Random Access Response Mapping for Two-Step Random Access Channel Procedure

Abstract

In summary, various aspects of the present disclosure relate to wireless communications. In some aspects, a base station (BS) may group and selectively multiplex multiple random access channel responses (RARs) and radio resource control (RRC) messages in a message B (msgB) communication along with supplemental scheduling information for other RARs to be mapped to different msgB communications. The BS may send msgB communications to one or more user equipments (UEs). Many other aspects are provided.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This patent application claims priority to the following applications: U.S. Provisional Patent Application No. 62 / 912,558, filed on October 8, 2019, entitled “RAMDOM ACCESS RESPONSE MAPPING FOR TWO-STEP RANDOM ACCESS CHANNEL PROCEDURE,” and U.S. Non-Provisional Patent Application No. 16 / 948,956, filed on October 7, 2020, entitled “RAMDOM ACCESS RESPONSE MAPPING FOR TWO-STEP RANDOM ACCESS CHANNEL PROCEDURE,” which are expressly incorporated herein by reference. Technical Field

[0003]

[0008] In general, aspects of the present disclosure relate to wireless communications and techniques and apparatus for random access response mapping for a two-step random access channel procedure. Background Art

[0004] Wireless communication systems are widely deployed to provide various telecommunication services, such as telephony, video, data, messaging, and broadcasting. Typical wireless communication systems may employ multiple access technologies that can support communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power, etc.). Examples of such multiple access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single carrier frequency division multiple access (SC-FDMA) systems, time division synchronous code division multiple access (TD-SCDMA) systems, and long term evolution (LTE). LTE / LTE-Advanced is a set of enhancements to the Universal Mobile Telecommunications System (UMTS) mobile standard promulgated by the Third Generation Partnership Project (3GPP).

[0005] A wireless communication network may include several base stations (BS) that can support communications for several user equipments (UEs). User equipments (UEs) may communicate with base stations (BSs) via downlinks and uplinks. Downlinks (or forward links) refer to the communication link from a BS to a UE, and uplinks (or reverse links) refer to the communication link from a UE to a BS. As will be described in more detail herein, a BS may be referred to as a Node B, gNB, access point (AP), radio head, transmit receive point (TRP), new radio (NR) BS, 5G Node B, etc.

[0006] The above multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different user equipment to communicate at the city, country, region, and even global level. New Radio (NR) (which may also be referred to as 5G) is an enhancement set to the LTE mobile standard released by the Third Generation Partnership Project (3GPP). NR is designed to be better integrated with other open standards by improving spectrum efficiency, reducing costs, improving services, utilizing new spectrum, and using orthogonal frequency division multiplexing (OFDM) (CP-OFDM) with cyclic prefix (CP) on the downlink (DL), using CP-OFDM and / or SC-FDM (e.g., also referred to as discrete Fourier transform spread OFDM (DFT-s-OFDM)) on the uplink (UL), and supporting beamforming, multiple input multiple output (MIMO) antenna technology and carrier aggregation to better support mobile broadband Internet access. However, as the demand for mobile broadband access continues to grow, there is a need for further improvements in LTE and NR technologies. Preferably, these improvements should be applicable to other multiple access technologies and telecommunication standards that adopt these technologies. Summary of the invention

[0007] In some aspects, a wireless communication method performed by a base station (BS) may include: grouping and selectively multiplexing multiple random access channel responses (RARs) in a message B (msgB) communication; and sending the msgB communication to one or more user equipments (UEs).

[0008] In some aspects, a method of wireless communication performed by a UE may include: receiving, from a BS, msgB communications associated with a two-step RACH process between the UE and the BS; and identifying a RAR associated with the UE among a plurality of RARs multiplexed in the msgB communications and supplemental scheduling information for other RARs.

[0009] In some aspects, a BS for wireless communication may include a memory and one or more processors coupled to the memory. The memory and one or more processors may be configured to: group and selectively multiplex multiple RARs in msgB communications; and send msgB communications to one or more UEs.

[0010] In some aspects, a UE for wireless communication may include a memory and one or more processors coupled to the memory. The memory and the one or more processors may be configured to: receive msgB communications associated with a two-step RACH procedure between the UE and the BS from a BS; and identify a RAR associated with the UE among a plurality of RARs multiplexed in the msgB communications and supplemental scheduling information for other RARs.

[0011] In some aspects, a non-transitory computer-readable medium may store one or more instructions for wireless communication. When executed by one or more processors of a BS, the one or more instructions may cause the one or more processors to perform the following operations: grouping and selectively multiplexing multiple RARs in msgB communications; and sending msgB communications to one or more UEs.

[0012] In some aspects, a non-transitory computer-readable medium may store one or more instructions for wireless communication. The one or more instructions, when executed by one or more processors of a UE, may cause the one or more processors to perform the following operations: receiving msgB communications associated with a two-step RACH process between the UE and the BS from a BS; and identifying a RAR associated with the UE among a plurality of RARs multiplexed in the msgB communications and supplemental scheduling information for other RARs.

[0013]

[0013] In some aspects, an apparatus for wireless communication may include means for grouping and selectively multiplexing a plurality of RARs in a msgB communication and means for transmitting the msgB communication to one or more UEs.

[0014] In some aspects, an apparatus for wireless communication may include: a unit for receiving, from a BS, msgB communications associated with a two-step RACH process between the apparatus and the BS; and a unit for identifying a RAR associated with the apparatus among a plurality of RARs multiplexed in the msgB communications and supplemental scheduling information for other RARs.

[0015] The various aspects generally include methods, apparatus, systems, computer program products, non-transitory computer-readable media, user equipment, base stations, wireless communication devices and / or processing systems as fully described herein with reference to the accompanying drawings and description and as illustrated by the accompanying drawings and description.

[0016] The foregoing has been fairly broadly outlined according to the features and technical advantages of the examples of the present disclosure, so that the following specific embodiments may be better understood. Additional features and advantages will be described below. The disclosed concepts and specific examples may be easily used as the basis for modifying or designing other structures for the same purpose of achieving the present disclosure. Such equivalent constructions do not depart from the scope of the appended claims. When considered in conjunction with the accompanying drawings, the characteristics of the concepts disclosed herein (both their organization and method of operation) together with the associated advantages will be better understood according to the following description. Each of the figures in the accompanying drawings is provided for the purpose of illustration and description, and is not intended to be a definition of limitations to the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to understand the above-mentioned features of the present disclosure in detail, the contents briefly summarized above may be described in more detail with reference to various aspects, some of which are shown in the accompanying drawings. However, it should be noted that the accompanying drawings only illustrate certain typical aspects of the present disclosure and are therefore not considered to be limiting of its scope, as the specification may admit other equally effective aspects. The same reference numerals in different drawings may identify the same or similar elements.

[0018] Figure 1 is a block diagram illustrating an example of a wireless communication network in accordance with various aspects of the present disclosure.

[0019] Figure 2 is a block diagram illustrating an example of a base station (BS) communicating with a user equipment (UE) in a wireless communication network according to various aspects of the present disclosure.

[0020] Figures 3A-3H is a diagram illustrating one or more examples of random access response mapping for a two-step random access channel procedure in accordance with various aspects of the present disclosure.

[0021] Figure 4 is a diagram illustrating example processes performed, for example, by a BS, according to various aspects of the present disclosure.

[0022] Figure 5 is a diagram illustrating example processes performed, for example, by a UE according to various aspects of the present disclosure. DETAILED DESCRIPTION

[0023] The following is a more complete description of various aspects of the present disclosure with reference to the accompanying drawings. However, the present disclosure can be embodied in many different forms, and should not be interpreted as being limited to any specific structure or function presented throughout the present disclosure. More specifically, these aspects are provided so that the present disclosure will be thorough and complete, and the scope of the present disclosure will be fully conveyed to those skilled in the art. Based on the teachings of this article, it should be understood by those skilled in the art that the scope of the present disclosure is intended to cover any aspect of the disclosure disclosed herein, whether it is implemented independently of any other aspect of the present disclosure or implemented in combination with any other aspect. For example, any number of aspects set forth herein can be used to implement a device or a method can be practiced. In addition, the scope of the present disclosure is intended to cover such devices or methods, and the devices and methods are implemented using other structures, functions, or structures and functions other than or different from the various aspects of the disclosure set forth herein. It should be understood that any aspect of the disclosure disclosed herein can be embodied by one or more elements of the claims.

[0024] Several aspects of telecommunication systems will now be presented with reference to various devices and techniques. These devices and techniques will be described in the following detailed description and illustrated in the accompanying drawings by various blocks, modules, components, circuits, steps, processes, algorithms, etc. (collectively referred to as "elements"). These elements can be implemented using hardware, software, or a combination thereof. Whether such elements are implemented as hardware or software depends on the specific application and the design constraints imposed on the overall system.

[0025] It should be noted that although various aspects may be described herein using terms commonly associated with 3G and / or 4G wireless technologies, various aspects of the present disclosure may be applicable to communication systems based on other generations, such as 5G and beyond (including NR technology).

