EP4666762A1

EP4666762A1 - Random access enhancement for multi-transmission and reception points

Info

Publication number: EP4666762A1
Application number: EP23921733.4A
Authority: EP
Inventors: Shaozhen GUO; Mostafa KHOSHNEVISAN; Peter Gaal; Xiaoxia Zhang; Tao Luo
Original assignee: Qualcomm Inc
Current assignee: Qualcomm Inc
Priority date: 2023-02-15
Filing date: 2023-02-15
Publication date: 2025-12-24
Also published as: WO2024168568A1; CN120660414A

Abstract

Methods, systems, and devices for wireless communications are described. A user equipment (UE) may receive, from a network entity, a random access order message instructing the UE to perform a random access procedure using a random access configuration associated with a control resource set pool (CORESET) index or a physical cell identifier (PCI). The UE may transmit a random access preamble and may receive a random access response (RAR) in an RAR window. The UE may transmit, in accordance with a feedback configuration based on the RAR, a feedback message indicating whether the UE successfully received the RAR. In some examples, the UE may monitor for transmissions of an RAR data message based on an RAR control message of the RAR. The UE may also transmit a second random access preamble at a power level based on a power adjustment size and a random access attempt counter.

Description

RANDOM ACCESS ENHANCEMENT FOR MULTI-TRANSMISSION AND RECEPTION POINTS

FIELD OF TECHNOLOGY
The following relates to wireless communications, including random access enhancement for multi-transmission and reception points.

BACKGROUND

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 FDMA (OFDMA) , or discrete Fourier transform spread orthogonal frequency division multiplexing (DFT-S-OFDM) . A wireless multiple-access communications system may include one or more base stations, each supporting wireless communication for communication devices, which may be known as user equipment (UE) .
SUMMARY
The described techniques relate to improved methods, systems, devices, and apparatuses that support random access enhancement for multi-transmission and reception points (multi-TRP) . For example, the described techniques provide for a user equipment (UE) to receive, from a network entity, a random access order message instructing the UE to perform a random access procedure using a random access configuration associated with a control resource set (CORESET) pool index or a physical cell identifier (PCI) . The UE may transmit a random access preamble associated with the CORESET pool index or the PCI in response to the random access order message. In response to the preamble, the network entity may transmit a random access response (RAR) to the UE within an RAR window. In some examples, the UE may respond to the RAR by transmitting a feedback message, in accordance with a feedback configuration, indicating whether the UE successfully received the RAR to the network entity, where the feedback configuration may be based on the RAR. Additionally, or alternatively, the UE may receive an RAR control message as part of the RAR, and may monitor for multiple blind transmissions of an RAR data message based on a retransmission configuration that the UE may determine using the RAR control message. In some examples, the UE may receive a random access order message and may transmit a random access preamble at a transmission power level based on a power adjustment size and a random access attempt counter. In some examples, the random access attempt counter may be based on whether a preamble index, a PCI, and a synchronization signal block (SSB) associated with the random access order message are the same as those of a previous random access order message.
A method for wireless communication at a UE is described. The method may include receiving, from a network entity, a random access order message instructing the UE to perform a random access procedure using a random access configuration associated with a CORESET pool index or a PCI, transmitting, to the network entity, a random access preamble of the random access procedure associated with the CORESET pool index or the PCI in response to the random access order message, receiving, from the network entity, an RAR of the random access procedure in an RAR window, and transmitting, to the network entity in accordance with a feedback configuration, a feedback message indicating whether the UE successfully received the RAR, the feedback configuration being based on the RAR.
An apparatus for wireless communication at a UE is described. The apparatus may include a processor, memory coupled with the processor, and instructions stored in the memory. The instructions may be executable by the processor to cause the apparatus to receive, from a network entity, a random access order message instructing the UE to perform a random access procedure using a random access configuration associated with a CORESET pool index or a PCI, transmit, to the network entity, a random access preamble of the random access procedure associated with the CORESET pool index or the PCI in response to the random access order message, receive, from the network entity, an RAR of the random access procedure in an RAR window, and transmit, to the network entity in accordance with a feedback configuration, a feedback message indicating whether the UE successfully received the RAR, the feedback configuration being based on the RAR.
Another apparatus for wireless communication at a UE is described. The apparatus may include means for receiving, from a network entity, a random access order message instructing the UE to perform a random access procedure using a random access configuration associated with a CORESET pool index or a PCI, means for transmitting, to the network entity, a random access preamble of the random access procedure associated with the CORESET pool index or the PCI in response to the random access order message, means for receiving, from the network entity, an RAR of the random access procedure in an RAR window, and means for transmitting, to the network entity in accordance with a feedback configuration, a feedback message indicating whether the UE successfully received the RAR, the feedback configuration being based on the RAR.
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 receive, from a network entity, a random access order message instructing the UE to perform a random access procedure using a random access configuration associated with a CORESET pool index or a PCI, transmit, to the network entity, a random access preamble of the random access procedure associated with the CORESET pool index or the PCI in response to the random access order message, receive, from the network entity, an RAR of the random access procedure in an RAR window, and transmit, to the network entity in accordance with a feedback configuration, a feedback message indicating whether the UE successfully received the RAR, the feedback configuration being based on the RAR.
In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the feedback configuration may include at least one of a feedback timing indicator indicating a timing offset between receipt of the RAR and transmission of the feedback message, a physical uplink control channel (PUCCH) resource indicator indicating a PUCCH resource for transmission of the feedback message, or a transmission power control (TPC) command indicating transmission power related parameter for transmission of the feedback message.
In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the feedback configuration may be based on a payload of the RAR.
Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for transmitting the feedback message in accordance with the feedback configuration may be based on the RAR being associated with the PCI that includes an inactive PCI.
Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for transmitting the feedback message in accordance with the feedback configuration may be based on an indication in the random access order message.
Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for transmitting the feedback message in accordance with the feedback configuration may be based on a format of the payload.
In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the feedback configuration may be based on one or more reserved bits in a physical downlink control channel (PDCCH) order scrambled by a random access radio network temporary identifier (RA-RNTI) .
Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for transmitting the feedback message in accordance with the feedback configuration may be based on a radio resource control (RRC) configuration.
Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for transmitting the feedback message based on the one or more reserved bits may be based on an indication in the random access order message.
Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for transmitting the feedback message in accordance with the feedback configuration may be based on an indication in the random access order message.
In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the random access order message indicates that a payload of the RAR indicates the feedback configuration or that one or more reserved bits in a PDCCH order scrambled by an RA-RNTI indicates the feedback configuration.
A method for wireless communication at a UE is described. The method may include receiving, from a network entity, a random access order message instructing the UE to perform a random access procedure using a random access configuration associated with a CORESET pool index or a PCI, transmitting, to the network entity, a random access preamble of the random access procedure associated with the CORESET pool index or the PCI in response to the random access order message, receiving, from the network entity, an RAR control message of the random access procedure in an RAR window, the RAR control message indicating a retransmission configuration that identifies a quantity of transmissions of an RAR data message, and monitoring for the quantity of transmissions of the RAR data message based on the RAR control message.
An apparatus for wireless communication at a UE is described. The apparatus may include a processor, memory coupled with the processor, and instructions stored in the memory. The instructions may be executable by the processor to cause the apparatus to receive, from a network entity, a random access order message instructing the UE to perform a random access procedure using a random access configuration associated with a CORESET pool index or a PCI, transmit, to the network entity, a random access preamble of the random access procedure associated with the CORESET pool index or the PCI in response to the random access order message, receive, from the network entity, an RAR control message of the random access procedure in an RAR window, the RAR control message indicating a retransmission configuration that identifies a quantity of transmissions of an RAR data message, and monitor for the quantity of transmissions of the RAR data message based on the RAR control message.
Another apparatus for wireless communication at a UE is described. The apparatus may include means for receiving, from a network entity, a random access order message instructing the UE to perform a random access procedure using a random access configuration associated with a CORESET pool index or a PCI, means for transmitting, to the network entity, a random access preamble of the random access procedure associated with the CORESET pool index or the PCI in response to the random access order message, means for receiving, from the network entity, an RAR control message of the random access procedure in an RAR window, the RAR control message indicating a retransmission configuration that identifies a quantity of transmissions of an RAR data message, and means for monitoring for the quantity of transmissions of the RAR data message based on the RAR control message.
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 receive, from a network entity, a random access order message instructing the UE to perform a random access procedure using a random access configuration associated with a CORESET pool index or a PCI, transmit, to the network entity, a random access preamble of the random access procedure associated with the CORESET pool index or the PCI in response to the random access order message, receive, from the network entity, an RAR control message of the random access procedure in an RAR window, the RAR control message indicating a retransmission configuration that identifies a quantity of transmissions of an RAR data message, and monitor for the quantity of transmissions of the RAR data message based on the RAR control message.
In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, receiving the RAR control message may include operations, features, means, or instructions for receiving the RAR control message that indicates a redundancy version sequence mapped to a set of multiple RAR data message occasions, where monitoring for the quantity of transmissions of the RAR data message occurs within the set of multiple RAR data message occasions in accordance with the redundancy version sequence.
In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, receiving the RAR control message indicating the redundancy version sequence may include operations, features, means, or instructions for receiving the RAR control message that indicates the retransmission configuration that identifies a starting redundancy version value of the redundancy version sequence, where redundancy version values of the redundancy version sequence may be cyclically mapped to the set of multiple RAR data message occasions in a defined order beginning with the starting redundancy version value.
In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, receiving the RAR control message may include operations, features, means, or instructions for receiving the RAR control message that includes one or more reserved bits indicating the retransmission configuration, the one or more reserved bits being processed based on the RAR control message being associated with the PCI that includes an inactive PCI.
In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, receiving the RAR control message may include operations, features, means, or instructions for receiving the RAR control message that includes one or more reserved bits indicating the retransmission configuration, the one or more reserved bits being processed based on an indication in the random access order message.
Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving the RAR data message based on monitoring for the quantity of transmissions.
A method for wireless communication at a UE is described. The method may include receiving, from a network entity, a first random access order message of a random access procedure instructing the UE to transmit a first random access preamble associated with a first preamble index, a first PCI, and a first SSB index, transmitting, to the network entity at a first transmission power level, the first random access preamble of the random access procedure in response to the first random access order message, receiving, from the network entity, a second random access order message instructing the UE to transmit a second random access preamble associated with a second preamble index, a second PCI, and a second SSB index, and transmitting, to the network entity at a second transmission power level, the second random access preamble, where the second transmission power level is based on a power adjustment size and a random access attempt counter, the random access attempt counter being based at least in part on whether the second preamble index, the second PCI, and the second SSB index are the same as the first preamble index, the first PCI, and the first SSB index.
An apparatus for wireless communication at a UE is described. The apparatus may include a processor, memory coupled with the processor, and instructions stored in the memory. The instructions may be executable by the processor to cause the apparatus to receive, from a network entity, a first random access order message of a random access procedure instructing the UE to transmit a first random access preamble associated with a first preamble index, a first PCI, and a first SSB index, transmit, to the network entity at a first transmission power level, the first random access preamble of the random access procedure in response to the first random access order message, receive, from the network entity, a second random access order message instructing the UE to transmit a second random access preamble associated with a second preamble index, a second PCI, and a second SSB index, and transmit, to the network entity at a second transmission power level, the second random access preamble, where the second transmission power level is based on a power adjustment size and a random access attempt counter, the random access attempt counter being based at least in part on whether the second preamble index, the second PCI, and the second SSB index are the same as the first preamble index, the first PCI, and the first SSB index.
Another apparatus for wireless communication at a UE is described. The apparatus may include means for receiving, from a network entity, a first random access order message of a random access procedure instructing the UE to transmit a first random access preamble associated with a first preamble index, a first PCI, and a first SSB index, means for transmitting, to the network entity at a first transmission power level, the first random access preamble of the random access procedure in response to the first random access order message, means for receiving, from the network entity, a second random access order message instructing the UE to transmit a second random access preamble associated with a second preamble index, a second PCI, and a second SSB index, and means for transmitting, to the network entity at a second transmission power level, the second random access preamble, where the second transmission power level is based on a power adjustment size and a random access attempt counter, the random access attempt counter being based at least in part on whether the second preamble index, the second PCI, and the second SSB index are the same as the first preamble index, the first PCI, and the first SSB index.
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 receive, from a network entity, a first random access order message of a random access procedure instructing the UE to transmit a first random access preamble associated with a first preamble index, a first PCI, and a first SSB index, transmit, to the network entity at a first transmission power level, the first random access preamble of the random access procedure in response to the first random access order message, receive, from the network entity, a second random access order message instructing the UE to transmit a second random access preamble associated with a second preamble index, a second PCI, and a second SSB index, and transmit, to the network entity at a second transmission power level, the second random access preamble, where the second transmission power level is based on a power adjustment size and a random access attempt counter, the random access attempt counter being based at least in part on whether the second preamble index, the second PCI, and the second SSB index are the same as the first preamble index, the first PCI, and the first SSB index.
In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the second transmission power level may be further based on a power ramping counter, the power ramping counter being based on whether the second preamble index, the second PCI, and the second SSB index may be the same as the first preamble index, the first PCI, and the first SSB index.
Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for incrementing the random access attempt counter based on the second preamble index, the second PCI, and the second SSB index being the same as the first preamble index, the first PCI, and the first SSB index.
Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for resetting the random access attempt counter based on the second preamble index, the second PCI, or the second SSB index being different from the first preamble index, the first PCI, or the first SSB index.
Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for incrementing the random access attempt counter based on the second preamble index and the second PCI being the same as the first preamble index and the first PCI and incrementing a power ramping counter based on the second preamble index, the second PCI, and the second SSB index being the same as the first preamble index, the first PCI, and the first SSB index.
Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for incrementing the random access attempt counter based on the second preamble index and the second PCI being the same as the first preamble index and the first PCI and keeping a power ramping counter unchanged based on the second preamble index and the second PCI being the same as the first preamble index and the first PCI, and the second SSB index being different from the first SSB index.
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 network entity, a control element message in response to the first random access preamble transmission, where one or more of the random access attempt counter and a power ramping counter may be based on the receipt of the control element message.
Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for resetting the random access attempt counter based on the receipt of the control element message indicating a timing advance corresponding to a timing advance group identifier associated with the random access procedure.
Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for resetting the power ramping counter based on the receipt of the control element message indicating a timing advance corresponding to a timing advance group identifier associated with the random access procedure.
Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for resetting the random access attempt counter and a power ramping counter based on the random access attempt counter reaching a maximum count quantity.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example of a wireless communications system that supports random access enhancement for multi-transmission and reception points (multi-TRP) in accordance with one or more aspects of the present disclosure.
FIG. 2 illustrates an example of a wireless communications system that supports random access enhancement for multi-TRP in accordance with one or more aspects of the present disclosure.
FIG. 3 illustrates an example of a transmission configuration indication (TCI) state assignment diagram that supports random access enhancement for multi-TRP in accordance with one or more aspects of the present disclosure.
FIGs. 4A and 4B illustrate examples of a process flow and a payload format, respectively, that support random access enhancement for multi-TRP in accordance with one or more aspects of the present disclosure.
FIG. 5 illustrates an example of a process flow that supports random access enhancement for multi-TRP in accordance with one or more aspects of the present disclosure.
FIGs. 6A and 6B illustrate examples of payload formats that support random access enhancement for multi-TRP in accordance with one or more aspects of the present disclosure.
FIG. 7 illustrates an example of a physical downlink control channel (PDCCH) format that supports random access enhancement for multi-TRP in accordance with one or more aspects of the present disclosure.
FIG. 8 illustrates an example of a process flow that supports random access enhancement for multi-TRP in accordance with one or more aspects of the present disclosure.
FIG. 9 illustrates an example of a process flow that supports random access enhancement for multi-TRP in accordance with one or more aspects of the present disclosure.
FIGs. 10A and 10B illustrate examples of process flows that support random access enhancement for multi-TRP in accordance with one or more aspects of the present disclosure.
FIG. 11A and 11B illustrate examples of process flows that support random access enhancement for multi-TRP in accordance with one or more aspects of the present disclosure.
FIGs. 12 and 13 illustrate block diagrams of devices that support random access enhancement for multi-TRP in accordance with one or more aspects of the present disclosure.
FIG. 14 illustrates a block diagram of a communications manager that supports random access enhancement for multi-TRP in accordance with one or more aspects of the present disclosure.
FIG. 15 illustrates a diagram of a system including a device that supports random access enhancement for multi-TRP in accordance with one or more aspects of the present disclosure.
FIGs. 16 through 19 illustrate flowcharts showing methods that support random access enhancement for multi-TRP in accordance with one or more aspects of the present disclosure.

