WO2021237487A1

WO2021237487A1 - Apparatus and method for wireless communication using dual connectivity techniques

Info

Publication number: WO2021237487A1
Application number: PCT/CN2020/092488
Authority: WO
Inventors: Haojun WANG; Yi Liu; Kaikai YANG; Jinglin Zhang; Zhenqing CUI; Fan Shen
Original assignee: Qualcomm Incorporated
Priority date: 2020-05-27
Filing date: 2020-05-27
Publication date: 2021-12-02

Abstract

A user equipment (UE) can detect a delay in an LTE leg in a wireless network using dual connectivity, for example, E-UTRAN New Radio–Dual Connectivity (ENDC). The UE can take actions to mitigate the delay caused by the LTE leg. The UE determines a relative delay between two downlink (DL) paths used for receiving DL data packets using different radio access technologies (e.g., LTE and NR). If the relative delay satisfies a predetermined condition, the UE transmits an indication of the relative delay to the network to mitigate the relative delay.

Description

APPARATUS AND METHOD FOR WIRELESS COMMUNICATION USING DUAL CONNECTIVITY TECHNIQUES

TECHNICAL FIELD

The technology discussed below relates generally to wireless communication systems, and more particularly, to communication between a user equipment (UE) and a wireless network using dual connectivity techniques.

INTRODUCTION

In 5G New Radio, ENDC (E-UTRAN New Radio–Dual Connectivity) allows a user equipment (UE) to connect to an LTE base station (e.g., eNB) that acts as a master node and a 5G base station (e.g., gNB) that acts as a secondary node. ENDC is a technology that enables the introduction of 5G services in a predominantly 4G network (e.g., LTE) . UEs supporting ENDC can connect simultaneously to an LTE master node eNB (MeNB) and a New Radio (NR) secondary node gNB (En-gNB) . ENDC permits a cellular carrier to roll out 5G services without the expense of a full scale 5G core network. In an ENDC enabled network, a UE first registers for service with a 4G network. Then, the UE can report measurements on 5G frequencies. If the signal quality for the UE can support 5G service (e.g., NR) , the LTE eNB can communicate with the NR gNB to assign resources for a 5G bearer. The LTE eNB can signal the NR resource assignment to the UE so that the UE can simultaneously connect to the 4G and 5G networks. As the demand for mobile broadband access continues to increase, research and development continue to advance wireless communication technologies using dual connectivity not only to meet the growing demand for mobile broadband access, but to advance and enhance the user experience with mobile communications.

BRIEF SUMMARY OF SOME EXAMPLES

The following presents a summary of one or more aspects of the present disclosure, in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated features of the disclosure, and is intended neither to identify key or critical elements of all aspects of the disclosure nor to delineate the scope of any or all aspects of the disclosure. Its sole purpose is to present some concepts of one or more aspects of the disclosure in a form as a prelude to the more detailed description that is presented later.

Aspects of the present disclosure provide an apparatus and a method for improving downlink data transmission in a wireless network using dual connectivity, for example, E-UTRAN New Radio–Dual Connectivity (ENDC) . In some aspects, a user equipment (UE) can detect a delay in an LTE leg in a wireless network using ENDC techniques such that the UE can take actions to mitigate the delay caused by the LTE leg.

One aspect of the present disclosure provides a method of wireless communication at a user equipment (UE) . The UE receives a first portion of first downlink (DL) data from a network using a first radio access technology (RAT) . The UE receives a second portion of the first DL data from the network using a second RAT different from the first RAT. The second portion represents a first proportion of the first DL data. The UE determines a relative delay in receiving the first portion relative to receiving the second portion. The UE transmits, if the relative delay satisfies a predetermined condition, an indication of the relative delay to the network. The UE receives, after transmitting the indication, a portion of second DL data from the network using the second RAT. The portion of second DL data represents a proportion of the second DL data that is greater than the first proportion of the first DL data.

Another aspect of the present disclosure provides a UE for wireless communication. The UE includes a communication interface, a memory, and a processor operatively coupled with the communication interface and the memory. The processor and the memory are configured to receive a first portion of first downlink (DL) data from a network using a first radio access technology (RAT) . The UE may use the communication interface to receive the first portion. The processor and the memory are further configured to receive a second portion of the first DL data from the network using a second RAT different from the first RAT. The second portion represents a first proportion of the first DL data. The UE may use the communication interface to receive the second portion. The processor and the memory are further configured to determine a relative delay in receiving the first portion relative to receiving the second portion. The processor and the memory are further configured to transmit an indication of the relative delay to the network in connection with a determination that the relative delay satisfies a predetermined condition. The UE may use the communication interface to transmit the indication. The processor and the memory are further configured to receive, after transmitting the indication, a portion of second DL data from the network using the second RAT. The portion of second DL data represents a proportion of the second DL data that is greater than the first proportion of the first DL data.

Another aspect of the present disclosure provides a method of wireless communication at a wireless network. The wireless network transmits a first portion of first DL data to a UE using a first RAT. The wireless network transmits a second portion of the first DL data to the UE using a second RAT different from the first RAT. The second portion represents a first proportion of the first DL data. The wireless network receives an indication from the UE of a relative delay in receiving the first portion relative to receiving the second portion. The network apportion, in response to the indication of the relative delay, a transmission of second DL data to the UE among the first RAT and the second RAT such that a proportion of the second DL data transmitted using the second RAT is greater than the first proportion of the first DL data transmitted using the second RAT.

Another aspect of the present disclosure provides a master node for wireless communication. The master node includes a communication interface, a memory, and a processor operatively coupled with the communication interface and the memory. The processor and the memory are configured to transmit a first portion of first DL data to a UE using a first RAT, in coordination with a secondary node that transmits a second portion of the first DL data to the UE using a second RAT different from the first RAT. The second portion represents a first proportion of the first DL data. The processor and the memory are further configured to receive an indication from the UE of a relative delay in receiving the first portion relative to receiving the second portion. The processor and the memory are further configured to apportion, in coordination with the secondary node and in response to the indication of the relative delay, a transmission of second DL data to the UE among the first RAT and the second RAT such that a proportion of the second DL data transmitted using the second RAT is greater than the first proportion of the first DL data transmitted using the second RAT.

Another aspect of the present disclosure provides a UE for wireless communication. The UE includes means for receiving a first portion of first DL data from a network using a first RAT. The UE includes means for receiving a second portion of the first DL data from the network using a second RAT different from the first RAT. The second portion represents a first proportion of the first DL data. The UE includes means for determining a relative delay in receiving the first portion relative to receiving the second portion. The UE includes means for transmitting, if the relative delay satisfies a predetermined condition, an indication of the relative delay to the network. The UE includes means for receiving, after transmitting the indication, a portion of second DL data from the network using the second RAT. The portion of second DL data represents a proportion of the second DL data that is greater than the first proportion of the first DL data.

Another aspect of the present disclosure provides a master node for wireless communication. The master node includes means for transmitting a first portion of first DL data to a UE using a RAT, in coordination with a secondary node that transmits a second portion of the first DL data to the UE using a second RAT different from the first RAT. The second portion represents a first proportion of the first DL data. The master node further includes means for receiving an indication from the UE of a relative delay in receiving the first portion relative to receiving the second portion. The master node further includes means for apportioning, in coordination with the secondary node and in response to the indication of the relative delay, a transmission of second DL data to the UE among the first RAT and the second RAT such that a proportion of the second DL data transmitted using the second RAT is greater than the first proportion of the first DL data transmitted using the second RAT.

Another aspect of the present disclosure provides a non-transitory computer-readable medium storing computer-executable code. The code causes a UE to receive a first portion of first DL data from a network using a first RAT. The code further causes the UE to receive a second portion of the first DL data from the network using a second RAT different from the first RAT. The second portion represents a first proportion of the first DL data. The code further causes the UE to determine a relative delay in receiving the first portion relative to receiving the second portion. The code further causes the UE to transmit, if the relative delay satisfies a predetermined condition, an indication of the relative delay to the network. The code further causes the UE to receive, after transmitting the indication, a portion of second DL data from the network using the second RAT. The portion of second DL data represents a proportion of the second DL data that is greater than the first proportion of the first DL data.

Another aspect of the present disclosure provides a non-transitory computer-readable medium storing computer-executable code. The code causes a master node to transmit a first portion of first DL data to a UE using a first RAT, in coordination with a secondary node that transmits a second portion of the first DL data to the UE using a second RAT different from the first RAT. The second portion represents a first proportion of the first DL data. The code further causes the master node to receive an indication from the UE of a relative delay in receiving the first portion relative to receiving the second portion. The code further causes the master node to apportion, in coordination with the secondary node and in response to the indication of the relative delay, a transmission of second DL data to the UE among the first RAT and the second RAT such that a proportion of the second DL data transmitted using the second RAT is greater than the first proportion of the first DL data transmitted using the second RAT.