[0026] Figure 1 1 is a schematic diagram showing a wireless network 100 in which various aspects of the present disclosure may be practiced. The wireless network 100 may be an LTE network or some other wireless network, such as a 5G or NR network. The wireless network 100 may include several BSs 110 (shown as BS 110a, BS 110b, BS 110c, and BS 110d) and other network entities. A BS is an entity that communicates with a user equipment (UE) and may also be referred to as a base station, NR BS, Node B, gNB, 5G Node B (NB), access point, transmit receive point (TRP), etc. Each BS may provide communication coverage for a specific geographic area. In 3GPP, the term "cell" may refer to a coverage area of ​​a BS and / or a BS subsystem serving the coverage area, depending on the context in which the term is used.

[0027] A BS may provide communication coverage for a macro cell, a pico cell, a femto cell, and / or another type of cell. A macro cell may cover a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by UEs with service subscription. A pico cell may cover a relatively small geographic area and may allow unrestricted access by UEs with service subscription. A femto cell may cover a relatively small geographic area (e.g., a residence) and may allow restricted access by UEs associated with the femto cell (e.g., UEs in a closed subscriber group (CSG)). A BS for a macro cell may be referred to as a macro BS. A BS for a pico cell may be referred to as a pico BS. A BS for a femto cell may be referred to as a femto BS or a home BS. In Figure 1In the example shown in , BS 110a may be a macro BS for macro cell 102a, BS 110b may be a pico BS for pico cell 102b, and BS 110c may be a femto BS for femto cell 102c. A BS may support one or more (e.g., three) cells. The terms "eNB", "base station", "NR BS", "gNB", "TRP", "AP", "Node B", "5G NB", and "cell" may be used interchangeably herein.

[0028] In some aspects, the cells may not necessarily be stationary, and the geographic area of ​​the cells may move depending on the location of the mobile BS. In some aspects, the BSs may be interconnected with each other and / or with one or more other BSs or network nodes (not shown) in the wireless network 100 through various types of backhaul interfaces (e.g., direct physical connections, virtual networks, etc.) using any appropriate transport network.

[0029] The wireless network 100 may also include a relay station. A relay station is an entity that can receive transmissions of data from an upstream station (e.g., a BS or a UE) and send transmissions of the data to a downstream station (e.g., a UE or a BS). A relay station may also be a UE that can relay transmissions for other UEs. Figure 1 In the example shown in FIG. 1 , a relay station 110 d may communicate with a macro BS 110 a and a UE 120 d to facilitate communication between the BS 110 a and the UE 120 d. A relay station may also be referred to as a relay BS, a relay base station, a relay, or the like.

[0030] The wireless network 100 may be a heterogeneous network including different types of BSs (e.g., macro BSs, pico BSs, femto BSs, relay BSs, etc.). These different types of BSs may have different transmit power levels, different coverage areas, and different effects on interference in the wireless network 100. For example, a macro BS may have a high transmit power level (e.g., 5 to 40 watts), while a pico BS, a femto BS, and a relay BS may have a lower transmit power level (e.g., 0.1 to 2 watts).

[0031] A network controller 130 may be coupled to a set of BSs and may provide coordination and control for these BSs. The network controller 130 may communicate with the BSs via a backhaul. The BSs may also communicate with each other directly or indirectly, for example, via a wireless or wired backhaul.

[0032] UE 120 (e.g., 120a, 120b, 120c) can be dispersed throughout the wireless network 100, and each UE can be stationary or mobile. UE can also be referred to as an access terminal, terminal, mobile station, subscriber unit, station, etc. UE can be a cellular phone (e.g., a smart phone), a personal digital assistant (PDA), a wireless modem, a wireless communication device, a handheld device, a laptop computer, a cordless phone, a wireless local loop (WLL) station, a tablet computer, a camera, a gaming device, a netbook, a smartbook, an ultrabook, a medical device or apparatus, a biometric sensor / device, a wearable device (smart watch, smart clothing, smart glasses, smart wristband, smart jewelry (e.g., smart ring, smart bracelet, etc.)), an entertainment device (e.g., a music or video device, or a satellite radio unit, etc.), a vehicle component or sensor, a smart meter / sensor, an industrial manufacturing device, a global positioning system device, or any other suitable device configured to communicate via a wireless or wired medium.

[0033] Some UEs may be considered machine type communication (MTC) or evolved or enhanced machine type communication (eMTC) UEs. MTC and eMTC UEs include, for example, robots, drones, remote devices, sensors, meters, monitors, location tags, etc. that can communicate with a base station, another device (e.g., a remote device), or some other entity. A wireless node may provide a connection to or to a network (e.g., a wide area network such as the Internet or a cellular network), for example, via a wired or wireless communication link. Some UEs may be considered Internet of Things (IoT) devices, and / or may be implemented as NB-IoT (narrowband Internet of Things) devices. Some UEs may be considered customer premises equipment (CPE). UE 120 may be included inside a housing that houses components of UE 120 (e.g., processor components, memory components, etc.).

[0034] Typically, any number of wireless networks can be deployed in a given geographic area. Each wireless network can support a specific RAT and can operate on one or more frequencies. RAT can also be referred to as radio technology, air interface, etc. Frequency can also be referred to as carrier, channel, etc. Each frequency can support a single RAT in a given geographic area to avoid interference between wireless networks of different RATs. In some cases, NR or 5G RAT networks can be deployed.

[0035] In some aspects, two or more UEs 120 (e.g., shown as UE 120a and UE 120e) may communicate directly (e.g., without using base station 110 as an intermediary to communicate with each other) using one or more side link channels. For example, UE 120 may communicate using peer-to-peer (P2P) communication, device-to-device (D2D) communication, vehicle-to-everything (V2X) protocol (e.g., which may include vehicle-to-vehicle (V2V) protocol, vehicle-to-infrastructure (V2I) protocol, etc.), mesh network, etc. In this case, UE 120 may perform scheduling operations, resource selection operations, and / or other operations described elsewhere herein as being performed by base station 110.

[0036] As pointed out above, Figure 1 is provided as an example. Other examples may differ from those described above. Figure 1 as described.

[0037] Figure 2 The base station 110 and the UE 120 are shown (the base station 110 and the UE 120 may be Figure 1 1. Block diagram of design 200 of a base station in a base station and a UE in a UE. Base station 110 may be equipped with T antennas 234a through 234t, and UE 120 may be equipped with R antennas 252a through 252r, where in general, T≥1 and R≥1.

[0038] At the base station 110, the transmit processor 220 may receive data for one or more UEs from the data source 212, select one or more modulation and coding schemes (MCS) for each UE based at least in part on a channel quality indicator (CQI) received from the UE, process (e.g., encode and modulate) the data for each UE based at least in part on the MCS selected for the UE, and provide data symbols for all UEs. The transmit processor 220 may also process system information (e.g., for semi-static resource partitioning information (SRPI), etc.) and control information (e.g., CQI requests, grants, upper layer signaling, etc.), and provide overhead symbols and control symbols. The transmit processor 220 may also generate reference symbols for reference signals (e.g., cell-specific reference signals (CRS)) and synchronization signals (e.g., primary synchronization signals (PSS) and secondary synchronization signals (SSS)). The transmit (TX) multiple-input multiple-output (MIMO) processor 230 may perform spatial processing (e.g., precoding) on ​​data symbols, control symbols, overhead symbols, and / or reference symbols, if applicable, and may provide T output symbol streams to T modulators (MOD) 232a to 232t. Each modulator 232 may process a corresponding output symbol stream (e.g., for OFDM, etc.) to obtain an output sample stream. Each modulator 232 may further process the output sample stream (e.g., convert to analog, amplify, filter, and up-convert) to obtain a downlink signal. The T downlink signals from modulators 232a to 232t may be transmitted via T antennas 234a to 234t, respectively. According to various aspects described in more detail below, synchronization signals may be generated using position coding to transmit additional information.

[0039] At UE 120, antennas 252a to 252r may receive downlink signals from base station 110 and / or other base stations, and may provide received signals to demodulators (DEMODs) 254a to 254r, respectively. Each demodulator 254 may condition (e.g., filter, amplify, downconvert, and digitize) the received signal to obtain input samples. Each demodulator 254 may further process the input samples (e.g., for OFDM, etc.) to obtain received symbols. A MIMO detector 256 may obtain received symbols from all R demodulators 254a to 254r, perform MIMO detection on the received symbols (if applicable), and provide detected symbols. A receive processor 258 may process (e.g., demodulate and decode) the detected symbols, provide decoded data for UE 120 to a data sink 260, and provide decoded control information and system information to a controller / processor 280. The channel processor may determine reference signal received power (RSRP), received signal strength indicator (RSSI), reference signal received quality (RSRQ), channel quality indicator (CQI), etc. In some aspects, one or more components of UE 120 may be included in a housing.

[0040] On the uplink, at the UE 120, a transmit processor 264 may receive and process data from a data source 262 and control information from a controller / processor 280 (e.g., for reports including RSRP, RSSI, RSRQ, CQI, etc.). The transmit processor 264 may also generate reference symbols for one or more reference signals. The symbols from the transmit processor 264 may be precoded by a TX MIMO processor 266 (if applicable), further processed by modulators 254a through 254r (e.g., for DFT-s-OFDM, CP-OFDM, etc.), and transmitted to the base station 110. At the base station 110, uplink signals from the UE 120 and other UEs may be received by the antenna 234, processed by the demodulator 232, detected by the MIMO detector 236 (if applicable), and further processed by the receive processor 238 to obtain decoded data and control information transmitted by the UE 120. The receive processor 238 may provide decoded data to a data sink 239 and decoded control information to a controller / processor 240. The base station 110 may include a communication unit 244 and communicate with the network controller 130 via the communication unit 244. The network controller 130 may include a communication unit 294, a controller / processor 290, and a memory 292.

