Techniques for performing random access using multiple beams in wireless communication

Abstract

Aspects described herein relate to: determining a plurality of beams to be used when transmitting a message during a random access procedure with one or more transmit / receive points (TRPs) of a cell, and transmitting a plurality of instances of a first random access message to one or more TRPs of the cell based on the plurality of beams, wherein each instance of the plurality of instances of the first random access message includes a preamble portion and a payload portion. In another aspect, a node receiving the plurality of instances of the first random access message may determine a plurality of beams to be used when transmitting a message during a random access procedure, and may utilize one or more TRPs to transmit a plurality of instances of a second random access message to a UE and in response to the first random access message based on the plurality of beams.

Description

[0001] Cross - Reference to Related Applications

[0002] This patent application claims the benefit of priority to Provisional Patent Application No. 63 / 003,606, filed on April 1, 2020, entitled "TECHNIQUES FOR PERFORMING RANDOM ACCESS USING MULTIPLE BEAMS IN WIRELESS COMMUNICATIONS" and U.S. Patent Application No. 17 / 217,665, filed on March 30, 2021, entitled "TECHNIQUES FOR PERFORMING RANDOM ACCESS USING MULTIPLE BEAMS IN WIRELESS COMMUNICATIONS". Both of these applications have been assigned to the assignee of the present application, and the entire contents of both are hereby incorporated by reference in their entirety. Field of the Disclosure

[0003] Broadly speaking, aspects of the present disclosure relate to wireless communication systems, and more particularly, aspects of the present disclosure relate to random access procedures. Background Art

[0004] Wireless communication systems are widely deployed to provide various types of communication content, such as telephony, video, packet data, messaging, broadcasting, etc. These systems can be multi - access systems capable of supporting communication with multiple users by sharing available system resources. Examples of such multi - access systems 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, and Single - Carrier Frequency Division Multiple Access (SC - FDMA) systems.

[0005] These multi - access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate over urban, national, regional, or even global scales. For example, consider the fifth - generation (5G) wireless communication technology (which may be referred to as 5G New Radio (5G NR)) for expanding and supporting various use cases and applications regarding the current mobile network generation. In one aspect, 5G communication technology can include: enhanced mobile broadband to address use cases for human - centric access to multimedia content, services, and data; ultra - reliable low - latency communication (URLLC) with certain specifications for latency and reliability; and massive machine - type communication, which can allow a very large number of connected devices to transmit relatively small amounts of non - latency - sensitive information.

[0006] In some wireless communication technologies, a User Equipment (UE) may use a random access procedure to establish a connection with a base station. The random access procedure typically may include four steps of transmitting messages between the UE and the base station to establish the connection. Recent proposals have introduced a two-step random access procedure, in which the UE sends a first message including a random access preamble and a payload in a shared random access opportunity, and the base station receives the first message and may send a second message including a random access response (e.g., for the random access preamble) and / or contention resolution information. The first message may include two separate transmissions (e.g., in time) of a preamble and a payload part of the message, and the gap between the preamble transmission and the payload transmission is configurable. SUMMARY

[0007] A brief overview of one or more aspects is presented below to provide a basic understanding of such aspects. This overview is not an extensive review of all contemplated aspects, and is neither intended to identify key or critical elements of all aspects nor to delineate the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that follows.

[0008] According to one aspect, a method for wireless communication is provided. The method includes: determining a plurality of beams to be used when sending a message during a random access procedure with one or more Transmission / Reception Points (TRPs) of a cell; and sending a plurality of instances of a first random access message to the one or more TRPs of the cell based on the plurality of beams, wherein each instance of the first random access message includes a preamble part and a payload part.

[0009] In another example, a method for wireless communication is provided. The method includes: as part of a random access procedure, receiving, by one or more TRPs, one or more instances of a first random access message from a User Equipment (UE), wherein each instance of the first random access message includes a preamble part and a payload part; determining a plurality of beams to be used when sending a message during the random access procedure; and sending, by one or more TRPs, a plurality of instances of a second random access message to the UE based on the plurality of beams and in response to the first random access message.

[0010] In a further example, a device for wireless communication is provided, the device including a transceiver, a memory configured to store instructions, and one or more processors coupled to the transceiver and the memory (e.g., communicatively coupled, operatively coupled, electrically coupled, electronically coupled, or otherwise coupled). The one or more processors are configured to execute the instructions to perform the operations of the methods described herein. In another aspect, a device for wireless communication is provided, the device including units for performing the operations of the methods described herein. In yet another aspect, a computer-readable medium is provided, the computer-readable medium including code executable by one or more processors to perform the operations of the methods described herein.

[0011] In one aspect, a device for wireless communication is provided, the device including a transceiver, a memory configured to store instructions, and one or more processors coupled to the memory and the transceiver (e.g., communicatively coupled, operatively coupled, electronically coupled, electrically coupled, or otherwise coupled). The one or more processors are configured to: determine a plurality of beams to be used when transmitting a message during a random access procedure with one or more TRPs of a cell; and transmit a plurality of instances of a first random access message to the one or more TRPs of the cell based on the plurality of beams, wherein each instance of the plurality of instances of the first random access message includes a preamble portion and a payload portion.

[0012] In another aspect, a device for wireless communication is provided, the device including a transceiver, a memory configured to store instructions, and one or more processors coupled to the memory and the transceiver (e.g., communicatively coupled, operatively coupled, electronically coupled, electrically coupled, or otherwise coupled). The one or more processors are configured to: as part of a random access procedure, receive, from a UE, one or more instances of a first random access message using one or more TRPs, wherein each instance of the one or more instances of the first random access message includes a preamble portion and a payload portion; determine a plurality of beams to be used when transmitting a message during the random access procedure; and transmit, using one or more TRPs, a plurality of instances of a second random access message to the UE and in response to the first random access message based on the plurality of beams.

[0013] To achieve the foregoing and related purposes, one or more aspects include the features that are fully described hereinafter and particularly pointed out in the claims. The following description and the drawings set forth in detail certain illustrative features of one or more aspects. However, these features are merely indicative of the various ways in which the principles of the various aspects may be employed, and this specification is intended to include all such aspects and their equivalents. Description of the Drawings

[0014] The disclosed aspects of the present invention will be described below with reference to the accompanying drawings. These accompanying drawings are provided for illustration purposes and not for limiting the disclosed aspects, where like reference numerals denote like elements, and wherein:

[0015] Figure 1 Shows an example of a wireless communication system according to various aspects of the present disclosure;

[0016] Figure 2 Is a block diagram showing an example of a UE according to various aspects of the present disclosure;

[0017] Figure 3 Is a block diagram showing an example of a base station according to various aspects of the present disclosure;

[0018] Figure 4 Is a flowchart showing an example of a method for transmitting a first random access message based on multiple beams according to various aspects of the present disclosure;

[0019] Figure 5 Is a flowchart showing an example of a method for transmitting a second random access message based on multiple beams according to various aspects of the present disclosure;

[0020] Figure 6 Shows a first example of a timeline for transmitting a first random access message based on multiple beams according to various aspects of the present disclosure;

[0021] Figure 7 Shows a second example of a timeline for transmitting a first random access message based on multiple beams according to various aspects of the present disclosure;

[0022] Figure 8 Shows an example of a timeline for transmitting a second random access message based on multiple beams according to various aspects of the present disclosure;

[0023] Figure 9 Shows an example of a timeline for transmitting feedback for a second random access message based on multiple beams according to various aspects of the present disclosure; and

[0024] Figure 10 Is a block diagram showing an example of a MIMO communication system including a base station and a UE according to various aspects of the present disclosure.

