, the communications resumption component 1625 may resume communications on the first cell, where the first cell is from a currently-serving MCG associated with a currently-serving master node of a DC deployment, and where the second cell is from a previously-serving MCG associated with a previously-serving master node of the DC deployment. In some examples, the communications resumption component 1625 may communicate on the third cell as part of a currently-serving SCG associated with a secondary node of the DC deployment.

In some examples, the communications resumption component 1625 may resume communications on the first cell, where the first cell is from a previously-serving SCG associated with a previously-serving secondary node of a DC deployment, and where the first cell is from a previously-serving MCG associated with a previously-serving master node of the DC deployment. In some examples, the communications resumption component 1625 may communicate on the third cell as part of a currently-serving MCG of a currently-serving master node of the DC deployment.

In some examples, the communications resumption component 1625 may resume communications on the first cell, where the first cell is from an MCG associated with a master node of a DC deployment, and where the second cell is from a previously-serving SCG associated with a previously-serving secondary node of the DC deployment. In some examples, the communications resumption component 1625 may resume communications on the first cell, where the first cell is from a previously-serving SCG associated with a secondary node of a DC deployment, and where the second cell is from a previously-serving MCG associated with a previously-serving master node of the DC deployment.

In some examples, the communications resumption component 1625 may resume communications on the second cell based at least in part on the reconfiguration message indicating a difference between a current lower-layer configuration for the second cell and the stored second lower-layer configuration for the second cell, the difference being based at least in part on the measurement report for the second cell. Additionally or alternatively, the communications resumption component 1625 may communicate on the third cell based at least in part on the reconfiguration message indicating a difference between a current lower- layer configuration for the third cell and the stored second lower-layer configuration for the second cell, the difference being based at least in part on the measurement report for the third cell.

In some examples, the communications resumption component 1625 may refrain from communicating with the second cell based at least in part on the reconfiguration message, wherein the reconfiguration message indicates that the second cell has been released based at least in part on the unavailability of the measurement reports. In some cases, the communications resumption component 1625 may resume communications with the second cell based at least in part on the reconfiguration message indicating a difference between a current lower-layer configuration for the second cell and the stored second lower-layer configuration for the second cell, the difference being based at least in part on the measurement report for the second cell.

FIG. 17 shows a diagram of a system 1700 including a device 1705 that supports measurement-based DC and CA activation in accordance with aspects of the present disclosure. The device 1705 may be an example of or include the components of device 1405, device 1505, or a UE 115 as described herein. The device 1705 may include components for bi-directional voice and data communications including components for transmitting and receiving communications, including a UE communications manager 1710, an I/O controller 1715, a transceiver 1720, an antenna 1725, memory 1730, and a processor 1740. These components may be in electronic communication via one or more buses (e.g., bus 1745) .

The UE communications manager 1710 may perform a state transition to an inactive communication state with a first cell and a second cell, determine that communications with at least one of the first cell or the second cell are to resume, store, based on the state transition to the inactive communication state, a first lower-layer configuration for the first cell and a second lower-layer configuration for the second cell, receive a reconfiguration message that indicates a difference between a current lower-layer configuration and at least one of the stored first lower-layer configuration or the second lower-layer configuration, and transmit, based on the determination, an indication of whether one or more measurement reports are available.

The I/O controller 1715 may manage input and output signals for the device 1705. The I/O controller 1715 may also manage peripherals not integrated into the device 1705. In some cases, the I/O controller 1715 may represent a physical connection or port to an external peripheral. In some cases, the I/O controller 1715 may utilize an operating system such as

or another known operating system. In other cases, the I/O controller 1715 may represent or interact with a modem, a keyboard, a mouse, a touchscreen, or a similar device. In some cases, the I/O controller 1715 may be implemented as part of a processor. In some cases, a user may interact with the device 1705 via the I/O controller 1715 or via hardware components controlled by the I/O controller 1715.

The transceiver 1720 may communicate bi-directionally, via one or more antennas, wired, or wireless links as described herein. For example, the transceiver 1720 may represent a wireless transceiver and may communicate bi-directionally with another wireless transceiver. The transceiver 1720 may also include a modem to modulate the packets and provide the modulated packets to the antennas for transmission, and to demodulate packets received from the antennas. In some cases, the wireless device may include a single antenna 1725. However, in some cases the device may have more than one antenna 1725, which may be capable of concurrently transmitting or receiving multiple wireless transmissions.

The memory 1730 may include RAM and ROM. The memory 1730 may store computer-readable, computer-executable code 1735 including instructions that, when executed, cause the processor to perform various functions described herein. In some cases, the memory 1730 may contain, among other things, a BIOS which may control basic hardware or software operation such as the interaction with peripheral components or devices.

The processor 1740 may include an intelligent hardware device, (e.g., a general-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof) . In some cases, the processor 1740 may be configured to operate a memory array using a memory controller. In other cases, a memory controller may be integrated into the processor 1740. The processor 1740 may be configured to execute computer-readable instructions stored in a memory (e.g., the memory 1730) to cause the device 1705 to perform various functions (e.g., functions or tasks supporting measurement-based DC and CA activation) .

The code 1735 may include instructions to implement aspects of the present disclosure, including instructions to support wireless communications. The code 1735 may be stored in a non-transitory computer-readable medium such as system memory or other type of memory. In some cases, the code 1735 may not be directly executable by the processor 1740 but may cause a computer (e.g., when compiled and executed) to perform functions described herein.

FIG. 18 shows a block diagram 1800 of a device 1805 that supports measurement-based DC and CA activation in accordance with aspects of the present disclosure. The device 1805 may be an example of aspects of a base station 105 as described herein. The device 1805 may include a receiver 1810, a base station communications manager 1815, and a transmitter 1820. The device 1805 may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses) .

The receiver 1810 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to measurement-based DC and CA activation, etc. ) . Information may be passed on to other components of the device 1805. The receiver 1810 may be an example of aspects of the transceiver 2120 described with reference to FIG. 21. The receiver 1810 may utilize a single antenna or a set of antennas.

The base station communications manager 1815 may communicate with a UE 115 using a first lower-layer configuration for a first cell of the base station 105, store the first lower-layer configuration based on a determination that the UE 115 has transitioned to an inactive communication state, determine a current lower-layer configuration for at least one of the first cell or a second cell, receive, from the UE 115, a request to resume communications, the request including an indication of whether one or more measurement reports are available at the UE 115, and transmit, to the UE 115, a reconfiguration message that indicates a difference between a current lower-layer configuration and at least one of the stored first lower-layer configuration or a second lower-layer configuration for the second cell. The base station communications manager 1815 may also communicate with a UE 115 using a lower-layer configuration for a cell of the base station 105, where the cell is from an SCG of a DC deployment, store the first lower-layer configuration based on a determination that the UE 115 has transitioned to an inactive communication state, and receive, from the UE 115, a request to resume communications, the request including an indication of whether one or more measurement reports are available at the UE 115. The base station communications manager 1815 may be an example of aspects of the base station communications manager 2110 described herein.

The base station communications manager 1815, or its sub-components, may be implemented in hardware, code (e.g., software or firmware) executed by a processor, or any combination thereof. If implemented in code executed by a processor, the functions of the base station communications manager 1815, or its sub-components may be executed by a general-purpose processor, a DSP, an application-specific integrated circuit (ASIC) , a FPGA or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described in the present disclosure.

The base station communications manager 1815, or its sub-components, may be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations by one or more physical components. In some examples, the base station communications manager 1815, or its sub-components, may be a separate and distinct component in accordance with various aspects of the present disclosure. In some examples, the base station communications manager 1815, or its sub-components, may be combined with one or more other hardware components, including but not limited to an input/output (I/O) component, a transceiver, a network server, another computing device, one or more other components described in the present disclosure, or a combination thereof in accordance with various aspects of the present disclosure.

The transmitter 1820 may transmit signals generated by other components of the device 1805. In some examples, the transmitter 1820 may be collocated with a receiver 1810 in a transceiver module. For example, the transmitter 1820 may be an example of aspects of the transceiver 2120 described with reference to FIG. 21. The transmitter 1820 may utilize a single antenna or a set of antennas.