[0041] The controller / processor 240 of the base station 110, the controller / processor 280 of the UE 120, and / or Figure 2Any other component in the base station 110 may perform one or more techniques associated with random access response (RAR) mapping for a two-step random access channel (RACH) procedure, as described in more detail elsewhere herein. For example, the controller / processor 240 of the base station 110, the controller / processor 280 of the UE 120, and / or Figure 2 Any other component in the Figure 4 The process of 400 Figure 5 The process 500 and / or other processes as described herein, or instructions Figure 4 The process of 400 Figure 5 The operations of process 500 and / or other processes as described herein. Memories 242 and 282 may store data and program codes for base station 110 and UE 120, respectively. In some aspects, memory 242 and / or memory 282 may include a non-transitory computer-readable medium storing one or more instructions for wireless communication. For example, when one or more instructions are executed by one or more processors of base station 110 and / or UE 120, the execution may be performed, for example, Figure 4 The process of 400 Figure 5 The process 500 and / or other processes as described herein, or instructions Figure 4 The process of 400 Figure 5 The scheduler 246 may schedule UEs for data transmission on the downlink and / or uplink.

[0042] In some aspects, UE 120 may include: means for receiving a message B (msgB) communication associated with a two-step RACH procedure between UE 120 and BS 110 from BS 110; means for identifying a RAR associated with UE 120 among a plurality of RARs multiplexed in the msgB communication and supplemental scheduling information for other RARs, etc. In some aspects, such means may include a combination of Figure 2 One or more components of UE 120 are depicted, such as controller / processor 280, transmit processor 264, TX MIMO processor 266, MOD 254, antenna 252, DEMOD 254, MIMO detector 256, receive processor 258, etc.

[0043] In some aspects, the base station 110 may include: means for grouping and selectively multiplexing multiple RARs in msgB communications; means for sending msgB communications to one or more UEs 120; and the like. In some aspects, such means may include combining Figure 2One or more components of the base station 110 are depicted, such as antenna 234, DEMOD 232, MIMO detector 236, receive processor 238, controller / processor 240, transmit processor 220, TX MIMO processor 230, MOD 232, antenna 234, etc.

[0044] As pointed out above, Figure 2 is provided as an example. Other examples may differ from those described above. Figure 2 as described.

[0045] The UE may access the wireless network by negotiating a connection with a BS included in the wireless network. During connection establishment, the UE and the BS may be connected synchronously in a downlink direction (ie, from the BS to the UE) and an uplink direction (ie, from the UE to the BS).

[0046] In order to synchronize the connection in the downlink direction, the UE may read a synchronization signal block (SSB) including various synchronization signals sent from the BS. The synchronization signal may include a primary synchronization signal (PSS), a secondary synchronization signal (SSS), a primary broadcast channel (PBCH), etc. The UE may use the PSS to determine symbol timing in the downlink direction, may use the SSS to determine a physical cell identifier associated with the BS, and may use the PBCH to determine frame timing.

[0047] In order to synchronize the connection in the uplink direction, the UE and the BS may perform a RACH procedure. In some aspects, the UE and the BS may perform a four-step RACH procedure. In the four-step RACH procedure, the UE and the BS may exchange four main RACH communications. The UE may send a message 1 (msg1) communication (e.g., as defined in the 3GPP four-step RACH procedure) to the BS. The msg1 communication may be a RACH preamble communication sent in a RACH opportunity (e.g., a specific set of time-frequency resources), and the combination of RACH preamble communications may be referred to as a RACH signature. The BS may respond to the msg1 communication with a message 2 (msg2) communication (e.g., as defined in the 3GPP four-step RACH procedure), and the msg2 communication may be a random access response (RAR) communication. The UE may respond to the msg2 communication (e.g., as defined in the 3GPP four-step RACH procedure) with a message 3 (msg3) communication, and the msg3 communication may be a radio resource control (RRC) connection request communication. The BS may respond to the msg3 communication using a message 4 (msg4) communication (eg, as defined in the 3GPP four-step RACH procedure), which may be a medium access control (MAC) control element (MAC-CE) contention resolution identifier communication, and may include an RRCSetup command, etc.

[0048] In some cases, the four-step RACH procedure may not meet the low latency requirements of the 5G / NR wireless system. Therefore, the UE and the BS may use a two-step RACH procedure to reduce the latency in synchronizing the connection in the uplink direction. In the two-step RACH procedure, the UE may combine the msg1 communication and the msg3 communication into a communication called message A (msgA) communication (e.g., as defined in the 3GPP two-step RACH procedure). The msg1 portion of the msgA communication may be referred to as the preamble portion of the msgA communication. The msg3 portion of the msgA communication may be referred to as the payload portion of the msgA communication. The UE may send the msg1 portion and the msg3 portion sequentially before receiving the msg2 communication and the msg4 communication.

[0049] The BS may receive msgA communications and may send msgB communications (e.g., as defined in the 3GPP four-step RACH procedure), which may include msg2 communications and msg4 communications. The msgB communications may include a physical downlink control channel (PDCCH) portion and a physical downlink shared channel (PDSCH) portion. The PDSCH portion may carry the payload of the msgB communications, which may include a RAR for the UE.

[0050] The RAR may be a fallback RAR, a success RAR (with or without an associated radio resource control (RRC) message), a backoff indicator, etc. A fallback RAR may be sent if the preamble portion of a msgA communication is detected and decoded but not the payload portion. The fallback RAR may indicate that the UE falls back to the four-step RACH procedure and may include a random access preamble identifier (RAPID) for the UE for retransmission of the msg3 or payload portion of the msgA communication, a RAR grant, a timing advance command, and a temporary cell radio network temporary identifier (TC-RNTI).

[0051] If the preamble part and the payload part are detected and decoded, a success RAR may be sent. The success RAR may indicate that the UE continues with the two-step RACH procedure and may identify a contention resolution identifier, a timing advance command, and a cell radio network temporary identifier (C-RNTI).

[0052] The UE may monitor msgB communications during the RAR receive window. The start of the RAR receive window may be aligned with the first PDCCH symbol of the earliest search space for msgB communications. If the UE does not receive a successful RAR or fallback RAR before the RAR receive window expires, the UE may resend msgA communications.

[0053] In some cases, the BS may send a respective RAR to each of the multiple UEs, where each RAR is included in a separate msgB communication. This may result in increased power consumption at the multiple UEs, because each UE may have to monitor and decode multiple msgB communications during an associated RAR receive window to receive the RAR for the UE. In addition, the BS may also send RAR retransmissions in separate msgB communications during the RAR receive window, which further increases the number of msgB communications that each UE may have to monitor and decode during the associated RAR receive window.

[0054] Some aspects described herein provide techniques and apparatus for RAR mapping for a two-step RACH process. In some aspects, a BS may multiplex multiple RARs into a single msgB communication, and may send the msgB communication to one or more UEs. This allows the BS to reduce the number of msgB communications sent to a UE relative to sending multiple RARs in separate and / or separate msgB communications. The reduced number of msgB communications in turn reduces processing, memory, and power resource consumption at the UE, because the UE can monitor and decode fewer msgB communications to receive the RARs during the associated RAR receive window.

[0055] To further reduce processing, memory, and power resource consumption at the UE, the BS may multiplex the same type of RAR and / or different types of RAR in the same msgB communication, which allows successful RAR, fallback RAR, initial RAR transmission, and / or RAR retransmission to be included in the same msgB communication. The BS may also provide early indication of which msgB communication will carry the RAR for a particular UE or a group of UEs, which further reduces processing, memory, and power resource consumption at the UE.

[0056] Figures 3A-3H is a diagram illustrating one or more examples 300 of RAR mapping for a two-step RACH procedure according to various aspects of the present disclosure. Figures 3A-3H As shown in , example 300 may include communication between a BS (eg, BS 100) and a plurality of UEs (eg, UE 120) (eg, UE1-UEn, etc.). The BS and the plurality of UEs may be included in a wireless network (eg, wireless network 100, etc.).

[0057] In some aspects, each of the multiple UEs may perform a RACH procedure with the BS to establish a wireless connection with the BS. The RACH procedure may include, for example, a two-step RACH procedure, a four-step RACH procedure, etc. In some aspects, the UE of the multiple UEs may initiate a two-step RACH procedure by sending msgA communication to the BS. In this case, the UE may send a preamble portion of the msgA communication in a preamble opportunity (e.g., one or more time-frequency resources configured for RACH preamble transmission), and may send a payload portion of the msgA communication in a physical uplink shared channel (PUSCH) opportunity (e.g., one or more time-frequency resources configured for msgA payload transmission).