These and other aspects of the invention will become more fully understood upon a review of the detailed description, which follows. Other aspects, features, and embodiments will become apparent to those of ordinary skill in the art, upon reviewing the following description of specific, exemplary embodiments in conjunction with the accompanying figures. While features may be discussed relative to certain embodiments and figures below, all embodiments can include one or more of the advantageous features discussed herein. In other words, while one or more embodiments may be discussed as having certain advantageous features, one or more of such features may also be used in accordance with the various embodiments discussed herein. In similar fashion, while exemplary embodiments may be discussed below as device, system, or method embodiments it should be understood that such exemplary embodiments can be implemented in various devices, systems, and methods.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of a wireless communication system according to some aspects of the disclosure.

FIG. 2 is an illustration of an example of a radio access network according to some aspects of the disclosure.

FIG. 3 is a schematic illustration of an exemplary wireless network using dual connectivity to provide radio access to a user equipment (UE) according to some aspects of the disclosure.

FIG. 4 is a flow chart illustrating an exemplary process for mitigating a downlink date rate drop in a wireless network using dual connectivity according to some aspects of the disclosure.

FIG. 5 is a schematic illustration of an exemplary flow of packet data convergence protocol (PDCP) packet data units transmitted from a network to a UE using dual connectivity according to some aspects of the disclosure.

FIG. 6 is a flow chart illustrating an exemplary process for determining the delay of an LTE leg in a network using dual connectivity according to some aspects of the disclosure.

FIG. 7 is a block diagram conceptually illustrating an example of a hardware implementation for a scheduled entity according to some aspects of the disclosure.

FIG. 8 is a flow chart illustrating an exemplary process for wireless communication using dual connectivity according to some aspects of the disclosure.

FIG. 9 is a flow chart illustrating an exemplary process for determining the delay of downlink data in a wireless network using dual connectivity.

FIG. 10 is a block diagram conceptually illustrating an example of a hardware implementation for a scheduling entity according to some aspects of the disclosure.

FIG. 11 is a flow chart illustrating another exemplary process for wireless communication using dual connectivity according to some aspects of the disclosure.

DETAILED DESCRIPTION

The detailed description set forth below in connection with the appended drawings is intended as a description of various configurations and is not intended to represent the only configurations in which the concepts described herein may be practiced. The detailed description includes specific details for the purpose of providing a thorough understanding of various concepts. However, it will be apparent to those skilled in the art that these concepts may be practiced without these specific details. In some instances, well-known structures and components are shown in block diagram form in order to avoid obscuring such concepts.

While aspects and embodiments are described in this application by illustration to some examples, those skilled in the art will understand that additional implementations and use cases may come about in many different arrangements and scenarios. Innovations described herein may be implemented across many differing platform types, devices, systems, shapes, sizes, packaging arrangements. For example, embodiments and/or uses may come about via integrated chip embodiments and other non-module-component based devices (e.g., end-user devices, vehicles, communication devices, computing devices, industrial equipment, retail/purchasing devices, medical devices, AI-enabled devices, etc. ) . While some examples may or may not be specifically directed to use cases or applications, a wide assortment of applicability of described innovations may occur. Implementations may range a spectrum from chip-level or modular components to non-modular, non-chip-level implementations and further to aggregate, distributed, or OEM devices or systems incorporating one or more aspects of the described innovations. In some practical settings, devices incorporating described aspects and features may also necessarily include additional components and features for implementation and practice of claimed and described embodiments. For example, transmission and reception of wireless signals necessarily includes a number of components for analog and digital purposes (e.g., hardware components including antenna, RF-chains, power amplifiers, modulators, buffer, processor (s) , interleaver, adders/summers, etc. ) . It is intended that innovations described herein may be practiced in a wide variety of devices, chip-level components, systems, distributed arrangements, end-user devices, etc. of varying sizes, shapes and constitution.

The various concepts presented throughout this disclosure may be implemented across a broad variety of telecommunication systems, network architectures, and communication standards. Referring now to FIG. 1, as an illustrative example without limitation, various aspects of the present disclosure are illustrated with reference to a wireless communication system 100. The wireless communication system 100 includes three interacting domains: a core network 102, a radio access network (RAN) 104, and a user equipment (UE) 106. By virtue of the wireless communication system 100, the UE 106 may be enabled to carry out data communication with an external data network 110, such as (but not limited to) the Internet.

The RAN 104 may implement any suitable wireless communication technology or technologies to provide radio access to the UE 106. As one example, the RAN 104 may operate according to 3 ^rd Generation Partnership Project (3GPP) New Radio (NR) specifications, often referred to as 5G. As another example, the RAN 104 may operate under a hybrid of 5G NR and Evolved Universal Terrestrial Radio Access Network (eUTRAN) standards, often referred to as LTE. The 3GPP refers to this hybrid RAN as a next-generation RAN, or NG-RAN. Of course, many other examples may be utilized within the scope of the present disclosure.

As illustrated, the RAN 104 includes a plurality of base stations 108, for example, LTE eNBs and 5G gNBs. Broadly, a base station is a network element in a radio access network responsible for radio transmission and reception in one or more cells to or from a UE. In different technologies, standards, or contexts, a base station may variously be referred to by those skilled in the art as a base transceiver station (BTS) , a radio base station, a radio transceiver, a transceiver function, a basic service set (BSS) , an extended service set (ESS) , an access point (AP) , a Node B (NB) , an eNode B (eNB) , a gNode B (gNB) , or some other suitable terminology.

The radio access network 104 is further illustrated supporting wireless communication for multiple mobile apparatuses. A mobile apparatus may be referred to as user equipment (UE) in 3GPP standards, but may also be referred to by those skilled in the art as a mobile station (MS) , a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communications device, a remote device, a mobile subscriber station, an access terminal (AT) , a mobile terminal, a wireless terminal, a remote terminal, a handset, a terminal, a user agent, a mobile client, a client, or some other suitable terminology. A UE may be an apparatus (e.g., a mobile apparatus) that provides a user with access to network services.

Within the present document, a “mobile” apparatus need not necessarily have a capability to move, and may be stationary. The term mobile apparatus or mobile device broadly refers to a diverse array of devices and technologies. UEs may include a number of hardware structural components sized, shaped, and arranged to help in communication; such components can include antennas, antenna arrays, RF chains, amplifiers, one or more processors, etc. electrically coupled to each other. For example, some non-limiting examples of a mobile apparatus include a mobile, a cellular (cell) phone, a smart phone, a session initiation protocol (SIP) phone, a laptop, a personal computer (PC) , a notebook, a netbook, a smartbook, a tablet, a personal digital assistant (PDA) , and a broad array of embedded systems, e.g., corresponding to an “Internet of things” (IoT) . A mobile apparatus may additionally be an automotive or other transportation vehicle, a remote sensor or actuator, a robot or robotics device, a satellite radio, a global positioning system (GPS) device, an object tracking device, a drone, a multi-copter, a quad-copter, a remote control device, a consumer and/or wearable device, such as eyewear, a wearable camera, a virtual reality device, a smart watch, a health or fitness tracker, a digital audio player (e.g., MP3 player) , a camera, a game console, etc. A mobile apparatus may additionally be a digital home or smart home device such as a home audio, video, and/or multimedia device, an appliance, a vending machine, intelligent lighting, a home security system, a smart meter, etc. A mobile apparatus may additionally be a smart energy device, a security device, a solar panel or solar array, a municipal infrastructure device controlling electric power (e.g., a smart grid) , lighting, water, etc.; an industrial automation and enterprise device; a logistics controller; agricultural equipment; military defense equipment, vehicles, aircraft, ships, and weaponry, etc. Still further, a mobile apparatus may provide for connected medicine or telemedicine support, e.g., health care at a distance. Telehealth devices may include telehealth monitoring devices and telehealth administration devices, whose communication may be given preferential treatment or prioritized access over other types of information, e.g., in terms of prioritized access for transport of critical service data, and/or relevant QoS for transport of critical service data.

Wireless communication between a RAN 104 and a UE 106 may be described as utilizing an air interface. Transmissions over the air interface from a base station (e.g., base station 108) to one or more UEs (e.g., UE 106) may be referred to as downlink (DL) transmission. In accordance with certain aspects of the present disclosure, the term downlink may refer to a point-to-multipoint transmission originating at a scheduling entity (described further below; e.g., base station 108) . Another way to describe this scheme may be to use the term broadcast channel multiplexing. Transmissions from a UE (e.g., UE 106) to a base station (e.g., base station 108) may be referred to as uplink (UL) transmissions. In accordance with further aspects of the present disclosure, the term uplink may refer to a point-to-point transmission originating at a scheduled entity (described further below; e.g., UE 106) .