[0025] Detailed Implementation Manner

[0026] Aspects will now be described with reference to the accompanying drawings. In the following description, numerous specific details are set forth for purposes of illustration in order to provide a thorough understanding of one or more aspects. It will be apparent, however, that the aspects may be practiced without these specific details.

[0027] The features described generally relate to sending messages in a two-step random access procedure using multiple beams to improve their reliability, but these concepts can also be applied to random access procedures with more or fewer than two steps. In a two-step random access procedure, a base station may broadcast a signal having parameters for establishing a connection with the base station. Such a signal may include a synchronization signal (SS) block (SSB), a system information block (SIB), a reference signal (RS), etc. that can be sent in a primary broadcast channel (PBCH) block. A user equipment (UE) may receive the broadcast signal and may synchronize with the downlink from the base station, perform system information decoding and measurements, etc. In addition, in contention-based random access (CBRA), the UE may determine one or more random access opportunities based on the parameters in the broadcast signal for sending a random access message to establish a connection with the base station. In contention-free random access (CFRA), the base station may assign a random access opportunity and / or related parameters (e.g., a random access preamble) to the UE.

[0028] In any case, when the UE wishes to establish a connection with the base station, the UE may send a first message of the two-step random access procedure (also referred to herein as "msgA"), which may include a preamble portion and a payload portion (e.g., where the payload portion may include physical uplink shared channel (PUSCH) data), and these portions may be sent separately in time via a transmission gap. The base station may receive the first message (e.g., as the preamble and payload portions) and may send a response message (also referred to herein as "msgB") to the UE, where the response message may include a random access response. In CBRA, the response message may also include contention resolution information.

[0029] In a specific example, in the fifth generation (5G) new radio (NR), a UE may select the type of random access (RA) at the start of a random access procedure based on network configuration. For example, in a case where the UE is not configured with CFRA resources, the UE may use a reference signal received power (RSRP) threshold to select between a two-step RA type and a four-step RA type. When the UE is configured with CFRA resources for the four-step RA type, in this example, the UE may perform a random access of the four-step RA type, or when the UE is configured with CFRA resources for the two-step RA type, the UE may perform a random access of the two-step RA type. The network may not configure CFRA resources for both the four-step and two-step RA types for a bandwidth part (BWP) simultaneously. Additionally, for example, only CFRA with a two-step RA type may be supported for handover. Further, for example, the UE may perform carrier selection (uplink (UL) or supplementary uplink (SUL)) before selecting between the two-step and four-step RA types. The RSRP thresholds for selecting the two-step and four-step RA types may be configured separately for UL and SUL.

[0030] Furthermore, for example, the two-step RA may include a fallback scenario when the RA procedure fails. In this example, if a fallback indication is received in the second random access message, the UE may perform a third message transmission (e.g., to be sent as part of a four-step RA procedure) and may monitor for contention resolution (e.g., to be sent as the fourth message in a four-step RA procedure). If contention resolution is not successful after the transmission of the third RA message and / or one or more retransmissions, the UE may revert to sending the first random access message (msgA) of the two-step RA procedure. If the random access procedure of the two-step RA type is not completed after multiple msgA transmissions, the UE may be configured to switch to the four-step RA type of CBRA.

[0031] In this example, the fallback random access response (fallbackRAR) message may have the same media access control (MAC) format as the second message of the four-step RA procedure (random access response (RAR)). The successRAR may have a format including multiple fields, which includes UE contention resolution identity, transmit power control (TPC), hybrid automatic repeat / request (HARQ) feedback timing indicator, physical uplink control channel (PUCCH) resource indicator, timing advance (TA) command, cell radio network temporary identifier (C-RNTI), and so on. For example, the UE contention resolution identity may include the UL common control channel (CCCH) service data unit (SDU). If the UL CCCH SDU is longer than 48 bits, this field may include the first 48 bits of the UL CCCH SDU. In one example, the TPC may include a TPC command for the PUCCH resource that contains the HARQ feedback for msgB. The HARQ feedback timing indicator may include a physical downlink shared channel (PDSCH) to HARQ feedback timing indicator field for the msgB HARQ feedback. The PUCCH resource indicator may include a PUCCH resource indicator for the HARQ feedback for msgB. The timing advance command may include an index value TA for controlling the amount of timing adjustment applied by the MAC entity.

[0032] In one example, a UE may be configured to communicate with multiple cell groups in a multi-connection, referred to as dual connectivity (DC) of two cell groups. For example, these cell groups may include a master cell group (MCG) and one or more secondary cell groups (SCGs). For the MCG, the UE may be configured to communicate with an associated primary cell (PCell) and / or one or more associated secondary cells (SCells). For the SCG, the UE may be configured to communicate with an associated primary cell (PSCell) and / or one or more associated secondary cells. Once the UE has established communication with the PCell, it may be configured to establish communication with one or more PSCs in one or more SCGs. For example, the PCell may configure the UE to perform layer 3 (L3) measurements on the PSCell. The UE may measure the PSCell SSB in a corresponding SS / PBCH block measurement timing configuration (SMTC) window. The UE may send an L3 beam report to the PCell via event triggering or periodic reporting, and based on the L3 report, the PCell may initiate a PSCell addition process for the UE. The UE may receive a PSCell RA channel (RACH) configuration from the PCell, may identify the best downlink (DL) reference signal (RS) beam received from the PSCell, and may send a first random access message (e.g., msgA in a two-step RA process or Msg 1 in a four-step RA process) to the PSCell in a corresponding RACH opportunity. Other random access messages may be exchanged based on the same RS beam to complete the random access process.

[0033] Aspects described herein relate to using multiple beams to send random access messages (e.g., using beam scanning) during a random access process. Beam scanning generally may refer to a transmitting device sending / receiving multiple beams that are separated in time, frequency, space, etc., such that a receiving device may receive at least one of the multiple beams and / or may determine an optimal beam for communicating with the transmitting device. In this aspect, using multiple beams to send / receive random access messages may enhance the reliability of the random access process by increasing the likelihood of successful message transmission, and in turn may reduce latency by increasing the likelihood of a successful random access process (e.g., making fallback and retransmission scenarios less likely).