DETAILED DESCRIPTION

A UE may communicate with a network entity via multiple transmission-reception points (TRPs) within a multi-transmission and reception points (multi-TRP) configuration. For example, a UE may communicate with a network entity via two TRPs while performing random access channel (RACH) procedures, such as physical RACH (PRACH) procedures, including contention free random access (CFRA) . In some examples, during CFRA, a network entity may determine whether a UE successfully receives a random access response (RAR) based on receiving uplink signals from the UE. However, in a multi-TRP configuration, a UE might send PRACH to a TRP having a physical cell identifier (PCI) that is an inactive PCI (e.g., limited or no ongoing communication between the UE and the TRP via a cell corresponding to the PCI) to measure a timing advance (TA) for the inactive PCI. Thus there may be a delay after CFRA before any uplink information is sent, which may make it difficult for the network entity to determine if the RAR was successfully received, which may result in additional retransmissions and delays in further signaling. Additionally, for CFRA triggered TA acquisition, a network entity may transmit a medium access control control element (MAC-CE) in response to a random access preamble in place of an RAR to signal a TA to the UE, which may be known as RAR-less PRACH. However, power ramping procedures for retransmissions of random access preambles may not yet be defined for RAR-less PRACH.
A wireless communications system may support HARQ-ACK feedback for RAR messages in RACH procedures (e.g., CFRA) . For example, a UE may receive, from a network entity, a random access order message (e.g., a physical downlink control channel (PDCCH) order) instructing the UE to perform a RACH procedure using a random access configuration associated with a control resource set (CORESET) pool index or a PCI. The UE may transmit a RACH preamble associated with the CORESET pool index or the PCI in response to the PDCCH order, and in response to the preamble, the network entity may transmit an RAR to the UE within an RAR window. In some examples, the UE may respond to the RAR by transmitting, to the network entity, a feedback message in accordance with a feedback configuration that the UE may determine using the RAR.
In some examples, by transmitting a feedback message in response to an RAR, a UE may indicate to a network entity 105 that a RACH procedure was successfully completed. The network entity may thus conserve resources and power by avoiding retransmissions of the random access order message, and may improve a speed of operations by allowing the network entity to perform post-RACH procedures with the UE without delay.
Additionally, or alternatively, the UE may receive an RAR control message (e.g., an RAR PDCCH message) as part of the RAR, and may monitor for multiple blind transmissions of an RAR data message (e.g., an RAR physical downlink shared channel (PDSCH) message) based on a retransmission configuration that the UE may determine using the RAR PDCCH message. By enabling blind retransmissions of an RAR data message, a network entity may improve a reliability of RAR by increasing a chance that the UE will successfully receive the RAR data message. Further, for RAR-less PRACH, the UE may support power ramping procedures for retransmitting RACH preambles based on receiving one or more PDCCH orders. By implementing power ramping for RAR-less PRACH, a UE may increase a reliability of preamble retransmissions by increasing a preamble transmission power, while utilizing less resources by decreasing an amount of preamble retransmissions as well.
Aspects of the disclosure are initially described in the context of wireless communications systems. Aspects of the disclosure are further illustrated by and described with reference to wireless communications systems, transmission configuration indication (TCI) state assignment diagrams, process flows, payload formats, and PDCCH formats. Aspects of the disclosure are further illustrated by and described with reference to apparatus diagrams, system diagrams, and flowcharts that relate to random access enhancement for multi-TRP.
FIG. 1 illustrates an example of a wireless communications system 100 that supports random access enhancement for multi-TRP in accordance with one or more aspects of the present disclosure. The wireless communications system 100 may include one or more network entities 105, one or more 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, a New Radio (NR) network, or a network operating in accordance with other systems and radio technologies, including future systems and radio technologies not explicitly mentioned herein.
The network entities 105 may be dispersed throughout a geographic area to form the wireless communications system 100 and may include devices in different forms or having different capabilities. In various examples, a network entity 105 may be referred to as a network element, a mobility element, a radio access network (RAN) node, or network equipment, among other nomenclature. In some examples, network entities 105 and UEs 115 may wirelessly communicate via one or more communication links 125 (e.g., a radio frequency (RF) access link) . For example, a network entity 105 may support a coverage area 110 (e.g., a geographic coverage area) over which the UEs 115 and the network entity 105 may establish one or more communication links 125. The coverage area 110 may be an example of a geographic area over which a network entity 105 and a UE 115 may support the communication of signals according to one or more radio access technologies (RATs) .
The UEs 115 may be dispersed throughout a coverage area 110 of the wireless communications system 100, and each UE 115 may be stationary, or mobile, or both at different times. The UEs 115 may be devices in different forms or having different capabilities. Some example UEs 115 are illustrated in FIG. 1. The UEs 115 described herein may be capable of supporting communications with various types of devices, such as other UEs 115 or network entities 105, as shown in FIG. 1.
As described herein, a node of the wireless communications system 100, which may be referred to as a network node, or a wireless node, may be a network entity 105 (e.g., any network entity described herein) , a UE 115 (e.g., any UE described herein) , a network controller, an apparatus, a device, a computing system, one or more components, or another suitable processing entity configured to perform any of the techniques described herein. For example, a node may be a UE 115. As another example, a node may be a network entity 105. As another example, a first node may be configured to communicate with a second node or a third node. In one aspect of this example, the first node may be a UE 115, the second node may be a network entity 105, and the third node may be a UE 115. In another aspect of this example, the first node may be a UE 115, the second node may be a network entity 105, and the third node may be a network entity 105. In yet other aspects of this example, the first, second, and third nodes may be different relative to these examples. Similarly, reference to a UE 115, network entity 105, apparatus, device, computing system, or the like may include disclosure of the UE 115, network entity 105, apparatus, device, computing system, or the like being a node. For example, disclosure that a UE 115 is configured to receive information from a network entity 105 also discloses that a first node is configured to receive information from a second node.
In some examples, network entities 105 may communicate with the core network 130, or with one another, or both. For example, network entities 105 may communicate with the core network 130 via one or more backhaul communication links 120 (e.g., in accordance with an S1, N2, N3, or other interface protocol) . In some examples, network entities 105 may communicate with one another via a backhaul communication link 120 (e.g., in accordance with an X2, Xn, or other interface protocol) either directly (e.g., directly between network entities 105) or indirectly (e.g., via a core network 130) . In some examples, network entities 105 may communicate with one another via a midhaul communication link 162 (e.g., in accordance with a midhaul interface protocol) or a fronthaul communication link 168 (e.g., in accordance with a fronthaul interface protocol) , or any combination thereof. The backhaul communication links 120, midhaul communication links 162, or fronthaul communication links 168 may be or include one or more wired links (e.g., an electrical link, an optical fiber link) , one or more wireless links (e.g., a radio link, a wireless optical link) , among other examples or various combinations thereof. A UE 115 may communicate with the core network 130 via a communication link 155.
One or more of the network entities 105 described herein may include or may be referred to as a base station 140 (e.g., a base transceiver station, a radio base station, an NR base station, an access point, a radio transceiver, a NodeB, an eNodeB (eNB) , a next-generation NodeB or a giga-NodeB (either of which may be referred to as a gNB) , a 5G NB, a next-generation eNB (ng-eNB) , a Home NodeB, a Home eNodeB, or other suitable terminology) . In some examples, a network entity 105 (e.g., a base station 140) may be implemented in an aggregated (e.g., monolithic, standalone) base station architecture, which may be configured to utilize a protocol stack that is physically or logically integrated within a single network entity 105 (e.g., a single RAN node, such as a base station 140) .
In some examples, a network entity 105 may be implemented in a disaggregated architecture (e.g., a disaggregated base station architecture, a disaggregated RAN architecture) , which may be configured to utilize a protocol stack that is physically or logically distributed among two or more network entities 105, such as an integrated access backhaul (IAB) network, an open RAN (O-RAN) (e.g., a network configuration sponsored by the O-RAN Alliance) , or a virtualized RAN (vRAN) (e.g., a cloud RAN (C-RAN) ) . For example, a network entity 105 may include one or more of a central unit (CU) 160, a distributed unit (DU) 165, a radio unit (RU) 170, a RAN Intelligent Controller (RIC) 175 (e.g., a Near-Real Time RIC (Near-RT RIC) , a Non-Real Time RIC (Non-RT RIC) ) , a Service Management and Orchestration (SMO) 180 system, or any combination thereof. An RU 170 may also be referred to as a radio head, a smart radio head, a remote radio head (RRH) , a remote radio unit (RRU) , or a transmission reception point (TRP) . One or more components of the network entities 105 in a disaggregated RAN architecture may be co-located, or one or more components of the network entities 105 may be located in distributed locations (e.g., separate physical locations) . In some examples, one or more network entities 105 of a disaggregated RAN architecture may be implemented as virtual units (e.g., a virtual CU (VCU) , a virtual DU (VDU) , a virtual RU (VRU) ) .
The split of functionality between a CU 160, a DU 165, and an RU 170 is flexible and may support different functionalities depending on which functions (e.g., network layer functions, protocol layer functions, baseband functions, RF functions, and any combinations thereof) are performed at a CU 160, a DU 165, or an RU 170. For example, a functional split of a protocol stack may be employed between a CU 160 and a DU 165 such that the CU 160 may support one or more layers of the protocol stack and the DU 165 may support one or more different layers of the protocol stack. In some examples, the CU 160 may host upper protocol layer (e.g., layer 3 (L3) , layer 2 (L2) ) functionality and signaling (e.g., Radio Resource Control (RRC) , service data adaption protocol (SDAP) , Packet Data Convergence Protocol (PDCP) ) . The CU 160 may be connected to one or more DUs 165 or RUs 170, and the one or more DUs 165 or RUs 170 may host lower protocol layers, such as layer 1 (L1) (e.g., physical (PHY) layer) or L2 (e.g., radio link control (RLC) layer, medium access control (MAC) layer) functionality and signaling, and may each be at least partially controlled by the CU 160. Additionally, or alternatively, a functional split of the protocol stack may be employed between a DU 165 and an RU 170 such that the DU 165 may support one or more layers of the protocol stack and the RU 170 may support one or more different layers of the protocol stack. The DU 165 may support one or multiple different cells (e.g., via one or more RUs 170) . In some cases, a functional split between a CU 160 and a DU 165, or between a DU 165 and an RU 170 may be within a protocol layer (e.g., some functions for a protocol layer may be performed by one of a CU 160, a DU 165, or an RU 170, while other functions of the protocol layer are performed by a different one of the CU 160, the DU 165, or the RU 170) . A CU 160 may be functionally split further into CU control plane (CU-CP) and CU user plane (CU-UP) functions. A CU 160 may be connected to one or more DUs 165 via a midhaul communication link 162 (e.g., F1, F1-c, F1-u) , and a DU 165 may be connected to one or more RUs 170 via a fronthaul communication link 168 (e.g., open fronthaul (FH) interface) . In some examples, a midhaul communication link 162 or a fronthaul communication link 168 may be implemented in accordance with an interface (e.g., a channel) between layers of a protocol stack supported by respective network entities 105 that are in communication via such communication links.
In wireless communications systems (e.g., wireless communications system 100) , infrastructure and spectral resources for radio access may support wireless backhaul link capabilities to supplement wired backhaul connections, providing an IAB network architecture (e.g., to a core network 130) . In some cases, in an IAB network, one or more network entities 105 (e.g., IAB nodes 104) may be partially controlled by each other. One or more IAB nodes 104 may be referred to as a donor entity or an IAB donor. One or more DUs 165 or one or more RUs 170 may be partially controlled by one or more CUs 160 associated with a donor network entity 105 (e.g., a donor base station 140) . The one or more donor network entities 105 (e.g., IAB donors) may be in communication with one or more additional network entities 105 (e.g., IAB nodes 104) via supported access and backhaul links (e.g., backhaul communication links 120) . IAB nodes 104 may include an IAB mobile termination (IAB-MT) controlled (e.g., scheduled) by DUs 165 of a coupled IAB donor. An IAB-MT may include an independent set of antennas for relay of communications with UEs 115, or may share the same antennas (e.g., of an RU 170) of an IAB node 104 used for access via the DU 165 of the IAB node 104 (e.g., referred to as virtual IAB-MT (vIAB-MT) ) . In some examples, the IAB nodes 104 may include DUs 165 that support communication links with additional entities (e.g., IAB nodes 104, UEs 115) within the relay chain or configuration of the access network (e.g., downstream) . In such cases, one or more components of the disaggregated RAN architecture (e.g., one or more IAB nodes 104 or components of IAB nodes 104) may be configured to operate according to the techniques described herein.
In the case of the techniques described herein applied in the context of a disaggregated RAN architecture, one or more components of the disaggregated RAN architecture may be configured to support random access enhancement for multi-TRP as described herein. For example, some operations described as being performed by a UE 115 or a network entity 105 (e.g., a base station 140) may additionally, or alternatively, be performed by one or more components of the disaggregated RAN architecture (e.g., IAB nodes 104, DUs 165, CUs 160, RUs 170, RIC 175, SMO 180) .
A UE 115 may include or may 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, among other examples. A UE 115 may also include or may be referred to as 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 include or be referred to as a wireless local loop (WLL) station, an Internet of Things (IoT) device, an Internet of Everything (IoE) device, or a machine type communications (MTC) device, among other examples, which may be implemented in various objects such as appliances, or vehicles, meters, among other examples.
The UEs 115 described herein may be able to communicate with various types of devices, such as other UEs 115 that may sometimes act as relays as well as the network entities 105 and the network equipment including macro eNBs or gNBs, small cell eNBs or gNBs, or relay base stations, among other examples, as shown in FIG. 1.
The UEs 115 and the network entities 105 may wirelessly communicate with one another via one or more communication links 125 (e.g., an access link) using resources associated with one or more carriers. The term “carrier” may refer to a set of RF spectrum resources having a defined physical layer structure for supporting the communication links 125. For example, a carrier used for a communication link 125 may include a portion of a RF spectrum band (e.g., a bandwidth part (BWP) ) that is operated according to one or more physical layer channels for a given radio access technology (e.g., LTE, LTE-A, LTE-A Pro, NR) . Each physical layer channel may carry acquisition signaling (e.g., synchronization signals, system information) , control signaling that coordinates operation for the carrier, user data, or other signaling. The wireless communications system 100 may support communication with a UE 115 using 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 frequency division duplexing (FDD) and time division duplexing (TDD) component carriers. Communication between a network entity 105 and other devices may refer to communication between the devices and any portion (e.g., entity, sub-entity) of a network entity 105. For example, the terms “transmitting, ” “receiving, ” or “communicating, ” when referring to a network entity 105, may refer to any portion of a network entity 105 (e.g., a base station 140, a CU 160, a DU 165, a RU 170) of a RAN communicating with another device (e.g., directly or via one or more other network entities 105) .
Signal waveforms transmitted via a carrier may be made up of multiple subcarriers (e.g., using multi-carrier modulation (MCM) techniques such as orthogonal frequency division multiplexing (OFDM) or discrete Fourier transform spread OFDM (DFT-S-OFDM) ) . In a system employing MCM techniques, a resource element may refer to resources of one symbol period (e.g., a duration of one modulation symbol) and one subcarrier, in which case the symbol period and subcarrier spacing may be inversely related. The quantity of bits carried by each resource element may depend on the modulation scheme (e.g., the order of the modulation scheme, the coding rate of the modulation scheme, or both) , such that a relatively higher quantity of resource elements (e.g., in a transmission duration) and a relatively higher order of a modulation scheme may correspond to a relatively higher rate of communication. A wireless communications resource may refer to a combination of an RF spectrum resource, a time resource, and a spatial resource (e.g., a spatial layer, a beam) , and the use of multiple spatial resources may increase the data rate or data integrity for communications with a UE 115.
The time intervals for the network entities 105 or the UEs 115 may be expressed in multiples of a basic time unit which may, for example, refer to a sampling period of T_s=1/ (Δf_max·N_f) seconds, for which Δf_max may represent a supported subcarrier spacing, and N_f may represent a supported discrete Fourier transform (DFT) size. Time intervals of a communications resource may be organized according to radio frames each having a specified duration (e.g., 10 milliseconds (ms) ) . Each radio frame may be identified by a system frame number (SFN) (e.g., ranging from 0 to 1023) .
Each frame may include multiple consecutively-numbered subframes or slots, and each subframe or slot may have the same duration. In some examples, a frame may be divided (e.g., in the time domain) into subframes, and each subframe may be further divided into a quantity of slots. Alternatively, each frame may include a variable quantity of slots, and the quantity of slots may depend on subcarrier spacing. Each slot may include a quantity of symbol periods (e.g., depending on the length of the cyclic prefix prepended to each symbol period) . In some wireless communications systems 100, a slot may further be divided into multiple mini-slots associated with one or more symbols. Excluding the cyclic prefix, each symbol period may be associated with one or more (e.g., N_f) sampling periods. The duration of a symbol period may depend on the subcarrier spacing or frequency band of operation.
A subframe, a slot, a mini-slot, or a symbol may be the smallest scheduling unit (e.g., in the time domain) of the wireless communications system 100 and may be referred to as a transmission time interval (TTI) . In some examples, the TTI duration (e.g., a quantity of symbol periods in a TTI) may be variable. Additionally, or alternatively, the smallest scheduling unit of the wireless communications system 100 may be dynamically selected (e.g., in bursts of shortened TTIs (sTTIs) ) .
In some examples, a network entity 105 (e.g., a base station 140, an RU 170) may be movable and therefore provide communication coverage for a moving coverage area 110. In some examples, different coverage areas 110 associated with different technologies may overlap, but the different coverage areas 110 may be supported by the same network entity 105. In some other examples, the overlapping coverage areas 110 associated with different technologies may be supported by different network entities 105. The wireless communications system 100 may include, for example, a heterogeneous network in which different types of the network entities 105 provide coverage for various coverage areas 110 using the same or different radio access technologies.
The wireless communications system 100 may be configured to support ultra-reliable communications or low-latency communications, or various combinations thereof. For example, the wireless communications system 100 may be configured to support ultra-reliable low-latency communications (URLLC) . The UEs 115 may be designed to support ultra-reliable, low-latency, or critical functions. Ultra-reliable communications may include private communication or group communication and may be supported by one or more services such as push-to-talk, video, or data. Support for ultra-reliable, low-latency functions may include prioritization of services, and such services may be used for public safety or general commercial applications. The terms ultra-reliable, low-latency, and ultra-reliable low-latency may be used interchangeably herein.
In some examples, a UE 115 may be configured to support communicating directly with other UEs 115 via a device-to-device (D2D) communication link 135 (e.g., in accordance with a peer-to-peer (P2P) , D2D, or sidelink protocol) . In some examples, one or more UEs 115 of a group that are performing D2D communications may be within the coverage area 110 of a network entity 105 (e.g., a base station 140, an RU 170) , which may support aspects of such D2D communications being configured by (e.g., scheduled by) the network entity 105. In some examples, one or more UEs 115 of such a group may be outside the coverage area 110 of a network entity 105 or may be otherwise unable to or not configured to receive transmissions from a network entity 105. In some examples, groups of the UEs 115 communicating via D2D communications may support a one-to-many (1: M) system in which each UE 115 transmits to each of the other UEs 115 in the group. In some examples, a network entity 105 may facilitate the scheduling of resources for D2D communications. In some other examples, D2D communications may be carried out between the UEs 115 without an involvement of a network entity 105.
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) or 5G core (5GC) , which may include at least one control plane entity that manages access and mobility (e.g., a mobility management entity (MME) , an access and mobility management function (AMF) ) and at least one user plane entity that routes packets or interconnects to external networks (e.g., a serving gateway (S-GW) , a Packet Data Network (PDN) gateway (P-GW) , or a user plane function (UPF) ) . The control plane entity may manage non-access stratum (NAS) functions such as mobility, authentication, and bearer management for the UEs 115 served by the network entities 105 (e.g., base stations 140) associated with the core network 130. User IP packets may be transferred through the user plane entity, which may provide IP address allocation as well as other functions. The user plane entity may be connected to IP services 150 for one or more network operators. The IP services 150 may include access to the Internet, Intranet (s) , an IP Multimedia Subsystem (IMS) , or a Packet-Switched Streaming Service.