In some examples, access to the air interface may be scheduled, wherein a scheduling entity (e.g., a base station 108) allocates resources for communication among some or all devices and equipment within its service area or cell. Within the present disclosure, as discussed further below, the scheduling entity may be responsible for scheduling, assigning, reconfiguring, and releasing resources for one or more scheduled entities. That is, for scheduled communication, UEs 106, which may be scheduled entities, may utilize resources allocated by the scheduling entity 108.

Base stations 108 are not the only entities that may function as scheduling entities. That is, in some examples, a UE may function as a scheduling entity, scheduling resources for one or more scheduled entities (e.g., one or more other UEs) .

As illustrated in FIG. 1, a scheduling entity 108 may broadcast downlink traffic 112 to one or more scheduled entities 106. Broadly, the scheduling entity 108 is a node or device responsible for scheduling traffic in a wireless communication network, including the downlink traffic 112 and, in some examples, uplink traffic 116 from one or more scheduled entities 106 to the scheduling entity 108. On the other hand, the scheduled entity 106 is a node or device that receives downlink control information 114, including but not limited to scheduling information (e.g., a grant) , synchronization or timing information, or other control information from another entity in the wireless communication network such as the scheduling entity 108.

In general, base stations 108 may include a backhaul interface for communication with a backhaul portion 120 of the wireless communication system. The backhaul 120 may provide a link between a base station 108 and the core network 102. Further, in some examples, a backhaul network may provide interconnection between the respective base stations 108. Various types of backhaul interfaces may be employed, such as a direct physical connection, a virtual network, or the like using any suitable transport network.

The core network 102 may be a part of the wireless communication system 100, and may be independent of the radio access technology used in the RAN 104. In some examples, the core network 102 may be configured according to 5G standards (e.g., 5GC) . In other examples, the core network 102 may be configured according to a 4G evolved packet core (EPC) , or any other suitable standard or configuration.

FIG. 2 is a conceptual illustration of an example of a radio access network 200 according to some aspects of the disclosure. In some examples, the radio access network (RAN) 200 may be the same as the RAN 104 described above and illustrated in FIG. 1. The geographic area covered by the RAN 200 may be divided into cellular regions (cells) that can be uniquely identified by a user equipment (UE) based on an identification broadcasted from one access point or base station. FIG. 2 illustrates

macrocells

202, 204, and 206, and a small cell 208, each of which may include one or more sectors (not shown) . A sector is a sub-area of a cell. All sectors within one cell are served by the same base station. A radio link within a sector can be identified by a single logical identification belonging to that sector. In a cell that is divided into sectors, the multiple sectors within a cell can be formed by groups of antennas with each antenna responsible for communication with UEs in a portion of the cell.

In FIG. 2, two base stations 210 and 212 are shown in

cells

202 and 204; and a third base station 214 is shown controlling a remote radio head (RRH) 216 in cell 206. That is, a base station can have an integrated antenna or can be connected to an antenna or RRH by feeder cables. In the illustrated example, the

cells

202, 204, and 126 may be referred to as macrocells, as the

base stations

210, 212, and 214 support cells having a large size. Further, a base station 218 is shown in the small cell 208 (e.g., a microcell, picocell, femtocell, home base station, home Node B, home eNode B, etc. ) which may overlap with one or more macrocells. In this example, the cell 208 may be referred to as a small cell, as the base station 218 supports a cell having a relatively small size. Cell sizing can be done according to system design as well as component constraints.

It is to be understood that the radio access network 200 may include any number of wireless base stations and cells. Further, a relay node may be deployed to extend the size or coverage area of a given cell. The

base stations

210, 212, 214, 218 provide wireless access points to a core network for any number of mobile apparatuses. In some examples, the

base stations

210, 212, 214, and/or 218 may be the same as the base station/scheduling entity 108 described above and illustrated in FIG. 1.

FIG. 2 further includes a quadcopter or drone 220, which may be configured to function as a base station. That is, in some examples, a cell may not necessarily be stationary, and the geographic area of the cell may move according to the location of a mobile base station such as the quadcopter 220.

Within the RAN 200, the cells may include UEs that may be in communication with one or more sectors of each cell. Further, each

base station

210, 212, 214, 218, and 220 may be configured to provide an access point to a core network 102 (see FIG. 1) for all the UEs in the respective cells. For example,

UEs

222 and 224 may be in communication with base station 210;

UEs

226 and 228 may be in communication with base station 212;

UEs

230 and 232 may be in communication with base station 214 by way of RRH 216; UE 234 may be in communication with base station 218; and UE 236 may be in communication with mobile base station 220. In some examples, the

UEs

222, 224, 226, 228, 230, 232, 234, 236, 238, 240, and/or 242 may be the same as the UE/scheduled entity 106 described above and illustrated in FIG. 1.

In some examples, a mobile network node (e.g., quadcopter 220) may be configured to function as a UE. For example, the quadcopter 220 may operate within cell 202 by communicating with base station 210.

In a further aspect of the RAN 200, sidelink signals may be used between UEs without necessarily relying on scheduling or control information from a base station. For example, two or more UEs (e.g., UEs 226 and 228) may communicate with each other using peer to peer (P2P) or sidelink signals 227 without relaying that communication through a base station (e.g., base station 212) . In a further example, UE 238 is illustrated communicating with

UEs

240 and 242. Here, the UE 238 may function as a scheduling entity or a primary sidelink device, and

UEs

240 and 242 may function as a scheduled entity or a non-primary (e.g., secondary) sidelink device. In still another example, a UE may function as a scheduling entity in a device-to-device (D2D) , peer-to-peer (P2P) , or vehicle-to-vehicle (V2V) network, and/or in a mesh network. In a mesh network example,

UEs

240 and 242 may optionally communicate directly with one another in addition to communicating with the scheduling entity 238. Thus, in a wireless communication system with scheduled access to time–frequency resources and having a cellular configuration, a P2P configuration, or a mesh configuration, a scheduling entity and one or more scheduled entities may communicate utilizing the scheduled resources.

In the radio access network 200, the ability for a UE to communicate while moving, independent of its location, is referred to as mobility. The various physical channels between the UE and the radio access network are generally set up, maintained, and released under the control of an access and mobility management function (AMF, not illustrated, part of the core network 102 in FIG. 1) , which may include a security context management function (SCMF) that manages the security context for both the control plane and the user plane functionality, and a security anchor function (SEAF) that performs authentication.

In various aspects of the disclosure, a radio access network 200 may utilize DL-based mobility or UL-based mobility to enable mobility and handovers (i.e., the transfer of a UE’s connection from one radio channel to another) . In a network configured for DL-based mobility, during a call with a scheduling entity, or at any other time, a UE may monitor various parameters of the signal from its serving cell as well as various parameters of neighboring cells. Depending on the quality of these parameters, the UE may maintain communication with one or more of the neighboring cells. During this time, if the UE moves from one cell to another, or if signal quality from a neighboring cell exceeds that from the serving cell for a given amount of time, the UE may undertake a handoff or handover from the serving cell to the neighboring (target) cell. For example, UE 224 (illustrated as a vehicle, although any suitable form of UE may be used) may move from the geographic area corresponding to its serving cell 202 to the geographic area corresponding to a neighbor cell 206. When the signal strength or quality from the neighbor cell 206 exceeds that of its serving cell 202 for a given amount of time, the UE 224 may transmit a reporting message to its serving base station 210 indicating this condition. In response, the UE 224 may receive a handover command, and the UE may undergo a handover to the cell 206.

In a network configured for UL-based mobility, UL reference signals from each UE may be utilized by the network to select a serving cell for each UE. In some examples, the

base stations

210, 212, and 214/216 may broadcast unified synchronization signals (e.g., unified Primary Synchronization Signals (PSSs) , unified Secondary Synchronization Signals (SSSs) and unified Physical Broadcast Channels (PBCH) ) . The

UEs

222, 224, 226, 228, 230, and 232 may receive the unified synchronization signals, derive the carrier frequency and slot timing from the synchronization signals, and in response to deriving timing, transmit an uplink pilot or reference signal. The uplink pilot signal transmitted by a UE (e.g., UE 224) may be concurrently received by two or more cells (e.g., base stations 210 and 214/216) within the radio access network 200. Each of the cells may measure a strength of the pilot signal, and the radio access network (e.g., one or more of the base stations 210 and 214/216 and/or a central node within the core network) may determine a serving cell for the UE 224. As the UE 224 moves through the radio access network 200, the network may continue to monitor the uplink pilot signal transmitted by the UE 224. When the signal strength or quality of the pilot signal measured by a neighboring cell exceeds that of the signal strength or quality measured by the serving cell, the network 200 may handover the UE 224 from the serving cell to the neighboring cell, with or without informing the UE 224.