[0034] In some aspects described herein, beam scanning is proposed to be used in the SCG in NR-DC in non-standalone (NSA) mode to enhance reliability and reduce latency, at least for two-step RACH. For example, a UE may use beam scanning to exchange messages with one or more transmit / receive points (TRPs) of a serving cell, where the serving cell may be a PSCell or an SCell or a PCell, etc. In addition, for example, time-division multiplexing (TDM), frequency-division multiplexing (FDM), or space-division multiplexing (SDM) may be used to provide beam scanning to separate beams. Further, in one example, a beam pool index may help solve possible beam pairing misalignment problems, which may occur in both single-TRP and multi-TRP (mTRP) based beam scanning. In the case of mTRP, different pool indexes may help the UE select a RACH beam with a larger angle of departure (AoD) from different TRPs, which may contribute to UL interference diversity. In the case of mTRP, different pool indexes may also contribute to load balancing, where RACH messages may help select a TRP without urgent traffic. In addition, for example, when using joint RACH across beam scanning, as long as one path among multiple transmissions of different random access message exchanges can succeed, the initial access can be successfully completed, which helps avoid failures due to burst UL / DL inter-cell interference, avoid blocking during the initial access process, and provide efficient PSCell establishment (e.g., reduce RACH latency, reduce failures or retransmissions), etc.

[0035] The features described above are given in more detail below with reference to Figure 1-10 to give the described features in more detail.

[0036] As used in this application, the terms "component", "module", "system", etc. are intended to include computer-related entities, such as, but not limited to: hardware, combinations of hardware and software, software, or software in execution. For example, a component can be, but is not limited to: a process running on a processor, a processor, an object, an executable, a thread of execution, a program, and / or a computer. By way of illustration, an application running on a computing device and the computing device can both be components. One or more components can exist in a process and / or thread of execution, and a component can be located on one computer and / or distributed between two or more computers. Further, these components can execute from various computer-readable media having various data structures stored thereon. These components can communicate in a local and / or remote process manner by, for example, according to signals having one or more data packets (e.g., data from one component that interacts with another component in a local system, a distributed system, and / or communicates with other systems in a signal manner via a network such as the Internet).

[0037] The techniques described herein can be used in various wireless communication systems such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and other systems. The terms "system" and "network" are often used interchangeably. CDMA systems may implement wireless technologies such as CDMA2000, Universal Terrestrial Radio Access (UTRA), etc. CDMA2000 covers the IS-2000, IS-95, and IS-856 standards. Release 0 and A of IS-2000 are commonly referred to as CDMA2000 1X, 1X, etc. IS-856 (TIA-856) is commonly referred to as CDMA2000 1xEV-DO, High Rate Packet Data (HRPD), etc. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. TDMA systems may implement wireless technologies such as Global System for Mobile Communications (GSM). OFDMA systems may implement wireless technologies such as Ultra Mobile Broadband (UMB), Evolved UTRA (E-UTRA), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDM TM and other wireless technologies. UTRA and E-UTRA are part of Universal Mobile Telecommunications System (UMTS). 3GPP Long Term Evolution (LTE) is a new version of UMTS that uses E-UTRA. UTRA, E-UTRA, UMTS, LTE, and GSM are described in documents from an organization named "3rd Generation Partnership Project" (3GPP). CDMA 2000 and UMB are described in documents from an organization named "3rd Generation Partnership Project 2" (3GPP2). The techniques described herein can be used in the systems and radio technologies mentioned above and other systems and radio technologies, including cellular (e.g., LTE) communication over a shared radio frequency spectrum band. However, the following description describes LTE / LTE-A systems for example purposes, and the LTE terminology is used in most of the following description, but the techniques are applicable beyond LTE / LTE-A applications (e.g., to 5th Generation (5G) New Radio (NR) networks or other next generation communication systems).

[0038] The following description provides examples and is not a limitation on the scope, applicability, or examples set forth in the claims. Changes may be made to the function and arrangement of the elements discussed without departing from the scope of the disclosure. Each example may omit, substitute, or add various processes or components as appropriate. For example, the methods described may be performed in an order different from that described, and various processes may be added, omitted, or combined. Additionally, the described features may be combined in other examples relative to some examples.

[0039] Each aspect or feature will be given in terms of a system that can include a number of devices, components, modules, etc. It is to be understood and appreciated that various systems can include additional devices, components, modules, etc. and / or may not include all of the items of the devices, components, modules, etc. discussed in connection with the figures. Combinations of these approaches may also be used.

[0040] Figure 1 FIG. is a schematic diagram illustrating an example of a wireless communication system and access network 100. A wireless communication system (also referred to as a wireless wide area network (WWAN)) can include base stations 102, UEs 104, an evolved packet core (EPC) 160, and / or a 5G core (5GC). The base stations 102 can include macro cells (high-power cellular base stations) and / or small cells (low-power cellular base stations). The macro cells can include base stations. The small cells can include femto cells, pico cells, and micro cells. In one example, the base stations 102 can also include gNBs 180, as further described herein. In one example, some nodes of the wireless communication system can have a modem 240 and a communication component 242 to perform a random access procedure based on multiple beams in accordance with various aspects described herein. Additionally, some nodes can have a modem 340 and a configuration component 342 to configure a device to perform a random access procedure based on multiple beams in accordance with various aspects described herein. Although the UE 104 is shown as having a modem 240 and a communication component 242 and the base station 102 / gNB 180 is shown as having a modem 340 and a configuration component 342, this is merely an illustrative example, and substantially any node or any type of node can include a modem 240 and a communication component 242 and / or a modem 340 and a configuration component 342 to provide the corresponding functionality described herein.

[0041] The base station 102 configured for 4G LTE (which may be collectively referred to as the evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN)) can be connected to the EPC 160 via a backhaul link 132 (e.g., using the S1 interface). The base station 102 configured for 5G NR (which may be collectively referred to as the Next Generation RAN (NG-RAN)) can be connected to the 5GC 190 via a backhaul link 184. In addition to other functions, the base station 102 can perform one or more of the following functions: transmission of user data, encryption and decryption of radio channels, integrity protection, header compression, mobility control functions (e.g., handover, dual connectivity), inter-cell interference coordination, connection establishment and release, load balancing, distribution of non-access stratum (NAS) messages, NAS node selection, synchronization, radio access network (RAN) sharing, multimedia broadcast multicast service (MBMS), user and device tracking, radio access network information management (RIM), paging, positioning, and delivery of warning messages. The base stations 102 can communicate with each other directly or indirectly (e.g., via the EPC 160 or 5GC 190) via a backhaul link 134 (e.g., using the X2 interface). The backhaul link 134 can be wired or wireless.