The wireless communications system 100 may operate using one or more frequency bands, which may be 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 because the wavelengths range from approximately one decimeter to one meter in length. UHF waves may be blocked or redirected by buildings and environmental features, which may be referred to as clusters, but the waves may penetrate structures sufficiently for a macro cell to provide service to the UEs 115 located indoors. Communications using UHF waves may be associated with smaller antennas and shorter ranges (e.g., less than 100 kilometers) compared to communications using the smaller frequencies and longer waves of the high frequency (HF) or very high frequency (VHF) portion of the spectrum below 300 MHz.
The wireless communications system 100 may utilize both licensed and unlicensed RF spectrum bands. For example, the wireless communications system 100 may employ License Assisted Access (LAA) , LTE-Unlicensed (LTE-U) radio access technology, or NR technology using an unlicensed band such as the 5 GHz industrial, scientific, and medical (ISM) band. While operating using unlicensed RF spectrum bands, devices such as the network entities 105 and the UEs 115 may employ carrier sensing for collision detection and avoidance. In some examples, operations using unlicensed bands may be based on a carrier aggregation configuration in conjunction with component carriers operating using a licensed band (e.g., LAA) . Operations using unlicensed spectrum may include downlink transmissions, uplink transmissions, P2P transmissions, or D2D transmissions, among other examples.
A network entity 105 (e.g., a base station 140, an RU 170) or a 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. The antennas of a network entity 105 or a UE 115 may be located within one or more antenna arrays or antenna panels, 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 examples, antennas or antenna arrays associated with a network entity 105 may be located at diverse geographic locations. A network entity 105 may include an antenna array with a set of rows and columns of antenna ports that the network entity 105 may use to support beamforming of communications with a UE 115. Likewise, a UE 115 may include one or more antenna arrays that may support various MIMO or beamforming operations. Additionally, or alternatively, an antenna panel may support RF beamforming for a signal transmitted via an antenna port.
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 network entity 105, a UE 115) to shape or steer an antenna beam (e.g., a transmit beam, a 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 some signals propagating along 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 amplitude offsets, phase offsets, or both to signals carried via 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) .
The UEs 115 and the network entities 105 may support retransmissions of data to increase the likelihood that data is received successfully. Hybrid automatic repeat request (HARQ) feedback is one technique for increasing the likelihood that data is received correctly via a communication link (e.g., a communication link 125, a D2D communication link 135) . 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., low signal-to-noise conditions) . In some examples, a device may support same-slot HARQ feedback, in which case the device may provide HARQ feedback in a specific slot for data received via a previous symbol in the slot. In some other examples, the device may provide HARQ feedback in a subsequent slot, or according to some other time interval.
Physical channels may be multiplexed for communication using a carrier according to various techniques. A physical control channel and a physical data channel may be multiplexed for signaling via a downlink carrier, for example, using one or more of time division multiplexing (TDM) techniques, frequency division multiplexing (FDM) techniques, or hybrid TDM-FDM techniques. A control region (e.g., a CORESET) for a physical control channel may be defined by a set of symbol periods and may extend across the system bandwidth or a subset of the system bandwidth of the carrier. One or more control regions (e.g., CORESETs) may be configured for a set of the UEs 115. For example, one or more of the UEs 115 may monitor or search control regions for control information according to one or more search space sets, and each search space set may include one or multiple control channel candidates in one or more aggregation levels arranged in a cascaded manner. An aggregation level for a control channel candidate may refer to an amount of control channel resources (e.g., control channel elements (CCEs) ) associated with encoded information for a control information format having a given payload size. Search space sets may include common search space sets configured for sending control information to multiple UEs 115 and UE-specific search space sets for sending control information to a specific UE 115.
A network entity 105 may provide communication coverage via one or more cells, for example a macro cell, a small cell, a hot spot, or other types of cells, or any combination thereof. The term “cell” may refer to a logical communication entity used for communication with a network entity 105 (e.g., using 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) , or others) . In some examples, a cell also may refer to a coverage area 110 or a portion of a coverage area 110 (e.g., a sector) over which the logical communication entity operates. Such cells may range from smaller areas (e.g., a structure, a subset of structure) to larger areas depending on various factors such as the capabilities of the network entity 105. For example, a cell may be or include a building, a subset of a building, or exterior spaces between or overlapping with coverage areas 110, among other examples.
The wireless communications system 100 may support HARQ-ACK feedback for RAR messages in RACH procedures as described herein. For example, in a multi-TRP configuration, a UE 115 may receive, from a network entity 105 via a TRP, a random access order message (e.g., a PDCCH order) instructing the UE 115 to perform a RACH procedure using a random access configuration associated with a CORESET pool index or a PCI (e.g., associated with the TRP) . The UE 115 may transmit a RACH preamble associated with the CORESET pool index or the PCI in response to the PDCCH order, and in response to the preamble, the network entity 105 may transmit an RAR to the UE within an RAR window. In some examples, the UE 115 may respond to the RAR by transmitting a feedback message to the network entity 105 in accordance with a feedback configuration that the UE 115 may determine using the RAR. Additionally, or alternatively, the UE 115 may receive an RAR control message (e.g., an RAR PDCCH message) as part of the RAR, and may monitor for multiple blind transmissions of an RAR data message (e.g., an RAR physical downlink shared channel (PDSCH) message) based on a retransmission configuration that the UE 115 may determine using the RAR PDCCH message. Further, for MAC-CE TA acquisition, the UE 115 may support power ramping procedures for retransmitting RACH preambles based on receiving one or more PDCCH orders.
FIG. 2 illustrates an example of a wireless communications system 200 that supports random access enhancement for multi-TRP in accordance with one or more aspects of the present disclosure. The wireless communications system 200 may illustrate an example for implementing one or more aspects of the wireless communications system 100. For example, the wireless communications system 200 may include a network entity 105-a in communication with a UE 115-a via one or more TRPs 205, including a first TRP 205-a and a second TRP 205-b. In some examples, the wireless communications system 200 may support multiple DCI (multi-DCI) based design multi-TRP transmission. For example, the network entity 105-a may transmit a first DCI (e.g., via the TRP 205-a) to schedule a PDSCH1 transmission from the TRP 205-a, and may transmit a second DCI to schedule a PDSCH2 transmission from the TRP 205-b.
In some examples, the UE 115-a may differentiate between the TRPs 205 based on an index of one or more CORESET pools. For example, each CORESET of a set of CORESETS (e.g., max of 5 CORESETs) may be configured with a value of a CORESETPoolIndex of 1 or 0 to group the CORESETS into two groups. In some examples, the UE 115-a may be configured by a higher layer parameter PDCCH-Config with two values for CORESETPoolIndex for an active BWP of a serving cell, where a CORESET ID=1 and CORESET ID=2 may be grouped under a CORESETPoolIndex=0, and where CORESET ID=3 and CORESET ID=4 may be grouped under a CORESETPoolIndex=1. With reference to FIG. 2, TRP 205-a and TRP 205-b may have each have a same or different CORESETPoolIndex.
In some examples, the TRP 205-a and the TRP 205-b may each have a same PCI (e.g., in an intra-cell layout) . For example, the TRPs 205 may both be part of a same cell (e.g., a serving cell for the UE 115-a) , and may be associated with different panels, RRHs, or other features of a base station (e.g., the network entity 105-a) . By way of another example, the TRPs 205 may have different PCIs (e.g., in an inter-cell layout) . For example, the TRP 205-a may be part of an active serving cell (e.g., active PCI) , and the TRP 205-b may be part of an inactive neighboring cell (e.g., inactive PCI) . In such an example, the UE 115-a may be aware of the PCI associated with the active serving cell and may not be aware of the PCI associated with the inactive serving cell as the UE 115-a may obtain the active PCI during a cell search.
FIG. 3 illustrates an example of a transmission configuration indication (TCI) state assignment diagram 300 that supports random access enhancement for multi-TRP in accordance with one or more aspects of the present disclosure. The TCI state assignment diagram 300 may illustrate an example for implementing one or more aspects of the wireless communications systems 100 and 200. For example, the TCI state assignment diagram may illustrate TCI assignments for one or more cells including the network entity 105-a in communication with the UE 115-a and TRPs 205 described with reference to FIG. 2. In some examples, a TCI state may represent an indication of transmission configurations including quasi-co-location (QCL) relationship between downlink reference signals and one or more ports.
For example, the UE 115-a may be configured (e.g., via RRC signaling) with a list of up to M candidate TCI states at least for the purposes of QCL indication (e.g., M=128) . The TCI states may be configured or defined in a PDSCH-Config. In some examples, a TCI-StateId field may be used for configuring the TCI states for a CORESET, for non-zero-power channel state information reference signal (NZP-CSI-RS) resources (NZP-CSI-RS-Resource) , for physical uplink control channel (PUCCH) resources, for sounding reference signal (SRS) resources, among configuring other parameters.
In some examples, a MAC-CE 305 may be used to activate up to 2^N TCI states out of M total TCI states for PDSCH QCL indication for a given CORESETPoolIndex. In some examples, N bits in DCI may dynamically indicate the TCI state for a PDSCH transmission (e.g., N=3) . For multi-DCI based multi-TRP, the PDSCH may be associated with the CORESETPoolIndex value of the CORESET in which a DCI is received. In some examples, under a PDSCH-config, TCI state configuration may be defined by tci-StatesToAddModList SEQUENCE (SIZE (1.. maxNrofTCI-States) ) OF TCI-State and by tci-StatesToReleaseList SEQUENCE (SIZE (1.. maxNrofTCI-States) ) OF TCI-StateId. In some examples, a TCI state configuration may indicate a CORESETPoolIndex (e.g., corresponding to a TRP 205) . In some cases, for PDCCH, a MAC-CE 305 may activate one TCI state.
In some examples, a TCI state may be associated with one or more synchronization signal blocks (SSBs) . For example, if a TCI state is associated with an SSB of a serving cell (e.g., indicated by an RRC configuration) , the TCI state may be associated with a corresponding PCI (e.g., PCI of active serving cell corresponding to the TRP 205-a) . Additionally, or alternatively, if a TCI state is associated with an SSB different than that of a serving cell, then the TCI state may be associated with a non-serving PCI (e.g., PCI of inactive cell corresponding to TRP 205-b) . In some examples, an RRC indicator or RRC signaling may be utilized for inter-cell multi-TRP. For example, a value SSB-MTC-AdditionalPCI-r17 may be indicated in RRC configuration to indicate non-serving cell information (e.g., corresponding to the inactive PCI of TRP 205-b) that a TCI state and/or QCL information is associated with. In some examples, the indicator or signaling may not convey the PCI value.
In some examples, PCIs may be associated with different active TCI states based on TCI state activation. For example, a serving cell PCI may be associated with one or more active TCI states of a set of active TCI states, while a maximum of 1 additional PCI may be associated with active TCI states of the set of active TCI states. By way of another example, for inter-cell multi-TRP, one PCI associated with one or more of the activated TCI states for PDSCH/PDCCH may be associated with one CORESETPoolIndex, while another PCI associated with one or more of the activated TCI states for PDSCH/PDCCH may be associated with another CORESETPoolIndex. For example, a first MAC-CE 305-a may be transmitted to activate a first set 310-a of TCI states for CORESETPoolIndex=0, where the first set 310-a may be associated with a PCI X, which may represent a PCI associated with a serving cell of the UE 115-a(e.g., a PCI associated with the TRP 205-a) . Additionally, or alternatively, a second MAC-CE 305-b may be transmitted to activate a second set 310-b of TCI states for CORESETPoolIndex=1, where the second set 310-b may be associated with a PCI Y, which may represent a PCI associated with a non-serving cell of the UE 115-a (e.g., an inactive PCI associated with the TRP 205-b) . In some examples, for multi-TRP, at least one PCI may be a serving cell PCI (e.g., PCI X associated with TRP 205-a) while at most one PCI may be associated with an inactive or non-serving cell PCI (e.g., PCI Y associated with the TRP 205-b) .
FIGs. 4A and 4B illustrate examples of a process flow 401 and a payload format 402, respectively, that support random access enhancement for multi-TRP in accordance with one or more aspects of the present disclosure. The process flow 401 and the payload format 402 may illustrate an example for implementing one or more aspects of the wireless communications systems 100 and 200 and the TCI state assignment diagram 300. For example, the process flow 401 may illustrate signaling between a UE 115-b and a network entity 105-b via a TRP 205-c, a TRP 205-d, or both, which may represent the UE 115-a, the network entity 105-a, the TRP 205-a, and the TRP 205-b, respectively, described in FIG. 2. Additionally, the payload format 402 may represent a format of an RAR payload of an RAR as described herein with reference to FIGs. 1–3.
The process flow 401 of FIG. 4A may represent a random access procedure performed between the UE 115-b and the network entity 105-b. For example, the process flow may represent signaling over time from top to bottom for a 2-step contention free RACH (e.g., CFRA) procedure. For example, the 2-step contention free RACH procedure shown in FIG. 4A may include two messages, including a MSG 1 (e.g., RACH preamble) and a MSG 2 (e.g., RAR) . In some examples, in preparation of the 2-step procedure, the network entity 105-a may transmit a MSG 0, or a random access order message, such as a PDCCH order 405-a, instructing the UE to perform random access using a random access configuration associated with a CORESETPoolIndex or a PCI. For example, the network entity 105-b may transmit a PDCCH order 405-a (MSG 0) indicating a random access configuration, the random access configuration indicating a CORESETPoolIndex=1, or the inactive PCI (e.g., PCI Y associated with an inactive cell) associated with the TRP 205-d, as well as one or more resources for a RACH procedure. In some examples, additional signaling, such as RRC signaling, MAC-CE signaling, DCI, a prior PDCCH order, or other signaling may indicate the random access configuration. In some examples, the CORESETPoolIndex may indicate to use the PCI associated with the TRP 205-d, or vice versa. In some examples, the network entity 105-b may transmit the PDCCH order 405-a to the UE 115-b via the TRP 205-c, which may represent a TRP 205 that the UE 115-b has already performed CFRA with. In some cases, the PDCCH order may indicate a resource allocation for a random access preamble 410 for the UE 115-b and a dedicated preamble assignment.
In response to the PDCCH order 405-a, the UE 115-b may transmit, as part of the 2-step CFRA procedure, a MSG 1, such as a random access preamble associated with the CORESETPoolIndex or the PCI. For example, the UE 115-b may transmit a random access preamble 410-a (MSG 1) to the network entity 105-b via the TRP 205-d (e.g., based on the dedicated random access preamble assignment) . After transmitting the random access preamble 410-a, the UE 115-b may receive a MSG 2, such as an RAR 415 from the network entity 105-a during an RAR window (e.g., RRC configured) . For example, during the RAR window, the network entity 105-b may transmit an RAR 415-a (MSG 2) to the UE 115-b via the TRP 205-d based on the random access preamble 410-a. In some examples, if the UE 115-b fails to receive the RAR 415-a, the UE 115-b may refrain from transmitting one or more signals to the network entity 105-b (or performing other communications in connected mode) based on the UE 115-b being out of sync. For example, if the UE 115-b transmits one or more signals after a failed CFRA procedure (or other RACH procedure) , the signals may be transmitted according to incorrect timing or other parameters as the UE 115-b has yet to acquire a TA for the TRP 205-d, which may result in failed reception of the signals at the network entity 105-b.
Additionally, or alternatively, the process flow 401 in FIG. 4A may represent a contention based RACH procedure. For example, in a 4-step contention based RACH procedure, the process flow 401 may include 4 messages, including a MSG 1 (preamble) , a MSG 2 (RAR) , a MSG 3 (a scheduled transmission) , and a MSG 4 (contention resolution) . In the example of FIG. 4, the UE 115-b may transmit a preamble 410-a (in response to the PDCCH order 405-a) , and may receive an RAR 415-a. After receiving the RAR 415-a, the UE 115-b may send a scheduled transmission to the network entity 105-b (e.g., using information in the RAR 415-a) . Based on the transmission, the network entity 105-b may transmit a contention resolution message to the UE 115-b. For example, the network entity 105-b may transmit a downlink message to the UE 115-b to confirm the procedure is successful, and if the UE 115-b receives and successfully decodes the downlink message for contention resolution, the UE 115-b may transmit a HARQ message to confirm. Additionally, or alternatively, the UE 115-b and the network entity 105-b may exchange a MSG A (including MSG 1 and MSG 3) and a MSG B (including MSG 2 and MSG 4) as part of a 2-step contention based RACH procedure.
The payload format 402 of FIG. 4B may represent a configuration of a format for an RAR payload, or an RAR PDSCH 420, of an RAR 415 (e.g., as defined in 3GPP standard TS 38.321, Version 17.3.0, Section 6.2.3) . For example, the RAR 415-a may include an RAR PDSCH 420-a as well as a control message PDCCH 425 (e.g., RAR PDCCH 425) . The RAR PDSCH 420-a may include one or more fields 430 across one or more resources (e.g., time, frequency, spatial resources) . In some examples, the RAR PDSCH 420-a may include fields for bits indicating one or more TA commands, one or more UL grants, one or more temporary cell radio network temporary identifiers (C-RNTIs) , among other fields. In some cases, the RAR PDSCH 420-a may include one or more reserved bits (R) . The RAR PDSCH 420-a may also be octet aligned (e.g., across 7 octets) .
In some examples, the UE 115-b may communicate one or more signals with the network entity 105-b based on performing CFRA. For example, the UE 115-b may acquire a TA for an active cell using CFRA (e.g., associated with the TRP 205-c) and may transmit one or more uplink signals to the network entity 105-b using the acquired TA and one or more active TCI states. In some cases, the UE 115-b may not yet have a TA for the inactive PCI associated with the TRP 205-d, and may thus perform the CFRA procedures described herein to acquire and/or measure a TA for the inactive PCI. In some examples, the network entity 105-b may determine that the CFRA was successfully completed based on receiving one or more uplink signals from the UE 115-b.
In some examples, the UE 115-b may experience a delay before transmitting one or more uplink signals to the network entity 105-b after performing CFRA procedures described with reference to FIG. 4A. For example, the TRP 205-d may be associated with an inactive PCI as described with reference to TRP 205-b in FIG. 2. The UE 115-b may perform CFRA to acquire a TA for the inactive PCI and the TRP 205-d. However, the UE 115-b may wait to perform communications with the network entity 105-b using the TRP 205-d due to the PCI being inactive. For example, the UE 115-b may wait until a MAC-CE 305 activates TCI states associated with the inactive PCI and of a corresponding CORESETPoolIndex (e.g., CORESETPoolIndex=1) . However, delays in uplink transmission following CFRA may make it difficult for the network entity 105-b to determine whether the RAR 415-a was successfully received, and whether CFRA was thus successfully completed, as no feedback is currently defined for CFRA. This may result in the network entity 105-a being unable to send retransmissions to the UE 115-b, or may result in unnecessary retransmissions if none are needed. Techniques described herein may thus enable a UE 115 to indicate successful RAR 415 acquisition and CFRA completion to a network entity 105 by utilizing HARQ-ACK feedback for RAR messages in CFRA or blind RAR payload retransmissions as described with respect to FIGs. 5–8.
FIG. 5 illustrates an example of a process flow 500 that supports random access enhancement for multi-TRP in accordance with one or more aspects of the present disclosure. The process flow 500 may illustrate an example for implementing one or more aspects of the wireless communications systems 100 and 200, the TCI state assignment diagram 300, the process flow 401, and the payload format 402. For example, the process flow 500 may illustrate signaling between a UE 115-c and a network entity 105-c via a TRP 205-e and a TRP 205-f, which may represent the UE 115-b, the network entity 105-b, the TRP 205-c, and the TRP 205-d, respectively, described in FIG. 4A. In some examples, the process flow 500 may illustrate a CFRA procedure between the UE 115-c and the network entity 105-c including communication of a feedback message 505 based on a feedback configuration 510 to indicate successful RAR acquisition. For example, the process flow 500 may illustrate indicating HARQ feedback related information.
For example, the UE 115-c and the network entity 105-c may exchange a PDCCH order 405-b (e.g., via the TRP 205-e) and a random access preamble 410-b (e.g., via the TRP 205-f) in response to the PDCCH order 405-b as described with respect to FIG. 4A. In an example, PDCCH order 405-b may be a PDCCH that includes DCI that instructs the UE 115-c to perform a random access procedure with a TRP 205-f. Based on the random access preamble 410-b, the network entity 105-c may transmit, and the UE 115-c may receive, an RAR 415-b via the TRP 205-f. In some examples, the UE 115-c may determine a feedback configuration 510-a for transmitting a feedback message 505-a to indicate whether the UE 115-c successfully received the RAR, where the UE 115-c may determine the feedback configuration 510-a based on the RAR 415-b. For example, the RAR 415-b may indicate the feedback configuration 510-a for transmitting a feedback message 505. After determining the feedback configuration 510-a, the UE 115-c may transmit the feedback message 505-a (e.g., a MSG 3) to the network entity 105-c (e.g., via the TRP 205-f) in accordance with the feedback configuration 510-a. For example, the UE 115-c may transmit a HARQ-ACK feedback message indicating successful reception of the RAR 415-b. In some examples, the network entity 105-c may determine that the RAR 415-b was successfully received based on receiving the feedback message 505-a. By transmitting HARQ-ACK feedback, the UE 115-c may enable the network entity 105-c to determine that CFRA was successfully completed, which may mitigating one or more delays and missed messages, as well as conserving resources at the UE 115-c and the network entity 105-c.