[0058] As in Figure 3A In some aspects, the BS may multiplex RARs for multiple UEs in msgB communications and as shown by reference numeral 302, the BS may multiplex RARs for multiple UEs in the same msgB communication. In some aspects, the BS may time-division multiplex RARs in msgB communications, may frequency-division multiplex RARs in msgB communications, may spatially multiplex RARs in msgB communications, or a combination thereof. In some aspects, the BS may multiplex subsets of RARs for multiple UEs in different msgB communications. In this case, the BS may scramble msgB communications using the same RNTI (e.g., the same msgB-RNTI and / or another type of RNTI). In some aspects, if the RAR window is long (e.g., ≥20 ms), the value of the msgB RNTI may vary over time. For example, msgB_RNTI(K)=msgB_RNTI(K-1)+delta(K-1), where delta(K-1) captures the temporal variation of msgB_RNTI from radio frame (K-1) to radio frame (K). In some cases, the BS may scramble msgB communications using the same set of msgB radio network temporary identifiers mapped to the same random access opportunity.

[0059] In some aspects, the BS may multiplex the same type of RARs in msgB communications, may multiplex different types of RARs in msgB communications, or a combination thereof. For example, the BS may multiplex one or more successful RARs (with or without associated RRC messages) in msgB communications, may multiplex one or more fallback RARs in msgB communications, etc. As another example, the BS may multiplex initial or first transmissions of one or more RARs (e.g., one or more initial or first transmissions of successful RARs, fallback RARs, etc.) in msgB communications, may multiplex retransmissions of one or more RARs (e.g., one or more retransmissions of successful RARs, fallback RARs, etc.) in msgB communications, etc.

[0060] Figure 3B and Figure 3C Various examples of RAR multiplexing in one or more msgB communications are shown. Figure 3B As shown in the example illustrated in , the BS may multiplex different subsets of RARs (e.g., RAR 1 to RAR 5) for five UEs in corresponding msgB communications. In particular, the BS may multiplex initial transmissions of RAR 1, RAR 2, and RAR 3 (e.g., for UE1, UE2, and UE3, respectively) in msgB 1, may multiplex initial transmissions of RAR 4 and RAR 5 (e.g., for UE4 and UE5, respectively) in msgB 2, and may multiplex retransmissions of RAR 1, RAR 2, and RAR 3 (e.g., for UE1, UE2, and UE3, respectively) in msgB 3.

[0061] As in Figure 3B As further shown in the examples illustrated in , different types of RARs may be multiplexed in the same msgB communication. For example, msgB 1 may include a successful RAR (e.g., RAR 1) without an associated RRC message, a successful RAR (e.g., RAR 2) with an associated RRC message, and a fallback RAR (e.g., RAR 3). As another example, msgB 2 may include a fallback RAR (e.g., RAR 4) and a successful RAR (e.g., RAR 5) with an associated RRC message. As another example, msgB 3 may include a successful RAR (e.g., RAR 1) without an associated RRC message, a successful RAR (e.g., RAR 2) with an associated RRC message, and a fallback RAR (e.g., RAR 3).

[0062] As in Figure 3CAs shown in the example illustrated in , the BS may multiplex different subsets of RARs (e.g., RAR 1 to RAR 5) for five UEs in corresponding msgB communications. In particular, the BS may multiplex initial transmissions of RAR 1, RAR 2, and RAR 3 (e.g., for UE 1, UE 2, and UE 3, respectively) in msgB 1, may multiplex retransmissions of RAR 1 with initial transmissions of RAR 4 (e.g., for UE 4) in msgB 2, and may include initial transmissions of RAR 5 (e.g., for UE 5) in msgB 3.

[0063] As in Figure 3B As further shown in the example illustrated in , different types of RARs may be multiplexed in the same msgB communication. For example, msgB 1 may include a successful RAR (e.g., RAR 1) without an associated RRC message, a successful RAR (e.g., RAR 2) with an associated RRC message, and a fallback RAR (e.g., RAR 3). As another example, msgB2 may include an initial transmission of a fallback RAR (e.g., RAR 4) and a retransmission of a successful RAR (e.g., RAR 1) without an associated RRC message.

[0064] The BS may use various techniques to identify the RARs to be multiplexed in the same msgB communication. In some aspects, the BS may multiplex the RARs in the same msgB communication based at least in part on respective priorities associated with each of the RARs. For example, the BS may multiplex a high priority RAR in the same msgB communication and send the msgB communication earlier in time relative to msgB communications carrying multiplexed RARs of relatively lower priority.

[0065] In some aspects, the BS may multiplex the RARs in the same msgB communication based at least in part on respective payload sizes associated with the RARs to efficiently use available space in the msgB communication. For example, the BS may be allowed to include a certain number of bits or bytes in the payload portion of the msgB communication, and the BS may multiplex the RARs in the msgB communication such that the RARs utilize a maximum amount of available space in the msgB communication.

[0066] In some aspects, the BS may group RARs for UEs that transmit preambles in the same preamble opportunity into one or more RAR sets. The BS may multiplex each RAR set into a corresponding msgB communication such that transmission of the RAR sets is time ordered. The order of the RAR sets may be based at least in part on the starting symbol of the respective RAR receive windows associated with each of the UEs. For example, the BS may multiplex RARs for a first group of UEs or a first set of UEs having associated RAR receive windows starting at the same symbol into a first msgB communication, may multiplex RARs for a second group of UEs or a second set of UEs having associated RAR receive windows starting at the same symbol into a second msgB communication, and so on.

[0067] Figure 3D and Figure 3E Various examples of grouping RARs into sets based at least in part on starting symbols of corresponding RAR receive windows associated with one or more UEs are shown. Figure 3D In the example shown, multiple UEs may send a RACH preamble in the same preamble opportunity X (e.g., a preamble portion of a msgA communication in a two-step RACH process). A first UE subset may send a msgA payload portion in a PUSCH opportunity Y, and a second UE subset may send a msgA payload portion in a PUSCH opportunity Z that occurs after PUSCH opportunity Y. In this example, a starting symbol of a first RAR receive window associated with a preamble opportunity / PUSCH opportunity combination (X, Y) may be a different symbol than a starting symbol of a second RAR receive window associated with the preamble opportunity / PUSCH opportunity combination (X, Z). Therefore, the BS may multiplex the RAR for the first UE subset into the first msgB communication (X, Y), and may send the first msgB communication in the first RAR receive window. In addition, the BS may multiplex the RAR for the second UE subset into the second msgB communication (X, Z), and may send the second msgB communication in the second RAR receive window.

[0068] exist Figure 3EIn the example shown, multiple UEs may send a RACH preamble in the same preamble opportunity X (e.g., a preamble portion of a msgA communication in a two-step RACH process). A first UE subset may send a msgA payload portion in a PUSCH opportunity Y, and a second UE subset may send a msgA payload portion in a PUSCH opportunity Z. In this example, a starting symbol of a first RAR receive window associated with a preamble opportunity / PUSCH opportunity combination (X, Y) may be the same symbol as a starting symbol of a second RAR receive window associated with a preamble opportunity / PUSCH opportunity combination (X, Z). Thus, the BS may multiplex RARs for the first UE subset and the second UE subset into the same msgB communications (X, Y) and (X, Z), and may send msgB communications in the RAR receive windows.

[0069] As in Figure 3F 3 and as shown by reference numeral 304, the BS may send msgB communications to the plurality of UEs. The msgB communications may include multiple RARs multiplexed for the plurality of UEs. In some aspects, the BS may send msgB communications to the plurality of UEs if the BS multiplexes subsets of the plurality of RARs in different msgB communications. The BS may send msgB communications during a RAR receive window associated with each of the plurality of UEs.

[0070] As described above, the UE may monitor and decode msgB communications during an associated RAR receive window. The UE may need to decode multiple msgB communications before identifying the RAR for the UE, which increases processing, memory, and / or power consumption at the UE. In order to reduce the number of msgB communications to be decoded by the UE during the RAR receive window, the BS may include an early indicator of the transmission timing of the msgB communication carrying the RAR for the UE in one or more msgB communications sent during the RAR receive window. In this way, the UE can decode the msgB communication, identify the early indicator in the msgB communication (e.g., which can identify the subsequent msgB communication that will carry the RAR for the UE), and avoid monitoring and decoding any interfering msgB communications before the msgB communication carrying the RAR for the UE.

[0071] Figure 3G An example of an early indicator of RAR for a UE (or a set of UEs or a group of UEs) is shown. Figure 3GAs shown in , a BS may send multiple msgB communications during a RAR receive window associated with one or more UEs. The RAR for the UE may be included in msgB 3, which may be sent after msgB 1 and msgB 2 in the RAR receive window. In this example, the BS may include an early indicator in msgB 1 and msgB 2 that the RAR will be included in msgB 3. Thus, the UE may receive and decode msgB 1, identify the early indicator, and avoid receiving and decoding msgB 2 based at least in part on the early indicator. If the UE misses or cannot decode msgB 1, the UE may receive and decode msgB 2, may identify the early indicator, and may monitor and receive msgB 3 based at least in part on the early indicator.

[0072] In some aspects, the BS may include an early indicator of transmission timing for the msgB communication carrying the RAR in a PDCCH portion of another msgB communication, in a PDSCH portion of another msgB communication, etc. For example, the early indicator may be included in downlink control information (DCI) in a PDCCH portion of another msgB communication, may be included in a medium access control (MAC) subheader in a PDCCH portion or a PDSCH portion, may be included in a MAC subprotocol data unit (PDU) in a PDCCH portion or a PDSCH portion, etc.