Although the synchronization signal transmitted by the

base stations

210, 212, and 214/216 may be unified, the synchronization signal may not identify a particular cell, but rather may identify a zone of multiple cells operating on the same frequency and/or with the same timing. The use of zones in 5G networks or other next generation communication networks enables the uplink-based mobility framework and improves the efficiency of both the UE and the network, since the number of mobility messages that need to be exchanged between the UE and the network may be reduced.

The air interface in the radio access network 200 may utilize one or more duplexing algorithms. Duplex refers to a point-to-point communication link where both endpoints can communicate with one another in both directions. Full duplex means both endpoints can simultaneously communicate with one another. Half duplex means only one endpoint can send information to the other at a time. In a wireless link, a full duplex channel generally relies on physical isolation of a transmitter and receiver, and suitable interference cancellation technologies. Full duplex emulation is frequently implemented for wireless links by utilizing frequency division duplex (FDD) or time division duplex (TDD) . In FDD, transmissions in different directions operate at different carrier frequencies. In TDD, transmissions in different directions on a given channel are separated from one another using time division multiplexing. That is, at some times the channel is dedicated for transmissions in one direction, while at other times the channel is dedicated for transmissions in the other direction, where the direction may change very rapidly, e.g., several times per slot.

The air interface in the radio access network 200 may utilize one or more multiplexing and multiple access algorithms to enable simultaneous communication of the various devices. For example, 5G NR specifications provide multiple access for UL transmissions from

UEs

222 and 224 to base station 210, and for multiplexing for DL transmissions from base station 210 to one or

more UEs

222 and 224, utilizing orthogonal frequency division multiplexing (OFDM) with a cyclic prefix (CP) . In addition, for UL transmissions, 5G NR specifications provide support for discrete Fourier transform-spread-OFDM (DFT-s-OFDM) with a CP (also referred to as single-carrier FDMA (SC-FDMA) ) . However, within the scope of the present disclosure, multiplexing and multiple access are not limited to the above schemes, and may be provided utilizing time division multiple access (TDMA) , code division multiple access (CDMA) , frequency division multiple access (FDMA) , sparse code multiple access (SCMA) , resource spread multiple access (RSMA) , or other suitable multiple access schemes. Further, multiplexing DL transmissions from the base station 210 to UEs 222 and 224 may be provided utilizing time division multiplexing (TDM) , code division multiplexing (CDM) , frequency division multiplexing (FDM) , orthogonal frequency division multiplexing (OFDM) , sparse code multiplexing (SCM) , or other suitable multiplexing schemes.

The channels or carriers described above and illustrated in FIGs. 1 and 2 are not necessarily all the channels or carriers that may be utilized between a scheduling entity 108 and scheduled entities 106, and those of ordinary skill in the art will recognize that other channels or carriers may be utilized in addition to those illustrated, such as other traffic, control, and feedback channels. These physical channels described above are generally multiplexed and mapped to transport channels for handling at the medium access control (MAC) layer. Transport channels carry blocks of information called transport blocks (TB) . The transport block size (TBS) , which may correspond to a number of bits of information, may be a controlled parameter, based on the modulation and coding scheme (MCS) and the number of resource blocks (RBs) used in a given transmission.

FIG. 3 is a schematic illustration of an exemplary wireless network 300 using dual connectivity to provide radio access (e.g., LTE and 5G NR) to a UE 302 according to some aspects of the disclosure. In one example, the wireless network may deploy ENDC Option 3x to provide LTE and NR radio access to a UE 302. In some aspects, the wireless network 300 may be a part of the RAN 200 described above in relation to FIG. 2. In the wireless network 300, an EPC 304 can send downlink (DL) data to the UE 302 via an LTE eNB 306 and/or an NR gNB 308. In one aspect, the LTE eNB 306 may be a master node, and the NR gNB 308 may be a secondary node in an ENDC configuration.

Among NR deployment options, Option 3 enables a network to provide both LTE and NR radio accesses, but the network routes the control signals using only the LTE network. The LTE side RAN provides the control plane anchor for the NR side, and both the LTE and NR networks can be used for user data traffic (user plane) . This type of 5G deployment can be called as non-standalone (NSA) NR. Three variations of option 3 are plain option 3, option 3A, and option 3X. For the plain option 3, user data traffic can be split between the LTE and NR networks at the LTE eNB 306. For the option 3A, user data traffic can be split between the LTE and NR networks at the EPC 304. For the option 3X, user data traffic can be split between the LTE and NR networks at the gNB 308. For example, the gNB 308 receives downlink data destined to the UE 302 from the EPC 304 and can split the downlink data to the LTE eNB leg 310. The gNB 308 can divide the downlink data between the NR leg and LTE leg according to a predetermined ratio. In one aspect, the gNB 308 may communicate with the eNB 306 via an X2-U interface. In some aspects, the gNB 308 may share some DL user data with the eNB 306 based on data volume and/or loading of the network 300.

The UE 302 has a packet data convergence protocol (PDCP) entity 312 that can receive the downlink (DL) data from the eNB 306 and/or gNB 308. In this case, the PDCP entity 312 can receive data via separate RLC layers (e.g., LTE RLC and NR RLC) , separate MAC layers (e.g., LTE MAC and NR MAC) , and separate PHY layers (e.g., LTE PHY and NR PHY) . The PDCP entity 312 provides its services to upper layers (e.g., RRC or service data adaptation protocol (SDAP) layers) , for example, transfer of user plane data, transfer of control plane data, header compression, ciphering, and integrity protection.

In some scenarios, a significant delay in the LTE leg can cause a TCP layer downlink data rate drop. The delay may occur on the X2-U interface between the gNB 308 and eNB 306 or between the eNB-to-UE air interface. Aspects of the present disclosure provide an apparatus and a method for mitigating the downlink data rate drop due to LTE side delay in an ENDC configuration.

FIG. 4 is a flow chart illustrating an exemplary process 400 for mitigating a downlink date rate drop in a wireless network using ENDC according to some aspects of the disclosure. In one aspect, the process 400 may be performed in a wireless network 300 including, for example, the UE 302, eNB 306, and gNB 308 of FIG. 3. In some aspects, the process 400 may be used in any networks that support dual connectivity, for example, ENDC Option 3x.

At block 402, the UE 302 enters an ENDC mode and establishes both LTE and NR connections with a wireless network using Option 3x. In Option 3x, three different radio bearers are used in the network. A master cell group (MCG) bearer is a radio bearer that is served by the master node (e.g., eNB 306) , and a secondary cell group (SCG) bearer is a radio bearer served by a secondary node (e.g., gNB 308) . In Option 3x, a split bearer is a radio bearer between the EPC 304 and the gNB 308 that can be used by the gNB to share DL user data.

At block 404, the gNB 308 can split or share some downlink (DL) user data with the LTE leg. For example, the gNB 308 can send some DL user data or traffic to the eNB 306 via an X2-U interface between the gNB and eNB. In this case, the UE 302 can receive DL user data from both the gNB 308 and eNB 306. In one aspect, the UE 302 can receive some PDCP PDUs through the LTE leg and some PDCP PDUs through the NR leg. Each PDCP PDU can be identified by a COUNT value. The COUNT value is incremented for each transmitted PDCP PDU. In one example, the COUNT value may have a length of 32 bits. During an RRC connection, the COUNT value is used by the UE and the network to keep track of each transmitted PDCP PDU. The COUNT value is composed of an HFN (hyper frame number) and a PDCP SN (sequence number) . FIG. 5 is a drawing illustrating an exemplary flow of PDCP PDUs 500 transmitted by the network to the UE via the eNB and/or gNB. For example, PDCP PDUs with sequence numbers from 1 through X+n+2 are illustrated in FIG. 5.

At block 406, the UE receives a PDCP PDU (e.g., PDU with SN = X+n) from the NR leg at time Timer_1. At block 408, the UE receives some PDCP PDUs (e.g., PDUs with SNs from X to X+n-1) via the LTE leg starting at time Timer_2 that may be later than Timer_1. In this case, the UE receives the PDCP PDUs out of order according to their sequence numbers due to LTE side delay. For example, the LTE leg PDCP PDUs with earlier SNs (X to X+n-1) arrive at the UE later than the NR leg PDCP PDU SN X+n.

At block 410, the UE may determine the LTE leg delay based on the time that the PDCP PDUs were received. In one aspect, the UE may determine the LTE leg delay when the UE reorders the PDCP PDUs buffered at the PDCP layer (e.g., at the PDCP entity 312) before delivering the PDUs to the upper layers. The UE can determine the delay of the LTE leg relative to the NR leg based on the time and order the PDCP PDUs received at the UE.