In some examples, indicating a feedback configuration 510 (or indicating other information) may refer to indicating one or more indexes or including data. For example, the RAR 415-b may indicate the feedback configuration 510-b by indicating an index associated with the feedback configuration 510-a. In an example, the RAR 415-b may indicate an index of a set of indexes mapped to a table of different feedback configurations 510 stored at the UE 115-c. Based on determining the index indicated within the RAR 415-b, the UE 115-c may determine the feedback configuration 510-a by locating the corresponding feedback configuration 510 within the table using index. By way of another example, the RAR 415-b may include the feedback configuration 510-a within one or more fields of the RAR 415-b. For example, the RAR 415-b may include the feedback configuration 510-a, where the feedback configuration 510-a may include one or more indexes related to one or more parameter values, where the UE 115-b may select the one or more parameter values using a parameter value table defined at the UE 115-b and the one or more indexes. Additionally, or alternatively, the feedback configuration 510-a within the RAR 415-b may explicitly indicate (e.g., include within one or more fields of the RAR 415-b) data defining the values for the one or more parameter values (e.g., a timing indicator, resources, transmit power levels, and the like described herein) .
In some examples, the feedback configuration 510-a in the RAR 415-b may include or indicate different HARQ feedback related information for the UE 115-c. For example, the HARQ feedback related information may be a feedback timing indicator, a control channel resource indicator, a transmit power level, or any combination thereof. In an example, the feedback configuration 510-a may indicate a feedback timing indicator, such as a K1 timing offset for feedback. Specifically, the feedback timing indicator may identify a timing offset between receipt of the RAR 415-b (e.g., RAR PDSCH) and the transmission of HARQ feedback, where the UE 115-c may transmit the feedback message 505-a based on the offset. Additionally, or alternatively, the feedback configuration 510-a may indicate a control channel resource indicator that identifies resources for HARQ feedback. For example, the feedback configuration 510-a may include or indicate a PUCCH resource indicator identifying one or more PUCCH resources, where the feedback message 505-a may be transmitted over the resources. The feedback configuration 510-a may also indicate a transmit power level at which the UE 115-a is to transmit the feedback message 505-a, such as a transmit/transmission power control (TPC) command indicating a transmission power (or other transmission power related parameter) for the HARQ feedback. The feedback message 505-a may be transmitted according to the TPC command.
In some examples, the feedback configuration may be indicated in existing UL grant fields of a payload (e.g., PDSCH) of the RAR 415-b as described with respect to FIG. 6A. Additionally, or alternatively, the feedback configuration may be indicated in a RAR PDSCH format as described with respect to FIG. 6B. In some cases, the feedback configuration may be indicated within reserved bits of a control message (e.g., PDCCH) of the RAR 415-b as described with respect to FIG. 7. Additionally, or alternatively, the network entity 105 may support performing multiple blind retransmissions of the RAR PDSCH as described with respect to FIG. 8.
FIGs. 6A and 6B illustrate examples of payload formats 601 and 602 that support random access enhancement for multi-TRP in accordance with one or more aspects of the present disclosure. The payload formats 601 and 602 may illustrate examples for implementing one or more aspects of the wireless communications systems 100 and 200, the TCI state assignment diagram 300, the process flows 401 and 500, and the payload format 402. For example, the payload formats 601 and 602 may illustrate payload message formats for RAR PDSCHs 420 of an RAR 415, such as the RAR 415-b communicated during a CFRA procedure between the UE 115-c and the network entity 105-c described in FIG. 5. In some examples, a feedback configuration 510 may be based on a payload (e.g., PDSCH 420) of the RAR 415-b as described herein. For example, the payload formats 601 and 602 may represent different configurations enabling the RAR 415-b to indicate a feedback configuration 510 for the UE 115-c to transmit a feedback message 505, where the feedback configurations 510 may represent the feedback configuration 510-a.
The payload format 601 of FIG. 6A may illustrate reusing existing bits within UL grants of an RAR 415 to indicate a feedback configuration 510. For example, the payload format 601 may represent an example of the payload format 402, including the fields 430 described with respect to FIG. 4B. For example, the payload format 601 may include fields 430 for reserved bits R, TA commands, UL grants 605, and temporary C-RNTIs fields. As shown in FIG. 6A, one or more bits within the UL grants 605 may be reused to indicate HARQ feedback information in place of UL grant information. For example, the UE 115-c may determine a feedback configuration 510-b based on one or more bits of an UL grant 605-a and at least part of an UL grant 605-b of the RAR PDSCH 420-b as shown in FIG. 6A, where the one or more bits may indicate HARQ feedback related information as described herein. By thus using existing UL grants, a UE 115 may obtain HARQ feedback related information without additional signaling or overhead.
In some examples, the UE 115-c may be determine whether an UL grant indicates grant information or HARQ information related to the feedback configuration 510-b (e.g., K1 timing, TPC, or resource information) based on one or more indications or configurations. In a representative example, the UE 115-c may determine to process one or more of the UL grants 605 (e.g., including UL grants 605-a through 605-d) based on the RAR 415 being associated with an inactive PCI (e.g., based on an indication of the inactive PCI within the PDCCH order 405-b) . For example, if the UE 115-c receives an RAR 415 in response to a random access preamble 410 transmission associated with an inactive PCI (e.g., of an inactive cell) , the UE 115-c may be configured (e.g., via RRC signaling) to process the UL grants 605 to determine HARQ feedback related information. If the UE 115-c is performing CFRA with an active PCI, the UE 115-c may be configured to process the UL grants 605 to determine grant related information instead.
By way of another example, the UE 115-c may process the UL grants 605 to determine the feedback configuration 510-b based on an explicit indication in a PDCCH order 405. For example, the UE 115-c may receive a PDCCH order 405 including a 1-bit indicator in a field of the PDCCH order 405. If the bit field is set to 0, the UE 115-c may process the UL grants 605 in the RAR PDSCH 420-a as containing grant related information. Otherwise, if the bit filed is set to 1, the UE 115-c may treat the UL grants 605 as containing HARQ feedback related information for transmission of a feedback message 505. By including an indication in a PDCCH order 405, additional signaling may be avoided and resources may be conserved.
The payload format 602 of FIG. 6B may illustrate introducing a RAR payload format for indicating HARQ related information and including different fields than the payload format 402 described with reference to FIG. 4B. For example, the RAR PDSCH 420-c may include a format with three reserved bits (instead of one) , and two TA commands. Further, the payload format 602 may be octet aligned with 3 octets (instead of 7) , and may not include additional fields for temporary C-RNTIs or UL grants. The RAR PDSCH 420-c may also include particular feedback fields 610 for indicating a feedback configuration 510, such as the feedback configuration 510-c. For example, the RAR PDSCH 420-c may include a feedback field 610 for a TPC, a feedback field 610 for a K1 timing indicator, and a feedback field 610 for a PUCCH resource indicator for transmitting HARQ feedback. In some examples, the UE 115-c may process information related to HARQ feedback based on a format of the RAR PDSCH 420-c. For example, if the UE 115-c determines that the RAR PDSCH 420-c is of the payload format, the UE 115-c may transmit a feedback message 505 based on the feedback configuration 510-c within the PDSCH 420-c (e.g., using the included TPC, K1 timing indicator, and PUCCH resource information) . In some examples, if UE receives an RAR PDSCH 420 of a different format (e.g., of the format of the RAR PDSCHs 420-a or 420-b) , the UE 115-c may refrain from transmitting a feedback message 505.
FIG. 7 illustrates an example of a PDCCH format 700 that supports random access enhancement for multi-TRP in accordance with one or more aspects of the present disclosure. The PDCCH DCI format 700 may illustrate an example for implementing one or more aspects of the wireless communications systems 100 and 200, the TCI state diagram 300, the process flows 401 and 500, and the payload formats 402, 601, and 602. For example, PDCCH format 700 may illustrate a configuration for RAR PDCCHs 425 of an RAR 415 communicated during a CFRA procedure between the UE 115-c and the network entity 105-c described in FIG. 5. In some examples, the PDCCH format 700 may represent a configuration for an RAR PDCCH 425-a to indicate a feedback configuration 510-d for the UE 115-c to transmit a feedback message 505, where the feedback configuration 510-d may represent the feedback configurations 510 in FIGs. 5, 6A, and 6B.
The RAR PDCCH 425-a may be a DCI format 1_0 scrambled by a random access radio network temporary identifier (RA-RNTI) . For example, a PDCCH 425-a may include a DCI with one or more fields 430 including bits, where the bits of the fields 430 are scrambled by the RA-RNTI. Scrambling with the RA-RNTI may indicate to the UE 115-c that the reserved bits of the PDCCH 425-a include or indicate the feedback configuration. The PDCCH 425-a DCI may include fields 430 for a frequency domain resource allocation (FDRA) , a time domain resource allocation (TDRA) , a virtual resource block (VRB) to physical resource block (PRB) mapping, a modulation and coding scheme (MCS) , a transport block (TB) scaling, and one or more least significant bits (LSBs) of an SFN. The PDCCH 425-a DCI may also include one or more reserved bits 705. In some examples, the UE 115-c may determine the feedback configuration 510-d based on one or more reserved bits in a PDCCH 425. For example, the PDCCH 425-a DCI may indicate the feedback configuration 510-d within the one or more reserved bits 705-a. Specifically, the reserved bits 705-a1 may indicate (e.g., an index associated with or a value of) a TPC, a K1 timing indicator, and a PUCCH resource indicator as described herein. The reserved bits 705-a may also include additional unused reserved bits 705-a2. In some examples, the reserved bits 705-a indicating the TPC, K1 timing indicator, and PUCCH resource indicator may be scrambled by RA-RNTI as well, where scrambling with the RA-RNTI may indicate to the UE 115-c that the reserved bits of the PDCCH 425-a include or indicate those parameters of the feedback configuration. In some examples, by determining HARQ feedback related information from reserved bits 705 of a PDCCH 425, the UE 115-c may avoid additional signaling and conserve one or more resources and power.
In some examples, the UE 115-c may be determine whether to process or ignore the reserved bits 705 based on one or more indications or configurations. In a representative example, the UE 115-c may determine to process the reserved bits 705-a based on an RAR 415 including the RAR PDCCH 425-a being associated with an inactive PCI (e.g., based on an indication of the inactive PCI within the PDCCH order 405-b) . For example, if the UE 115-c receives an RAR 415 in response to a random access preamble 410 transmission associated with an inactive PCI, the UE 115-c may be configured (e.g., via RRC signaling) to process the reserved bits 705-a1 to determine the feedback configuration 510-d. If the UE 115-c is performing CFRA with an active PCI, the UE 115-c may otherwise be configured to ignore the reserved bits 705-a including the reserved bits 705-a1 and 705-a2.
By way of another example, the UE 115 c may process the reserved bits 705-a1 to determine the feedback configuration 510-d based on an explicit indication in a PDCCH order 405. For example, the UE 115-c may receive a PDCCH order 405 including a 1-bit indicator in a field of the PDCCH order 405. If the bit field is set to 0, the UE 115-c may ignore the reserved bits 705. Otherwise, if the bit filed is set to 1, the UE 115-c process the reserved bits 705-a1 to obtain information for scheduling a feedback message 505.
In some examples, whether HARQ feedback information is being provided (e.g., by the network entity 105-c) may be indicated by a PDCCH order 405. If the PDCCH order indicates HARQ feedback information is being provided, a PDCCH order 405 may further indicate whether the related feedback configuration 510 is being indicated in the RAR PDSCH 420 or an RAR PDCCH 425. For example, a PDCCH order 405 may indicate whether a PDSCH 420 or whether one or more reserved bits 705 in a PDCCH 425 of an RAR 415 indicates a feedback configuration 510. Based on this indication, the UE 115-c may determine a feedback configuration 510, and may transmit a feedback message 505 according to a correct TPC, K1 timing indicator, and resources for reception at the network entity 105-c. Thus, by determining feedback configuration 510 indicating HARQ feedback related information from a PDSCH 420 or a PDCCH 425 of an RAR 415, the UE 115-c may be able to accurately transmit feedback to the network entity 105-c.
FIG. 8 illustrates an example of a process flow 800 that supports random access enhancement for multi-TRP in accordance with one or more aspects of the present disclosure. The process flow 800 may illustrate implementing one or more aspects of the wireless communications systems 100 and 200, the TCI state assignment diagram 300, the process flows 401 and 500, the payload formats 402, 601, and 602, and the PDCCH format 700. For example, the process flow 800 may illustrate transmitting one or more RAR PDCCHs 425 and PDSCHs 420 of an RAR 415 between a UE 115-d and a network entity 105-d via one or more TRPs 205, which may represent similar CFRA signaling between UEs 115 and network entities 105 described with reference to FIGs. 1–7. In some examples, the process flow 800 may performing one or more blind retransmissions of an RAR PDSCH 420 as described herein. In some examples, the process flow 800 may support blind retransmission for RAR in a 4-step CFRA or other random access procedure.
For example, the network entity 105-d may transmit a PDCCH order 405-c (e.g., PDCCH that includes DCI that instructs the UE 115-d to perform a random access procedure with a TRP 205-g) to the UE 115-d via a TRP 205-g (e.g., associated with an active PCI) , where the PDCCH order 405-c may instruct the UE 115-d to perform a CFRA procedure using a random access configuration associated with a CORESETPoolIndex or a PCI as described herein. For example, the PDCCH order 405-c may indicate an inactive PCI associated with the TRP 205-h so that the UE 115-d may perform CFRA with the TRP 205-h. The UE 115-d may transmit a RACH (e.g., physical RACH (PRACH) ) preamble associated with the PCI (or CORESETPoolIndex) to the network entity 105-d via the TRP 205-h in response PDCCH order 405-c.
Based on the preamble 410-c, the network entity 105-d may transmit one or more blind RAR PDSCH 420 retransmissions within an RAR window 805 to increase a reliability of the RAR 415 transmission. For example, the UE 115-d may receive, an RAR PDCCH 425-b of the RAR 415 transmission indicating a retransmission configuration 810-a that identifies a quantity of transmissions of an RAR PDSCH 420-d, where the UE 115-d may monitor for receiving the quantity of transmissions within an RAR window 805-a (e.g., a time duration) based on the RAR PDCCH 425-b. That is, after transmitting the RAR PDCCH 425-b, the network entity 105-d may transmit the RAR PDSCH 420-d multiple times (e.g., including a first transmission and three retransmissions) within the RAR window 805-a. Thus, by including multiple transmission of the RAR PDSCH 420-d, the network entity 105-d may improve a reliability of the RAR 415 transmission and increase a chance of the UE 115-d successfully receiving the RAR PDSCH 420-d. For example, the UE 115-d may successfully receive the PDSCH 420-d based on monitoring for the quantity of transmissions.
In some examples, the RAR PDCCH 425-b may indicate a redundancy version (RV) sequence that may be mapped to a plurality of RAR PDSCH occasions within the RAR window 805-a for communicating the RAR PDSCH 420-d transmissions. For example, the RAR PDCCH 425-b may indicate the retransmission configuration identifying a starting RV value within one or more fields of the RAR PDCCH 425-b (e.g., within one or more reserved bits 705) . RV values of the RV sequence may be cyclically mapped (e.g., by the UE 115-d or the network entity 105-d) to one or more RAR PDSCH occasions based on a predefined order and starting with the starting RV value. For example, an order of RV values {0, 2, 3, 1} may be mapped to four RAR PDSCH occasions that occur within the RAR window 805-a. In some examples, the UE 115-d may monitor for the quantity of transmissions of the RAR PDSCH 420-d within the plurality of RAR PDSCH occasions in accordance with the mapped RV sequence. In some examples, a default RV sequence may be used by the UE 115-d and mapped without any indication of the RV starting value within the RAR PDCCH 425-b.
In some examples, blind retransmission related information can be indicated by reusing some reserved bits in the RAR PDCCH 425-b (e.g., DCI format 1_0 scrambled by RA-RNTI) . For example, the UE 115-c may determine whether one or more reserved bits 705 of the RAR PDCCH 425-b indicate the retransmission configuration based on one or more indications or configurations. The blind retransmission related information may indicate, for example, the quantity of transmissions or retransmissions, or both, of the RAR PDCCH 425-b, the RV sequence, the starting RV value, or any combination thereof. In some examples, RRC signaling may indicate whether or not the UE 115-c is to use reserved bits of the PDCCH 425-b to obtain the blind retransmission related information. For example, the UE 115-c may be configured by RRC signaling to determine to process reserved bits 705 of the PDCCH 425-b. In some examples, if RACH (e.g., PRACH) is enabled for inactive PCI (e.g., by signaling from the network entity) , the RRC configuration may indicate that the UE 115-c may use the reserved bits 705 to determine the blind retransmission related information. Otherwise, if the UE 115-c is performing CFRA with an active PCI, the UE 115 c may be configured to ignore the reserved bits 705 and may refrain from monitoring for the retransmissions of the RAR PDSCH 420-d. By way of another example, the UE 115-c may process the reserved bits 705 to determine the feedback configuration 510-d based on an explicit indication in the PDCCH order 405-c. For example, the PDCCH order 405-c (e.g., via DCI) may indicate whether or not the UE 115-c is to process the reserved bits 705.
FIG. 9 illustrates an example of a process flow 900 that supports random access enhancement for multi-TRP in accordance with one or more aspects of the present disclosure. The process flow 900 may illustrate implementing one or more aspects of the wireless communications systems 100 and 200, the TCI state diagram 300, the process flows 401, 500, and 800, the payload formats 402, 601, and 602, and the PDCCH format 700. For example, the process flow 900 may illustrate a CFRA process between the UE 115-b and the network entity 105-b of FIG. 4 using the TRPs 205-c and 205-d.
In some examples, a CFRA process may include power ramping for retransmissions. For example, the UE 115-b and the network entity 105-b may exchange the PDCCH order 405-a, the random access preamble 410-a, and the RAR 415-a as described with reference to FIG. 4 with or without performing HARQ feedback. However, the UE 115-b may fail to receive the RAR 415-a due to interference, due to the network entity 105-b failing to receive the random access preamble 410-a and thus failing to transmit the RAR 415-a, or due one or more other factors. In response to a failed RAR reception at the UE 115-b, the UE 115-b may retransmit the random access preamble 410 according to a power ramping configuration to increase a chance of success of the preamble transmission. For example, the UE 115-b may include a preambleReceivedTargetPower configured by RRC to define an initial random access preamble transmit power. The total equation for the transmit power with ramping may then be defined to set a total transmit power, or PREAMBLE_RECEIVED_TARGET_POWER, to equation 1 below:
DELTA_PREAMBLE may represent a preamble format based power offset, while PREAMBLE_POWER_RAMPING_COUNTER may represent a counter for increasing a power at each additional attempt of a retransmission. For example, if the UE 115-b does not change a beam, the counter may keep increasing at each additional preamble transmission. In some examples, if the UE 115-b conducts beam switching, the counter may remain unchanged (i.e., suspending) . The PREAMBLE_POWER_RAMPING_STEP may represent a power ramping step for CFRA which may be configured by a parameter powerRampingStep for 4-step RACH or 4-step CFRA as described herein. A_dditionally, POWER_OFFSET_2STEP_RA may be used when switching from 2-step RACH to 4-step RACH. If switching, POWER_OFFSET_2STEP_RA may be defined by equation 2 below:
Otherwise, POWER_OFFSET_2STEP_RA may be set to 0. In some examples, for CFRA triggered for TA acquisition, only a TA command indication in an RAR 415 (e.g., the RAR 415-a) may be used. Thus, one or more additional fields 430 may remain empty, or unused, such as an UL grant or a TC-RNTI field as shown in FIG. 4B. Thus, in some cases, in place of using an RAR 415 as a response to a random access preamble 410 in CFRA, a MAC-CE 305 may be used to indicate an absolute TA command. For example, at 905, the UE 115-b may receive, in place of the RAR 415-a, a MAC-CE 305-c indicating the absolute TA command (e.g., associated with an inactive PCI and the TRP 205-d) . At 910, in response, the UE 115-b may transmit a feedback message 505-b in response to receiving the MAC-CE 305-c. For example, the UE 115-b may transmit a HARQ-ACK feedback message to indicate successful or unsuccessful receipt of the MAC-CE 305-c.
In some examples, the UE 115-b may be configured with an RAR window 805 following transmission of a random access preamble 410 for receiving an RAR 415 as described herein, where the UE 115-b may perform power ramping if an RAR 415 is not received within the RAR window 805. However, when receiving the MAC-CE 305-b, the UE 115-b may not be configured with a window, and may thus not be able to determine the power ramping to retransmit the random access preamble 410-a when a later PDCCH order is received that includes a same PCI, a same SSB, a same preamble, or any combination thereof, as a previously received PDCCH order. Further, the UE 115-b may be triggered to retransmit the random access preamble 410-a if the network entity 105-b (e.g., gNB) doesn’ t receive the random access preamble 410-a. Thus, techniques described herein may enable a UE 115 to define power ramping procedures for RAR-less CFRA as described with reference to FIGs. 10A, 10B, 11A, and 11B.
FIGs. 10A and 10B illustrate examples of process flows 1001 and 1002 that support random access enhancement for multi-TRP in accordance with one or more aspects of the present disclosure. The process flows 1001 and 1002 may illustrate implementing one or more aspects of the wireless communications systems 100 and 200, the TCI state assignment diagram 300, the process flows 401, 500, 800, and 900, the payload formats 402, 601, and 602, and the PDCCH format 700. For example, the process flows 1001 and 1002 may illustrate CFRA triggered TA acquisition communicated between a UE 115-e and a network entity 105 via a TRP 205-i, which may represent a UE 115, a network entity 105, and a TRP 205 as described with reference to FIGs. 1–9. In some examples, the process flows 1001 and 1002 may illustrate power ramping procedures for TA acquisition using RAR-less CFRA as described herein.