FIG. 19 shows a block diagram 1900 of a device 1905 that supports measurement-based DC and CA activation in accordance with aspects of the present disclosure. The device 1905 may be an example of aspects of a device 1805, or a base station 105 as described herein. The device 1905 may include a receiver 1910, a base station communications manager 1915, and a transmitter 1945. The device 1905 may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses) .

The receiver 1910 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to measurement-based DC and CA activation, etc. ) . Information may be passed on to other components of the device 1905. The receiver 1910 may be an example of aspects of the transceiver 2120 described with reference to FIG. 21. The receiver 1910 may utilize a single antenna or a set of antennas.

The base station communications manager 1915 may be an example of aspects of the base station communications manager 1815 as described herein. The base station communications manager 1915 may include a cell communications manager 1920, a lower-layer configuration manager 1925, a communications resumption manager 1930, a reconfiguration component 1935, and a secondary cell component 1940. The base station communications manager 1915 may be an example of aspects of the base station communications manager 2110 described herein.

The cell communications manager 1920 may communicate with a UE 115 using a first lower-layer configuration for a first cell of the base station 105. The lower-layer configuration manager 1925 may store the first lower-layer configuration based on a determination that the UE 115 has transitioned to an inactive communication state and determine a current lower-layer configuration for at least one of the first cell or a second cell.

The communications resumption manager 1930 may receive, from the UE 115, a request to resume communications, the request including an indication of whether one or more measurement reports are available at the UE 115. The reconfiguration component 1935 may transmit, to the UE 115, a reconfiguration message that indicates a difference between a current lower-layer configuration and at least one of the stored first lower-layer configuration or a second lower-layer configuration for the second cell.

The secondary cell component 1940 may communicate with a UE 115 using a lower-layer configuration for a cell of the base station 105, where the cell is from an SCG of a DC deployment. The lower-layer configuration manager 1925 may store the first lower- layer configuration based on a determination that the UE 115 has transitioned to an inactive communication state.

The transmitter 1945 may transmit signals generated by other components of the device 1905. In some examples, the transmitter 1945 may be collocated with a receiver 1910 in a transceiver module. For example, the transmitter 1945 may be an example of aspects of the transceiver 2120 described with reference to FIG. 21. The transmitter 1945 may utilize a single antenna or a set of antennas.

FIG. 20 shows a block diagram 2000 of a base station communications manager 2005 that supports measurement-based DC and CA activation in accordance with aspects of the present disclosure. The base station communications manager 2005 may be an example of aspects of a base station communications manager 1815, a base station communications manager 1915, or a base station communications manager 2110 described herein. The base station communications manager 2005 may include a cell communications manager 2010, a lower-layer configuration manager 2015, a communications resumption manager 2020, a reconfiguration component 2025, a measurement receiving component 2030, a node management component 2035, and a secondary cell component 2040. Each of these modules may communicate, directly or indirectly, with one another (e.g., via one or more buses) .

The cell communications manager 2010 may communicate with a UE 115 using a first lower-layer configuration for a first cell of the base station 105. In some cases, the cell is from an MCG of a DC deployment and the second cell is from a previously-serving SCG of the DC deployment. In some examples, the cell communications manager 2010 may activate the second cell based at least in part on a measurement report for the second cell.

The lower-layer configuration manager 2015 may store the first lower-layer configuration based on a determination that the UE 115 has transitioned to an inactive communication state. In some examples, the lower-layer configuration manager 2015 may determine a current lower-layer configuration for at least one of the first cell or a second cell. In some examples, the lower-layer configuration manager 2015 may store the first lower-layer configuration based on a determination that the UE 115 has transitioned to an inactive communication state. In some examples, the lower-layer configuration manager 2015 may determine a current lower-layer configuration for the cell.

The communications resumption manager 2020 may receive, from the UE 115, a request to resume communications, the request including an indication of whether one or more measurement reports are available at the UE 115. In some examples, the communications resumption manager 2020 may receive, from the UE 115, a request to resume communications, the request including an indication of whether one or more measurement reports are available at the UE 115. The reconfiguration component 2025 may transmit, to the UE 115, a reconfiguration message that indicates a difference between a current lower-layer configuration and at least one of the stored first lower-layer configuration or a second lower-layer configuration for the second cell.

In some examples, the reconfiguration component 2025 may receive, from the second base station 105, an indication of the second lower-layer configuration for the second cell, where determining the current lower-layer configuration is based on the received indication. In some examples, the reconfiguration component 2025 may transmit, to the UE 115, a reconfiguration message that indicates a difference between the current lower-layer configuration and at least one of the stored lower-layer configuration or a second lower-layer configuration for a second cell provided by a second base station 105, where the second cell is from an MCG of the DC deployment. In some cases, the reconfiguration message is transmitted via the signaling radio bearer associated with the second cell.

The measurement receiving component 2030 may receive an indication that a measurement report for the second cell is available based on measurements performed by the UE 115 while in the inactive communication state, the method further including. In some examples, the measurement receiving component 2030 may receive an indication that a measurement report for a third cell is available based on measurements performed by the UE 115 while in the inactive communication state, the method further including.

In some examples, the measurement receiving component 2030 may receive, via a signaling radio bearer associated with the second cell, an indication that a measurement report for a third cell is available based on measurements performed by the UE 115 while in the inactive communication state. In some examples, the measurement receiving component 2030 may receive an indication that measurement reports for one or more other cells are unavailable based on measurements performed by the UE 115 while in the inactive communication state, the method further including.

In some examples, the measurement receiving component 2030 may receive an indication that a measurement report for the second cell is available based on measurements performed by the UE 115 while in the inactive communication state, the method further including. In some examples, the measurement receiving component 2030 may receive an indication that a measurement report for a third cell is available based on measurements performed by the UE 115 while in the inactive communication state, the method further including.

In some examples, the measurement receiving component 2030 may receive an indication that measurement reports for one or more other cells are unavailable based on measurements performed by the UE 115 while in the inactive communication state, the method further including. In some cases, the indication that the measurement report for the second cell is received via a signaling radio bearer associated with the second cell, and where the reconfiguration message is transmitted via the signaling radio bearer associated with the second cell.

The node management component 2035 may transmit, as part of the secondary node addition request, an indication of the second lower-layer configuration to the target base station 105. In some examples, node management component 2035 may transmit, to a third base station 105 providing the third cell, a handover request based on the measurement report for the third cell, where the handover request includes an indication of the stored first lower-layer configuration for the first cell.

In some examples, node management component 2035 may transmit, based at least in part on the measurement report for the second cell, a context request to the second base station 105, the context request comprising an indication to exchange a master node and the secondary node. In some examples, node management component 2035 may receive, from the second base station 105, an indication of the second lower-layer configuration, wherein the reconfiguration message indicates a difference between a current lower-layer configuration for the cell and the second lower-layer configuration for the second cell.

In some examples, node management component 2035 may transmit, to a third base station 105 providing the third cell, an indication of the stored lower-layer configuration, wherein the reconfiguration message indicates a difference between a current lower-layer configuration for the cell and the second lower-layer configuration for the second cell. In some examples, node management component 2035 may transmit, to the second base station 105, a secondary node release request based at least in part on the unavailability of the measurement reports. In some examples, node management component 2035 may transmit, to the second base station 105, a handover request based at least in part on the unavailability of the measurement reports.

The secondary cell component 2040 may communicate with a UE 115 using a lower-layer configuration for a cell of the base station 105, where the cell is from an SCG of a DC deployment. In some examples, the secondary cell component 2040 may transmit, to a target base station 105 providing the third cell, a secondary node addition request based at least in part on the measurement report for the third cell. In some cases, the secondary cell component 2040 may transmit, to a second base station 105 providing the second cell, a secondary node release request, wherein the second cell is from a previously-serving SCG of a DC deployment. Additionally or alternatively, the secondary cell component 2040 may transmit, to a second base station 105 providing the second cell, a secondary node release request based at least in part on the unavailability of the measurement reports.