[0042] Base station 102 can communicate wirelessly with one or more UEs 104. Each base station in base station 102 can provide communication coverage for a corresponding geographic coverage area 110. There can be overlapping geographic coverage areas 110. For example, small cell 102' can have a coverage area 110' that overlaps with the coverage area 110 of one or more macro base stations 102. A network including both small cells and macro cells can be referred to as a heterogeneous network. The heterogeneous network can also include a Home evolved Node B (HeNB), which can provide services to a restricted group called a Closed Subscriber Group (CSG). The communication link 120 between base station 102 and UE 104 can include an uplink (UL) (also referred to as a reverse link) transmission from UE 104 to base station 102 and / or a downlink (DL) (also referred to as a forward link) transmission from base station 102 to UE 104. The communication link 120 can use multiple-input and multiple-output (MIMO) antenna technology, including spatial multiplexing, beamforming, and / or transmit diversity. The communication link can be over one or more carriers. Base station 102 / UE 104 can use a spectrum with a bandwidth of up to Y MHz (e.g., 5, 10, 15, 20, 100, 400, etc. MHz) per carrier allocated in carrier aggregation of up to Yx MHz (x component carriers) for transmission in the DL and / or UL directions. The carriers can be adjacent to each other or can be non-adjacent to each other. The allocation of carriers can be asymmetric with respect to DL and UL (e.g., more or fewer carriers can be allocated for DL compared to UL). The component carriers can include a primary component carrier and one or more secondary component carriers. The primary component carrier can be referred to as the Primary Cell (PCell), and the secondary component carriers can be referred to as Secondary Cells (SCells).

[0043] In another example, certain UEs 104 can communicate with each other using device-to-device (D2D) communication link 158. The D2D communication link 158 can use DL / UL WWAN spectrum. The D2D communication link 158 can use one or more sidelink channels, such as Physical Sidelink Broadcast Channel (PSBCH), Physical Sidelink Discovery Channel (PSDCH), Physical Sidelink Shared Channel (PSSCH), and Physical Sidelink Control Channel (PSCCH). D2D communication can be through various wireless D2D communication systems such as, for example, FlashLinQ, WiMedia, Bluetooth, ZigBee, Wi-Fi based on the IEEE 802.11 standard, LTE, or NR.

[0044] The wireless communication system may also include a Wi-Fi access point (AP) 150 that communicates with a Wi-Fi station (STA) 152 via a communication link 154 in the 5 GHz unlicensed spectrum. When communicating in the unlicensed spectrum, the STA 152 / AP 150 may perform a Clear Channel Assessment (CCA) before communication to determine whether the channel is available.

[0045] The small cell 102' may operate in licensed and / or unlicensed spectrum. When operating in the unlicensed spectrum, the small cell 102' may adopt NR and use the same 5 GHz unlicensed spectrum used by the Wi-Fi AP 150. The small cell 102' adopting NR in the unlicensed spectrum may enhance the coverage of the access network and / or increase the capacity of the access network.

[0046] The base station 102 (whether a small cell 102' or a large cell (e.g., a macro base station)) may include an eNB, a gNodeB (gNB), or other types of base stations. Some base stations such as the gNB 180 may operate in the traditional sub 6 GHz spectrum, in millimeter wave (mmW) frequencies, and / or in near mmW frequencies to communicate with the UE 104. When the gNB 180 operates in mmW or near mmW frequencies, the gNB 180 may be referred to as a mmW base station. The Extremely High Frequency (EHF) is a part of the RF in the electromagnetic spectrum. The EHF has a range of 30 GHz to 300 GHz, and a wavelength between 1 millimeter and 10 millimeters. The radio waves in the band may be referred to as millimeter waves. Near mmW may extend down to 3 GHz frequencies with a wavelength of 100 millimeters. The Super High Frequency (SHF) band extends between 3 GHz, which is also referred to as centimeter waves, and 30 GHz. Communication using the mmW / near mmW radio frequency band has extremely high path loss and short distance. The mmW base station 180 may use beamforming 182 with the UE 104 to compensate for the extremely high path loss and short distance. The base station 102 mentioned in this article may include the gNB 180.

[0047] The EPC 160 may include a Mobility Management Entity (MME) 162, other MMEs 164, a Serving Gateway 166, a Multimedia Broadcast Multicast Service (MBMS) Gateway 168, a Broadcast Multicast Service Center (BM-SC) 170, and a Packet Data Network (PDN) Gateway 172. The MME 162 may communicate with a Home Subscriber Server (HSS) 174. The MME 162 is a control node that processes signaling between the UE 104 and the EPC 160. Generally, the MME 162 provides bearer and connection management. All user Internet Protocol (IP) packets are transported through the Serving Gateway 166, which itself is connected to the PDN Gateway 172. The PDN Gateway 172 provides IP address allocation to the UE as well as other functions. The PDN Gateway 172 and the BM-SC 170 are connected to an IP service 176. The IP service 176 may include the Internet, an intranet, an IP Multimedia Subsystem (IMS), a PS streaming service, and / or other IP services. The BM-SC 170 may provide functions for MBMS user service provision and delivery. The BM-SC 170 may serve as an entry point for content provider MBMS transmission, may be used to authorize and initiate MBMS bearer services within a Public Land Mobile Network (PLMN), and may be used to schedule MBMS transmission. The MBMS Gateway 168 may be used to distribute MBMS services to base stations 102 belonging to a Multicast Broadcast Single Frequency Network (MBSFN) area for a particular service being broadcast, and may be responsible for session management (start / stop) and collecting charging information related to eMBMS.

[0048] The 5GC 190 may include an Access and Mobility Management Function (AMF) 192, other AMFs 193, a Session Management Function (SMF) 194, and a User Plane Function (UPF) 195. The AMF 192 may communicate with a Unified Data Management (UDM) 196. The AMF 192 is a control node that processes signaling between the UE 104 and the 5GC 190. Generally, the AMF 192 may provide QoS flow and session management. User Internet Protocol (IP) packets (e.g., from one or more UEs 104) are transported through the UPF 195. The UPF 195 may provide UE IP address allocation for one or more UEs as well as other functions. The UPF 195 is connected to an IP service 197. The IP service 197 may include the Internet, an intranet, an IP Multimedia Subsystem (IMS), a PS streaming service, and / or other IP services.

[0049] A base station may also be referred to as a gNB, Node B, evolved Node B (eNB), access point, base station transceiver, radio base station, radio transceiver, transceiver function, basic service set (BSS), extended service set (ESS), transmission and reception point (TRP), or some other suitable term. Base station 102 provides an access point to EPC 160 or 5GC 190 for UE 104. Examples of UE 104 include cellular phones, smart phones, session initiation protocol (SIP) phones, laptop computers, personal digital assistants (PDA), satellite radio units, global positioning systems, multimedia devices, video devices, digital audio players (e.g., MP3 players), cameras, game consoles, tablet devices, smart devices, wearable devices, vehicles, electricity meters, gas pumps, large or small kitchen appliances, healthcare devices, implants, sensors / actuators, displays, or any other device with similar functionality. Some of the UEs 104 in UE 104 may be referred to as IoT devices (e.g., parking meters, gas pumps, ovens, vehicles, cardiac monitors, etc.). IoT UEs may include machine type communication (MTC) / enhanced MTC (eMTC, also known as category (CAT)-M or Cat M1) UEs, NB-IoT (also known as CAT NB1) UEs, and other types of UEs. In the present disclosure, eMTC and NB-IoT may refer to future technologies that may evolve from or be based on these technologies. For example, eMTC may include FeMTC (further eMTC), eFeMTC (further enhanced eMTC), mMTC (massive MTC), etc., and NB-IoT may include eNB-IoT (enhanced NB-IoT), FeNB-IoT (further enhanced NB-IoT), etc. UE 104 may also be referred to as a station, mobile station, user station, mobile unit, user unit, wireless unit, remote unit, mobile device, wireless device, wireless communication device, remote device, mobile user station, access terminal, mobile terminal, wireless terminal, remote terminal, handheld device, user agent, mobile client, client, or some other suitable term.