For example, the process flows 1001 and 1002 may represent power ramping for RAR-less CFRA according to a random access attempt counter and a power adjustment size as described herein. A transmit power of a random access preamble 410 may be defined for RAR-less CFRA by equation 3 below based on the RACH attempt counter:
preambleReceivedTargetPower, DELTA_PREAMBLE, PREAMBLE_POWERAMPING_STEP, and POWER_OFFSET_2STEP_RA may be defined as described with reference to FIG. 9. For example, PRERMBLE_TRAMSMISSION_COUNTER may represent the RACH attempt counter, and PREAMBLE_POWER_RAMPING_STEP may represent the power adjustment size (e.g., configurable step size) . Further, PREAMBLE_TRANSMISSION_COUNTER may represent the random access attempt counter that may increment for each additional random access attempt using same resources, while PREAMBLE_POWER_RAMPING_STEP may represent the power adjustment size, or a configurable step size for adjusting the power of the preamble transmissions. In some examples, the UE 115-e may adjust a power of transmissions of a random access preamble 410 according to equation 3 as described herein.
The process flow 1001 of FIG. 10A may represent power ramp-up procedures within a same PRACH (e.g., CFRA) procedure. For example, the UE 115-e may attempt to receive one or more MAC-CEs in response to RACH (e.g., PRACH) transmissions and may perform power ramp-up procedures for multiple RACH attempts based on a RACH attempt counter and a configurable step size as described herein (e.g., ramp up power for each subsequent RACH attempt) . In FIG. 10A, at 1005, the network entity 105 may transmit, via the TRP 205-i, and the UE 115-e may receive, a first PDCCH order 405-d1 for a first PRACH procedure, where the PDCCH order 405-d1 may instruct the UE 115-d to transmit a first random access preamble 410 associated with a first preamble index, a first PCI, and a first SSB index. In some examples, when the first RACH procedure is initialized, the UE 115-e may set the RACH attempt counter to 1. For example, at 1006 after receiving the PDCCH order 405-d1, the UE 115-e may set PREAMBLE_TRANSMISSION_COUNTER, to 1.
At 1010, the network entity 105, may fail to receive a random access preamble 410 for the first PRACH procedure. For example, the UE 115-e may transmit a first random access preamble 410-d1 at a first power level, such as an initial power level, based on equation 3. The TRP 205-i may thus fail to receive the first preamble based on interference or one or more other failed messages or processes, or based on the power level being too low for the TRP 205-i to detect. In response to the failed preamble transmission, at 1015 the network entity 105 may transmit a second PDCCH order 405-d2 to the UE 115-e via the TRP 205-i. In some examples, the second PDCCH order 405-d2 may also instruct the UE 115-e to transmit a preamble using the first preamble index, the first PCI, and the first SSB index.
In some examples, the RACH attempt counter may be incremented by 1 if the UE 115-e receives a PDCCH order 405 indicating a RACH associated with the same PCI, SSB, and preamble as a previous RACH procedure. For example, at 1020 the UE 115-e may determine the value of the RREAMBLE_TRANSMISSION_COUNTER based on whether the second PDCCH order 405-d2 indicates a same preamble index, PCI, and SSB index as the first PDCCH order 405-d1. By determining such same parameters, the UE 115-e may determine that the PDCCH order 405-d2 belongs to the same first PRACH procedure, and may perform power ramping accordingly (as the reception of a new PDCCH order 405 indicates a failed preamble transmission) . Thus, based on the PDCCH order 405-d2 indicating the first preamble index, PCI and SSB index, the UE 115-e may increment a value of the PREAMBLE_TRANSMISSION_COUNTER to increase a power of a next preamble transmission. For example, at 1025, the UE 115-e may transmit a second preamble 410-d2 at a second, higher transmission power level based on the incremented PREAMBLE_TRANSMISSION_COUNTER to 1 according to equation 3. Thus, based on the second, higher transmission power level, the network entity 105 may transmit, via the TRP 205-i, a MAC-CE 305 at 1030 indicating a TA command for a timing advance group (TAG) identifier (e.g., TAG-ID) corresponding to the first PRACH procedure. The UE 115-e may receive the MAC-CE 305 and may transmit a HARQ-ACK response (e.g., ACK) to indicate that the MAC-CE 305 was successfully received.
In some examples, the RACH attempt counter may be reset to 1 at 1035 when the UE 115-e receives a MAC-CE that indicates a TA command for a corresponding TAG ID (e.g., 3ms after ACK corresponding to the PDSCH carrying the MAC CE) . For example, the UE 115-e may reset the PREAMBLE_TRANSMISSION_COUNTER to 1 based on receiving a MAC-CE 305 for the same PRACH procedure. That is, the UE 115-e may reset the attempt counter based on determining that the MAC-CE indicates the TA command for the TAG-ID associated with the first PRACH procedure. In some examples, the UE 115-e may reset the attempt counter after a duration X (e.g., 3ms) following transmission of the HARQ-ACK to the network entity 105.
The process flow 1002 of FIG. 10B may illustrate power ramp-up procedures performed according to a start of a new PRACH procedure. In some examples, the UE 115-e may reset the RACH attempt counter to 1 if the UE 115-e receives a PDCCH order 405 that indicates a PRACH associated with a different PCI, different SSB, and different preamble or associated with a different TAG ID. For example, the UE 115-e and the network entity 105 (via the TRP 205-i) may exchange one or more PDCCH orders and preambles 410-d1 and 410-d2 and perform power ramp-up as described with reference to FIG. 10A. In some examples, however, the UE 115-d may receive a PDCCH order 405 for a second PRACH procedure (e.g., before reception of a MAC-CE) . For example, at 1040, the UE 115-e may receive a third PDCCH order 405-d3 instructing the UE 115-e to transmit a random access preamble 410 associated with a second preamble index, a second PCI, and a second SSB index. Based on determining that the second preamble index, second PCI, and second SSB index are different than the first preamble index, PCI, and SSB index, the UE 115-e may determine that the PDCCH order 405-d3 corresponds to the second PRACH procedure (e.g., is transmitted by another TRP 205 or network entity 105) , and may reset the PREAMBLE_TRANSMISSION_COUNTER to 1 at 1045. In some examples, the UE 115-e may assume a start of a new RACH procedure when receiving a PDCCH order 405 that indicates a different PCI, different SSB, and different preamble during an ongoing RACH procedure. At 1050, the UE 115-e may transmit a random access preamble 410-d3 for the second PRACH procedure. In some examples, the UE 115-e may also determine that the PDCCH order 405-d3 corresponds to a different TAG ID and may reset the counter to 1 accordingly. Additionally, or alternatively, the UE 115-e may reset the PREAMBLE_TRANSMISSION_COUNTER to 1 based on the PREAMBLE_TRANSMISSION_COUNTER reaching a maximum count quantity.
In some examples, by implementing an attempt counter, the UE 115-e may enable successful retransmissions of preambles during PRACH. Additionally, or alternatively, the UE 115-e may conserve one or more resources by mitigating failed transmissions or miscommunication with the network entity 105.
FIGs. 11A &11B illustrate examples of process flows 1101 and 1102 that support random access enhancement for multi-TRP in accordance with one or more aspects of the present disclosure. The process flows 1101 and 1102 may illustrate implementing one or more aspects of the wireless communications systems 100 and 200, the TCI state assignment diagram 300, the process flows 401, 500, 800, 900, 1001, and 1002, the payload formats 402, 601, and 602, the PDCCH format 700. For example, the process flows 1101 and 1102 may illustrate CFRA triggered TA acquisition and power ramping for a UE 115-f in communication with a network entity 105 via a TRP 205-j as described with reference to FIGs. 10A and 10B, where the UE 115-f may represent the UE 115-e, and the TRP 205-j may represent the TRP 205-i. In some examples, the process flows 1101 and 1102 may illustrate power ramping for RAR-less CFRA according to a random access attempt counter, a power adjustment size, as well as a power ramping counter as described herein.
For example, power ramping for a transmit power of a random access preamble 410 for the UE 115-f may be defined based on a power ramping counter for a preamble according to equation 4 below:
For example, equation 4 may represent the same factors as in equation 3, but may replace PREAMBLE_TRANSMISSION_COUNTER with PREAMBLE_POWER_RAMPING_COUNTER. That is, PREAMBLE_POWER_RAMPING_COUNTER may represent a power ramping counter (e.g., preamble ramping rounter) for a preamble as described herein, and PREAMBLE_POWER_RAMPING_STEP may represent a power adjustment size (e.g., configurable step size) .
In an illustrative example as shown in the process flow 1101 of FIG. 11A, the UE 115-f may attempt to receive a MAC-CE 305 in response to a PRACH transmission of a preamble 410, and may perform power ramp-up for multiple RACH attempts based on the RACH attempt counter, the power ramping counter and the power adjustment size. For example, when RACH for a first PCI, SSB, and preamble is initialized, the UE 115-f may set both the PREAMBLE_TRANSMISSION_COUNTER and PREAMBLE_POWER_RAMPING_COUNTER to 1 as described with reference to FIG. 11A.
In some examples, the RACH attempt counter may incremented by 1 if UE receives a PDCCH order indicating a RACH associated with the same PCI/preamble as a previous RACH. For example, at 1105, the UE 115-f may receive a PDCCH order 405-e2 which may indicate a same preamble index and a same PCI as a previous PDCCH order 405-e1 for transmitting a first preamble 410-e1, and may increment the RACH attempt counter at 1110. However, the power ramping counter may not be changed if the PDCCH order 405-e2 indicates a different SSB than the PDCCH order 405-e1. Thus, at 1110, the UE 115-f may increment PREAMBLE_TRANSMISSION_COUNTER based on the PCI and the preamble index being the same, but may leave PREAMBLE_POWER_RAMPING_COUNTER unchanged based on SSB index being different. Based on the unchanged ramping counter, the UE 115-f may not increase a power of a next transmission and may transmit a random access preamble 410-e2 according to a same initial transmission power level.
In some examples, the RACH attempt counter and power ramping counter may be reset to 1 when the UE 115-f receives a MAC-CE 305 that indicates a TA command for a corresponding TAG ID (e.g., 3ms after ACK corresponding to the PDSCH 420 carrying the MAC-CE) . For example, the UE 115-f may receive a MAC-CE 305, transmit a HARQ-ACK response, and reset both PREAMBLE_TRANSMISSION_COUNTER and PREAMBLE_POWER_RAMPING_COUNTER after a duration X (e.g., 3 ms) based on the MAC-CE 305 indicating a TA associated with a same TAG-ID as described with reference to FIGs. 10A and 10B. The UE 115-f may additionally reset the RACH attempt counter and the power ramping counter when the RACH attempt counter reaches a maximum quantity of preamble transmissions.
Additionally, or alternatively, as shown in the process flow 1102 of FIG. 11B, if the UE 115-f receives a PDCCH Order with a same preamble index and PCI as well as a same SSB index as a previous PDCCH Order, the power ramping counter may be incremented by 1 and the RACH attempt counter may be incremented by 1. For example, at 1115, the UE 115-f may increment both PREAMBLE_TRANSMISSION_COUNTER and PREAMBLE_POWER_RAMPING_COUNTER in response to a PDCCH order 405 indicating a same PCI/preamble/SSB. The UE 115-f may also perform power ramping and transmit the random access preamble 410-e2 at a higher transmission power level according to equation 4 based on the incremented counters, and may reset counters after successfully receiving a MAC-CE 305 with a TA associated with the same TAG as the corresponding PRACH. Further, the UE 115-a may continue the ongoing PRACH procedure or initiate a new PRACH procedure if the UE 115-f receives a PDCCH indicating a different PCI, a different preamble index, and a different SSB. In some examples, if parallel RACH procedures are supported at the UE 115-f, the procedures described herein with respect to FIGs. 10A, 10B, 11A, and 11B may apply to each RACH procedure associated with a corresponding PCI/preamble separately.
In some examples, by implementing a random access attempt counter as well as a power ramping counter, the UE 115-f may enable selective power adjustments based on transmit beams. For example, as described herein with respect to FIG. 11A, the UE 115-f may perform power ramping when PCI, preamble, and SSB index are the same, but may refrain from power ramping when an SSB is different, even if a PCI and preamble index are the same. This may enable the UE 115-f to perform retransmissions at a same power level for different beams, which may conserve power at the UE 115-f.
FIG. 12 illustrates a block diagram 1200 of a device 1205 that supports random access enhancement for multi-TRP in accordance with one or more aspects of the present disclosure. The device 1205 may be an example of aspects of a UE 115 as described herein. The device 1205 may include a receiver 1210, a transmitter 1215, and a communications manager 1220. The device 1205 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 1210 may provide a means for receiving information such as packets, user data, control information, or any combination thereof associated with various information channels (e.g., control channels, data channels, information channels related to random access enhancement for multi-TRP) . Information may be passed on to other components of the device 1205. The receiver 1210 may utilize a single antenna or a set of multiple antennas.
The transmitter 1215 may provide a means for transmitting signals generated by other components of the device 1205. For example, the transmitter 1215 may transmit information such as packets, user data, control information, or any combination thereof associated with various information channels (e.g., control channels, data channels, information channels related to random access enhancement for multi-TRP) . In some examples, the transmitter 1215 may be co-located with a receiver 1210 in a transceiver module. The transmitter 1215 may utilize a single antenna or a set of multiple antennas.
The communications manager 1220, the receiver 1210, the transmitter 1215, or various combinations thereof or various components thereof may be examples of means for performing various aspects of random access enhancement for multi-TRP as described herein. For example, the communications manager 1220, the receiver 1210, the transmitter 1215, or various combinations or components thereof may support a method for performing one or more of the functions described herein.
In some examples, the communications manager 1220, the receiver 1210, the transmitter 1215, or various combinations or components thereof may be implemented in hardware (e.g., in communications management circuitry) . The hardware may include a processor, a digital signal processor (DSP) , a central processing unit (CPU) , an application-specific integrated circuit (ASIC) , a field-programmable gate array (FPGA) or other programmable logic device, a microcontroller, discrete gate or transistor logic, discrete hardware components, or any combination thereof configured as or otherwise supporting a means for performing the functions described in the present disclosure. In some examples, a processor and memory coupled with the processor may be configured to perform one or more of the functions described herein (e.g., by executing, by the processor, instructions stored in the memory) .
Additionally, or alternatively, in some examples, the communications manager 1220, the receiver 1210, the transmitter 1215, or various combinations or components thereof may be implemented in code (e.g., as communications management software or firmware) executed by a processor. If implemented in code executed by a processor, the functions of the communications manager 1220, the receiver 1210, the transmitter 1215, or various combinations or components thereof may be performed by a general-purpose processor, a DSP, a CPU, an ASIC, an FPGA, a microcontroller, or any combination of these or other programmable logic devices (e.g., configured as or otherwise supporting a means for performing the functions described in the present disclosure) .
In some examples, the communications manager 1220 may be configured to perform various operations (e.g., receiving, obtaining, monitoring, outputting, transmitting) using or otherwise in cooperation with the receiver 1210, the transmitter 1215, or both. For example, the communications manager 1220 may receive information from the receiver 1210, send information to the transmitter 1215, or be integrated in combination with the receiver 1210, the transmitter 1215, or both to obtain information, output information, or perform various other operations as described herein.
The communications manager 1220 may support wireless communication at a UE in accordance with examples as disclosed herein. For example, the communications manager 1220 may be configured as or otherwise support a means for receiving, from a network entity, a random access order message instructing the UE to perform a random access procedure using a random access configuration associated with a CORESET pool index or a PCI. The communications manager 1220 may be configured as or otherwise support a means for transmitting, to the network entity, a random access preamble of the random access procedure associated with the CORESET pool index or the PCI in response to the random access order message. The communications manager 1220 may be configured as or otherwise support a means for receiving, from the network entity, an RAR of the random access procedure in an RAR window. The communications manager 1220 may be configured as or otherwise support a means for transmitting, to the network entity in accordance with a feedback configuration, a feedback message indicating whether the UE successfully received the RAR, the feedback configuration being based on the RAR.
Additionally, or alternatively, the communications manager 1220 may support wireless communication at a UE in accordance with examples as disclosed herein. For example, the communications manager 1220 may be configured as or otherwise support a means for receiving, from a network entity, a random access order message instructing the UE to perform a random access procedure using a random access configuration associated with a CORESET pool index or a PCI. The communications manager 1220 may be configured as or otherwise support a means for transmitting, to the network entity, a random access preamble of the random access procedure associated with the CORESET pool index or the PCI in response to the random access order message. The communications manager 1220 may be configured as or otherwise support a means for receiving, from the network entity, an RAR control message of the random access procedure in an RAR window, the RAR control message indicating a retransmission configuration that identifies a quantity of transmissions of an RAR data message. The communications manager 1220 may be configured as or otherwise support a means for monitoring for the quantity of transmissions of the RAR data message based on the RAR control message.
Additionally, or alternatively, the communications manager 1220 may support wireless communication at a UE in accordance with examples as disclosed herein. For example, the communications manager 1220 may be configured as or otherwise support a means for receiving, from a network entity, a first random access order message of a random access procedure instructing the UE to transmit a first random access preamble associated with a first preamble index, a first PCI, and a first SSB index. The communications manager 1220 may be configured as or otherwise support a means for transmitting, to the network entity at a first transmission power level, the first random access preamble of the random access procedure in response to the first random access order message. The communications manager 1220 may be configured as or otherwise support a means for receiving, from the network entity, a second random access order message instructing the UE to transmit a second random access preamble associated with a second preamble index, a second PCI, and a second SSB index. The communications manager 1220 may be configured as or otherwise support a means for transmitting, to the network entity at a second transmission power level, the second random access preamble, where the second transmission power level is based on a power adjustment size and a random access attempt counter, the random access attempt counter being based at least in part on whether the second preamble index, the second PCI, and the second SSB index are the same as the first preamble index, the first PCI, and the first SSB index.
By including or configuring the communications manager 1220 in accordance with examples as described herein, the device 1205 (e.g., a processor controlling or otherwise coupled with the receiver 1210, the transmitter 1215, the communications manager 1220, or a combination thereof) may support techniques for reduced processing, reduced power consumption, and more efficient utilization of communication resources.
FIG. 13 illustrates a block diagram 1300 of a device 1305 that supports random access enhancement for multi-TRP in accordance with one or more aspects of the present disclosure. The device 1305 may be an example of aspects of a device 1205 or a UE 115 as described herein. The device 1305 may include a receiver 1310, a transmitter 1315, and a communications manager 1320. The device 1305 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 1310 may provide a means for receiving information such as packets, user data, control information, or any combination thereof associated with various information channels (e.g., control channels, data channels, information channels related to random access enhancement for multi-TRP) . Information may be passed on to other components of the device 1305. The receiver 1310 may utilize a single antenna or a set of multiple antennas.
The transmitter 1315 may provide a means for transmitting signals generated by other components of the device 1305. For example, the transmitter 1315 may transmit information such as packets, user data, control information, or any combination thereof associated with various information channels (e.g., control channels, data channels, information channels related to random access enhancement for multi-TRP) . In some examples, the transmitter 1315 may be co-located with a receiver 1310 in a transceiver module. The transmitter 1315 may utilize a single antenna or a set of multiple antennas.
The device 1305, or various components thereof, may be an example of means for performing various aspects of random access enhancement for multi-TRP as described herein. For example, the communications manager 1320 may include a random access order component 1325, a preamble component 1330, a random access response component 1335, a feedback component 1340, or any combination thereof. The communications manager 1320 may be an example of aspects of a communications manager 1220 as described herein. In some examples, the communications manager 1320, or various components thereof, may be configured to perform various operations (e.g., receiving, obtaining, monitoring, outputting, transmitting) using or otherwise in cooperation with the receiver 1310, the transmitter 1315, or both. For example, the communications manager 1320 may receive information from the receiver 1310, send information to the transmitter 1315, or be integrated in combination with the receiver 1310, the transmitter 1315, or both to obtain information, output information, or perform various other operations as described herein.
The communications manager 1320 may support wireless communication at a UE in accordance with examples as disclosed herein. The random access order component 1325 may be configured as or otherwise support a means for receiving, from a network entity, a random access order message instructing the UE to perform a random access procedure using a random access configuration associated with a CORESET pool index or a PCI. The preamble component 1330 may be configured as or otherwise support a means for transmitting, to the network entity, a random access preamble of the random access procedure associated with the CORESET pool index or the PCI in response to the random access order message. The random access response component 1335 may be configured as or otherwise support a means for receiving, from the network entity, an RAR of the random access procedure in an RAR window. The feedback component 1340 may be configured as or otherwise support a means for transmitting, to the network entity in accordance with a feedback configuration, a feedback message indicating whether the UE successfully received the RAR, the feedback configuration being based on the RAR.