FIG. 21 shows a diagram of a system 2100 including a device 2105 that supports measurement-based DC and CA activation in accordance with aspects of the present disclosure. The device 2105 may be an example of or include the components of device 1805, device 1905, or a base station 105 as described herein. The device 2105 may include components for bi-directional voice and data communications including components for transmitting and receiving communications, including a base station communications manager 2110, a network communications manager 2115, a transceiver 2120, an antenna 2125, memory 2130, a processor 2140, and an inter-station communications manager 2145. These components may be in electronic communication via one or more buses (e.g., bus 2150) .

The base station communications manager 2110 may communicate with a UE 115 using a first lower-layer configuration for a first cell of the base station 105, store the first lower-layer configuration based on a determination that the UE 115 has transitioned to an inactive communication state, determine a current lower-layer configuration for at least one of the first cell or a second cell, receive, from the UE 115, a request to resume communications, the request including an indication of whether one or more measurement reports are available at the UE 115, and transmit, to the UE 115, a reconfiguration message that indicates a difference between a current lower-layer configuration and at least one of the stored first lower-layer configuration or a second lower-layer configuration for the second cell. The base station communications manager 2110 may also communicate with a UE 115 using a lower-layer configuration for a cell of the base station 105, where the cell is from an SCG of a DC deployment, store the first lower-layer configuration based on a determination that the UE 115 has transitioned to an inactive communication state, and receive, from the UE 115, a request to resume communications, the request including an indication of whether one or more measurement reports are available at the UE 115.

The network communications manager 2115 may manage communications with the core network (e.g., via one or more wired backhaul links) . For example, the network communications manager 2115 may manage the transfer of data communications for client devices, such as one or more UEs 115.

The transceiver 2120 may communicate bi-directionally, via one or more antennas, wired, or wireless links as described herein. For example, the transceiver 2120 may represent a wireless transceiver and may communicate bi-directionally with another wireless transceiver. The transceiver 2120 may also include a modem to modulate the packets and provide the modulated packets to the antennas for transmission, and to demodulate packets received from the antennas. In some cases, the wireless device may include a single antenna 2125. However, in some cases the device may have more than one antenna 2125, which may be capable of concurrently transmitting or receiving multiple wireless transmissions.

The memory 2130 may include RAM, ROM, or a combination thereof. The memory 2130 may store computer-readable code 2135 including instructions that, when executed by a processor (e.g., the processor 2140) cause the device to perform various functions described herein. In some cases, the memory 2130 may contain, among other things, a BIOS which may control basic hardware or software operation such as the interaction with peripheral components or devices.

The processor 2140 may include an intelligent hardware device, (e.g., a general-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof) . In some cases, the processor 2140 may be configured to operate a memory array using a memory controller. In some cases, a memory controller may be integrated into processor 2140. The processor 2140 may be configured to execute computer-readable instructions stored in a memory (e.g., the memory 2130) to cause the device 2105 to perform various functions (e.g., functions or tasks supporting measurement-based DC and CA activation) .

The inter-station communications manager 2145 may manage communications with other base station 105, and may include a controller or scheduler for controlling communications with UEs 115 in cooperation with other base stations 105. For example, the inter-station communications manager 2145 may coordinate scheduling for transmissions to UEs 115 for various interference mitigation techniques such as beamforming or joint transmission. In some examples, the inter-station communications manager 2145 may provide an X2 interface within an LTE/LTE-Awireless communication network technology to provide communication between base stations 105.

The code 2135 may include instructions to implement aspects of the present disclosure, including instructions to support wireless communications. The code 2135 may be stored in a non-transitory computer-readable medium such as system memory or other type of memory. In some cases, the code 2135 may not be directly executable by the processor 2140 but may cause a computer (e.g., when compiled and executed) to perform functions described herein.

FIG. 22 shows a flowchart illustrating a method 2200 that supports measurement-based DC and CA activation in accordance with aspects of the present disclosure. The operations of method 2200 may be implemented by a UE 115 or its components as described herein. For example, the operations of method 2200 may be performed by a UE communications manager as described with reference to FIGs. 14 through 17. In some examples, a UE 115 may execute a set of instructions to control the functional elements of the UE 115 to perform the functions described herein. Additionally or alternatively, a UE 115 may perform aspects of the functions described herein using special-purpose hardware.

At 2205, the UE 115 may perform a state transition to an inactive communication state with a first cell and a second cell. The operations of 2205 may be performed according to the methods described herein. In some examples, aspects of the operations of 2205 may be performed by a communication state manager as described with reference to FIGs. 14 through 17.

At 2210, the UE 115 may store, based on the state transition to the inactive communication state, a first lower-layer configuration for the first cell and a second lower-layer configuration for the second cell. The operations of 2210 may be performed according to the methods described herein. In some examples, aspects of the operations of 2210 may be performed by a lower-layer configuration component as described with reference to FIGs. 14 through 17.

At 2215, the UE 115 may determine that communications with at least one of the first cell or the second cell are to resume. The operations of 2215 may be performed according to the methods described herein. In some examples, aspects of the operations of 2215 may be performed by a communication state manager as described with reference to FIGs. 14 through 17.

At 2220, the UE 115 may transmit, based on the determination, an indication of whether one or more measurement reports are available. The operations of 2220 may be performed according to the methods described herein. In some examples, aspects of the operations of 2220 may be performed by a measurement report manager as described with reference to FIGs. 14 through 17.

At 2225, the UE 115 may receive a reconfiguration message that indicates a difference between a current lower-layer configuration and at least one of the stored first lower-layer configuration or the second lower-layer configuration. The operations of 2225 may be performed according to the methods described herein. In some examples, aspects of the operations of 2225 may be performed by a lower-layer configuration component as described with reference to FIGs. 14 through 17.

FIG. 23 shows a flowchart illustrating a method 2300 that supports measurement-based DC and CA activation in accordance with aspects of the present disclosure. The operations of method 2300 may be implemented by a UE 115 or its components as described herein. For example, the operations of method 2300 may be performed by a UE communications manager as described with reference to FIGs. 14 through 17. In some examples, a UE 115 may execute a set of instructions to control the functional elements of the UE 115 to perform the functions described herein. Additionally or alternatively, a UE 115 may perform aspects of the functions described herein using special-purpose hardware.

At 2305, the UE 115 may perform a state transition to an inactive communication state with a first cell and a second cell. The operations of 2305 may be performed according to the methods described herein. In some examples, aspects of the operations of 2305 may be performed by a communication state manager as described with reference to FIGs. 14 through 17.

At 2310, the UE 115 may store, based on the state transition to the inactive communication state, a first lower-layer configuration for the first cell and a second lower-layer configuration for the second cell. The operations of 2310 may be performed according to the methods described herein. In some examples, aspects of the operations of 2310 may be performed by a lower-layer configuration component as described with reference to FIGs. 14 through 17.

At 2315, the UE 115 may determine that communications with at least one of the first cell or the second cell are to resume. The operations of 2315 may be performed according to the methods described herein. In some examples, aspects of the operations of 2315 may be performed by a communication state manager as described with reference to FIGs. 14 through 17.

At 2320, the UE 115 may transmit, via the first cell, an indication that a measurement report for the second cell is available based on measurements performed while in the inactive communication state. The operations of 2320 may be performed according to the methods described herein. In some examples, aspects of the operations of 2320 may be performed by a measurement report manager as described with reference to FIGs. 14 through 17.

At 2325, the UE 115 may receive a reconfiguration message that indicates a difference between a current lower-layer configuration and at least one of the stored first lower-layer configuration or the second lower-layer configuration. The operations of 2325 may be performed according to the methods described herein. In some examples, aspects of the operations of 2325 may be performed by a lower-layer configuration component as described with reference to FIGs. 14 through 17.

At 2330, the UE 115 may resume communications on the second cell based on the reconfiguration message indicating a difference between a current lower-layer configuration for the second cell and the stored second lower-layer configuration for the second cell, the difference being based at least in part on the measurement report for the second cell. The operations of 2330 may be performed according to the methods described herein. In some examples, aspects of the operations of 2330 may be performed by a communications resumption component as described with reference to FIGs. 14 through 17.