[0050] In one example, communication component 242 can initiate a two-step random access procedure with base station 102 by transmitting a first random access message (msgA) based on multiple transmit beams, where the first random access message can include multiple transmissions of a preamble portion and multiple transmissions of a payload portion based on the multiple beams. Configuration component 342 can receive the first random access message and determine, based on the multiple transmit beams, to transmit a second random access message (msgB), which can include multiple transmissions of a control channel portion (e.g., a physical downlink control channel (PDCCH)) and / or multiple transmissions of a data channel portion (e.g., a physical downlink shared channel (PDSCH)). Communication component 242 can receive the second random access message and, in some examples, complete the random access procedure and begin communicating with base station 102 on the configured resources. In one example, communication component 242 can also transmit feedback for the second random access message using the multiple transmit beams. Using multiple beams for various random access messages can improve communication reliability, reduce latency associated with communication, and so on.

[0051] Now go to Figure 2-10 , some aspects are described with reference to one or more components and one or more methods that can perform the actions or operations described herein, where the aspects in dashed form may be optional. Figure 4-5 The operations described in the foregoing are presented as having a specific order and / or being performed by certain exemplary components, but it should be understood that the order of these actions and the components performing these actions may vary depending on the implementation. In addition, it should be understood that the following actions, functions, and / or described components may be performed by a specially programmed processor, a processor executing specially programmed software or computer-readable media, or any other combination of hardware components and / or software components capable of performing the described actions or functions.

[0052] See also Figure 2 An example implementation of the UE 104 may include various components, some of which are described above and further described herein, including components such as one or more processors 212 and memory 216 communicating via one or more buses 244, and a transceiver 202, which may operate in conjunction with a modem 240 and / or a communication component 242 to perform a random access procedure based on multiple beams in accordance with various aspects described herein.

[0053] In one aspect, the one or more processors 212 may include a modem 240 that uses one or more modem processors, and / or may be part of the modem 240. Accordingly, various functions related to the communication component 242 may be included in the modem 240 and / or the processor 212, and in one aspect, they may be performed by a single processor, while in other aspects, different functions among these functions may be performed by a combination of two or more different processors. For example, in one aspect, the one or more processors 212 may include any one or any combination of the following: a modem processor, or a baseband processor, or a digital signal processor, or a transmit processor, or a receive processor, or a transceiver processor associated with the transceiver 202. In other aspects, some features associated with the communication component 242 in the features of the one or more processors 212 and / or the modem 240 may be performed by the transceiver 202.

[0054] In addition, the memory 216 may be configured to store data used herein and / or a local version of an application 275 executed by at least one processor 212 or one or more sub-components of the communication component 242 and / or its sub-components. The memory 216 may include any type of computer-readable medium that can be used by a computer or at least one processor 212, such as, for example, random access memory (RAM), read-only memory (ROM), magnetic tape, magnetic disk, optical disk, volatile memory, non-volatile memory, and any combination thereof. For example, in one aspect, when the UE 104 is operating at least one processor 212 to execute one or more sub-components of the communication component 242 and / or its sub-components, the memory 216 may be a non-transitory computer-readable storage medium that stores one or more computer-executable codes for specifying one or more sub-components of the communication component 242 and / or its sub-components and / or data associated therewith.

[0055] The transceiver 202 may include at least one receiver 206 and at least one transmitter 208. The receiver 206 may include hardware and / or software code (e.g., executable by a processor) for receiving data, the code including instructions and stored in a memory (e.g., a computer-readable medium). For example, the receiver 206 may be a radio frequency (RF) receiver. In one aspect, the receiver 206 may receive signals transmitted by at least one base station 102. Additionally, the receiver 206 may process these received signals and may also obtain measurements of these signals (e.g., but not limited to Ec / Io, signal-to-noise ratio (SNR), reference signal received power (RSRP), received signal strength indicator (RSSI), etc.). The transmitter 208 may include hardware and / or software code (e.g., executable by a processor) for transmitting data, the code including instructions and stored in a memory (e.g., a computer-readable medium). Suitable examples of the transmitter 208 may include, but are not limited to, an RF transmitter.

[0056] Furthermore, in one aspect, the UE 104 may include an RF front end 288, which may communicate with one or more antennas 265 and the transceiver 202 to receive and transmit radio transmissions (e.g., wireless communications transmitted by at least one base station 102 or wireless transmissions transmitted by the UE 104). The RF front end 288 may be connected to one or more antennas 265 and may include one or more low noise amplifiers (LNAs) 290, one or more switches 292, one or more power amplifiers (PAs) 298, and one or more filters 296 to transmit and receive RF signals.

[0057] In one aspect, the LNA 290 may amplify the received signal to a desired output level. In one aspect, each LNA 290 may have specified minimum and maximum gain values. In one aspect, the RF front end 288 may use one or more switches 292 to select a particular LNA 290 and its specified gain value based on the desired gain value for a particular application.

[0058] Additionally, for example, the RF front end 288 may use one or more PAs 298 to amplify the signal for RF output to a desired output power level. In one aspect, each PA 298 may have specified minimum and maximum gain values. In one aspect, the RF front end 288 may use one or more switches 292 to select a particular PA 298 and its specified gain value based on the desired gain value for a particular application.

[0059] In addition, for example, the RF front end 288 may use one or more filters 296 to filter the received signal to obtain an input RF signal. Similarly, in one aspect, for example, the corresponding filter 296 may be used to filter the output from the corresponding PA 298 to generate an output signal for transmission. In one aspect, each filter 296 may be connected to a specific LNA 290 and / or PA 298. In one aspect, the RF front end 288 may use one or more switches 292 to select a transmit path or a receive path using the specified filter 296, LNA 290, and / or PA 298 based on a configuration specified by, for example, the transceiver 202 and / or the processor 212.

[0060] Accordingly, the transceiver 202 may be configured to transmit and receive wireless signals via the RF front end 288 and one or more antennas 265. In one aspect, the transceiver may be tuned to operate at a specified frequency such that the UE 104 can communicate, for example, with one or more base stations 102 or with one or more cells associated with one or more base stations 102. In one aspect, for example, the modem 240 may configure the transceiver 202 to operate at a specified frequency and power level based on the UE configuration of the UE 104 and the communication protocol used by the modem 240.