Additionally, or alternatively, the communications manager 1320 may support wireless communication at a UE in accordance with examples as disclosed herein. The random access order component 1325 may be configured as or otherwise support a means for receiving, from a network entity, a random access order message instructing the UE to perform a random access procedure using a random access configuration associated with a CORESET pool index or a PCI. The preamble component 1330 may be configured as or otherwise support a means for transmitting, to the network entity, a random access preamble of the random access procedure associated with the CORESET pool index or the PCI in response to the random access order message. The random access response component 1335 may be configured as or otherwise support a means for receiving, from the network entity, an RAR control message of the random access procedure in an RAR window, the RAR control message indicating a retransmission configuration that identifies a quantity of transmissions of an RAR data message. The random access response component 1335 may be configured as or otherwise support a means for monitoring for the quantity of transmissions of the RAR data message based on the RAR control message.
Additionally, or alternatively, the communications manager 1320 may support wireless communication at a UE in accordance with examples as disclosed herein. The random access order component 1325 may be configured as or otherwise support a means for receiving, from a network entity, a first random access order message of a random access procedure instructing the UE to transmit a first random access preamble associated with a first preamble index, a first PCI, and a first SSB index. The preamble component 1330 may be configured as or otherwise support a means for transmitting, to the network entity at a first transmission power level, the first random access preamble of the random access procedure in response to the first random access order message. The random access order component 1325 may be configured as or otherwise support a means for receiving, from the network entity, a second random access order message instructing the UE to transmit a second random access preamble associated with a second preamble index, a second PCI, and a second SSB index. The preamble component 1330 may be configured as or otherwise support a means for transmitting, to the network entity at a second transmission power level, the second random access preamble, where the second transmission power level is based on a power adjustment size and a random access attempt counter, the random access attempt counter being based at least in part on whether the second preamble index, the second PCI, and the second SSB index are the same as the first preamble index, the first PCI, and the first SSB index.
FIG. 14 illustrates a block diagram 1400 of a communications manager 1420 that supports random access enhancement for multi-TRP in accordance with one or more aspects of the present disclosure. The communications manager 1420 may be an example of aspects of a communications manager 1220, a communications manager 1320, or both, as described herein. The communications manager 1420, or various components thereof, may be an example of means for performing various aspects of random access enhancement for multi-TRP as described herein. For example, the communications manager 1420 may include a random access order component 1425, a preamble component 1430, a random access response component 1435, a feedback component 1440, an attempt counter component 1445, a power ramping counter component 1450, a control element component 1455, or any combination thereof. Each of these components may communicate, directly or indirectly, with one another (e.g., via one or more buses) .
The communications manager 1420 may support wireless communication at a UE in accordance with examples as disclosed herein. The random access order component 1425 may be configured as or otherwise support a means for receiving, from a network entity, a random access order message instructing the UE to perform a random access procedure using a random access configuration associated with a CORESET pool index or a PCI. The preamble component 1430 may be configured as or otherwise support a means for transmitting, to the network entity, a random access preamble of the random access procedure associated with the CORESET pool index or the PCI in response to the random access order message. The random access response component 1435 may be configured as or otherwise support a means for receiving, from the network entity, an RAR of the random access procedure in an RAR window. The feedback component 1440 may be configured as or otherwise support a means for transmitting, to the network entity in accordance with a feedback configuration, a feedback message indicating whether the UE successfully received the RAR, the feedback configuration being based on the RAR.
In some examples, the feedback configuration may include at least one of a feedback timing indicator indicating a timing offset between receipt of the RAR and transmission of the feedback message, a PUCCH resource indicator indicating a PUCCH resource for transmission of the feedback message, or a TPC command indicating transmission power related parameter for transmission of the feedback message.
In some examples, the feedback configuration is based on a payload of the RAR.
In some examples, transmitting the feedback message in accordance with the feedback configuration is based on the RAR being associated with the PCI that includes an inactive PCI.
In some examples, transmitting the feedback message in accordance with the feedback configuration is based on an indication in the random access order message.
In some examples, transmitting the feedback message in accordance with the feedback configuration is based on a format of the payload.
In some examples, the feedback configuration is based on one or more reserved bits in a PDCCH order scrambled by an RA-RNTI.
In some examples, transmitting the feedback message in accordance with the feedback configuration is based on an RRC configuration.
In some examples, transmitting the feedback message based on the one or more reserved bits is based on an indication in the random access order message.
In some examples, transmitting the feedback message in accordance with the feedback configuration is based on an indication in the random access order message.
In some examples, the random access order message indicates that a payload of the RAR indicates the feedback configuration or that one or more reserved bits in a PDCCH order scrambled by an RA-RNTI indicates the feedback configuration.
Additionally, or alternatively, the communications manager 1420 may support wireless communication at a UE in accordance with examples as disclosed herein. In some examples, the random access order component 1425 may be configured as or otherwise support a means for receiving, from a network entity, a random access order message instructing the UE to perform a random access procedure using a random access configuration associated with a CORESET pool index or a PCI. In some examples, the preamble component 1430 may be configured as or otherwise support a means for transmitting, to the network entity, a random access preamble of the random access procedure associated with the CORESET pool index or the PCI in response to the random access order message. In some examples, the random access response component 1435 may be configured as or otherwise support a means for receiving, from the network entity, an RAR control message of the random access procedure in an RAR window, the RAR control message indicating a retransmission configuration that identifies a quantity of transmissions of an RAR data message. In some examples, the random access response component 1435 may be configured as or otherwise support a means for monitoring for the quantity of transmissions of the RAR data message based on the RAR control message.
In some examples, to support receiving the RAR control message, the random access response component 1435 may be configured as or otherwise support a means for receiving the RAR control message that indicates a redundancy version sequence mapped to a set of multiple RAR data message occasions, where monitoring for the quantity of transmissions of the RAR data message occurs within the set of multiple RAR data message occasions in accordance with the redundancy version sequence.
In some examples, to support receiving the RAR control message indicating the redundancy version sequence, the random access response component 1435 may be configured as or otherwise support a means for receiving the RAR control message that indicates the retransmission configuration that identifies a starting redundancy version value of the redundancy version sequence, where redundancy version values of the redundancy version sequence are cyclically mapped to the set of multiple RAR data message occasions in a defined order beginning with the starting redundancy version value.
In some examples, to support receiving the RAR control message, the random access response component 1435 may be configured as or otherwise support a means for receiving the RAR control message that includes one or more reserved bits indicating the retransmission configuration, the one or more reserved bits being processed based on the RAR control message being associated with the PCI that includes an inactive PCI.
In some examples, to support receiving the RAR control message, the random access response component 1435 may be configured as or otherwise support a means for receiving the RAR control message that includes one or more reserved bits indicating the retransmission configuration, the one or more reserved bits being processed based on an indication in the random access order message.
In some examples, the random access response component 1435 may be configured as or otherwise support a means for receiving the RAR data message based on monitoring for the quantity of transmissions.
Additionally, or alternatively, the communications manager 1420 may support wireless communication at a UE in accordance with examples as disclosed herein. In some examples, the random access order component 1425 may be configured as or otherwise support a means for receiving, from a network entity, a first random access order message of a random access procedure instructing the UE to transmit a first random access preamble associated with a first preamble index, a first PCI, and a first SSB index. In some examples, the preamble component 1430 may be configured as or otherwise support a means for transmitting, to the network entity at a first transmission power level, the first random access preamble of the random access procedure in response to the first random access order message. In some examples, the random access order component 1425 may be configured as or otherwise support a means for receiving, from the network entity, a second random access order message instructing the UE to transmit a second random access preamble associated with a second preamble index, a second PCI, and a second SSB index. In some examples, the preamble component 1430 may be configured as or otherwise support a means for transmitting, to the network entity at a second transmission power level, the second random access preamble, where the second transmission power level is based on a power adjustment size and a random access attempt counter, the random access attempt counter being based at least in part on whether the second preamble index, the second PCI, and the second SSB index are the same as the first preamble index, the first PCI, and the first SSB index.
In some examples, the second transmission power level is further based on a power ramping counter, the power ramping counter being based on whether the second preamble index, the second PCI, and the second SSB index are the same as the first preamble index, the first PCI, and the first SSB index.
In some examples, the attempt counter component 1445 may be configured as or otherwise support a means for incrementing the random access attempt counter based on the second preamble index, the second PCI, and the second SSB index being the same as the first preamble index, the first PCI, and the first SSB index.
In some examples, the attempt counter component 1445 may be configured as or otherwise support a means for resetting the random access attempt counter based on the second preamble index, the second PCI, or the second SSB index being different from the first preamble index, the first PCI, or the first SSB index.
In some examples, the attempt counter component 1445 may be configured as or otherwise support a means for incrementing the random access attempt counter based on the second preamble index and the second PCI being the same as the first preamble index and the first PCI. In some examples, the power ramping counter component 1450 may be configured as or otherwise support a means for incrementing a power ramping counter based on the second preamble index, the second PCI, and the second SSB index being the same as the first preamble index, the first PCI, and the first SSB index.
In some examples, the attempt counter component 1445 may be configured as or otherwise support a means for incrementing the random access attempt counter based on the second preamble index and the second PCI being the same as the first preamble index and the first PCI. In some examples, the power ramping counter component 1450 may be configured as or otherwise support a means for keeping a power ramping counter unchanged based on the second preamble index and the second PCI being the same as the first preamble index and the first PCI, and the second SSB index being different from the first SSB index.
In some examples, the control element component 1455 may be configured as or otherwise support a means for receiving, from the network entity, a control element message in response to the first random access preamble transmission, where one or more of the random access attempt counter and a power ramping counter is based on the receipt of the control element message.
In some examples, the attempt counter component 1445 may be configured as or otherwise support a means for resetting the random access attempt counter based on the receipt of the control element message indicating a TA corresponding to a timing advance group identifier (e.g., TAG-ID) associated with the random access procedure.
In some examples, the power ramping counter component 1450 may be configured as or otherwise support a means for resetting the power ramping counter based on the receipt of the control element message indicating a TA corresponding to a timing advance group identifier (e.g., TAG-ID) associated with the random access procedure.
In some examples, the attempt counter component 1445 and the power ramping counter component 1450 may be configured as or otherwise support a means for resetting the random access attempt counter and a power ramping counter, respectively, based on the random access attempt counter reaching a maximum count quantity.
FIG. 15 illustrates a diagram of a system 1500 including a device 1505 that supports random access enhancement for multi-TRP in accordance with one or more aspects of the present disclosure. The device 1505 may be an example of or include the components of a device 1205, a device 1305, or a UE 115 as described herein. The device 1505 may communicate (e.g., wirelessly) with one or more network entities 105, one or more UEs 115, or any combination thereof. The device 1505 may include components for bi-directional voice and data communications including components for transmitting and receiving communications, such as a communications manager 1520, an input/output (I/O) controller 1510, a transceiver 1515, an antenna 1525, a memory 1530, code 1535, and a processor 1540. These components may be in electronic communication or otherwise coupled (e.g., operatively, communicatively, functionally, electronically, electrically) via one or more buses (e.g., a bus 1545) .
The I/O controller 1510 may manage input and output signals for the device 1505. The I/O controller 1510 may also manage peripherals not integrated into the device 1505. In some cases, the I/O controller 1510 may represent a physical connection or port to an external peripheral. In some cases, the I/O controller 1510 may utilize an operating system such as or another known operating system. Additionally, or alternatively, the I/O controller 1510 may represent or interact with a modem, a keyboard, a mouse, a touchscreen, or a similar device. In some cases, the I/O controller 1510 may be implemented as part of a processor, such as the processor 1540. In some cases, a user may interact with the device 1505 via the I/O controller 1510 or via hardware components controlled by the I/O controller 1510.
In some cases, the device 1505 may include a single antenna 1525. However, in some other cases, the device 1505 may have more than one antenna 1525, which may be capable of concurrently transmitting or receiving multiple wireless transmissions. The transceiver 1515 may communicate bi-directionally, via the one or more antennas 1525, wired, or wireless links as described herein. For example, the transceiver 1515 may represent a wireless transceiver and may communicate bi-directionally with another wireless transceiver. The transceiver 1515 may also include a modem to modulate the packets, to provide the modulated packets to one or more antennas 1525 for transmission, and to demodulate packets received from the one or more antennas 1525. The transceiver 1515, or the transceiver 1515 and one or more antennas 1525, may be an example of a transmitter 1215, a transmitter 1315, a receiver 1210, a receiver 1310, or any combination thereof or component thereof, as described herein.
The memory 1530 may include random access memory (RAM) and read-only memory (ROM) . The memory 1530 may store computer-readable, computer-executable code 1535 including instructions that, when executed by the processor 1540, cause the device 1505 to perform various functions described herein. The code 1535 may be stored in a non-transitory computer-readable medium such as system memory or another type of memory. In some cases, the code 1535 may not be directly executable by the processor 1540 but may cause a computer (e.g., when compiled and executed) to perform functions described herein. In some cases, the memory 1530 may contain, among other things, a basic I/O system (BIOS) which may control basic hardware or software operation such as the interaction with peripheral components or devices.
The processor 1540 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 1540 may be configured to operate a memory array using a memory controller. In some other cases, a memory controller may be integrated into the processor 1540. The processor 1540 may be configured to execute computer-readable instructions stored in a memory (e.g., the memory 1530) to cause the device 1505 to perform various functions (e.g., functions or tasks supporting random access enhancement for multi-TRP) . For example, the device 1505 or a component of the device 1505 may include a processor 1540 and memory 1530 coupled with or to the processor 1540, the processor 1540 and memory 1530 configured to perform various functions described herein.
The communications manager 1520 may support wireless communication at a UE in accordance with examples as disclosed herein. For example, the communications manager 1520 may be configured as or otherwise support a means for receiving, from a network entity, a random access order message instructing the UE to perform a random access procedure using a random access configuration associated with a CORESET pool index or a PCI. The communications manager 1520 may be configured as or otherwise support a means for transmitting, to the network entity, a random access preamble of the random access procedure associated with the CORESET pool index or the PCI in response to the random access order message. The communications manager 1520 may be configured as or otherwise support a means for receiving, from the network entity, an RAR of the random access procedure in an RAR window. The communications manager 1520 may be configured as or otherwise support a means for transmitting, to the network entity in accordance with a feedback configuration, a feedback message indicating whether the UE successfully received the RAR, the feedback configuration being based on the RAR.
Additionally, or alternatively, the communications manager 1520 may support wireless communication at a UE in accordance with examples as disclosed herein. For example, the communications manager 1520 may be configured as or otherwise support a means for receiving, from a network entity, a random access order message instructing the UE to perform a random access procedure using a random access configuration associated with a CORESET pool index or a PCI. The communications manager 1520 may be configured as or otherwise support a means for transmitting, to the network entity, a random access preamble of the random access procedure associated with the CORESET pool index or the PCI in response to the random access order message. The communications manager 1520 may be configured as or otherwise support a means for receiving, from the network entity, an RAR control message of the random access procedure in an RAR window, the RAR control message indicating a retransmission configuration that identifies a quantity of transmissions of an RAR data message. The communications manager 1520 may be configured as or otherwise support a means for monitoring for the quantity of transmissions of the RAR data message based on the RAR control message.
Additionally, or alternatively, the communications manager 1520 may support wireless communication at a UE in accordance with examples as disclosed herein. For example, the communications manager 1520 may be configured as or otherwise support a means for receiving, from a network entity, a first random access order message of a random access procedure instructing the UE to transmit a first random access preamble associated with a first preamble index, a first PCI, and a first SSB index. The communications manager 1520 may be configured as or otherwise support a means for transmitting, to the network entity at a first transmission power level, the first random access preamble of the random access procedure in response to the first random access order message. The communications manager 1520 may be configured as or otherwise support a means for receiving, from the network entity, a second random access order message instructing the UE to transmit a second random access preamble associated with a second preamble index, a second PCI, and a second SSB index. The communications manager 1520 may be configured as or otherwise support a means for transmitting, to the network entity at a second transmission power level, the second random access preamble, where the second transmission power level is based on a power adjustment size and a random access attempt counter, the random access attempt counter being based at least in part on whether the second preamble index, the second PCI, and the second SSB index are the same as the first preamble index, the first PCI, and the first SSB index.
By including or configuring the communications manager 1520 in accordance with examples as described herein, the device 1505 may support techniques for improved communication reliability, reduced latency, reduced power consumption, more efficient utilization of communication resources, improved coordination between devices, and longer battery life.
In some examples, the communications manager 1520 may be configured to perform various operations (e.g., receiving, monitoring, transmitting) using or otherwise in cooperation with the transceiver 1515, the one or more antennas 1525, or any combination thereof. Although the communications manager 1520 is illustrated as a separate component, in some examples, one or more functions described with reference to the communications manager 1520 may be supported by or performed by the processor 1540, the memory 1530, the code 1535, or any combination thereof. For example, the code 1535 may include instructions executable by the processor 1540 to cause the device 1505 to perform various aspects of random access enhancement for multi-TRP as described herein, or the processor 1540 and the memory 1530 may be otherwise configured to perform or support such operations.