FIG. 6 is a flow chart illustrating an exemplary process 600 for determining the delay of the LTE leg according to one aspect of the disclosure. At block 602, the UE can determine the NR PDCP PDU in a buffer or memory that is received out of order. The UE can compare the COUNT values (e.g., SNs) of the PDCP PDUs and arrival time of the PDUs to determine the out of order NR PDCP PDU. An NR PDCP PDU is out of order when the NR PDCP PDU has an SN later than the SNs of LTE PDCP PDUs but received before the LTE PDCP PDUs.

At block 604, the UE can determine the earliest PDCP PDU received from the LTE leg in a PDCP buffer or memory. For example, the PDCP PDUs with SNs from X to X+n-1 are received by the UE via the LTE leg starting at Timer_2. In this case, the PDCP PDU with SN=X is the earliest buffered PDCP PDU that is received at Timer_2.

At block 606, the UE can determine the LTE leg delay based on a time difference between the earliest received LTE PDCP PDU and out of order NR PDCP PDU. In this example, the out of order NR PDCP PDU (e.g., SN=X+n) is received at Timer_1, the earliest LTE PDCP PDU (e.g., SN=X) in the buffer is received at time Timer_2, and Timer_2 is later than Timer_2. Therefore, the LTE delay can be determined as a different between Timer_1 and Timer_2.

Referring back to FIG. 4, at decision block 412, the UE can determine whether or not the LTE leg delay is greater than a predetermined delay threshold (e.g., a value between 30 ms and 2750 ms) . If the LTE leg delay is greater than the delay threshold, the process 400 proceeds to block 414; otherwise the process 400 goes back to block 404. At block 414, the UE increments an LTE delay counter. For example, the UE may maintain a variable in a memory or storage device that can be updated to keep track of the LTE delay counter. The UE may initiate or reset the counter before entering the ENDC mode.

At decision block 416, the UE can determine whether or not the LTE delay counter has a value that is greater than a predetermined maximum count value (e.g., a value between 1 and 50) . If the LTE delay counter has a value that is greater than the maximum count value, the process 400 proceeds to block 418; otherwise, the process 400 goes back to block 404.

At block 418, the UE can report the LTE leg delay situation in connection with the determination that the LTE delay counter exceeds the maximum count value. In one aspect, the UE may transmit a special channel quality indicator (CQI) to the network (e.g., gNB or eNB) . In general, the CQI carries information that indicates the quality of the communication channel between the UE and the network. In one aspect, the special CQI may have a predetermined value (e.g., zero) that indicates that the UE is experiencing significant LTE leg delay. In response to the special CQI, the network (e.g., eNB) may reduce or stop sending DL user data via the LTE DL connection or channel (e.g., PDSCH) , while the network can contemporaneously send DL user data via the NR DL connection or channel (e.g., PDSCH) .

At block 420, the UE can determine whether or not the LTE serving cell has changed. Each LTE cell (e.g., eNB 306) may be associated with a cell identifier (ID) that is broadcasted to UEs in the cell. If the LTE serving cell ID received by the UE has changed, the UE can determine that the LTE serving cell has changed, for example, due to UE’s movement and/or changing channel conditions among neighboring cells. If the LTE serving cell has changed, the process 400 proceeds to block 422; otherwise, the process 400 proceeds to block 424. At block 422, the UE reports normal CQI (i.e., not special CQI) for the LTE connection. The UE transmits normal or regular CQI values to the network to report channel condition. For example, the regular CQI may a non-zero value.

At decision block 424, the UE can determine whether or not the NR serving cell has changed. Each NR cell (e.g., gNB 308) may be associated with a cell ID that is broadcasted to UEs in the cell. If the NR serving cell ID received by the UE has changed, the UE can determine that the NR serving cell has changed, for example, due to UE’s movement and/or changing channel conditions among neighboring cells. If the NR serving cell has changed, the process 400 continues at block 422 described above; otherwise, the process 400 proceeds to block 426. At block 426, the UE can continue to report the special CQI to indicate the LTE delay until the UE exits the ENDC mode.

FIG. 7 is a block diagram illustrating an example of a hardware implementation for a scheduled entity 700 employing a processing system 714. For example, the scheduled entity 700 may be a user equipment (UE) as illustrated in any one or more of FIGs. 1, 2, and/or 3.

The scheduled entity 700 may be implemented with a processing system 714 that includes one or more processors 704. Examples of processors 704 include microprocessors, microcontrollers, digital signal processors (DSPs) , field programmable gate arrays (FPGAs) , programmable logic devices (PLDs) , state machines, gated logic, discrete hardware circuits, and other suitable hardware configured to perform the various functionality described throughout this disclosure. In various examples, the scheduled entity 700 may be configured to perform any one or more of the functions described herein. That is, the processor 704, as utilized in a scheduled entity 700, may be used to implement any one or more of the processes and procedures described and illustrated in FIGs. 4–6, 8, and 9.

In this example, the processing system 714 may be implemented with a bus architecture, represented generally by the bus 702. The bus 702 may include any number of interconnecting buses and bridges depending on the specific application of the processing system 714 and the overall design constraints. The bus 702 communicatively couples together various circuits including one or more processors (represented generally by the processor 704) , a memory 705, and computer-readable media (represented generally by the computer-readable medium 706) . The bus 702 may also link various other circuits such as timing sources, peripherals, voltage regulators, and power management circuits, which are well known in the art, and therefore, will not be described any further. A bus interface 708 provides an interface between the bus 702 and one or more transceivers 710. The transceiver 710 provides a communication interface or means for communicating with various other apparatus over a transmission medium using one or more RATs. Depending upon the nature of the apparatus, a user interface 712 (e.g., keypad, display, speaker, microphone, joystick) may also be provided. Of course, such a user interface 712 is optional, and may be omitted in some examples, such as a base station.

In some aspects of the disclosure, the processor 704 may include circuitry configured for various functions, including, for example, wireless communication using dual connectivity (e.g., ENDC) . For example, the circuitry may be configured to implement one or more of the functions described in relation to FIGs. 4–6, 8, and 9.

The processor 704 may include a processing circuit 740. The scheduled entity 700 may use the processing circuit 740 alone or in connection with other circuitry to perform various data and signal processing functions and algorithm used in wireless communication, for example, between the scheduled entity and a wireless network using dual connectivity techniques (e.g., ENDC) .

The processor 704 may include a first RAT communication circuit 742. The scheduled entity 700 may use the first RAT communication circuit 742 to perform various UL and DL communication functions with a network using a first RAT (e.g., LTE) . For example, the first RAT communication circuit 742 can perform scrambling, descrambling, modulation, demodulation, mapping, demapping, coding, decoding, and other functions used in UL/DL communication with a network using, for example, LTE.

The processor 704 may include a second RAT communication circuit 744. The scheduled entity 700 may use the second RAT communication circuit 744 to perform various UL and DL communication functions with a network using a second RAT (e.g., NR) . For example, the second RAT communication circuit 744 can perform scrambling, descrambling, modulation, demodulation, mapping, demapping, coding, decoding, and other functions used in UL/DL communication with a network using, for example, NR.

The processor 704 is responsible for managing the bus 702 and general processing, including the execution of software stored on the computer-readable medium 706. The software, when executed by the processor 704, causes the processing system 714 to perform the various functions described below for any particular apparatus. The computer-readable medium 706 and the memory 705 may also be used for storing data that is manipulated by the processor 704 when executing software.

One or more processors 704 in the processing system may execute software. Software shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. The software may reside on a computer-readable medium 706. The computer-readable medium 706 may be a non-transitory computer-readable medium. A non-transitory computer-readable medium includes, by way of example, a magnetic storage device (e.g., hard disk, floppy disk, magnetic strip) , an optical disk (e.g., a compact disc (CD) or a digital versatile disc (DVD) ) , a smart card, a flash memory device (e.g., a card, a stick, or a key drive) , a random access memory (RAM) , a read only memory (ROM) , a programmable ROM (PROM) , an erasable PROM (EPROM) , an electrically erasable PROM (EEPROM) , a register, a removable disk, and any other suitable medium for storing software and/or instructions that may be accessed and read by a computer. The computer-readable medium 706 may reside in the processing system 714, external to the processing system 714, or distributed across multiple entities including the processing system 714. The computer-readable medium 706 may be embodied in a computer program product. By way of example, a computer program product may include a computer-readable medium in packaging materials. Those skilled in the art will recognize how best to implement the described functionality presented throughout this disclosure depending on the particular application and the overall design constraints imposed on the overall system.

In one or more examples, the computer-readable storage medium 706 may include software configured for various functions, including, for example, wireless communication using dual connectivity techniques (e.g., ENDC) . For example, the software may be configured to implement one or more of the functions described in relation to FIGs. 4–6, 8, and 9.