[0061] In one aspect, the modem 240 may be a multi-band multi-mode modem that can process digital data and communicate with the transceiver 202 such that the transceiver 202 is used to transmit and receive digital data. In one aspect, the modem 240 may be multi-band and configured to support multiple bands with a specific communication protocol. In one aspect, the modem 240 may be multi-mode and configured to support multiple operating networks and communication protocols. In one aspect, the modem 240 may control one or more components of the UE 104 (e.g., the RF front end 288, the transceiver 202) to enable transmission and / or reception of signals from the network based on a specified modem configuration. In one aspect, the modem configuration may be based on the mode of the modem and the band in use. In another aspect, the modem configuration may be based on UE configuration information associated with the UE 104, such as provided by the network during cell selection and / or cell reselection.

[0062] In one aspect, according to the aspects described herein, the communication component 242 may optionally include: a msgA generation component 252 that generates a first random access message for transmission using multiple beams; a msgB processing component 254 that receives and decodes a second random access message based on the first random access message; and / or a feedback component 256 that generates feedback for the second random access message for transmission using multiple beams.

[0063] In one aspect, the processor 212 may correspond to one or more of the processors described in connection with the UE in Figure 10 Similarly, the memory 216 may correspond to the memory described in connection with the UE in Figure 10 .

[0064] Referring to Figure 3 , an example implementation of the base station 102 (e.g., the base station 102 and / or gNB 180 as described above) may include various components, some of which have been described above, but including components such as one or more processors 312, a memory 316, and a transceiver 302 that communicate via one or more buses 344. In accordance with aspects described herein, these components may operate in conjunction with a modem 340 and a configuration component 342 to configure the device to perform a random access procedure based on multiple beams.

[0065] The transceiver 302, the receiver 306, the transmitter 308, one or more processors 312, the memory 316, the application 375, the bus 344, the RF front end 388, the LNA 390, the switch 392, the filter 396, the PA 398, and one or more antennas 365 may be the same as or similar to the corresponding components of the UE 104 as described above, but are configured or otherwise programmed to perform base station operations contrary to UE operations.

[0066] In one aspect, in accordance with aspects described herein, the configuration component 342 may optionally include: a msgA processing component 352 for receiving and processing a first random access message in a two-step random access procedure; a msgB generation component 354 for generating a second random access message for transmission in response to the first random access message and using multiple transmission beams; and / or a feedback processing component 356 for receiving and processing feedback for the second random access message.

[0067] In one aspect, the processor 312 may correspond to one or more of the processors described in connection with the base station in Figure 10 Similarly, the memory 316 may correspond to the memory described in connection with the base station in Figure 10 .

[0068] Figure 4 A flowchart illustrating an example of a method 400 for performing a random access procedure with one or more TRPs of a cell in accordance with aspects described herein. Figure 5 A flowchart illustrating an example of a method 500 for performing a random access procedure with a UE via one or more TRPs of a cell in accordance with aspects described herein. In one example, the UE may useFigure 1 and Figure 2 one or more components described in Figure 2 to perform the functions described in method 400. In one example, base station 102 and / or a cell via one or more TRPs may use Figure 1 and Figure 3 one or more components described in Figure 3 to perform the functions described in method 500. Methods 400 and 500 are described in conjunction with each other below to facilitate the explanation of related functions and concepts. In at least one example, methods 400 and 500 do not need to be performed in conjunction with each other. In fact, one device may be configured to perform method 400 without having a corresponding device for performing method 500, and vice versa.

[0069] In one example, one or more TRPs may provide a cell (e.g., a PCell, a PSCell, an SCell, etc.) by providing concurrent communications related to the cell via each TRP (e.g., in the presence of multiple TRPs). In this example, UE 104 may receive and process concurrent communications from multiple TRPs to communicate in the cell.

[0070] In method 500, at block 502, one or more TRPs may be utilized to transmit multiple reference signal beams. In one aspect, configuration component 342, for example in conjunction with processor 312, memory 316, transceiver 302, etc., may utilize one or more TRPs to transmit multiple reference signal beams. For example, configuration component 342 of base station 102 (or multiple base stations 102 or associated TRPs) that form a cell (e.g., a PCell, a PSCell, an SCell, etc.) may transmit multiple reference signal beams. For example, these reference signal beams may include reference signals corresponding to a physical broadcast channel (PBCH) (e.g., a synchronization signal block (SSB), a channel state information reference signal (CSI-RS), etc.), which are beamformed in different beamforming directions to increase the likelihood that UE 104 receives a reference signal with a desired signal quality. Beamforming generally performed by base station 102 or UE 104 as further described herein may include or involve: modifying antenna resources to achieve a spatial direction for transmitting or receiving a signal (or antenna power for a certain spatial direction). In one example, a beam may be configured for UE 104 by base station 102 (e.g., in RRC signaling, dedicated control signaling, or other signaling), indicated or implemented in UE 104 based on a radio communication technology, and / or similar methods. In one example, various beams may be specified using a radio communication technology, and base station 102 may select down from the various beams to configure a subset of beams that may be used in the communication between base station 102 and UE 104.

[0071] In one example, the TRP may use beams belonging to a single or multiple pool indices to transmit multiple reference signals. Additionally, for example, multiple TRPs may use beams belonging to each TRP to transmit multiple reference signals. Further, the configuration component 342 may use FDM, TDM, or SDM to transmit multiple reference signal beams to separate the reference signal beams in frequency, time, or space. For example, whether to use one or more of FDM, TDM, or SDM may be selected based on a scheme selection indicator configured for UE 104 and / or a repetition value configured for the beam.

[0072] In method 400, at block 402, the UE may receive reference signal beams from one or more TRPs of a cell. In one aspect, the communication component 242, for example in conjunction with the processor 212, the memory 216, the transceiver 202, etc., may receive reference signal beams from one or more TRPs of a cell. As described above, the one or more TRPs may transmit reference signal beams including reference signals on the PBCH (e.g., SSB, CSI-RS, etc.), and the communication component 242 may receive at least one or some of these beams, and / or may determine a desired beam for communicating with one or more TRPs of the cell. Additionally, the communication component 242 may receive reference signal beams based on a configuration from the cell, which may include a radio resource control (RRC) configuration for defining and / or configuring RS indices for each beam pool index. For example, the configuration may specify multiple beam pools with multiple RS indices, and UE104 may accordingly receive and process the RSs based on this configuration. For example, UE104 may use this configuration to identify received beams based on known beam identifiers of the beams received over a certain period of time, and may use this identifier to indicate a desired beam for communicating with the cell.

[0073] In method 400, at block 404, the UE may determine multiple beams to be used when transmitting a message during a RA procedure with one or more TRPs of the cell. In one aspect, the msgA generation component 252, for example in conjunction with the processor 212, the memory 216, the transceiver 202, the communication component 242, etc., may determine multiple beams to be used when transmitting a message during a RA procedure with one or more TRPs of the cell. For example, the msgA generation component 252 may determine or identify the multiple beams based on the beams received from one or more TRPs of the cell. When determining the multiple beams, the msgA generation component 252 may receive these beams (as described above), and / or measure one or more parameters of the beams, such as signal strength or quality metrics (e.g., reference signal received power (RSRP), reference signal received quality (RSRQ), received signal strength indicator (RSSI), signal-to-noise ratio (SNR), signal-to-interference and noise ratio (SINR), etc.).