[0073] In some aspects, an early indicator for transmission timing of a msgB communication carrying a RAR may include a compressed UE identifier associated with one (or more) UEs to which the RAR is directed. The UE may determine that the early indicator is for the UE based at least in part on the compressed UE identifier indicated in the msgB communication carrying the early indicator. The compressed UE identifier may include a RAPID associated with the UE, a most significant bit (MSB) of a C-RNTI associated with the UE, a least significant bit (LSB) of the C-RNTI associated with the UE, an idle or inactive radio network temporary identifier (I-RNTI) associated with the UE, an LSB of the I-RNTI associated with the UE, and / or another type of compressed UE identifier.

[0074] In some aspects, the early indicator may include a timing offset between a msgB communication carrying the early indicator and a msgB communication carrying a RAR for the UE, and the timing offset may include a slot level offset, a symbol level offset, a backoff indication, or a combination thereof. The timing offset may be specified for a control resource set (CORESET) or search space associated with the msgB communication carrying the RAR for the UE, and the timing offset may be indicated relative to the msgB communication carrying the early indicator. In some aspects, the early indicator may include an index of a search space associated with the msgB communication carrying the RAR for the UE. Thus, the UE may identify the msgB communication carrying the RAR for the UE based at least in part on the timing offset and / or the index of the search space.

[0075] As in Figure 3H , and as shown by reference numeral 306, UE1 may receive msgB communications from a BS and may identify a RAR associated with UE1 included in the msgB communications. In some aspects, UE1 may identify the RAR among a plurality of RARs multiplexed in the msgB communications. In some aspects, UE1 may identify the RAR based at least in part on the RAR being scrambled using an RNTI associated with the UE and / or another type of UE identifier pair associated with the UE. In some aspects, other UEs in the plurality of UEs may receive msgB communications from the BS and may use similar techniques to identify the associated RARs.

[0076] In some aspects, a UE (e.g., UE1 and / or another UE in the plurality of UEs) may send a hybrid automatic repeat request (HARQ) feedback to a BS based at least in part on msgB communications. If the UE is able to decode the msgB communication, the HARQ feedback may include an acknowledgement (ACK), or if the UE is unable to decode the msgB communication or does not receive the msgB communication, the HARQ feedback may include a negative ACK (NACK). In some aspects, the UE may send the HARQ feedback to the BS in a physical uplink control channel (PUCCH) communication (e.g., during a two-step RACH process, after a two-step RACH process, etc.).

[0077] In some aspects, the BS may send one or more PUCCH parameters for HARQ feedback in an associated msgB communication, in another msgB communication sent prior to the associated msgB communication (e.g., with an early indicator), etc. The one or more PUCCH parameters may be included in a PDCCH portion of the msgB communication, in a PDSCH portion of the msgB communication, etc. In some aspects, the UE may send HARQ feedback associated with the msgB communication based at least in part on the one or more PUCCH parameters.

[0078] In order to reduce the signaling overhead of sending indications of one or more PUCCH parameters, the BS may configure the one or more PUCCH parameters to include one or more common PUCCH parameters shared by multiple UEs and one or more UE-specific PUCCH parameters specific to a specific UE. The one or more common PUCCH parameters may include common PUCCH power control parameters (e.g., an indication of the transmit power for PUCCH communications carrying HARQ feedback), PUCCH resource allocation (e.g., an indication of a common set of time-frequency resources for sending PUCCH communications carrying HARQ feedback), HARQ feedback timing indicators (e.g., an indication of the timing for sending HARQ feedback), etc. The one or more UE-specific PUCCH parameters may include UE-specific PUCCH power control parameters, PDSCH to HARQ feedback timing indicators, UE-specific PUCCH resource allocations, UE-specific HARQ feedback timing indicators, and / or other UE-specific parameters.

[0079] In some aspects, one or more common PUCCH parameters may be included in the DCI of the PDCCH portion of the msgB communication, in the MAC subheader of the PDSCH portion of the msgB communication, in the MAC sub-PDU of the PDSCH portion of the msgB communication, etc. In some aspects, one or more UE-specific PUCCH parameters may be included in the MAC subheader of the PDSCH portion of the msgB communication, in the MAC sub-PDU of the PDSCH portion of the msgB communication, or may be implicitly derived based on the following: the ordering of the UE-specific MAC subheader, the ordering of the UE-specific MAC subPDU, the preamble sequence index, the demodulation reference signal (DMRS) resource index, the PUSCH resource unit index, etc.

[0080] In this way, the BS can multiplex multiple RARs into a single msgB communication, and can send the msgB communication to one or more UEs of the multiple UEs. This allows the BS to reduce the number of msgB communications sent to the UE relative to sending multiple RARs in separate and / or separate msgB communications. The reduced number of msgB communications in turn reduces processing, memory, and power resource consumption at the UE, because the UE can monitor and decode fewer msgB communications to receive RARs during the associated RAR reception window. In addition, the BS can further reduce processing, memory, and power resource consumption at the UE by multiplexing the same type of RAR and / or different types of RARs in the same msgB communication (which can allow successful RARs, fallback RARs, initial RAR transmissions, and / or RAR retransmissions to be included in the same msgB communication). The BS can also provide early indications about which msgB communication will carry RARs for a specific UE or a group of UEs, which further reduces processing, memory, and power resource consumption at the UE.

[0081] As pointed out above, Figures 3A-3H is provided as one or more examples. Other examples may differ from Figures 3A-3H as described.

[0082] Figure 4 is a diagram illustrating an example process 400, performed, for example, by a BS, in accordance with various aspects of the present disclosure. Example process 400 is an example of a BS (eg, BS 110) performing operations associated with RAR mapping for a two-step RACH procedure.

[0083] As in Figure 4 As shown in , in some aspects, process 400 may include: grouping and selectively multiplexing multiple RARs in msgB communication (block 410). For example, the BS (e.g., using transmit processor 220, receive processor 238, controller / processor 240, memory 242, etc.) may group and selectively multiplex multiple RARs in msgB communication as described above.

[0084] As in Figure 4 As further shown in FIG. 4 , in some aspects, process 400 may include sending msgB communications to one or more UEs (block 420). For example, the BS (e.g., using transmit processor 220, receive processor 238, controller / processor 240, memory 242, etc.) may send msgB communications to one or more UEs, as described above.

[0085] Process 400 may include additional aspects, such as any single aspect or any combination of the aspects described below and / or described in conjunction with one or more other processes described elsewhere herein.

[0086] In a first aspect, grouping and selectively multiplexing multiple RARs in msgB communications includes: multiplexing multiple RARs and supplemental scheduling information for other RARs in multiple msgB communications, the msgB communications included in the multiple msgB communications, wherein the multiple msgB communications are time-division multiplexed. In a second aspect, alone or in combination with the first aspect, process 400 includes: scrambling multiple msgB communications using the same msgB radio network temporary identifier or the same set of msgB radio network temporary identifiers mapped to the same random access opportunity (RO). In a third aspect, alone or in combination with one or more of the first and second aspects, the multiple RARs include at least one of the following: one or more fallback RARs, one or more successful RARs with associated RRC messages, or one or more successful RARs without RRC messages.

[0087] In a fourth aspect, alone or in combination with one or more of the first to third aspects, the plurality of RARs comprises at least one of the following: an initial transmission of one or more of the plurality of RARs, or a retransmission of one or more of the plurality of RARs. In a fifth aspect, alone or in combination with one or more of the first to fourth aspects, multiplexing the plurality of RARs in msgB communication comprises: multiplexing the plurality of RARs in msgB communication based at least in part on at least one of the following: a start symbol of a corresponding RAR receive window associated with each of the one or more UEs sharing the same random access opportunity, a corresponding priority associated with each of the plurality of RARs, a corresponding quality of service (QoS) category associated with each of the plurality of RARs, or a corresponding payload size of each of the plurality of RARs.

[0088] In a sixth aspect, either alone or in combination with one or more of the first to fifth aspects, the process 400 includes: sending an indication of transmission timing for msgB communication to one or more UEs. In a seventh aspect, either alone or in combination with one or more of the first to sixth aspects, the indication of transmission timing for msgB communication is included in another msgB communication, and sending the indication of transmission timing for msgB communication includes: sending the other msgB communication before sending the msgB communication.

[0089] In the eighth aspect, alone or in combination with one or more of the first to seventh aspects, the indication of transmission timing for msgB communication is included in at least one of the following: DCI of another msgB communication, MAC subheader of another msgB communication, or MAC subprotocol data unit of another msgB communication. In the ninth aspect, alone or in combination with one or more of the first to eighth aspects, the indication of transmission timing for msgB communication includes at least one of the following: a corresponding compressed UE identifier associated with each of one or more UEs, a timing offset of a control resource set or search space associated with msgB communication relative to another msgB communication, or an index of a search space associated with msgB communication.