The software may include processing instructions 752 that can be executed by the processor 704 to perform various data and signal processing functions and algorithm used in wireless communication, for example, between the scheduled entity and a wireless network using dual connectivity techniques (e.g., ENDC) .

The software 706 may include first RAT communication instructions 754 that can be executed by the processor 704 to perform various UL and DL communication functions with a network using a first RAT (e.g., LTE) . For example, the first RAT communication instructions 754 can cause the processor 704 to perform scrambling, descrambling, modulation, demodulation, mapping, demapping, coding, decoding, and other functions used in UL/DL communication with a network using, for example, LTE.

The processor 704 may include second RAT communication instructions 756 that can be executed by the processor 704 to perform various UL and DL communication functions with a network using a second RAT (e.g., NR) . For example, the second RAT communication instructions 756 can cause the processor 704 to perform scrambling, descrambling, modulation, demodulation, mapping, demapping, coding, decoding, and other functions used in UL/DL communication with a network using, for example, NR.

FIG. 8 is a flow chart illustrating an exemplary process 800 for wireless communication in accordance with some aspects of the present disclosure. As described below, some or all illustrated features may be omitted in a particular implementation within the scope of the present disclosure, and some illustrated features may not be required for implementation of all embodiments. In some examples, the process 800 may be carried out by the scheduled entity 700 illustrated in FIG. 7. In some examples, the process 800 may be carried out by any suitable apparatus (e.g., UE) or means for carrying out the functions or algorithm described below.

At block 802, the scheduled entity (e.g., UE 302) receives a first portion of first DL data from a network using a first radio access technology (RAT) . In one aspect, the scheduled entity may use the first RAT communication circuit 742 to receive the first portion of first DL data from the network 300 (e.g., eNB 306) . In one example, the first RAT may be an LTE RAT. In one aspect, the scheduled entity may receive the first portion of first DL data (e.g., user data) in a downlink channel, for example, a physical downlink shared channel (PDSCH) from the eNB 306.

At block 804, the scheduled entity receives a second portion of the first DL data from the network using a second RAT that is different from the first RAT. The second portion represents a certain proportion of the first DL data. In one aspect, the scheduled entity may use the second RAT communication circuit 744 to receive the second portion of the first DL data from the network 300 (e.g., gNB 308) . In one example, the second RAT may be a NR RAT. The scheduled entity may receive the second portion of the first DL data (e.g., user data) in a downlink channel, for example, a PDSCH from the gNB 308. In one aspect, the scheduled entity communicates with the network 300 using LTE and NR in an ENDC configuration or other dual connectivity techniques.

At block 806, the scheduled entity determines a delay (relative delay) in receiving the first portion relative to receiving the second portion. For example, the scheduled entity may use the processing circuit 740 to determine the relative delay. The scheduled entity may use one or more timers (e.g., first timer 720 and second timer 722) to keep track of the time for receiving the first portion and second portion. More detail on determining the relative delay will be described below in relation to FIG. 9.

At block 808, the scheduled entity can transmit an indication (e.g., delay indication) of the relative delay to the network, if the relative delay satisfies a predetermined condition. In one aspect, the scheduled entity may use the first RAT communication circuit 742 to transmit a special CQI (e.g., CQI with a zero value) to the eNB 306 as the delay indication of the relative delay.

At block 810, after transmitting the indication, the scheduled entity receive a portion of second DL data from the network using the second RAT. The portion of second DL data can represent a proportion of the second DL data that is greater than the first proportion of the first DL data. It is because, in response to the special CQI, the scheduling entity (e.g., eNB) , can reduce, throttle, or stop sending DL data to the scheduled entity via the LTE leg. For example, the eNB 306 may communicate to the gNB 308 to stop sharing DL data (user data to the UE) with the eNB.

FIG. 9 is a flow chart illustrating an exemplary process for determining the delay in receiving the first portion of the DL data relative to the second portion. At block 902, the scheduled entity can determine a first arrival time of a first protocol data unit (PDU) of the first portion of the DL data. In one aspect, the scheduled entity may use a first timer 720 in the memory 705 to keep track of the reception or arrival time of the PDUs of the first RAT. At block 904, the scheduled entity determines a second arrival time of a second PDU of the second portion of the DL data. The first PDU and the second PDU may be received at the scheduled entity out of order according to the respective sequence numbers of the first PDU and the second PDU. In one aspect, the first PDU and second PDU may be PDCP PDUs similar to those illustrated in FIG. 5 above. In one aspect, the scheduled entity may use a second timer 722 in the memory 705 to keep track of the reception or arrival time of the PDUs of the second RAT. At block 906, the scheduled entity can determine the delay as a difference between the first arrival time and the second arrival time.

In one configuration, the apparatus 700 for wireless communication includes means for wireless communication using dual connectivity techniques (e.g., ENDC) . In one aspect, the aforementioned means may be the processor 704 shown in FIG. 7 configured to perform the functions recited by the aforementioned means. In another aspect, the aforementioned means may be a circuit or any apparatus configured to perform the functions recited by the aforementioned means.

Of course, in the above examples, the circuitry included in the processor 704 is merely provided as an example, and other means for carrying out the described functions may be included within various aspects of the present disclosure, including but not limited to the instructions stored in the computer-readable storage medium 706, or any other suitable apparatus or means described in any one of the FIGs. 1, 2, and/or 3, and utilizing, for example, the processes and/or algorithms described herein in relation to FIGs. 4–6, 8, and/or 9.

FIG. 10 is a conceptual diagram illustrating an example of a hardware implementation for an exemplary scheduling entity 1000 employing a processing system 1014. In accordance with various aspects of the disclosure, an element, or any portion of an element, or any combination of elements may be implemented with a processing system 1014 that includes one or more processors 1004. For example, the scheduling entity 1000 may be a base station (e.g., gNB or eNB) as illustrated in any one or more of FIGs. 1, 2, and/or 3.

The processing system 1014 may be substantially the same as the processing system 714 illustrated in FIG. 7, including a bus interface 1008, a bus 1002, memory 1005, a processor 1004, and a computer-readable medium 1006. Furthermore, the scheduling entity 1000 may include a user interface 1012 and a transceiver 1010 substantially similar to those described above in FIG. 7. That is, the processor 1004, as utilized in a scheduling entity 1000, may be used to implement any one or more of the processes described and illustrated in FIGs. 3–6 and 11.

In some aspects of the disclosure, the processor 1004 may include circuitry configured for various functions, including, for example, wireless communication using dual connectivity (e.g., ENDC) . For example, the circuitry may be configured to implement one or more of the functions described in relation to FIGs. 3–6 and 11.

In one aspect, the processor 1004 may include a processing circuit 1040, UL/DL communication circuit 1042, and inter-RAN communication circuit 1044. The scheduling entity 1000 may use the processing circuit 1040 alone or in connection with other circuitry to perform various data and signal processing functions and algorithm used in wireless communication, for example, using dual connectivity techniques (e.g., ENDC) . The scheduling entity 1000 may use the UL/DL communication circuit 1042 to perform various UL and DL communication functions with a scheduled entity (e.g., UE) . For example, the UL/DL communication circuit 1042 can perform scrambling, descrambling, modulation, demodulation, mapping, demapping, coding, decoding, and other functions used in UL/DL communication with a scheduled entity. The scheduling entity 1000 may use the inter-RAN communication circuit 1044 to communicate with another scheduling entity (e.g., eNB or gNB) using, for example, an X2-U interface or the like.

In one or more examples, the computer-readable storage medium 1006 may include software configured for various functions, including, for example, wireless communication using dual connectivity techniques (e.g., ENDC) . The software may include processing instructions 1052 that can be executed by the processor 1004 to perform various data and signal processing functions and algorithm used in wireless communication, for example, using ENDC. The software may include UL/DL communication instructions 1054 that can be executed by the processor 1004 to perform various UL and DL communication functions with a scheduled entity (e.g., UE) . The software may include inter-RAN communication instructions 1056 that can be executed by the processor 1004 to communicate with another scheduling entity (e.g., eNB or gNB) using, for example, an X2-U interface or the like.

FIG. 11 is a flow chart illustrating an exemplary process 1100 for wireless communication in accordance with some aspects of the present disclosure. As described below, some or all illustrated features may be omitted in a particular implementation within the scope of the present disclosure, and some illustrated features may not be required for implementation of all embodiments. In some examples, the process 1100 may be carried out by the one or more scheduling entities (e.g., scheduling entity 1000 illustrated in FIG. 10) . In some examples, the process 1100 may be carried out by any suitable apparatus (e.g., eNB or gNB) or means for carrying out the functions or algorithm described below.