FIG. 16 illustrates a flowchart showing a method 1600 that supports random access enhancement for multi-TRP in accordance with one or more aspects of the present disclosure. The operations of the method 1600 may be implemented by a UE or its components as described herein. For example, the operations of the method 1600 may be performed by a UE 115 as described with reference to FIGs. 1 through 15. In some examples, a UE may execute a set of instructions to control the functional elements of the UE to perform the described functions. Additionally, or alternatively, the UE may perform aspects of the described functions using special-purpose hardware.
At 1605, the method may include receiving, from a network entity, a random access order message instructing the UE to perform a random access procedure using a random access configuration associated with a CORESET pool index or a PCI. The operations of 1605 may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of 1605 may be performed by a random access order component 1425 as described with reference to FIG. 14.
At 1610, the method may include transmitting, to the network entity, a random access preamble of the random access procedure associated with the CORESET pool index or the PCI in response to the random access order message. The operations of 1610 may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of 1610 may be performed by a preamble component 1430 as described with reference to FIG. 14.
At 1615, the method may include receiving, from the network entity, an RAR of the random access procedure in an RAR window. The operations of 1615 may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of 1615 may be performed by a random access response component 1435 as described with reference to FIG. 14.
At 1620, the method may include transmitting, to the network entity in accordance with a feedback configuration, a feedback message indicating whether the UE successfully received the RAR, the feedback configuration being based on the RAR. The operations of 1620 may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of 1620 may be performed by a feedback component 1440 as described with reference to FIG. 14.
FIG. 17 illustrates a flowchart showing a method 1700 that supports random access enhancement for multi-TRP in accordance with one or more aspects of the present disclosure. The operations of the method 1700 may be implemented by a UE or its components as described herein. For example, the operations of the method 1700 may be performed by a UE 115 as described with reference to FIGs. 1 through 15. In some examples, a UE may execute a set of instructions to control the functional elements of the UE to perform the described functions. Additionally, or alternatively, the UE may perform aspects of the described functions using special-purpose hardware.
At 1705, the method may include receiving, from a network entity, a random access order message instructing the UE to perform a random access procedure using a random access configuration associated with a CORESET pool index or a PCI. The operations of 1705 may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of 1705 may be performed by a random access order component 1425 as described with reference to FIG. 14.
At 1710, the method may include transmitting, to the network entity, a random access preamble of the random access procedure associated with the CORESET pool index or the PCI in response to the random access order message. The operations of 1710 may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of 1710 may be performed by a preamble component 1430 as described with reference to FIG. 14.
At 1715, the method may include receiving, from the network entity, an RAR control message of the random access procedure in an RAR window, the RAR control message indicating a retransmission configuration that identifies a quantity of transmissions of an RAR data message. The operations of 1715 may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of 1715 may be performed by a random access response component 1435 as described with reference to FIG. 14.
At 1720, the method may include monitoring for the quantity of transmissions of the RAR data message based on the RAR control message. The operations of 1720 may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of 1720 may be performed by a random access response component 1435 as described with reference to FIG. 14.
FIG. 18 illustrates a flowchart showing a method 1800 that supports random access enhancement for multi-TRP in accordance with one or more aspects of the present disclosure. The operations of the method 1800 may be implemented by a UE or its components as described herein. For example, the operations of the method 1800 may be performed by a UE 115 as described with reference to FIGs. 1 through 15. In some examples, a UE may execute a set of instructions to control the functional elements of the UE to perform the described functions. Additionally, or alternatively, the UE may perform aspects of the described functions using special-purpose hardware.
At 1805, the method may include receiving, from a network entity, a first random access order message of a random access procedure instructing the UE to transmit a first random access preamble associated with a first preamble index, a first PCI, and a first SSB index. The operations of 1805 may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of 1805 may be performed by a random access order component 1425 as described with reference to FIG. 14.
At 1810, the method may include transmitting, to the network entity at a first transmission power level, the first random access preamble of the random access procedure in response to the first random access order message. The operations of 1810 may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of 1810 may be performed by a preamble component 1430 as described with reference to FIG. 14.
At 1815, the method may include receiving, from the network entity, a second random access order message instructing the UE to transmit a second random access preamble associated with a second preamble index, a second PCI, and a second SSB index. The operations of 1815 may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of 1815 may be performed by a random access order component 1425 as described with reference to FIG. 14.
At 1820, the method may include transmitting, to the network entity at a second transmission power level, the second random access preamble, where the second transmission power level is based on a power adjustment size and a random access attempt counter, the random access attempt counter being based at least in part on whether the second preamble index, the second PCI, and the second SSB index are the same as the first preamble index, the first PCI, and the first SSB index. The operations of 1820 may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of 1820 may be performed by a preamble component 1430 as described with reference to FIG. 14.
FIG. 19 illustrates a flowchart showing a method 1900 that supports random access enhancement for multi-TRP in accordance with one or more aspects of the present disclosure. The operations of the method 1900 may be implemented by a UE or its components as described herein. For example, the operations of the method 1900 may be performed by a UE 115 as described with reference to FIGs. 1 through 15. In some examples, a UE may execute a set of instructions to control the functional elements of the UE to perform the described functions. Additionally, or alternatively, the UE may perform aspects of the described functions using special-purpose hardware.
At 1905, the method may include receiving, from a network entity, a first random access order message of a random access procedure instructing the UE to transmit a first random access preamble associated with a first preamble index, a first PCI, and a first SSB index. The operations of 1905 may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of 1905 may be performed by a random access order component 1425 as described with reference to FIG. 14.
At 1910, the method may include transmitting, to the network entity at a first transmission power level, the first random access preamble of the random access procedure in response to the first random access order message. The operations of 1910 may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of 1910 may be performed by a preamble component 1430 as described with reference to FIG. 14.
At 1915, the method may include receiving, from the network entity, a second random access order message instructing the UE to transmit a second random access preamble associated with a second preamble index, a second PCI, and a second SSB index. The operations of 1915 may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of 1915 may be performed by a random access order component 1425 as described with reference to FIG. 14.
At 1920, the method may include transmitting, to the network entity at a second transmission power level, the second random access preamble, where the second transmission power level is based on a power adjustment size, a random access attempt counter, and a power ramping counter, the random access attempt counter and the power ramping counter being based at least in part on whether the second preamble index, the second PCI, and the second SSB index are the same as the first preamble index, the first PCI, and the first SSB index. The operations of 1920 may be performed in accordance with examples as disclosed herein. In some examples, aspects of the operations of 1920 may be performed by a preamble component 1430 as described with reference to FIG. 14.
The following provides an overview of aspects of the present disclosure:
Aspect 1: A method for wireless communication at a UE, comprising: receiving, from a network entity, a random access order message instructing the UE to perform a random access procedure using a random access configuration associated with a control resource set pool index or a physical cell identifier (PCI) ; transmitting, to the network entity, a random access preamble of the random access procedure associated with the control resource set pool index or the PCI in response to the random access order message; receiving, from the network entity, a random access response of the random access procedure in a random access response window; and transmitting, to the network entity in accordance with a feedback configuration, a feedback message indicating whether the UE successfully received the random access response, the feedback configuration being based at least in part on the random access response.
Aspect 2: The method of aspect 1, wherein the feedback configuration comprises at least one of: a feedback timing indicator indicating a timing offset between receipt of the random access response and transmission of the feedback message; a PUCCH resource indicator indicating a PUCCH resource for transmission of the feedback message; or a transmission power control (TPC) command indicating transmission power related parameter for transmission of the feedback message.
Aspect 3: The method of any of aspects 1 through 2, wherein the feedback configuration is based at least in part on a payload of the random access response.
Aspect 4: The method of aspect 3, wherein transmitting the feedback message in accordance with the feedback configuration is based at least in part on the random access response being associated with the PCI that comprises an inactive PCI.
Aspect 5: The method of any of aspects 3 through 4, wherein transmitting the feedback message in accordance with the feedback configuration is based at least in part on an indication in the random access order message.
Aspect 6: The method of any of aspects 3 through 5, wherein transmitting the feedback message in accordance with the feedback configuration is based at least in part on a format of the payload.
Aspect 7: The method of any of aspects 1 through 6, wherein the feedback configuration is based at least in part on one or more reserved bits in a PDCCH order scrambled by a random access radio network temporary identifier (RA-RNTI) .
Aspect 8: The method of aspect 7, wherein transmitting the feedback message in accordance with the feedback configuration is based at least in part on an RRC configuration.
Aspect 9: The method of any of aspects 7 through 8, wherein transmitting the feedback message based at least in part on the one or more reserved bits is based at least in part on an indication in the random access order message.
Aspect 10: The method of any of aspects 1 through 9, wherein transmitting the feedback message in accordance with the feedback configuration is based at least in part on an indication in the random access order message.
Aspect 11: The method of aspect 10, wherein the random access order message indicates that a payload of the random access response indicates the feedback configuration or that one or more reserved bits in a PDCCH order scrambled by a random access radio network temporary identifier (RA-RNTI) indicates the feedback configuration.
Aspect 12: A method for wireless communication at a UE, comprising: receiving, from a network entity, a random access order message instructing the UE to perform a random access procedure using a random access configuration associated with a control resource set pool index or a physical cell identifier (PCI) ; transmitting, to the network entity, a random access preamble of the random access procedure associated with the control resource set pool index or the PCI in response to the random access order message; receiving, from the network entity, a random access response control message of the random access procedure in a random access response window, the random access response control message indicating a retransmission configuration that identifies a quantity of transmissions of a random access response data message; and monitoring for the quantity of transmissions of the random access response data message based at least in part on the random access response control message.
Aspect 13: The method of aspect 12, wherein receiving the random access response control message comprises: receiving the random access response control message that indicates a redundancy version sequence mapped to a plurality of random access response data message occasions, wherein monitoring for the quantity of transmissions of the random access response data message occurs within the plurality of random access response data message occasions in accordance with the redundancy version sequence.
Aspect 14: The method of aspect 13, wherein receiving the random access response control message indicating the redundancy version sequence comprises: receiving the random access response control message that indicates the retransmission configuration that identifies a starting redundancy version value of the redundancy version sequence, wherein redundancy version values of the redundancy version sequence are cyclically mapped to the plurality of random access response data message occasions in a defined order beginning with the starting redundancy version value.
Aspect 15: The method of any of aspects 12 through 14, wherein receiving the random access response control message comprises: receiving the random access response control message that comprises one or more reserved bits indicating the retransmission configuration, the one or more reserved bits being processed based at least in part on the random access response control message being associated with the PCI that comprises an inactive PCI.
Aspect 16: The method of any of aspects 12 through 15, wherein receiving the random access response control message comprises: receiving the random access response control message that comprises one or more reserved bits indicating the retransmission configuration, the one or more reserved bits being processed based at least in part on an indication in the random access order message.
Aspect 17: The method of any of aspects 12 through 16, further comprising: receiving the random access response data message based at least in part on monitoring for the quantity of transmissions.
Aspect 18: A method for wireless communication at a UE, comprising: receiving, from a network entity, a first random access order message of a random access procedure instructing the UE to transmit a first random access preamble associated with a first preamble index, a first physical cell identifier (PCI) , and a first synchronization signal block (SSB) index; transmitting, to the network entity at a first transmission power level, the first random access preamble of the random access procedure in response to the first random access order message; receiving, from the network entity, a second random access order message instructing the UE to transmit a second random access preamble associated with a second preamble index, a second PCI, and a second SSB index; and transmitting, to the network entity at a second transmission power level, the second random access preamble, wherein the second transmission power level is based at least in part on a power adjustment size and a random access attempt counter, the random access attempt counter being based at least in part on whether the second preamble index, the second PCI, and the second SSB index are the same as the first preamble index, the first PCI, and the first SSB index.
Aspect 19: The method of aspect 18, wherein the second transmission power level is further based at least in part on a power ramping counter, the power ramping counter being based at least in part on whether the second preamble index, the second PCI, and the second SSB index are the same as the first preamble index, the first PCI, and the first SSB index.
Aspect 20: The method of any of aspects 18 through 19, further comprising: incrementing the random access attempt counter based at least in part on the second preamble index, the second PCI, and the second SSB index being the same as the first preamble index, the first PCI, and the first SSB index.
Aspect 21: The method of any of aspects 18 through 19, further comprising: resetting the random access attempt counter based at least in part on the second preamble index, the second PCI, or the second SSB index being different from the first preamble index, the first PCI, or the first SSB index.
Aspect 22: The method of any of aspects 18 through 19, further comprising: incrementing the random access attempt counter based at least in part on the second preamble index and the second PCI being the same as the first preamble index and the first PCI; and incrementing a power ramping counter based at least in part on the second preamble index, the second PCI, and the second SSB index being the same as the first preamble index, the first PCI, and the first SSB index.
Aspect 23: The method of any of aspects 18 through 19, further comprising: incrementing the random access attempt counter based at least in part on the second preamble index and the second PCI being the same as the first preamble index and the first PCI; and keeping a power ramping counter unchanged based at least in part on the second preamble index and the second PCI being the same as the first preamble index and the first PCI, and the second SSB index being different from the first SSB index.
Aspect 24: The method of any of aspects 18 through 23, further comprising: receiving, from the network entity, a control element message in response to the first random access preamble transmission, wherein one or more of the random access attempt counter and a power ramping counter is based at least in part on the receipt of the control element message.
Aspect 25: The method of aspect 24, further comprising: resetting the random access attempt counter based at least in part on the receipt of the control element message indicating a timing advance corresponding to a timing advance group identifier associated with the random access procedure.
Aspect 26: The method of any of aspects 24 through 25, further comprising: resetting the power ramping counter based at least in part on the receipt of the control element message indicating a timing advance corresponding to a timing advance group identifier associated with the random access procedure.
Aspect 27: The method of any of aspects 18 through 26, further comprising: resetting the random access attempt counter and a power ramping counter based at least in part on the random access attempt counter reaching a maximum count quantity.
Aspect 28: An apparatus for wireless communication at a UE, comprising a processor; memory coupled with the processor; and instructions stored in the memory and executable by the processor to cause the apparatus to perform a method of any of aspects 1 through 11.
Aspect 29: An apparatus for wireless communication at a UE, comprising at least one means for performing a method of any of aspects 1 through 11.
Aspect 30: A non-transitory computer-readable medium storing code for wireless communication at a UE, the code comprising instructions executable by a processor to perform a method of any of aspects 1 through 11.
Aspect 31: An apparatus for wireless communication at a UE, comprising a processor; memory coupled with the processor; and instructions stored in the memory and executable by the processor to cause the apparatus to perform a method of any of aspects 12 through 17.
Aspect 32: An apparatus for wireless communication at a UE, comprising at least one means for performing a method of any of aspects 12 through 17.
Aspect 33: A non-transitory computer-readable medium storing code for wireless communication at a UE, the code comprising instructions executable by a processor to perform a method of any of aspects 12 through 17.
Aspect 34: An apparatus for wireless communication at a UE, comprising a processor; memory coupled with the processor; and instructions stored in the memory and executable by the processor to cause the apparatus to perform a method of any of aspects 18 through 27.
Aspect 35: An apparatus for wireless communication at a UE, comprising at least one means for performing a method of any of aspects 18 through 27.
Aspect 36: A non-transitory computer-readable medium storing code for wireless communication at a UE, the code comprising instructions executable by a processor to perform a method of any of aspects 18 through 27.
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.
Although 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 networks. For example, the described techniques may be applicable to various other wireless communications systems such as Ultra Mobile Broadband (UMB) , Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi) , IEEE 802.16 (WiMAX) , IEEE 802.20, Flash-OFDM, as well as other systems and radio technologies not explicitly mentioned herein.
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 components described in connection with the disclosure herein may be implemented or performed using a general-purpose processor, a DSP, an ASIC, a CPU, 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 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 using hardware, software executed by a processor, firmware, or any combination thereof. If implemented using software executed by a processor, the functions may be stored as or transmitted using one or more instructions or code of 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 may 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 location to another. A non-transitory storage medium may be any available medium that may be accessed by a general-purpose or special-purpose computer. By way of example, and not limitation, non-transitory computer-readable media may include RAM, 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 may be used to carry or store desired program code means in the form of instructions or data structures and that may 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 computer-readable medium. Disk and disc, as used herein, include CD, laser disc, optical disc, digital versatile disc (DVD) , floppy disk and Blu-ray disc. Disks may reproduce data magnetically, and discs may reproduce data optically using 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 example 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. ”
The term “determine” or “determining” encompasses a variety of actions and, therefore, “determining” can include calculating, computing, processing, deriving, investigating, looking up (such as via looking up in a table, a database or another data structure) , ascertaining and the like. Also, “determining” can include receiving (e.g., receiving information) , accessing (e.g., accessing data stored in memory) and the like. Also, “determining” can include resolving, obtaining, selecting, choosing, establishing, and other such similar actions.
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 “example” 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, 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 having ordinary skill in the art to make or use the disclosure. Various modifications to the disclosure will be apparent to a person having ordinary skill 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