[0090] In the tenth aspect, either alone or in combination with one or more aspects from the first to the ninth aspect, the corresponding compressed UE identifier associated with each UE in the one or more UEs includes: a random access preamble identifier, an MSB of a C-RNTI, an LSB of a C-RNTI, an MSB of an I-RNTI, or an LSB of an I-RNTI. In the eleventh aspect, either alone or in combination with one or more aspects from the first to the tenth aspect, a msgB communication identifier is used for one or more PUCCH parameters of HARQ feedback associated with the msgB communication, wherein the one or more PUCCH parameters include at least one of the following: one or more common PUCCH parameters, or one or more UE-specific PUCCH parameters.

[0091] In the twelfth aspect, alone or in combination with one or more of the first to eleventh aspects, the one or more common PUCCH parameters include at least one of the following: a PUCCH power control parameter, a PUCCH resource allocation, a PDSCH to HARQ feedback timing indicator, or a HARQ feedback timing indicator. In the thirteenth aspect, alone or in combination with one or more of the first to twelfth aspects, the one or more common PUCCH parameters are included in at least one of the following: a DCI included in the PDCCH portion of msgB communication, a common MAC subheader included in the PDSCH portion of msgB communication, or a common MAC sub-PDU included in the PDSCH portion of msgB communication, and the one or more UE-specific PUCCH parameters are included in at least one of the following: a UE-specific MAC subheader included in the PDSCH portion of msgB communication, or a UE-specific MAC sub-PDU included in the PDSCH portion of msgB communication. The UE-specific PUCCH parameters may also be derived based on implicit indications based on: the UE-specific ordering of the MAC sub-headers, the UE-specific ordering of the MAC sub-PDUs, the preamble sequence index used by the UE in the two-step random access procedure, the DMRS resource index, or the PUSCH resource unit index.

[0092] In the fourteenth aspect, alone or in combination with one or more of the first to twelfth aspects, process 400 also includes: sending an indication of transmission timing for msgB communication to one or more UEs in supplementary scheduling information for other RARs to be mapped to different msgB communications.

[0093] Although Figure 4 Example blocks of process 400 are shown, but in some aspects process 400 may include Figure 4 The blocks of process 400 may include additional blocks, fewer blocks, different blocks, or blocks arranged in a different manner than those depicted in process 400. Additionally or alternatively, two or more of the blocks of process 400 may be executed in parallel.

[0094] Figure 5 is a diagram illustrating an example process 500, performed, for example, by a UE, in accordance with various aspects of the present disclosure. Example process 500 is an example of a UE (eg, UE 120) performing operations associated with RAR mapping for a two-step RACH procedure.

[0095] As in Figure 5As shown in , in some aspects, process 500 may include receiving, from a BS, msgB communications associated with a two-step RACH procedure between a UE and the BS (block 510). For example, the UE (e.g., using receive processor 258, transmit processor 264, controller / processor 280, memory 282, etc.) may receive, from a BS, msgB communications associated with a two-step RACH procedure between the UE and the BS, as described above.

[0096] As in Figure 5 As further shown in FIG. 5 , in some aspects, process 500 may include identifying a RAR associated with the UE among a plurality of RARs multiplexed in msgB communications and supplemental scheduling information for other RARs (block 520). For example, the UE (e.g., using receive processor 258, transmit processor 264, controller / processor 280, memory 282, etc.) may identify a RAR associated with the UE among a plurality of RARs multiplexed in msgB communications and supplemental scheduling information for other RARs, as described above.

[0097] Process 500 may include additional aspects, such as any single aspect or any combination of the aspects described below and / or described in conjunction with one or more other processes described elsewhere herein.

[0098] In a first aspect, the plurality of RARs comprises at least one of: one or more fallback RARs, one or more successful RARs with associated RRC messages, or one or more successful RARs without RRC messages. In a second aspect, alone or in combination with the first aspect, the plurality of RARs comprises at least one of: an initial transmission of one or more RARs in the plurality of RARs, or a retransmission of one or more RARs in the plurality of RARs. In a third aspect, alone or in combination with one or more of the first and second aspects, the process 500 comprises: receiving an indication of transmission timing for msgB communication from a BS; and identifying msgB communication based at least in part on the indication of transmission timing for msgB communication in supplemental scheduling information multiplexed with the RARs.

[0099] In a fourth aspect, alone or in combination with one or more of the first to third aspects, the process 500 includes: receiving an indication of transmission timing for msgB communication in another msgB communication sent before the msgB communication. In a fifth aspect, alone or in combination with one or more of the first to fourth aspects, the process 500 includes: receiving an indication of transmission timing for msgB communication in at least one of the following: a DCI of another msgB communication, a MAC subheader of another msgB communication, or a MAC subprotocol data unit of another msgB communication.

[0100] In the sixth aspect, either alone or in combination with one or more of the first to fifth aspects, the indication of transmission timing for msgB communication comprises at least one of: a corresponding compressed UE identifier associated with each of one or more UEs, a timing offset of a control resource set or search space associated with the msgB communication relative to another msgB communication, or an index of a search space associated with the msgB communication.

[0101] In a seventh aspect, either alone or in combination with one or more of aspects 1 to 6, a corresponding compressed UE identifier associated with each of the one or more UEs comprises: a random access preamble identifier, an MSB of a C-RNTI, an LSB of a C-RNTI, an MSB of an I-RNTI, or an LSB of an I-RNTI, and wherein the timing offset comprises at least one of the following: a slot level offset, a symbol level offset, or a backoff indicator. In an eighth aspect, either alone or in combination with one or more of aspects 1 to 7, process 500 comprises: identifying one or more PUCCH parameters for HARQ feedback, and sending HARQ feedback associated with msgB communication to a BS based at least in part on the one or more PUCCH parameters.

[0102] In the ninth aspect, alone or in combination with one or more of the first to eighth aspects, the one or more PUCCH parameters include at least one of the following: one or more common PUCCH parameters, or one or more UE-specific PUCCH parameters.

[0103] In the tenth aspect, alone or in combination with one or more of the first to ninth aspects, the one or more common PUCCH parameters include at least one of the following: a PUCCH power control parameter, a PUCCH resource allocation, a PDSCH to HARQ feedback timing indicator, or a HARQ feedback timing indicator. In the eleventh aspect, alone or in combination with one or more of the first to tenth aspects, the one or more common PUCCH parameters are included in at least one of the following: a DCI included in the PDCCH portion of msgB communication, a common MAC subheader included in the PDSCH portion of msgB communication, or a common MAC sub-PDU included in the PDSCH portion of msgB communication, and the one or more UE-specific PUCCH parameters are included in at least one of the following: a UE-specific MAC subheader included in the PDSCH portion of msgB communication, or a UE-specific MAC sub-PDU included in the PDSCH portion of msgB communication. UE-specific PUCCH parameters may also be derived from implicit indications based on the ordering of MAC sub-headers, the ordering of MAC sub-PDUs, the preamble sequence index used by the UE in the two-step random access procedure, the DMRS resource index and the PUSCH resource unit index.

[0104] Although Figure 5 Example blocks of process 500 are shown, but in some aspects process 500 may include Figure 5 The blocks of process 500 may include additional blocks, fewer blocks, different blocks, or blocks arranged in a different manner than those depicted in process 500. Additionally or alternatively, two or more of the blocks of process 500 may be performed in parallel.

[0105] The foregoing disclosure provides illustration and description, but is not intended to be exhaustive or to limit the aspects to the precise forms disclosed. Modifications and variations may be made in light of the above disclosure or may be acquired from practice of the various aspects.

[0106] As used herein, the term "component" is intended to be broadly interpreted as hardware, firmware, and / or a combination of hardware and software. As used herein, a processor is implemented in hardware, firmware, and / or a combination of hardware and software.

[0107] As used herein, satisfying a threshold may refer to a value being greater than a threshold, greater than or equal to a threshold, less than a threshold, less than or equal to a threshold, equal to a threshold, not equal to a threshold, etc., depending on the context.

[0108] It will be apparent that the systems and / or methods described herein can be implemented in various forms of hardware, firmware, and / or combinations of hardware and software. The actual specialized control hardware or software code used to implement these systems and / or methods is not limiting in any respect. Therefore, the operation and behavior of the systems and / or methods are described herein without reference to specific software code, it being understood that software and hardware can be designed to implement the systems and / or methods based, at least in part, on the description herein.

[0109] Although the specific combination of features is recorded in the claims and / or disclosed in the specification, these combinations are not intended to limit the disclosure of various aspects. In fact, many of these features can be combined in a manner not specifically recorded in the claims and / or specifically disclosed in the specification. Although each dependent claim listed below can directly rely on only one claim, the disclosure of various aspects includes the combination of each dependent claim and each other claim in the claim set. The phrase "at least one of" referring to the list of items refers to any combination of those items, including a single member. As an example, "at least one of a, b or c" is intended to cover any combination of a, b, c, ab, ac, bc and abc, and with multiples of the same element (e.g., aa, aaa, aab, aac, abb, acc, bb, bbb, bbc, cc and ccc or any other sorting of a, b and c).

[0110] The elements, actions or instructions used herein should not be interpreted as key or necessary, unless clearly described as such. In addition, as used herein, the articles "a" and "an" are intended to include one or more projects, and can be used interchangeably with "one or more". In addition, as used herein, the terms "set" and "group" are intended to include one or more projects (e.g., related projects, unrelated projects, combinations of related projects and unrelated projects, etc.), and can be used interchangeably with "one or more". In the case of being intended to only one project, the phrase "only one" or similar language is used. In addition, as used herein, the terms "has", "have", "containing", etc. are intended to be open terms. In addition, unless otherwise expressly stated, the phrase "based on" is intended to mean "based at least in part on".