At block 1102, a first scheduling entity (e.g., eNB 306) transmits a first portion of first DL data to a UE using a first radio access technology (RAT) . In one example, the first scheduling entity may use an UL/DL communication circuit 1042 to transmit the first portion of first DL data (e.g., DL data via LTE leg) to the UE using LTE.

At block 1104, a second scheduling entity (e.g., gNB 308) transmits a second portion of the first DL data to the UE using a second RAT different from the first RAT. The second portion represents a first proportion of the first DL data. In one example, the second scheduling entity may use an UL/DL communication circuit 1042 to transmit the second portion (e.g., DL data via NR leg) to the UE using NR.

At block 1106, the first scheduling entity receives an indication from the UE of a relative delay in receiving the first portion relative to receiving the second portion. In one example, the first scheduling entity may use the UL/DL communication circuit 1042 to receive the indication from the UE. In one aspect, the indication may include a special CQI that indicates the delay.

At block 1108, the first scheduling entity in coordination with the second scheduling entity apportion, in response to the indication of the relative delay, a transmission of second DL data to the UE among the first RAT and the second RAT such that a proportion of the second DL data transmitted using the second RAT is greater than the first proportion of the first DL data transmitted using the second RAT. In one example, the first scheduling entity may use the Inter-RAN communication circuit 1044 to communicate with the second scheduling entity to apportion the second DL data among the first RAT and second RAT. For example, the first scheduling entity, response to the indication of relative delay, may reduce or stop sending DL data to the UE using the first RAT.

In one configuration, the apparatus 1000 for wireless communication includes means for wireless communication using dual connectivity techniques (e.g., ENDC) at a scheduling entity (e.g., eNB or gNB) . In one aspect, the aforementioned means may be the processor 1004 shown in FIG. 10 configured to perform the functions recited by the aforementioned means. In another aspect, the aforementioned means may be a circuit or any apparatus configured to perform the functions recited by the aforementioned means.

Of course, in the above examples, the circuitry included in the processor 1004 is merely provided as an example, and other means for carrying out the described functions may be included within various aspects of the present disclosure, including but not limited to the instructions stored in the computer-readable storage medium 1006, or any other suitable apparatus or means described in any one of the FIGs. 1, 2, and/or 3, and utilizing, for example, the processes and/or algorithms described herein in relation to FIGs. 4–6, and/or 11.

Several aspects of a wireless communication network have been presented with reference to an exemplary implementation. As those skilled in the art will readily appreciate, various aspects described throughout this disclosure may be extended to other telecommunication systems, network architectures and communication standards.

By way of example, various aspects may be implemented within other systems defined by 3GPP, such as Long-Term Evolution (LTE) , the Evolved Packet System (EPS) , the Universal Mobile Telecommunication System (UMTS) , and/or the Global System for Mobile (GSM) . Various aspects may also be extended to systems defined by the 3rd Generation Partnership Project 2 (3GPP2) , such as CDMA2000 and/or Evolution-Data Optimized (EV-DO) . Other examples may be implemented within systems employing IEEE 802.11 (Wi-Fi) , IEEE 802.16 (WiMAX) , IEEE 802.20, Ultra-Wideband (UWB) , Bluetooth, and/or other suitable systems. The actual telecommunication standard, network architecture, and/or communication standard employed will depend on the specific application and the overall design constraints imposed on the system.

Within the present disclosure, the word “exemplary” is used to mean “serving as an example, instance, or illustration. ” Any implementation or aspect described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other aspects of the disclosure. Likewise, the term “aspects” does not require that all aspects of the disclosure include the discussed feature, advantage or mode of operation. The term “coupled” is used herein to refer to the direct or indirect coupling between two objects. For example, if object A physically touches object B, and object B touches object C, then objects A and C may still be considered coupled to one another-even if they do not directly physically touch each other. For instance, a first object may be coupled to a second object even though the first object is never directly physically in contact with the second object. The terms “circuit” and “circuitry” are used broadly, and intended to include both hardware implementations of electrical devices and conductors that, when connected and configured, enable the performance of the functions described in the present disclosure, without limitation as to the type of electronic circuits, as well as software implementations of information and instructions that, when executed by a processor, enable the performance of the functions described in the present disclosure.

One or more of the components, steps, features and/or functions illustrated in FIGs. 1–11 may be rearranged and/or combined into a single component, step, feature or function or embodied in several components, steps, or functions. Additional elements, components, steps, and/or functions may also be added without departing from novel features disclosed herein. The apparatus, devices, and/or components illustrated in FIGs. 1–11 may be configured to perform one or more of the methods, features, or steps described herein. The novel algorithms described herein may also be efficiently implemented in software and/or embedded in hardware.

It is to be understood that the specific order or hierarchy of steps in the methods disclosed is an illustration of exemplary processes. Based upon design preferences, it is understood that the specific order or hierarchy of steps in the methods may be rearranged. The accompanying method claims present elements of the various steps in a sample order, and are not meant to be limited to the specific order or hierarchy presented unless specifically recited therein.

The previous description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects. Thus, the claims are not intended to be limited to the aspects shown herein, but are to be accorded the full scope consistent with the language of the claims, wherein reference to an element in the singular is not intended to mean “one and only one” unless specifically so stated, but rather “one or more. ” Unless specifically stated otherwise, the term “some” refers to one or more. A phrase referring to “at least one of” a list of items refers to any combination of those items, including single members. As an example, “at least one of: a, b, or c” is intended to cover: a; b; c; a and b; a and c; b and c; and a, b and c. All structural and functional equivalents to the elements of the various aspects described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims.

Claims

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

receiving a first portion of first downlink (DL) data from a network using a first radio access technology (RAT) ;

receiving a second portion of the first DL data from the network using a second RAT different from the first RAT, the second portion representing a first proportion of the first DL data;

determining a relative delay in receiving the first portion relative to receiving the second portion;

transmitting, if the relative delay satisfies a predetermined condition, an indication of the relative delay to the network; and

receiving, after transmitting the indication, a portion of second DL data from the network using the second RAT, the portion of the second DL data representing a proportion of the second DL data that is greater than the first proportion of the first DL data.
The method of claim 1, wherein the receiving the portion of the second DL data comprises:

receiving all of the second DL data from the network using the second RAT without receiving any portion of the second DL data using the first RAT.
The method of claim 1, further comprising:

receiving a second portion of the second DL data from the network using the first RAT, wherein the second portion of the second DL data represents a proportion of the second DL data that is less than a proportion of the first DL represented by the first portion.
The method of claim 1, wherein the transmitting the indication comprises:

transmitting a channel quality indicator (CQI) configured with a first value to indicate the relative delay of the first portion relative to the second portion.
The method of claim 4, wherein the CQI is configurable with at least one second value that is different from the first value, to indicate a channel quality of a downlink channel between the UE and the network.
The method of claim 5, further comprising:

determining a serving cell change associated with the first RAT;

determining a serving cell change associated with the second RAT; and

transmitting the CQI with the at least one second value in a condition that a serving cell change is determined for the first RAT or the second RAT.
The method of claim 1, further comprising:

receiving the first portion of the first DL data using a first DL channel of the first RAT; and

receiving the second portion of the first DL data using a second DL channel of the second RAT,

wherein the first DL channel and the second DL channel are configured in an E-UTRAN New Radio–Dual Connectivity (ENDC) configuration.
The method of claim 1, wherein the determining the relative delay of the first portion of the first DL data comprises:

determining a first arrival time of a first protocol data unit (PDU) of the first portion of the first DL data;

determining a second arrival time of a second PDU of the second portion of the first DL data, wherein the first PDU and the second PDU are received out of order according to respective sequence numbers of the first PDU and the second PDU; and

determining the relative delay as a difference between the first arrival time and the second arrival time.
The method of claim 8, further comprising:

reordering a plurality of packet data convergence protocol (PDCP) PDUs including the first PDU and the second PDU according to respective sequence numbers of the plurality of PDCP PDUs; and

delivering the plurality of PDCP PDUs to a protocol layer above a PDCP layer in an order according to the sequence numbers of the plurality of PDCP PDUs.
The method of claim 1, further comprising:

determining that the relative delay satisfies the predetermined condition by determining that a preselected number of occurrences of the relative delay were detected.
A user equipment (UE) for wireless communication, comprising:

a communication interface;

a memory; and

a processor operatively coupled with the communication interface and the memory, wherein the processor and the memory are configured to:

receive, using the communication interface, a first portion of first downlink (DL) data from a network using a first radio access technology (RAT) ;

receive, using the communication interface, a second portion of the first DL data from the network using a second RAT different from the first RAT, the second portion representing a first proportion of the first DL data;

determine a relative delay in receiving the first portion relative to receiving the second portion;