FIG. 24 shows a flowchart illustrating a method 2400 that supports measurement-based DC and CA activation in accordance with aspects of the present disclosure. The operations of method 2400 may be implemented by a UE 115 or its components as described herein. For example, the operations of method 2400 may be performed by a UE communications manager as described with reference to FIGs. 14 through 17. In some examples, a UE 115 may execute a set of instructions to control the functional elements of the UE 115 to perform the functions described herein. Additionally or alternatively, a UE 115 may perform aspects of the functions described herein using special-purpose hardware.

At 2405, the UE 115 may perform a state transition to an inactive communication state with a first cell and a second cell. The operations of 2405 may be performed according to the methods described herein. In some examples, aspects of the operations of 2405 may be performed by a communication state manager as described with reference to FIGs. 14 through 17.

At 2410, the UE 115 may store, based on the state transition to the inactive communication state, a first lower-layer configuration for the first cell and a second lower-layer configuration for the second cell. The operations of 2410 may be performed according to the methods described herein. In some examples, aspects of the operations of 2410 may be performed by a lower-layer configuration component as described with reference to FIGs. 14 through 17.

At 2415, the UE 115 may determine that communications with at least one of the first cell or the second cell are to resume. The operations of 2415 may be performed according to the methods described herein. In some examples, aspects of the operations of 2415 may be performed by a communication state manager as described with reference to FIGs. 14 through 17.

At 2420, the UE 115 may transmit, via the first cell, an indication that a measurement report for a third cell is available based on measurements performed by the UE 115 while in the inactive communication state. The operations of 2420 may be performed according to the methods described herein. In some examples, aspects of the operations of 2420 may be performed by a measurement report manager as described with reference to FIGs. 14 through 17.

At 2425, the UE 115 may receive a reconfiguration message that indicates a difference between a current lower-layer configuration and at least one of the stored first lower-layer configuration or the second lower-layer configuration. The operations of 2425 may be performed according to the methods described herein. In some examples, aspects of the operations of 2425 may be performed by a lower-layer configuration component as described with reference to FIGs. 14 through 17.

At 2430, the UE 115 may communicate on the third cell based on the reconfiguration message indicating a difference between a current lower-layer configuration for the third cell and the stored second lower-layer configuration for the second cell, the difference being based at least in part on the measurement report for the third cell. The operations of 2430 may be performed according to the methods described herein. In some examples, aspects of the operations of 2430 may be performed by a communications resumption component as described with reference to FIGs. 14 through 17.

FIG. 25 shows a flowchart illustrating a method 2500 that supports measurement-based DC and CA activation in accordance with aspects of the present disclosure. The operations of method 2500 may be implemented by a UE 115 or its components as described herein. For example, the operations of method 2500 may be performed by a UE communications manager as described with reference to FIGs. 14 through 17. In some examples, a UE 115 may execute a set of instructions to control the functional elements of the UE 115 to perform the functions described herein. Additionally or alternatively, a UE 115 may perform aspects of the functions described herein using special-purpose hardware.

At 2505, the UE 115 may perform a state transition to an inactive communication state with a first cell and a second cell. The operations of 2505 may be performed according to the methods described herein. In some examples, aspects of the operations of 2505 may be performed by a communication state manager as described with reference to FIGs. 14 through 17.

At 2510, the UE 115 may store, based on the state transition to the inactive communication state, a first lower-layer configuration for the first cell and a second lower-layer configuration for the second cell. The operations of 2510 may be performed according to the methods described herein. In some examples, aspects of the operations of 2510 may be performed by a lower-layer configuration component as described with reference to FIGs. 14 through 17.

At 2515, the UE 115 may determine that communications with at least one of the first cell or the second cell are to resume. The operations of 2515 may be performed according to the methods described herein. In some examples, aspects of the operations of 2515 may be performed by a communication state manager as described with reference to FIGs. 14 through 17.

At 2520, the UE 115 may transmit, to the first cell, an indication that measurement reports for one or more cells are unavailable based on measurements performed while in the inactive communication state. The operations of 2520 may be performed according to the methods described herein. In some examples, aspects of the operations of 2520 may be performed by a measurement report manager as described with reference to FIGs. 14 through 17.

At 2525, the UE 115 may receive a reconfiguration message that indicates a difference between a current lower-layer configuration and at least one of the stored first lower-layer configuration or the second lower-layer configuration. The operations of 2525 may be performed according to the methods described herein. In some examples, aspects of the operations of 2525 may be performed by a lower-layer configuration component as described with reference to FIGs. 14 through 17.

At 2530, the UE 115 may refrain from communicating with the second cell based at least in part on the reconfiguration message, where the reconfiguration message indicates that the second cell has been released based on the unavailability of the measurement reports. The operations of 2530 may be performed according to the methods described herein. In some examples, aspects of the operations of 2530 may be performed by a communications resumption component as described with reference to FIGs. 14 through 17.

FIG. 26 shows a flowchart illustrating a method 2600 that supports measurement-based DC and CA activation in accordance with aspects of the present disclosure. The operations of method 2600 may be implemented by a base station 105 or its components as described herein. For example, the operations of method 2600 may be performed by a base station communications manager as described with reference to FIGs. 18 through 21. In some examples, a base station 105 may execute a set of instructions to control the functional elements of the base station 105 to perform the functions described herein. Additionally or alternatively, a base station 105 may perform aspects of the functions described herein using special-purpose hardware.

At 2605, the base station 105 may communicate with a UE 115 using a first lower-layer configuration for a first cell of the base station 105. The operations of 2605 may be performed according to the methods described herein. In some examples, aspects of the operations of 2605 may be performed by a cell communications manager as described with reference to FIGs. 18 through 21.

At 2610, the base station 105 may store the first lower-layer configuration based on a determination that the UE 115 has transitioned to an inactive communication state. The operations of 2610 may be performed according to the methods described herein. In some examples, aspects of the operations of 2610 may be performed by a lower-layer configuration manager as described with reference to FIGs. 18 through 21.

At 2615, the base station 105 may receive, from the UE 115, a request to resume communications, the request including an indication of whether one or more measurement reports are available at the UE 115. The operations of 2615 may be performed according to the methods described herein. In some examples, aspects of the operations of 2615 may be performed by a communications resumption manager as described with reference to FIGs. 18 through 21.

At 2620, the base station 105 may determine a current lower-layer configuration for at least one of the first cell or a second cell. The operations of 2620 may be performed according to the methods described herein. In some examples, aspects of the operations of 2620 may be performed by a lower-layer configuration manager as described with reference to FIGs. 18 through 21.

At 2625, the base station 105 may transmit, to the UE 115, a reconfiguration message that indicates a difference between a current lower-layer configuration and at least one of the stored first lower-layer configuration or a second lower-layer configuration for the second cell. The operations of 2625 may be performed according to the methods described herein. In some examples, aspects of the operations of 2625 may be performed by a reconfiguration component as described with reference to FIGs. 18 through 21.

FIG. 27 shows a flowchart illustrating a method 2700 that supports measurement-based DC and CA activation in accordance with aspects of the present disclosure. The operations of method 2700 may be implemented by a base station 105 or its components as described herein. For example, the operations of method 2700 may be performed by a base station communications manager as described with reference to FIGs. 18 through 21. In some examples, a base station 105 may execute a set of instructions to control the functional elements of the base station 105 to perform the functions described herein. Additionally or alternatively, a base station 105 may perform aspects of the functions described herein using special-purpose hardware.

At 2705, the base station 105 may communicate with a UE 115 using a lower-layer configuration for a cell of the base station 105, where the cell is from an SCG of a DC deployment. The operations of 2705 may be performed according to the methods described herein. In some examples, aspects of the operations of 2705 may be performed by a secondary cell component as described with reference to FIGs. 18 through 21.

At 2710, the base station 105 may store the first lower-layer configuration based on a determination that the UE 115 has transitioned to an inactive communication state. The operations of 2710 may be performed according to the methods described herein. In some examples, aspects of the operations of 2710 may be performed by a lower-layer configuration manager as described with reference to FIGs. 18 through 21.