Claims

1. A method of wireless communication performed by a network entity, comprising: Sending a first message B (msgB) communication to a plurality of user equipments (UEs), the first msgB communication comprising: an indication that a plurality of random access channel responses (RARs) for the plurality of UEs are included in the second msgB communication, and Supplementary scheduling information for other RARs; grouping and selectively multiplexing the plurality of RARs in the second msgB communication, wherein the plurality of UEs are grouped into a first group based at least in part on the plurality of UEs transmitting respective random access channel (RACH) preambles in the same preamble opportunity and transmitting respective msgA payload parts in the same physical uplink shared channel (PUSCH) opportunity, and wherein multiplexing the plurality of RARs in the second msgB communication is based at least in part on a starting symbol of a corresponding RAR reception window associated with the preamble opportunity and the PUSCH opportunity; and The second msgB communication is sent to the plurality of UEs, wherein the second msgB communication is sent after the first msgB communication.

2. The method according to claim 1, wherein: Multiplexing the plurality of RARs in the second msgB communication includes: grouping and multiplexing the plurality of RARs and the supplementary scheduling information for the other RARs in a plurality of msgB communications, the first msgB communication and the second msgB communication being included in the plurality of msgB communications, Wherein, the multiple msgB communications are time division multiplexed.

3. The method according to claim 2, further comprising: The plurality of msgB communications are scrambled using a same msgB radio network temporary identifier or using a same set of msgB radio network temporary identifiers mapped to a same random access opportunity (RO).

4. The method according to claim 2, further comprising: The indication is sent to the plurality of UEs in the supplemental scheduling information for other RARs.

5. The method according to claim 1, wherein: The plurality of RARs include at least one of the following: One or more rollback RARs, One or more successful RARs with associated Radio Resource Control (RRC) messages, or One or more successful RARs without RRC messages.

6. The method according to claim 1, wherein: The plurality of RARs include at least one of the following: an initial transmission of one or more of the plurality of RARs, or Retransmission of one or more RARs of the plurality of RARs.

7. The method according to claim 1, wherein: Multiplexing the plurality of RARs in the second msgB communication includes: multiplexing the plurality of RARs in the second msgB communication based at least in part on at least one of: a respective priority level associated with each RAR in the plurality of RARs, a respective quality of service (QoS) class associated with each of the plurality of RARs, or A respective payload size of each RAR in the plurality of RARs.

8. The method according to claim 1, wherein: The indication is included in the supplemental scheduling information for the other RAR.

9. The method according to claim 1, wherein: grouping the plurality of RARs into a plurality of groups based at least in part on a size of a payload portion of the second msgB communication and respective payload sizes associated with the plurality of RARs, and wherein each of the plurality of groups maximizes usage of the size of the payload portion.

10. The method according to claim 1, wherein: The indication is included in at least one of the following: downlink control information of the first msgB communication, a medium access control (MAC) subheader of the first msgB communication, or The MAC sub-protocol data unit of the first msgB communication.

11. The method according to claim 1, wherein: The indication includes at least one of the following: a respective compressed UE identifier associated with each UE of the plurality of UEs, a timing offset of a set of control resources or a search space associated with the second msgB communication relative to the first msgB communication, or An index into the search space associated with the second msgB communication.

12. The method according to claim 11, wherein: The corresponding compressed UE identifier associated with each UE of the plurality of UEs comprises: Random access preamble identifier, The most significant bit (MSB) of the cell radio network temporary identifier (C-RNTI), the least significant bit (LSB) of the C-RNTI, The MSB of the Implicit Radio Network Temporary Identifier (I-RNTI), or the LSB of the I-RNTI; and The timing offset includes at least one of the following: Slot level offset, symbol level offset, or Backoff indicator.

13. The method according to claim 1, wherein: The second msgB communication identifies one or more physical uplink control channel (PUCCH) parameters for hybrid automatic repeat request (HARQ) feedback associated with the second msgB communication, The one or more PUCCH parameters include at least one of the following: One or more common PUCCH parameters, or One or more UE-specific PUCCH parameters.

14. The method according to claim 13, wherein: The one or more PUCCH parameters include at least one of the following: PUCCH power control parameters, Physical Downlink Shared Channel (PDSCH) to HARQ feedback timing indicator, PUCCH resource allocation, or HARQ feedback timing indicator.

15. The method according to claim 13, wherein: The one or more common PUCCH parameters are included in at least one of the following: downlink control information included in the physical downlink control channel portion of said second msgB communication, a common MAC subheader included in a physical downlink shared channel (PDSCH) portion of said second msgB communication, or a common MAC sub-protocol data unit (PDU) included in the PDSCH portion of the second msgB communication; and The one or more UE-specific PUCCH parameters are included in at least one of the following: a UE-specific MAC subheader included in said PDSCH portion of said second msgB communication, a UE-specific MAC sub-PDU included in said PDSCH portion of said second msgB communication, or Based on an implicit indication of: an ordering of a UE-specific MAC subheader or a UE-specific MAC sub-PDU, a preamble sequence index, a demodulation reference signal (DMRS) resource index, or a PUSCH resource unit index used by the multiple UEs in a two-step random access procedure.

16. A method of wireless communication performed by a user equipment (UE), comprising: Receiving a first message B (msgB) communication from a network entity, wherein the first msgB communication comprises: an indication that a Random Access Channel Response (RAR) associated with a two-step Random Access Channel (RACH) procedure between the UE and the network entity is included in the second msgB communication, and Supplemental scheduling information for other RARs; and receiving the second msgB communication, wherein the RAR is included in a plurality of RARs multiplexed in the second msgB communication, wherein the plurality of RARs are multiplexed in the second msgB communication based at least in part on a starting symbol of a respective RAR receive window associated with a preamble opportunity and a physical uplink shared channel (PUSCH) opportunity in which each of a plurality of UEs including the UE transmits a RACH preamble and in which each of the plurality of UEs transmits a msgA payload portion, and wherein the second msgB communication is received after the first msgB communication.

17. The method according to claim 16, wherein: The plurality of RARs include at least one of the following: One or more rollback RARs, One or more successful RARs with associated Radio Resource Control (RRC) messages, or One or more successful RARs without RRC messages.

18. The method according to claim 16, wherein: The plurality of RARs include at least one of the following: an initial transmission of one or more of the plurality of RARs, or Retransmission of one or more RARs of the plurality of RARs.

19. The method according to claim 16, further comprising: The second msgB communication is identified based at least in part on the indication.

20. The method according to claim 16, wherein: grouping the plurality of RARs into a plurality of groups based at least in part on a size of a payload portion of the second msgB communication and respective payload sizes associated with the plurality of RARs, and, wherein each of the plurality of groups maximizes usage of the size of the payload portion.

21. The method of claim 16, further comprising: The indication is identified in at least one of the following: downlink control information of the first msgB communication, a medium access control (MAC) subheader of the first msgB communication, or The MAC sub-protocol data unit of the first msgB communication.

22. The method according to claim 16, wherein: The indication includes at least one of the following: a compressed UE identifier associated with the UE, a timing offset of a set of control resources or a search space associated with the second msgB communication relative to the first msgB communication, or An index into the search space associated with the second msgB communication.

23. The method according to claim 22, wherein: The compressed UE identifier associated with the UE comprises: Random access preamble identifier, The most significant bit (MSB) of the cell radio network temporary identifier (C-RNTI), the least significant bit (LSB) of the C-RNTI, The MSB of the idle or inactive radio network temporary identifier (I-RNTI), or the LSB of the I-RNTI; and The timing offset includes at least one of the following: Slot level offset, symbol level offset, or Backoff indicator.

24. The method of claim 16, further comprising: identifying one or more physical uplink control channel (PUCCH) parameters for hybrid automatic repeat request (HARQ) feedback; as well as HARQ feedback associated with the second msgB communication is sent to the network entity based at least in part on the one or more PUCCH parameters.

25. The method according to claim 24, wherein: The one or more PUCCH parameters include at least one of the following: PUCCH power control parameters, Physical Downlink Shared Channel (PDSCH) to HARQ feedback timing indicator, PUCCH resource allocation, or HARQ feedback timing indicator.

26. The method according to claim 24, wherein: The one or more PUCCH parameters include at least one of the following: One or more common PUCCH parameters, or One or more UE-specific PUCCH parameters.

27. The method according to claim 26, wherein: The one or more common PUCCH parameters are included in at least one of the following: downlink control information included in the physical downlink control channel portion of said second msgB communication, a common Medium Access Control (MAC) subheader included in a Physical Downlink Shared Channel (PDSCH) portion of said second msgB communication, or a common MAC sub-protocol data unit (PDU) included in the PDSCH portion of the second msgB communication; and The one or more UE-specific PUCCH parameters are included in at least one of the following: a UE-specific MAC subheader included in said PDSCH portion of said second msgB communication, a UE-specific MAC sub-PDU included in said PDSCH portion of said second msgB communication, or Based on an implicit indication of: the ordering of a UE-specific MAC subheader or a UE-specific MAC sub-PDU, a preamble sequence index used by the UE in a two-step random access procedure, a demodulation reference signal (DMRS) resource index, or a physical uplink shared channel (PUSCH) resource unit index.