transmit, using the communication interface, an indication of the relative delay to the network in connection with a determination that the relative delay satisfies a predetermined condition; and

receive, after transmitting the indication, a portion of second DL data from the network using the second RAT, the portion of the second DL data representing a proportion of the second DL data that is greater than the first proportion of the first DL data.
The UE of claim 11, wherein to receive the portion of the second DL data, the processor and the memory are further configured to:

receive all of the second DL data from the network using the second RAT without receiving any portion of the second DL data using the first RAT.
The UE of claim 11, wherein the processor and the memory are further configured to:

receive a second portion of the second DL data from the network using the first RAT, wherein the second portion of the second DL data represents a proportion of the second DL data that is less than a proportion of the first DL data represented by the first portion.
The UE of claim 11, wherein, to transmit the indication, the processor and the memory are further configured to:

transmit a channel quality indicator (CQI) configured with a first value to cause a reduction of the first portion of the first DL data.
The UE of claim 14, wherein the CQI is configurable with at least one second value that is different from the first value, to indicate a channel quality of a downlink channel between the UE and the network.
The UE of claim 15, wherein the processor and the memory are further configured to:

determine a serving cell change associated with the first RAT;

determine a serving cell change associated with the second RAT; and

transmit the CQI with the at least one second value in a condition that a serving cell change is determined for the first RAT or the second RAT.
The UE of claim 11, wherein the processor and the memory are further configured to:

receive, via the communication interface, the first portion of the first DL data using a first DL channel of the first RAT; and

receive, via the communication interface, the second portion of the first DL data using a second DL channel of the second RAT,

wherein the first DL channel and the second DL channel are configured in an E-UTRAN New Radio–Dual Connectivity (ENDC) configuration.
The UE of claim 11, wherein, to determine the relative delay of the first portion of the first DL data, the processor and the memory are further configured to:

determine a first arrival time of a first protocol data unit (PDU) of the first portion of the first DL data;

determine a second arrival time of a second PDU of the second portion of the first DL data, wherein the first PDU and the second PDU are received out of order according to respective sequence numbers of the first PDU and the second PDU; and

determine the relative delay as a difference between the first arrival time and the second arrival time.
The UE of claim 18, wherein the processor and the memory are further configured to:

reorder a plurality of packet data convergence protocol (PDCP) PDUs including the first PDU and the second PDU according to respective sequence numbers of the plurality of PDCP PDUs; and

deliver the plurality of PDCP PDUs to a protocol layer above a PDCP layer in an order according to the sequence numbers of the plurality of PDCP PDUs.
The UE of claim 11, wherein the processor and the memory are further configured to:

determine that the relative delay satisfies the predetermined condition by determining that a preselected number of occurrences of the relative delay were detected.
A method of wireless communication at a wireless network, comprising:

transmitting a first portion of first DL data to a user equipment (UE) using a first radio access technology (RAT) ;

transmitting a second portion of the first DL data to the UE using a second RAT different from the first RAT, the second portion representing a first proportion of the first DL data;

receiving an indication from the UE of a relative delay in receiving the first portion relative to receiving the second portion; and

apportioning, in response to the indication of the relative delay, a transmission of second DL data to the UE among the first RAT and the second RAT such that a proportion of the second DL data transmitted using the second RAT is greater than the first proportion of the first DL data transmitted using the second RAT.
The method of claim 21, further comprising:

transmitting, at a first scheduling entity, the first portion of first DL data to the UE at using the first RAT;

transmitting, at a second scheduling entity, the second portion of the first DL data to the UE using the second RAT; and

signaling, at the first scheduling entity in response to the indication, the second scheduling entity to stop diverting DL data destined to the UE to the first scheduling entity.
The method of claim 21, wherein the receiving the indication comprises:

receiving a channel quality indicator (CQI) configured with a first value to indicate the relative delay, wherein the CQI is configurable with at least one second value that is different from the first value, to indicate a channel quality of a downlink channel between the UE and the wireless network.
The method of claim 21, further comprising:

stopping, in response to the indication, transmission of third DL data destined to the UE using the first RAT, contemporaneously transmitting the third DL data to the UE using the second RAT.
The method of claim 21, further comprising:

transmitting the first portion of the first DL data using a first DL channel of the first RAT; and

transmitting the second portion of the first DL data using a second DL channel of the second RAT,

wherein the first DL channel and the second DL channel are configured in an E-UTRAN New Radio–Dual Connectivity (ENDC) configuration.
A master node for wireless communication, comprising:

a communication interface;

a memory; and

a processor operatively coupled with the communication interface and the memory, wherein the processor and the memory are configured to:

transmit a first portion of first DL data to a user equipment (UE) using a first radio access technology (RAT) , in coordination with a secondary node that transmits a second portion of the first DL data to the UE using a second RAT different from the first RAT, the second portion representing a first proportion of the first DL data;

receive an indication from the UE of a relative delay in receiving the first portion relative to receiving the second portion; and

apportion, in coordination with the secondary node and in response to the indication of the relative delay, a transmission of second DL data to the UE among the first RAT and the second RAT such that a proportion of the second DL data transmitted using the second RAT is greater than the first proportion of the first DL data transmitted using the second RAT.
The master node of claim 26, wherein the processor and the memory are further configured to:

signal, in response to the indication, the secondary node to stop diverting DL data destined to the UE to the master node.
The master node of claim 26, wherein for receiving the indication, the processor and the memory are further configured to:

receive a channel quality indicator (CQI) configured with a first value to indicate the relative delay, wherein the CQI is configurable with at least one second value that is different from the first value, to indicate a channel quality of a downlink channel between the UE and the master node.
The master node of claim 26, wherein the processor and the memory are further configured to:

stop, in response to the indication, transmission of third DL data to the UE using the first RAT, in coordination with the secondary node that contemporaneously transmits the third DL data to the UE using the second RAT.
The master node of claim 26, wherein the processor and the memory are further configured to:

transmit the first portion of the first DL data using a first DL channel of the first RAT, in coordination with the secondary node that transmits the second portion of the first DL data using a second DL channel of the second RAT,

wherein the first DL channel and the second DL channel are configured in an E-UTRAN New Radio–Dual Connectivity (ENDC) configuration.
A user equipment (UE) for wireless communication, comprising:

means for receiving a first portion of first downlink (DL) data from a network using a first radio access technology (RAT) ;

means for receiving a second portion of the first DL data from the network using a second RAT different from the first RAT, the second portion representing a first proportion of the first DL data;

means for determining a relative delay in receiving the first portion relative to receiving the second portion;

means for transmitting, if the relative delay satisfies a predetermined condition, an indication of the relative delay to the network; and

means for receiving, after transmitting the indication, a portion of second DL data from the network using the second RAT, the portion of the second DL data representing a proportion of the second DL data that is greater than the first proportion of the first DL data.
A master node for wireless communication, comprising:

means for transmitting a first portion of first downlink (DL) data to a user equipment (UE) using a first radio access technology (RAT) , in coordination with a secondary node that transmits a second portion of the first DL data to the UE using a second RAT different from the first RAT, the second portion representing a first proportion of the first DL data;

means for receiving an indication from the UE of a relative delay in receiving the first portion relative to receiving the second portion; and

means for apportioning, in coordination with the secondary node and in response to the indication of the relative delay, a transmission of second DL data to the UE among the first RAT and the second RAT such that a proportion of the second DL data transmitted using the second RAT is greater than the first proportion of the first DL data transmitted using the second RAT.
A non-transitory computer-readable medium storing computer-executable code, comprising code for causing a user equipment (UE) to:

receive a first portion of first downlink (DL) data from a network using a first radio access technology (RAT) ;

receive a second portion of the first DL data from the network using a second RAT different from the first RAT, the second portion representing a first proportion of the first DL data;

determine a relative delay in receiving the first portion relative to receiving the second portion;

transmit, if the relative delay satisfies a predetermined condition, an indication of the relative delay to the network; and

receive, after transmitting the indication, a portion of second DL data from the network using the second RAT, the portion of the second DL data representing a proportion of the second DL data that is greater than the first proportion of the first DL data.
A non-transitory computer-readable medium storing computer-executable code, comprising code for causing a master node to:

transmit a first portion of first downlink (DL) data to a user equipment (UE) using a first radio access technology (RAT) , in coordination with a secondary node that transmits a second portion of the first DL data to the UE using a second RAT different from the first RAT, the second portion representing a first proportion of the first DL data;

receive an indication from the UE of a relative delay in receiving the first portion relative to receiving the second portion; and

apportion, in coordination with the secondary node and in response to the indication of the relative delay, a transmission of second DL data to the UE among the first RAT and the second RAT such that a proportion of the second DL data transmitted using the second RAT is greater than the first proportion of the first DL data transmitted using the second RAT.