At 2715, the base station 105 may receive, from the UE 115, a request to resume communications, the request including an indication of whether one or more measurement reports are available at the UE 115. The operations of 2715 may be performed according to the methods described herein. In some examples, aspects of the operations of 2715 may be performed by a communications resumption manager as described with reference to FIGs. 18 through 21.

It should be noted that the methods described herein describe possible implementations, and that the operations and the steps may be rearranged or otherwise modified and that other implementations are possible. Further, aspects from two or more of the methods may be combined.

Techniques described herein may be used for various wireless communications systems such as code division multiple access (CDMA) , time division multiple access (TDMA) , frequency division multiple access (FDMA) , orthogonal frequency division multiple access (OFDMA) , single carrier frequency division multiple access (SC-FDMA) , and other systems. A CDMA system may implement a radio technology such as CDMA2000, Universal Terrestrial Radio Access (UTRA) , etc. CDMA2000 covers IS-2000, IS-95, and IS-856 standards. IS-2000 Releases may be commonly referred to as CDMA2000 1X, 1X, etc. IS-856 (TIA-856) is commonly referred to as CDMA2000 1xEV-DO, High Rate Packet Data (HRPD) , etc. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. A TDMA system may implement a radio technology such as Global System for Mobile Communications (GSM) .

An OFDMA system may implement a radio technology such as Ultra Mobile Broadband (UMB) , Evolved UTRA (E-UTRA) , Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi) , IEEE 802.16 (WiMAX) , IEEE 802.20, Flash-OFDM, etc. UTRA and E-UTRA are part of Universal Mobile Telecommunications System (UMTS) . LTE, LTE-A, and LTE-A Pro are releases of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A, LTE-A Pro, NR, and GSM are described in documents from the organization named “3rd Generation Partnership Project” (3GPP) . CDMA2000 and UMB are described in documents from an organization named “3rd Generation Partnership Project 2” (3GPP2) . The techniques described herein may be used for the systems and radio technologies mentioned herein as well as other systems and radio technologies. While aspects of an LTE, LTE-A, LTE-A Pro, or NR system may be described for purposes of example, and LTE, LTE-A, LTE-A Pro, or NR terminology may be used in much of the description, the techniques described herein are applicable beyond LTE, LTE-A, LTE-A Pro, or NR applications.

A macro cell generally covers a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by UEs with service subscriptions with the network provider. A small cell may be associated with a lower-powered base station, as compared with a macro cell, and a small cell may operate in the same or different (e.g., licensed, unlicensed, etc. ) frequency bands as macro cells. Small cells may include pico cells, femto cells, and micro cells according to various examples. A pico cell, for example, may cover a small geographic area and may allow unrestricted access by UEs with service subscriptions with the network provider. A femto cell may also cover a small geographic area (e.g., a home) and may provide restricted access by UEs having an association with the femto cell (e.g., UEs in a closed subscriber group (CSG) , UEs for users in the home, and the like) . An eNB for a macro cell may be referred to as a macro eNB. An eNB for a small cell may be referred to as a small cell eNB, a pico eNB, a femto eNB, or a home eNB. An eNB may support one or multiple (e.g., two, three, four, and the like) cells, and may also support communications using one or multiple component carriers.

The wireless communications systems described herein may support synchronous or asynchronous operation. For synchronous operation, the base stations may have similar frame timing, and transmissions from different base stations may be approximately aligned in time. For asynchronous operation, the base stations may have different frame timing, and transmissions from different base stations may not be aligned in time. The techniques described herein may be used for either synchronous or asynchronous operations.

Information and signals described herein may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

The various illustrative blocks and modules described in connection with the disclosure herein may be implemented or performed with a general-purpose processor, a DSP, an ASIC, an FPGA, or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration) .

The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Other examples and implementations are within the scope of the disclosure and appended claims. For example, due to the nature of software, functions described herein can be implemented using software executed by a processor, hardware, firmware, hardwiring, or combinations of any of these. Features implementing functions may also be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations.

Computer-readable media includes both non-transitory computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A non-transitory storage medium may be any available medium that can be accessed by a general purpose or special purpose computer. By way of example, and not limitation, non-transitory computer-readable media may include random-access memory (RAM) , read-only memory (ROM) , electrically erasable programmable ROM (EEPROM) , flash memory, compact disk (CD) ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other non-transitory medium that can be used to carry or store desired program code means in the form of instructions or data structures and that can be accessed by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor. Also, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL) , or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. Disk and disc, as used herein, include CD, laser disc, optical disc, digital versatile disc (DVD) , floppy disk and Blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above are also included within the scope of computer-readable media.

As used herein, including in the claims, “or” as used in a list of items (e.g., a list of items prefaced by a phrase such as “at least one of” or “one or more of” ) indicates an inclusive list such that, for example, a list of at least one of A, B, or C means A or B or C or AB or AC or BC or ABC (i.e., A and B and C) . Also, as used herein, the phrase “based on” shall not be construed as a reference to a closed set of conditions. For example, an exemplary step that is described as “based on condition A” may be based on both a condition A and a condition B without departing from the scope of the present disclosure. In other words, as used herein, the phrase “based on” shall be construed in the same manner as the phrase “based at least in part on. ”

In the appended figures, similar components or features may have the same reference label. Further, various components of the same type may be distinguished by following the reference label by a dash and a second label that distinguishes among the similar components. If just the first reference label is used in the specification, the description is applicable to any one of the similar components having the same first reference label irrespective of the second reference label, or other subsequent reference label.

The description set forth herein, in connection with the appended drawings, describes example configurations and does not represent all the examples that may be implemented or that are within the scope of the claims. The term “exemplary” used herein means “serving as an example, instance, or illustration, ” and not “preferred” or “advantageous over other examples. ” The detailed description includes specific details for the purpose of providing an understanding of the described techniques. These techniques, however, may be practiced without these specific details. In some instances, well-known structures and devices are shown in block diagram form in order to avoid obscuring the concepts of the described examples.

The description herein is provided to enable a person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other variations without departing from the scope of the disclosure. Thus, the disclosure is not limited to the examples and designs described herein, but is to be accorded the broadest scope consistent with the principles and novel features disclosed herein.

Claims

A method for wireless communication at a user equipment (UE) , comprising:

performing a state transition to an inactive communication state with a first cell and a second cell;

storing, based at least in part on the state transition to the inactive communication state, a first lower-layer configuration for the first cell and a second lower-layer configuration for the second cell;

determining that communications with at least one of the first cell or the second cell are to resume;

transmitting, based at least in part on the determination, an indication of whether one or more measurement reports are available; and

receiving a reconfiguration message that indicates a difference between a current lower-layer configuration and at least one of the stored first lower-layer configuration or the second lower-layer configuration.
The method of claim 1, wherein transmitting the indication of whether the one or more measurement reports are available comprises:

transmitting, via the first cell, an indication that a measurement report for the second cell is available based at least in part on measurements performed by the UE while in the inactive communication state, the method further comprising:

resuming communications on the second cell based at least in part on the reconfiguration message indicating a difference between a current lower-layer configuration for the second cell and the stored second lower-layer configuration for the second cell, the difference being based at least in part on the measurement report for the second cell.
The method of claim 2, further comprising:

resuming communications on the first cell, wherein the first cell is from a master cell group associated with a master node of a dual connectivity deployment, and wherein the second cell is from a secondary cell group associated with a secondary node of the dual connectivity deployment.
The method of claim 2, further comprising:

resuming communications on the first cell, wherein the first cell is from a previously-serving secondary cell group associated with a previously-serving secondary node of a dual connectivity deployment, and wherein the second cell is from a previously-serving master cell group associated with a previously-serving master node of the dual connectivity deployment.
The method of claim 1, wherein transmitting the indication of whether the one or more measurement reports are available comprises:

transmitting, via the first cell, an indication that a measurement report for a third cell is available based at least in part on measurements performed by the UE while in the inactive communication state, the method further comprising:

communicating on the third cell based at least in part on the reconfiguration message indicating a difference between a current lower-layer configuration for the third cell and the stored second lower-layer configuration for the second cell, the difference being based at least in part on the measurement report for the third cell.
The method of claim 5, further comprising:

resuming communications on the first cell, wherein the first cell is from a master cell group associated with a master node of a dual connectivity deployment, and wherein the second cell is from a previously-serving secondary cell group associated with a previously-serving secondary node of the dual connectivity deployment; and

communicating on the third cell as part of a currently-serving secondary cell group associated with a currently-serving secondary node of the dual connectivity deployment.
The method of claim 5, further comprising:

resuming communications on the first cell, wherein the first cell is from a currently-serving master cell group associated with a currently-serving master node of a dual connectivity deployment, and wherein the second cell is from a previously-serving master cell group associated with a previously-serving master node of the dual connectivity deployment; and

communicating on the third cell as part of a currently-serving secondary cell group associated with a secondary node of the dual connectivity deployment.
The method of claim 5, wherein the indication that the measurement report for the third cell is available is transmitted via a signaling radio bearer associated with the second cell, and wherein the reconfiguration message is received on the signaling radio bearer associated with the second cell.
The method of claim 8, further comprising:

resuming communications on the first cell, wherein the first cell is from a previously-serving secondary cell group associated with a previously-serving secondary node of a dual connectivity deployment, and wherein the first cell is from a previously-serving master cell group associated with a previously-serving master node of the dual connectivity deployment; and

communicating on the third cell as part of a currently-serving master cell group of a currently-serving master node of the dual connectivity deployment.
The method of claim 1, wherein transmitting the indication of whether the one or more measurement reports are available comprises:

transmitting, to the first cell, an indication that measurement reports for one or more cells are unavailable based at least in part on measurements performed by the UE while in the inactive communication state, the method further comprising:

refraining from communicating with the second cell based at least in part on the reconfiguration message, wherein the reconfiguration message indicates that the second cell has been released based at least in part on the unavailability of the measurement reports.
The method of claim 10, further comprising:

resuming communications on the first cell, wherein the first cell is from a master cell group associated with a master node of a dual connectivity deployment, and wherein the second cell is from a previously-serving secondary cell group associated with a previously-serving secondary node of the dual connectivity deployment.
The method of claim 10, further comprising:

resuming communications on the first cell, wherein the first cell is from a previously-serving secondary cell group associated with a secondary node of a dual connectivity deployment, and wherein the second cell is from a previously-serving master cell group associated with a previously-serving master node of the dual connectivity deployment.
The method of claim 1, wherein transmitting the indication of whether the one or more measurement reports are available comprises:

transmitting, to the first cell and via a signaling radio bearer associated with the second cell, an indication that a measurement report for the first cell and the second cell is available based at least in part on measurements performed by the UE while in the inactive communication state, the method further comprising:

resuming communications with the second cell based at least in part on the reconfiguration message indicating a difference between a current lower-layer configuration for the second cell and the stored second lower-layer configuration for the second cell, the difference being based at least in part on the measurement report for the second cell.
The method of claim 13, wherein the reconfiguration message is received via the signaling radio bearer associated with the second cell.
The method of claim 13, further comprising:

resuming communications on the first cell, wherein the first cell is from a master cell group associated with a master node of a dual connectivity deployment, and wherein the second cell is from a secondary cell group associated with a secondary node of the dual connectivity deployment.
The method of claim 1, wherein the first cell comprises a primary cell of a carrier aggregation deployment and the second cell comprises a secondary cell of the carrier aggregation deployment.
A method for wireless communication at a base station, comprising:

communicating with a user equipment (UE) using a first lower-layer configuration for a first cell of the base station;

storing the first lower-layer configuration based at least in part on a determination that the UE has transitioned to an inactive communication state;

receiving, from the UE, a request to resume communications, the request comprising an indication of whether one or more measurement reports are available at the UE;

determining a current lower-layer configuration for at least one of the first cell or a second cell; and

transmitting, to the UE, a reconfiguration message that indicates a difference between a current lower-layer configuration and at least one of the stored first lower-layer configuration or a second lower-layer configuration for the second cell.
The method of claim 17, wherein receiving the indication of whether the one or more measurement reports are available comprises:

receiving an indication that a measurement report for the second cell is available based at least in part on measurements performed by the UE while in the inactive communication state, the method further comprising:

activating the second cell based at least in part on the measurement report for the second cell.
The method of claim 18, wherein the indication that the measurement report for the second cell is received via a signaling radio bearer associated with the second cell, and wherein the reconfiguration message is transmitted via the signaling radio bearer associated with the second cell.
The method of claim 18, wherein the cell is from a master cell group of a dual connectivity deployment and the second cell is from a previously-serving secondary cell group of the dual connectivity deployment.
The method of claim 17, wherein receiving the indication of whether the one or more measurement reports are available comprises:

receiving an indication that a measurement report for a third cell is available based at least in part on measurements performed by the UE while in the inactive communication state, the method further comprising:

transmitting, to a target base station providing the third cell, a secondary node addition request based at least in part on the measurement report for the third cell; and

transmitting, to a second base station providing the second cell, a secondary node release request, wherein the second cell is from a previously-serving secondary cell group of a dual connectivity deployment.
The method of claim 21, further comprising:

receiving, from the second base station, an indication of the second lower-layer configuration for the second cell, wherein determining the current lower-layer configuration is based at least in part on the received indication; and

transmitting, as part of the secondary node addition request, an indication of the second lower-layer configuration to the target base station.
The method of claim 17, wherein receiving the indication of whether the one or more measurement reports are available comprises:

receiving, via a signaling radio bearer associated with the second cell, an indication that a measurement report for a third cell is available based at least in part on measurements performed by the UE while in the inactive communication state; and

transmitting, to a third base station providing the third cell, a handover request based at least in part on the measurement report for the third cell, wherein the handover request comprises an indication of the stored first lower-layer configuration for the first cell.
The method of claim 23, wherein the reconfiguration message is transmitted via the signaling radio bearer associated with the second cell.
The method of claim 17, wherein receiving the indication of whether the one or more measurement reports are available comprises:

receiving an indication that measurement reports for one or more other cells are unavailable based at least in part on measurements performed by the UE while in the inactive communication state, the method further comprising:

transmitting, to a second base station providing the second cell, a secondary node release request based at least in part on the unavailability of the measurement reports.
A method for wireless communication at a base station, comprising:

communicating with a user equipment (UE) using a lower-layer configuration for a cell of the base station, wherein the cell is from a secondary cell group of a dual connectivity deployment;

storing the first lower-layer configuration based at least in part on a determination that the UE has transitioned to an inactive communication state; and

receiving, from the UE, a request to resume communications, the request comprising an indication of whether one or more measurement reports are available at the UE.
The method of claim 26, further comprising:

determining a current lower-layer configuration for the cell; and

transmitting, to the UE, a reconfiguration message that indicates a difference between the current lower-layer configuration and at least one of the stored lower-layer configuration or a second lower-layer configuration for a second cell provided by a second base station, wherein the second cell is from a master cell group of the dual connectivity deployment.
The method of claim 27, wherein receiving the indication of whether the one or more measurement reports are available comprises:

receiving an indication that a measurement report for the second cell is available based at least in part on measurements performed by the UE while in the inactive communication state, the method further comprising:

transmitting, based at least in part on the measurement report for the second cell, a context request to the second base station, the context request comprising an indication to exchange a master node and the secondary node; and

receiving, from the second base station, an indication of the second lower-layer configuration, wherein the reconfiguration message indicates a difference between a current lower-layer configuration for the cell and the second lower-layer configuration for the second cell.
The method of claim 27, wherein receiving the indication of whether the one or more measurement reports are available comprises:

receiving an indication that a measurement report for a third cell is available based at least in part on measurements performed by the UE while in the inactive communication state, the method further comprising:

transmitting, to a third base station providing the third cell, an indication of the stored lower-layer configuration, wherein the reconfiguration message indicates a difference between a current lower-layer configuration for the cell and the second lower-layer configuration for the second cell.
The method of claim 27, wherein receiving the indication of whether the one or more measurement reports are available comprises:

receiving an indication that measurement reports for one or more other cells are unavailable based at least in part on measurements performed by the UE while in the inactive communication state, the method further comprising:

transmitting, to the second base station, a secondary node release request based at least in part on the unavailability of the measurement reports.
The method of claim 27, wherein receiving the indication of whether the one or more measurement reports are available comprises:

receiving an indication that measurement reports for one or more other cells are unavailable based at least in part on measurements performed by the UE while in the inactive communication state, the method further comprising:

transmitting, to the second base station, a handover request based at least in part on the unavailability of the measurement reports.
An apparatus for wireless communication at a user equipment (UE) , comprising:

a processor,

memory in electronic communication with the processor; and

instructions stored in the memory and executable by the processor to cause the apparatus to:

perform a state transition to an inactive communication state with a first cell and a second cell;

store, based at least in part on the state transition to the inactive communication state, a first lower-layer configuration for the first cell and a second lower-layer configuration for the second cell;

determine that communications with at least one of the first cell or the second cell are to resume;

transmit, based at least in part on the determination, an indication of whether one or more measurement reports are available; and

receive a reconfiguration message that indicates a difference between a current lower-layer configuration and at least one of the stored first lower-layer configuration or the second lower-layer configuration.
The apparatus of claim 32, wherein the instructions to transmit the indication of whether the one or more measurement reports are available are executable by the processor to cause the apparatus to:

transmit, via the first cell, an indication that a measurement report for the second cell is available based at least in part on measurements performed by the UE while in the inactive communication state, the instructions being further executable by the processor to cause the apparatus to:

resume communications on the second cell based at least in part on the reconfiguration message indicating a difference between a current lower-layer configuration for the second cell and the stored second lower-layer configuration for the second cell, the difference being based at least in part on the measurement report for the second cell.
The apparatus of claim 33, wherein the instructions are further executable by the processor to cause the apparatus to:

resume communications on the first cell, wherein the first cell is from a master cell group associated with a master node of a dual connectivity deployment, and wherein the second cell is from a secondary cell group associated with a secondary node of the dual connectivity deployment.
The apparatus of claim 33, wherein the instructions are further executable by the processor to cause the apparatus to:

resume communications on the first cell, wherein the first cell is from a previously-serving secondary cell group associated with a previously-serving secondary node of a dual connectivity deployment, and wherein the second cell is from a previously-serving master cell group associated with a previously-serving master node of the dual connectivity deployment.
The apparatus of claim 32, wherein the instructions to transmit the indication of whether the one or more measurement reports are available are executable by the processor to cause the apparatus to:

transmit, via the first cell, an indication that a measurement report for a third cell is available based at least in part on measurements performed by the UE while in the inactive communication state, the instructions being further executable by the processor to cause the apparatus to:

communicate on the third cell based at least in part on the reconfiguration message indicating a difference between a current lower-layer configuration for the third cell and the stored second lower-layer configuration for the second cell, the difference being based at least in part on the measurement report for the third cell.
The apparatus of claim 36, wherein the instructions are further executable by the processor to cause the apparatus to:

resume communications on the first cell, wherein the first cell is from a master cell group associated with a master node of a dual connectivity deployment, and wherein the second cell is from a previously-serving secondary cell group associated with a previously-serving secondary node of the dual connectivity deployment; and

communicate on the third cell as part of a currently-serving secondary cell group associated with a currently-serving secondary node of the dual connectivity deployment.
The apparatus of claim 36, wherein the instructions are further executable by the processor to cause the apparatus to:

resume communications on the first cell, wherein the first cell is from a currently-serving master cell group associated with a currently-serving master node of a dual connectivity deployment, and wherein the second cell is from a previously-serving master cell group associated with a previously-serving master node of the dual connectivity deployment; and

communicate on the third cell as part of a currently-serving secondary cell group associated with a secondary node of the dual connectivity deployment.
The apparatus of claim 36, wherein the indication that the measurement report for the third cell is available is transmitted via a signaling radio bearer associated with the second cell, and wherein the reconfiguration message is received on the signaling radio bearer associated with the second cell.
The apparatus of claim 39, wherein the instructions are further executable by the processor to cause the apparatus to:

resume communications on the first cell, wherein the first cell is from a previously-serving secondary cell group associated with a previously-serving secondary node of a dual connectivity deployment, and wherein the first cell is from a previously-serving master cell group associated with a previously-serving master node of the dual connectivity deployment; and

communicate on the third cell as part of a currently-serving master cell group of a currently-serving master node of the dual connectivity deployment.
The apparatus of claim 32, wherein the instructions to transmit the indication of whether the one or more measurement reports are available are executable by the processor to cause the apparatus to:

transmit, to the first cell, an indication that measurement reports for one or more cells are unavailable based at least in part on measurements performed by the UE while in the inactive communication state, the instructions being further executable by the processor to cause the apparatus to:

refrain from communicating with the second cell based at least in part on the reconfiguration message, wherein the reconfiguration message indicates that the second cell has been released based at least in part on the unavailability of the measurement reports.
The apparatus of claim 41, wherein the instructions are further executable by the processor to cause the apparatus to:

resume communications on the first cell, wherein the first cell is from a master cell group associated with a master node of a dual connectivity deployment, and wherein the second cell is from a previously-serving secondary cell group associated with a previously-serving secondary node of the dual connectivity deployment.
The apparatus of claim 41, wherein the instructions are further executable by the processor to cause the apparatus to:

resume communications on the first cell, wherein the first cell is from a previously-serving secondary cell group associated with a secondary node of a dual connectivity deployment, and wherein the second cell is from a previously-serving master cell group associated with a previously-serving master node of the dual connectivity deployment.
The apparatus of claim 32, wherein the instructions to transmit the indication of whether the one or more measurement reports are available are executable by the processor to cause the apparatus to:

transmit, to the first cell and via a signaling radio bearer associated with the second cell, an indication that a measurement report for the first cell and the second cell is available based at least in part on measurements performed by the UE while in the inactive communication state, the instructions being further executable by the processor to cause the apparatus to:

resume communications with the second cell based at least in part on the reconfiguration message indicating a difference between a current lower-layer configuration for the second cell and the stored second lower-layer configuration for the second cell, the difference being based at least in part on the measurement report for the second cell.
The apparatus of claim 44, wherein the reconfiguration message is received via the signaling radio bearer associated with the second cell.
The apparatus of claim 44, wherein the instructions are further executable by the processor to cause the apparatus to:

resume communications on the first cell, wherein the first cell is from a master cell group associated with a master node of a dual connectivity deployment, and wherein the second cell is from a secondary cell group associated with a secondary node of the dual connectivity deployment.
The apparatus of claim 32, wherein the first cell comprises a primary cell of a carrier aggregation deployment and the second cell comprises a secondary cell of the carrier aggregation deployment.
An apparatus for wireless communication at a base station, comprising:

a processor,

memory in electronic communication with the processor; and

instructions stored in the memory and executable by the processor to cause the apparatus to:

communicate with a user equipment (UE) using a first lower-layer configuration for a first cell of the base station;

store the first lower-layer configuration based at least in part on a determination that the UE has transitioned to an inactive communication state;

receive, from the UE, a request to resume communications, the request comprising an indication of whether one or more measurement reports are available at the UE;

determine a current lower-layer configuration for at least one of the first cell or a second cell; and

transmit, to the UE, a reconfiguration message that indicates a difference between a current lower-layer configuration and at least one of the stored first lower-layer configuration or a second lower-layer configuration for the second cell.
The apparatus of claim 48, wherein the instructions to receive the indication of whether the one or more measurement reports are available are executable by the processor to cause the apparatus to:

receive an indication that a measurement report for the second cell is available based at least in part on measurements performed by the UE while in the inactive communication state, the instructions being further executable by the processor to cause the apparatus to:

activate the second cell based at least in part on the measurement report for the second cell.
The apparatus of claim 49, wherein the indication that the measurement report for the second cell is received via a signaling radio bearer associated with the second cell, and wherein the reconfiguration message is transmitted via the signaling radio bearer associated with the second cell.
The apparatus of claim 49, wherein the cell is from a master cell group of a dual connectivity deployment and the second cell is from a previously-serving secondary cell group of the dual connectivity deployment.
The apparatus of claim 48, wherein the instructions to receive the indication of whether the one or more measurement reports are available are executable by the processor to cause the apparatus to:

receive an indication that a measurement report for a third cell is available based at least in part on measurements performed by the UE while in the inactive communication state, the instructions being further executable by the processor to cause the apparatus to:

transmit, to a target base station providing the third cell, a secondary node addition request based at least in part on the measurement report for the third cell; and

transmit, to a second base station providing the second cell, a secondary node release request, wherein the second cell is from a previously-serving secondary cell group of a dual connectivity deployment.
The apparatus of claim 52, wherein the instructions are further executable by the processor to cause the apparatus to:

receive, from the second base station, an indication of the second lower-layer configuration for the second cell, wherein determining the current lower-layer configuration is based at least in part on the received indication; and

transmit, as part of the secondary node addition request, an indication of the second lower-layer configuration to the target base station.
The apparatus of claim 48, wherein the instructions to receive the indication of whether the one or more measurement reports are available are executable by the processor to cause the apparatus to:

receive, via a signaling radio bearer associated with the second cell, an indication that a measurement report for a third cell is available based at least in part on measurements performed by the UE while in the inactive communication state; and

transmit, to a third base station providing the third cell, a handover request based at least in part on the measurement report for the third cell, wherein the handover request comprises an indication of the stored first lower-layer configuration for the first cell.
The apparatus of claim 54, wherein the reconfiguration message is transmitted via the signaling radio bearer associated with the second cell.
The apparatus of claim 48, wherein the instructions to receive the indication of whether the one or more measurement reports are available are executable by the processor to cause the apparatus to:

receive an indication that measurement reports for one or more other cells are unavailable based at least in part on measurements performed by the UE while in the inactive communication state, the instructions being further executable by the processor to cause the apparatus to:

transmit, to a second base station providing the second cell, a secondary node release request based at least in part on the unavailability of the measurement reports.
An apparatus for wireless communication at a base station, comprising:

a processor,

memory in electronic communication with the processor; and

instructions stored in the memory and executable by the processor to cause the apparatus to:

communicate with a user equipment (UE) using a lower-layer configuration for a cell of the base station, wherein the cell is from a secondary cell group of a dual connectivity deployment;

store the first lower-layer configuration based at least in part on a determination that the UE has transitioned to an inactive communication state; and

receive, from the UE, a request to resume communications, the request comprising an indication of whether one or more measurement reports are available at the UE.
The apparatus of claim 57, wherein the instructions are further executable by the processor to cause the apparatus to:

determine a current lower-layer configuration for the cell; and

transmit, to the UE, a reconfiguration message that indicates a difference between the current lower-layer configuration and at least one of the stored lower-layer configuration or a second lower-layer configuration for a second cell provided by a second base station, wherein the second cell is from a master cell group of the dual connectivity deployment.
The apparatus of claim 58, wherein the instructions to receive the indication of whether the one or more measurement reports are available are executable by the processor to cause the apparatus to:

receive an indication that a measurement report for the second cell is available based at least in part on measurements performed by the UE while in the inactive communication state, the instructions being further executable by the processor to cause the apparatus to:

transmit, based at least in part on the measurement report for the second cell, a context request to the second base station, the context request comprising an indication to exchange a master node and the secondary node; and

receive, from the second base station, an indication of the second lower-layer configuration, wherein the reconfiguration message indicates a difference between a current lower-layer configuration for the cell and the second lower-layer configuration for the second cell.
The apparatus of claim 58, wherein the instructions to receive the indication of whether the one or more measurement reports are available are executable by the processor to cause the apparatus to:

receive an indication that a measurement report for a third cell is available based at least in part on measurements performed by the UE while in the inactive communication state, the instructions being further executable by the processor to cause the apparatus to:

transmit, to a third base station providing the third cell, an indication of the stored lower-layer configuration, wherein the reconfiguration message indicates a difference between a current lower-layer configuration for the cell and the second lower-layer configuration for the second cell.
The apparatus of claim 58, wherein the instructions to receive the indication of whether the one or more measurement reports are available are executable by the processor to cause the apparatus to:

receive an indication that measurement reports for one or more other cells are unavailable based at least in part on measurements performed by the UE while in the inactive communication state, the instructions being further executable by the processor to cause the apparatus to:

transmit, to the second base station, a secondary node release request based at least in part on the unavailability of the measurement reports.
The apparatus of claim 58, wherein the instructions to receive the indication of whether the one or more measurement reports are available are executable by the processor to cause the apparatus to:

receive an indication that measurement reports for one or more other cells are unavailable based at least in part on measurements performed by the UE while in the inactive communication state, the instructions being further executable by the processor to cause the apparatus to:

transmit, to the second base station, a handover request based at least in part on the unavailability of the measurement reports.
An apparatus for wireless communication at a user equipment (UE) , comprising:

means for performing a state transition to an inactive communication state with a first cell and a second cell;

means for storing, based at least in part on the state transition to the inactive communication state, a first lower-layer configuration for the first cell and a second lower-layer configuration for the second cell;

means for determining that communications with at least one of the first cell or the second cell are to resume;

means for transmitting, based at least in part on the determination, an indication of whether one or more measurement reports are available; and

means for receiving a reconfiguration message that indicates a difference between a current lower-layer configuration and at least one of the stored first lower-layer configuration or the second lower-layer configuration.
An apparatus for wireless communication at a base station, comprising:

means for communicating with a user equipment (UE) using a first lower-layer configuration for a first cell of the base station;

means for storing the first lower-layer configuration based at least in part on a determination that the UE has transitioned to an inactive communication state;

means for receiving, from the UE, a request to resume communications, the request comprising an indication of whether one or more measurement reports are available at the UE;

means for determining a current lower-layer configuration for at least one of the first cell or a second cell; and

means for transmitting, to the UE, a reconfiguration message that indicates a difference between a current lower-layer configuration and at least one of the stored first lower-layer configuration or a second lower-layer configuration for the second cell.
An apparatus for wireless communication at a base station, comprising:

means for communicating with a user equipment (UE) using a lower-layer configuration for a cell of the base station, wherein the cell is from a secondary cell group of a dual connectivity deployment;

means for storing the first lower-layer configuration based at least in part on a determination that the UE has transitioned to an inactive communication state; and

means for receiving, from the UE, a request to resume communications, the request comprising an indication of whether one or more measurement reports are available at the UE.
A non-transitory computer-readable medium storing code for wireless communication at a user equipment (UE) , the code comprising instructions executable by a processor to:

perform a state transition to an inactive communication state with a first cell and a second cell;

store, based at least in part on the state transition to the inactive communication state, a first lower-layer configuration for the first cell and a second lower-layer configuration for the second cell;

determine that communications with at least one of the first cell or the second cell are to resume;

transmit, based at least in part on the determination, an indication of whether one or more measurement reports are available; and

receive a reconfiguration message that indicates a difference between a current lower-layer configuration and at least one of the stored first lower-layer configuration or the second lower-layer configuration.
A non-transitory computer-readable medium storing code for wireless communication at a base station, the code comprising instructions executable by a processor to:

communicate with a user equipment (UE) using a first lower-layer configuration for a first cell of the base station;

store the first lower-layer configuration based at least in part on a determination that the UE has transitioned to an inactive communication state;

receive, from the UE, a request to resume communications, the request comprising an indication of whether one or more measurement reports are available at the UE;

determine a current lower-layer configuration for at least one of the first cell or a second cell; and

transmit, to the UE, a reconfiguration message that indicates a difference between a current lower-layer configuration and at least one of the stored first lower-layer configuration or a second lower-layer configuration for the second cell.
A non-transitory computer-readable medium storing code for wireless communication at a base station, the code comprising instructions executable by a processor to:

communicate with a user equipment (UE) using a lower-layer configuration for a cell of the base station, wherein the cell is from a secondary cell group of a dual connectivity deployment;

store the first lower-layer configuration based at least in part on a determination that the UE has transitioned to an inactive communication state; and

receive, from the UE, a request to resume communications, the request comprising an indication of whether one or more measurement reports are available at the UE.