[0074] In one example, when determining the plurality of beams at block 404, optionally at block 406, the UE may determine the plurality of beams to include, for one TRP, at least a first beam from a first beam pool index and a second beam from a second beam pool index. In one aspect, the msgA generation component 252, in conjunction with, for example, the processor 212, the memory 216, the transceiver 202, the communication component 242, etc., may determine the plurality of beams to include, for one TRP, at least a first beam from a first beam pool index and a second beam from a second beam pool index. For example, the msgA generation component 252 may determine a plurality of beams for a given TRP to include beams from different beam pool indexes. For example, the TRP may broadcast beams from different beam pools by sending a plurality of beams (e.g., four beams) from a first pool and then a plurality of beams from a second pool, and so on. In this example, the msgA generation component 252 may determine at least one beam (and associated beam pool index) from the first beam pool and at least one beam (and associated beam pool index) from the second pool for sending the random access message.

[0075] In one example, when determining the plurality of beams at block 404, optionally at block 408, the UE may determine the plurality of beams to include a first beam from a first TRP and a second beam from a second TRP. In one aspect, the msgA generation component 252, in conjunction with, for example, the processor 212, the memory 216, the transceiver 202, the communication component 242, etc., may determine the plurality of beams to include a first beam from a first TRP and a second beam from a second TRP. For example, the msgA generation component 252 may determine the plurality of beams to include beams from different TRPs. For example, each TRP may broadcast beams from one or more beam pools by sending a plurality of beams (e.g., four beams) from a first TRP and then a plurality of beams from a second TRP, and so on. In this example, the msgA generation component 252 may determine at least one beam from the first TRP and at least one beam from the second TRP for sending the random access message.

[0076] In one example, in method 400, optionally at block 410, the UE may send an indication of the plurality of beams to one or more TRPs. In one aspect, the msgA generation component 252, for example in combination with the processor 212, the memory 216, the transceiver 202, the communication component 242, etc., may send an indication of the plurality of beams to one or more TRPs. For example, the msgA generation component 252 may send an indication of the plurality of beams to one or more TRPs in a report to notify one or more TRPs of the desired beams at the UE 104. For example, the indication may include beam identifiers for identifying each of the plurality of beams. The beam identifier may include an identifier (e.g., an index) of a beam within a beam pool, a beam pool index of the beam pool, or other identifiers. For example, the index of a beam within a beam pool may be determined and / or specified based on the order of receiving beams over a period of time. In one example, one or more TRPs may use this information to determine the beam for sending a random access message to the UE 104, to determine the beam to be used for indicating to the UE when transmitting to one or more TRPs (e.g., when sending feedback for a random access message from one or more TRPs), etc., as described herein.

[0077] In method 400, at block 412, the UE may send multiple instances of a first RA message to one or more TRPs of a cell based on the plurality of beams. In one aspect, the communication component 242, for example in combination with the processor 212, the memory 216, the transceiver 202, etc., may send multiple instances of a first RA message to one or more TRPs of a cell based on the plurality of beams. For example, the communication component 242 may send multiple instances of the first RA message, where for each instance, it includes at least one preamble portion and one or more payload portions, and each instance may be sent based on (e.g., using) one of the plurality of beams. In one example, the UE 104 may be configured with a RA occasion during which to send multiple instances of a first random access message. In one example, an RS beam or other signal sent by one or more TRPs may indicate the RA occasion that can be used to send the RA message. In one example, the UE 104 may be configured with a scheme selection indicator to indicate whether the beam sent by the UE 104 is to be sent based on an FDM scheme, a TDM scheme, or an SDM scheme and / or the repetition factor for sending the beam. Additionally, the UE 104 may be configured with a corresponding RA occasion for sending multiple instances of the first RA message.

[0078] For example, in method 500, optionally at block 504, a configuration of the RA occasion may be sent. In one aspect, a configuration component 342, e.g., in conjunction with a processor 312, a memory 316, a transceiver 302, etc., may send (e.g., via one or more TRPs of a cell) a configuration of the RA occasion (e.g., to UE 104). For example, the configuration component 342 may send the configuration of the RA occasion in one or more RS beams sent at block 502 or in other signaling to configure, for UE 104, time and / or frequency resources for sending a first RA message (or multiple instances of the first RA message). For example, the configuration may indicate a scheme selection indicator and / or a repetition factor. In one example, a base station or one or more TRPs providing a PCell may send the configuration to UE 104. Additionally, for example, the configuration component 342 may send the configuration in RRC signaling, dedicated control signaling, broadcast signaling, etc.

[0079] In this example, in method 400, optionally at block 414, a configuration of the RA occasion may be received from one or more TRPs of a cell. In one aspect, a communication component 242, e.g., in conjunction with a processor 212, a memory 216, a transceiver 202, etc., may receive a configuration of the RA occasion from one or more TRPs of a cell. For example, the configuration may indicate resources for sending a first random access message (e.g., or at least its preamble part). In one example, the configuration may further indicate a scheme selection indicator and / or a repetition factor for FDM, TDM, or SDM for multiple instances of the first RA message. In one example, the communication component 242 may determine, based on the configuration, resources for sending multiple instances of the first RA message. For example, the communication component 242 may determine the number of multiple instances to send, resources for sending at least the preamble part of each of the multiple instances, etc. In one example, the communication component 242 may derive resources for sending each of the multiple instances based on an indication of resources for a first instance (e.g., an indication of time and / or frequency resources specified in the configuration) and additionally based on a scheme selection indicator (e.g., determining a frequency for FDM, a time for TDM, a space for SDM, etc.), based on a number of repetitions (e.g., determining resources for each repetition based on an interval of resources for the first instance and frequency, time, space, etc.), etc. Additionally, the communication component 242 may select an RA occasion associated with a particular RS beam used by the TRP to receive multiple first RA messages (e.g., as specified in a configuration received from base station 102), and a corresponding RS beam used by the UE to send the multiple first RA messages.

[0080] In one example, when sending multiple instances of the first RA message at block 412, optionally at block 416, the UE may send the preamble portion of each instance of the multiple instances, followed by the payload portion of each instance of the multiple instances. In one aspect, the communication component 242, for example in combination with the processor 212, the memory 216, the transceiver 202, etc., may send the preamble portion of each instance of the multiple instances, followed by the payload portion of each instance of the multiple instances. In this example, the communication component 242 may send the preamble portion of the first instance based on a first beam, then send the preamble portion of the second instance based on a second beam, and so on. After sending the preamble portion, the communication component 242 may send one or more transmissions of the payload portion of the first instance based on the first beam, followed by one or more transmissions of the payload portion of the second instance based on the second beam, and so on. In Figure 6 an example is shown.