28. A network entity for wireless communication, comprising: one or more memories; as well as One or more processors coupled to the one or more memories, configured alone or in any combination to: Sending a first message B (msgB) communication to a plurality of user equipments (UEs), the first msgB communication comprising: an indication that a plurality of random access channel responses (RARs) for the plurality of UEs are included in the second msgB communication, and Supplementary scheduling information for other RARs; grouping and selectively multiplexing the plurality of RARs in the second msgB communication, wherein the plurality of UEs are grouped into a first group based at least in part on the plurality of UEs transmitting respective random access channel (RACH) preambles in the same preamble opportunity and transmitting respective msgA payload parts in the same physical uplink shared channel (PUSCH) opportunity, and wherein multiplexing the plurality of RARs in the second msgB communication is based at least in part on a starting symbol of a corresponding RAR reception window associated with the preamble opportunity and the PUSCH opportunity; and The second msgB communication is sent to the plurality of UEs, wherein the second msgB communication is sent after the first msgB communication.

29. The network entity according to claim 28, wherein: The one or more processors are configured to: grouping and multiplexing the plurality of RARs and the supplementary scheduling information for the other RARs in a plurality of msgB communications, the first msgB communication and the second msgB communication being included in the plurality of msgB communications, Wherein, the multiple msgB communications are time division multiplexed.

30. The network entity according to claim 29, wherein: The one or more processors are further configured to: The plurality of msgB communications are scrambled using a same msgB radio network temporary identifier or using a same set of msgB radio network temporary identifiers mapped to a same random access opportunity (RO).

31. The network entity according to claim 29, wherein: The indication is included in the supplemental scheduling information for the other RAR.

32. The network entity according to claim 28, wherein: The plurality of RARs include at least one of the following: One or more rollback RARs, One or more successful RARs with associated Radio Resource Control (RRC) messages, or One or more successful RARs without RRC messages.

33. The network entity according to claim 28, wherein: The plurality of RARs include at least one of the following: an initial transmission of one or more of the plurality of RARs, or Retransmission of one or more RARs of the plurality of RARs.

34. The network entity according to claim 28, wherein: The one or more processors, when multiplexing the plurality of RARs in the second msgB communication, are configured to: multiplexing the plurality of RARs in the second msgB communication based at least in part on at least one of: a respective priority level associated with each RAR in the plurality of RARs, a respective quality of service (QoS) class associated with each of the plurality of RARs, or A respective payload size of each RAR in the plurality of RARs.

35. The network entity according to claim 28, wherein: The indication is included in the supplemental scheduling information for the other RAR.

36. The network entity according to claim 28, wherein: The indication is included in at least one of the following: downlink control information of the first msgB communication, a medium access control (MAC) subheader of the first msgB communication, or The MAC sub-protocol data unit of the first msgB communication.

37. The network entity according to claim 28, wherein: The indication includes at least one of the following: a respective compressed UE identifier associated with each UE of the plurality of UEs, a timing offset of a set of control resources or a search space associated with the second msgB communication relative to the first msgB communication, or An index into the search space associated with the second msgB communication.

38. The network entity according to claim 37, wherein: The corresponding compressed UE identifier associated with each UE of the plurality of UEs comprises: Random access preamble identifier, The most significant bit (MSB) of the cell radio network temporary identifier (C-RNTI), the least significant bit (LSB) of the C-RNTI, The MSB of the Implicit Radio Network Temporary Identifier (I-RNTI), or the LSB of the I-RNTI; and The timing offset includes at least one of the following: Slot level offset, symbol level offset, or Backoff indicator.

39. The network entity according to claim 28, wherein: The second msgB communication identifies one or more physical uplink control channel (PUCCH) parameters for hybrid automatic repeat request (HARQ) feedback associated with the second msgB communication, The one or more PUCCH parameters include at least one of the following: One or more common PUCCH parameters, or One or more UE-specific PUCCH parameters.

40. The network entity according to claim 39, wherein: The one or more PUCCH parameters include at least one of the following: PUCCH power control parameters, Physical Downlink Shared Channel (PDSCH) to HARQ feedback timing indicator, PUCCH resource allocation, or HARQ feedback timing indicator.

41. The network entity according to claim 39, wherein: The one or more common PUCCH parameters are included in at least one of the following: downlink control information included in the physical downlink control channel portion of said second msgB communication, a common Medium Access Control (MAC) subheader included in a Physical Downlink Shared Channel (PDSCH) portion of said second msgB communication, or a common MAC sub-protocol data unit (PDU) included in the PDSCH portion of the second msgB communication; and The one or more UE-specific PUCCH parameters are included in at least one of the following: a UE-specific MAC subheader included in said PDSCH portion of said second msgB communication, a UE-specific MAC sub-PDU included in said PDSCH portion of said second msgB communication, or Based on an implicit indication of: the ordering of a UE-specific MAC subheader or a UE-specific MAC sub-PDU, a preamble sequence index used by the multiple UEs in a two-step random access procedure, a demodulation reference signal (DMRS) resource index, or a physical uplink shared channel (PUSCH) resource unit index.

42. A user equipment (UE) for wireless communication, comprising: one or more memories; as well as One or more processors coupled to the one or more memories, configured alone or in any combination to: Receiving a first message B (msgB) communication from a network entity, wherein the first msgB communication comprises: an indication that a Random Access Channel Response (RAR) associated with a two-step Random Access Channel (RACH) procedure between the UE and the network entity is included in the second msgB communication, and Supplemental scheduling information for other RARs; and receiving the second msgB communication, wherein the RAR is included in a plurality of RARs multiplexed in the second msgB communication, wherein the plurality of RARs are multiplexed in the second msgB communication based at least in part on a starting symbol of a respective RAR receive window associated with a preamble opportunity and a physical uplink shared channel (PUSCH) opportunity in which each of a plurality of UEs including the UE transmits a RACH preamble and in which each of the plurality of UEs transmits a msgA payload portion, and wherein the second msgB communication is received after the first msgB communication.

43. The UE according to claim 42, wherein: The plurality of RARs include at least one of the following: One or more rollback RARs, One or more successful RARs with associated Radio Resource Control (RRC) messages, or One or more successful RARs without RRC messages.

44. The UE according to claim 42, wherein: The plurality of RARs include at least one of the following: an initial transmission of one or more of the plurality of RARs, or Retransmission of one or more RARs of the plurality of RARs.

45. The UE according to claim 42, wherein: The one or more processors are further configured to: The second msgB communication is identified based at least in part on the indication.

46. ​​The UE according to claim 42, wherein: The one or more processors are further configured to: The indication is identified in at least one of the following: downlink control information of the first msgB communication, a medium access control (MAC) subheader of the first msgB communication, or The MAC sub-protocol data unit of the first msgB communication.

47. The UE according to claim 42, wherein: The indication includes at least one of the following: a respective compressed UE identifier associated with each UE of the plurality of UEs, a timing offset of a set of control resources or a search space associated with the second msgB communication relative to the first msgB communication, or An index into the search space associated with the second msgB communication.

48. The UE according to claim 47, wherein: The corresponding compressed UE identifier associated with each UE of the plurality of UEs comprises: Random access preamble identifier, The most significant bit (MSB) of the cell radio network temporary identifier (C-RNTI), the least significant bit (LSB) of the C-RNTI, The MSB of the idle or inactive radio network temporary identifier (I-RNTI), or the LSB of the I-RNTI; and The timing offset includes at least one of the following: Slot level offset, symbol level offset, or Backoff indicator.

49. The UE according to claim 42, wherein: The one or more processors are further configured to: identifying one or more physical uplink control channel (PUCCH) parameters for hybrid automatic repeat request (HARQ) feedback; and HARQ feedback associated with the second msgB communication is sent to the network entity based at least in part on the one or more PUCCH parameters.

50. The UE according to claim 49, wherein: The one or more PUCCH parameters include at least one of the following: PUCCH power control parameters, Physical Downlink Shared Channel (PDSCH) to HARQ feedback timing indicator, PUCCH resource allocation, or HARQ feedback timing indicator.

51. The UE according to claim 49, wherein: The one or more PUCCH parameters include at least one of the following: One or more common PUCCH parameters, or One or more UE-specific PUCCH parameters.

52. The UE according to claim 51, wherein: The one or more common PUCCH parameters are included in at least one of the following: downlink control information included in the physical downlink control channel portion of said second msgB communication, a common Medium Access Control (MAC) subheader included in a Physical Downlink Shared Channel (PDSCH) portion of said second msgB communication, or a common MAC sub-protocol data unit (PDU) included in the PDSCH portion of the second msgB communication; and The one or more UE-specific PUCCH parameters are included in at least one of the following: a UE-specific MAC subheader included in said PDSCH portion of said second msgB communication, a UE-specific MAC sub-PDU included in said PDSCH portion of said second msgB communication, or Based on an implicit indication of: the ordering of a UE-specific MAC subheader or a UE-specific MAC sub-PDU, a preamble sequence index used by the UE in a two-step random access procedure, a demodulation reference signal (DMRS) resource index, or a physical uplink shared channel (PUSCH) resource unit index.

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