An apparatus for wireless communication at a user equipment (UE) , comprising:

a processor;

memory coupled with the processor; and

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

receive, from a network entity, a random access order message instructing the UE to perform a random access procedure using a random access configuration associated with a control resource set pool index or a physical cell identifier (PCI) ;

transmit, to the network entity, a random access preamble of the random access procedure associated with the control resource set pool index or the PCI in response to the random access order message;

receive, from the network entity, a random access response of the random access procedure in a random access response window; and

transmit, to the network entity in accordance with a feedback configuration, a feedback message indicating whether the UE successfully received the random access response, the feedback configuration being based at least in part on the random access response.
The apparatus of claim 1, wherein the feedback configuration comprises at least one of:

a feedback timing indicator indicate a timing offset between receipt of the random access response and transmission of the feedback message;

a physical uplink control channel (PUCCH) resource indicator indicate a PUCCH resource for transmission of the feedback message; or

a transmission power control (TPC) command indicate transmission power related parameter for transmission of the feedback message.
The apparatus of claim 1, wherein the feedback configuration is based at least in part on a payload of the random access response.
The apparatus of claim 3, wherein transmitting the feedback message in accordance with the feedback configuration is based at least in part on the random access response being associated with the PCI that comprises an inactive PCI.
The apparatus of claim 3, wherein transmitting the feedback message in accordance with the feedback configuration is based at least in part on an indication in the random access order message.
The apparatus of claim 3, wherein transmitting the feedback message in accordance with the feedback configuration is based at least in part on a format of the payload.
The apparatus of claim 1, wherein the feedback configuration is based at least in part on one or more reserved bits in a physical downlink control channel (PDCCH) order scrambled by a random access radio network temporary identifier (RA-RNTI) .
The apparatus of claim 7, wherein transmitting the feedback message in accordance with the feedback configuration is based at least in part on a radio resource control (RRC) configuration.
The apparatus of claim 7, wherein transmitting the feedback message based at least in part on the one or more reserved bits is based at least in part on an indication in the random access order message.
The apparatus of claim 1, wherein transmitting the feedback message in accordance with the feedback configuration is based at least in part on an indication in the random access order message.
The apparatus of claim 10, wherein the random access order message indicates that a payload of the random access response indicates the feedback configuration or that one or more reserved bits in a physical downlink control channel (PDCCH) order scrambled by a random access radio network temporary identifier (RA-RNTI) indicates the feedback configuration.
An apparatus for wireless communication at a user equipment (UE) , comprising:

a processor;

memory coupled with the processor; and

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

receive, from a network entity, a random access order message instructing the UE to perform a random access procedure using a random access configuration associated with a control resource set pool index or a physical cell identifier (PCI) ;

transmit, to the network entity, a random access preamble of the random access procedure associated with the control resource set pool index or the PCI in response to the random access order message;

receive, from the network entity, a random access response control message of the random access procedure in a random access response window, the random access response control message indicating a retransmission configuration that identifies a quantity of transmissions of a random access response data message; and

monitor for the quantity of transmissions of the random access response data message based at least in part on the random access response control message.
The apparatus of claim 12, wherein the instructions to receive the random access response control message are executable by the processor to cause the apparatus to:

receive the random access response control message that indicates a redundancy version sequence mapped to a plurality of random access response data message occasions, wherein monitoring for the quantity of transmissions of the random access response data message occurs within the plurality of random access response data message occasions in accordance with the redundancy version sequence.
The apparatus of claim 13, wherein the instructions to receive the random access response control message indicating the redundancy version sequence are executable by the processor to cause the apparatus to:

receive the random access response control message that indicates the retransmission configuration that identifies a starting redundancy version value of the redundancy version sequence, wherein redundancy version values of the redundancy version sequence are cyclically mapped to the plurality of random access response data message occasions in a defined order beginning with the starting redundancy version value.
The apparatus of claim 12, wherein the instructions to receive the random access response control message are executable by the processor to cause the apparatus to:

receive the random access response control message that comprises one or more reserved bits indicating the retransmission configuration, the one or more reserved bits being processed based at least in part on the random access response control message being associated with the PCI that comprises an inactive PCI.
The apparatus of claim 12, wherein the instructions to receive the random access response control message are executable by the processor to cause the apparatus to:

receive the random access response control message that comprises one or more reserved bits indicating the retransmission configuration, the one or more reserved bits being processed based at least in part on an indication in the random access order message.
The apparatus of claim 12, wherein the instructions are further executable by the processor to cause the apparatus to:

receive the random access response data message based at least in part on monitoring for the quantity of transmissions.
An apparatus for wireless communication at a user equipment (UE) , comprising:

a processor;

memory coupled with the processor; and

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

receive, from a network entity, a first random access order message of a random access procedure instructing the UE to transmit a first random access preamble associated with a first preamble index, a first physical cell identifier (PCI) , and a first synchronization signal block (SSB) index;

transmit, to the network entity at a first transmission power level, the first random access preamble of the random access procedure in response to the first random access order message;

receive, from the network entity, a second random access order message instructing the UE to transmit a second random access preamble associated with a second preamble index, a second PCI, and a second SSB index; and

transmit, to the network entity at a second transmission power level, the second random access preamble, wherein the second transmission power level is based at least in part on a power adjustment size and a random access attempt counter, the random access attempt counter being based at least in part on whether the second preamble index, the second PCI, and the second SSB index are the same as the first preamble index, the first PCI, and the first SSB index.
The apparatus of claim 18, wherein the second transmission power level is further based at least in part on a power ramping counter, the power ramping counter being based at least in part on whether the second preamble index, the second PCI, and the second SSB index are the same as the first preamble index, the first PCI, and the first SSB index.
The apparatus of claim 18, wherein the instructions are further executable by the processor to cause the apparatus to:

increment the random access attempt counter based at least in part on the second preamble index, the second PCI, and the second SSB index being the same as the first preamble index, the first PCI, and the first SSB index.
The apparatus of claim 18, wherein the instructions are further executable by the processor to cause the apparatus to:

reset the random access attempt counter based at least in part on the second preamble index, the second PCI, or the second SSB index being different from the first preamble index, the first PCI, or the first SSB index.
The apparatus of claim 18, wherein the instructions are further executable by the processor to cause the apparatus to:

increment the random access attempt counter based at least in part on the second preamble index and the second PCI being the same as the first preamble index and the first PCI; and

increment a power ramping counter based at least in part on the second preamble index, the second PCI, and the second SSB index being the same as the first preamble index, the first PCI, and the first SSB index.
The apparatus of claim 18, wherein the instructions are further executable by the processor to cause the apparatus to:

increment the random access attempt counter based at least in part on the second preamble index and the second PCI being the same as the first preamble index and the first PCI; and

keep a power ramping counter unchanged based at least in part on the second preamble index and the second PCI being the same as the first preamble index and the first PCI, and the second SSB index being different from the first SSB index.
The apparatus of claim 18, wherein the instructions are further executable by the processor to cause the apparatus to:

receive, from the network entity, a control element message in response to the first random access preamble transmission, wherein one or more of the random access attempt counter and a power ramping counter is based at least in part on the receipt of the control element message.
The apparatus of claim 24, wherein the instructions are further executable by the processor to cause the apparatus to:

reset the random access attempt counter based at least in part on the receipt of the control element message indicating a timing advance corresponding to a timing advance group identifier associated with the random access procedure.
The apparatus of claim 24, wherein the instructions are further executable by the processor to cause the apparatus to:

reset the power ramping counter based at least in part on the receipt of the control element message indicating a timing advance corresponding to a timing advance group identifier associated with the random access procedure.
The apparatus of claim 18, wherein the instructions are further executable by the processor to cause the apparatus to:

reset the random access attempt counter and a power ramping counter based at least in part on the random access attempt counter reaching a maximum count quantity.
A method for wireless communication at a user equipment (UE) , comprising:

receiving, from a network entity, a random access order message instructing the UE to perform a random access procedure using a random access configuration associated with a control resource set pool index or a physical cell identifier (PCI) ;

transmitting, to the network entity, a random access preamble of the random access procedure associated with the control resource set pool index or the PCI in response to the random access order message;

receiving, from the network entity, a random access response of the random access procedure in a random access response window; and

transmitting, to the network entity in accordance with a feedback configuration, a feedback message indicating whether the UE successfully received the random access response, the feedback configuration being based at least in part on the random access response.
The method of claim 28, wherein the feedback configuration comprises at least one of:

a feedback timing indicator indicating a timing offset between receipt of the random access response and transmission of the feedback message;

a physical uplink control channel (PUCCH) resource indicator indicating a PUCCH resource for transmission of the feedback message; or

a transmission power control (TPC) command indicating transmission power related parameter for transmission of the feedback message.
The method of claim 28, wherein the feedback configuration is based at least in part on a payload of the random access response or on one or more reserved bits in a physical downlink control channel (PDCCH) order scrambled by a random access radio network temporary identifier (RA-RNTI) .