[0081] Figure 6 An example of a timeline 600 for sending RA messages in accordance with aspects described herein is shown. In one example, the timeline 600 may correspond to a non-standalone (NSA) mode CFRA for establishing a connection on a secondary cell group (SCG) in NR-DC. During the timeline 600, at 602, a first primary cell (PSCell) transmit-receive point (TRP) may send multiple CSI-RS beams in a first beam pool (which may include beam 604), at 606, a second PSCell TRP may send multiple CSI-RS beams in a second beam pool (which may include beam 608), at 610, the first PSCell TRP may send multiple CSI-RS beams in a third beam pool, and at 612, the second PSCell TRP may send multiple CSI-RS beams in a fourth beam pool. In one example, the UE may determine which of the multiple CSI-RS beams has desired signal characteristics and may select these beams to send the first RA message. In this example, the UE may select beam 604 from the first TRP and beam 608 from the second TRP (although in other examples, the UE may select n beams regardless of the TRP, beams from each of multiple beam pools, etc., as described above).

[0082] The UE may transmit, at 614, a preamble portion (msgA preamble) for a first RA message based on a first beam (e.g., using a beam similar to beam 608), and transmit, at 616, a preamble portion for a second RA message based on a second beam (e.g., using a beam similar to beam 604). For example, the first beam 614 may correspond to beam 608 (e.g., may be a reciprocal beam for transmission from the UE similar to the beam 608 received from the base station). Similarly, for example, the second beam 616 may correspond to beam 604 (e.g., may be a reciprocal beam for transmission from the UE similar to the beam 604 received from the base station). Similarly, for example, the second TRP may attempt to receive the preamble portion based on a received beam that is the same as, similar to, or reciprocal to beam 608 (however, this reception may fail), and / or the first TRP may receive the preamble portion based on a received beam that is the same as, similar to, or reciprocal to beam 604, as shown in the figure.

[0083] After a gap N between the transmission of the preamble portion and the payload portion of the first RA message, the UE may transmit, at block 618, a first transmission of the payload portion (e.g., msgA PUSCH) for the first instance based on the first beam, and may transmit, at block 620, a second transmission of the payload portion for the first instance based on the first beam, both of which may not be successfully received by the second TRP. Subsequently, the UE may transmit, at block 622, a first transmission of the payload portion for the second instance based on the second beam, and may transmit, at block 624, a second transmission of the payload portion for the second instance based on the second beam, which may be received by the first TRP.

[0084] For example, the minimum transmission gap N between the end of the msgA preamble and the start of the msgA PUSCH may be defined as no less than N symbols (or N symbol time slots, N milliseconds, or other time metrics) between the last msgA preamble and the first msgA PUSCH. For example, the symbol may correspond to an orthogonal frequency division multiplexing (OFDM) symbol, a single carrier frequency division multiplexing (SC-FDM) symbol, or a similar symbol defined as a portion of time over a portion of frequency. In one example, the msgA preamble and the msgA PUSCH may have different beam scanning patterns. For example, the PCell may allocate two beam scans for the msgA preamble, but allocate two repetitions for each of the two beams of the msgA PUSCH, as Figure 6As shown. For example, due to high link budget requirements, the PCell can allocate different beam scans. In this case, the mapping from preamble to PUSCH occasion can be changed to 1:2 - each PRACH preamble is mapped to two valid PUSCH occasions, but basically any ratio of preamble to payload part is possible.

[0085] In one example, when sending multiple instances of the first RA message at block 412, optionally at block 418, the UE can send a preamble part followed by a payload part for each of the multiple instances. In one aspect, the communication component 242, for example in conjunction with the processor 212, the memory 216, the transceiver 202, etc., can send a preamble part followed by a payload part for each of the multiple instances. In this example, the communication component 242 can send the preamble part of the first instance based on the first beam, subsequently send one or more transmissions of the payload part of the first instance based on the first beam, then can send the preamble part of the second instance based on the second beam, followed by one or more transmissions of the payload part of the second instance based on the second beam, and so on. In Figure 7 An example is shown.

[0086] Figure 7 An example of a timeline 700 for sending RA messages in accordance with aspects described herein is shown. In one example, the timeline 700 can correspond to a non-standalone (NSA) mode CFRA for establishing a connection on the secondary cell group (SCG) in NR-DC. During the timeline 700, at 702, the first primary cell (PSCell) transceiver point (TRP) can send multiple channel state information reference signal (CSI-RS) beams in a first beam pool (which can include beam 704), at 706, the second PSCell TRP can send multiple CSI-RS beams in a second beam pool (which can include beam 708), at 710, the first PSCell TRP can send multiple CSI-RS beams in a third beam pool, and at 712, the second PSCell TRP can send multiple CSI-RS beams in a fourth beam pool. In one example, the UE can determine which of the multiple CSI-RS beams has desired signal characteristics and can select these beams to send the first RA message. In this example, the UE can select beam 704 from the first TRP and beam 708 from the second TRP (although in other examples, the UE can select n beams regardless of the TRP, beams from each of multiple beam pools, etc., as described above).

[0087] The UE may transmit a preamble portion (msgA preamble) for the first RA message at 714 based on the first beam (e.g., using a beam similar to beam 708), and may transmit a first transmission of the payload portion (msgA PUSCH) at 716 after gap N and a second transmission of the payload portion at 718 based on the first beam. After another gap N1, the UE may transmit a preamble portion (msgA preamble) for the second RA message at 720 based on the second beam (e.g., using a beam similar to beam 704) (in one example, followed by preamble portions for one or more other RA messages, etc.). After gap N, a first transmission of the payload portion (msgA PUSCH) may be transmitted at 722 based on the second beam, and a second transmission of the payload portion may be transmitted at 724 based on the second beam (in one example, followed by payload portions for one or more other RA messages, etc.). Similarly, for example, the second TRP may attempt to receive the preamble portion 714 and the two transmissions 716, 718 of the payload portion based on a receiving beam that is the same as, similar to, or reciprocal to beam 708 (but this reception may fail), and / or the first TRP may receive the preamble portion 720 and the two transmissions 722, 724 of the payload portion based on a receiving beam that is the same as, similar to, or reciprocal to beam 704, as shown in the figure.

[0088] For example, the minimum transmission gap N between the end of the msgA preamble and the start of the msgA PUSCH may remain unchanged. A minimum transmission gap N1 may be defined between the end of the msgA PUSCH and the next msgA preamble. In addition, for example, the msgA preamble and the msgA PUSCH may have different beam scanning patterns in each pair. For example, in each pair, the PCell may allocate one beam for the msgA preamble, but allocate one beam for two repeated beams of the msgA PUSCH, as Figure 7 shown. For example, due to high link budget requirements, the PCell may allocate different beam scans. In this case, the mapping from preamble to PUSCH timing may be changed to 1:2 - each PRACH preamble maps to two valid PUSCH timings, but basically any ratio of preamble to payload portion is possible.

[0089] In method 500, at block 506, as part of the RA procedure, one or more instances of a first RA message may be received from a UE by one or more TRPs. In one aspect, the msgA processing component 352, e.g., in conjunction with the processor 312, the memory 316, the transceiver 302, the configuration component 342, etc., may receive one or more instances of a first RA message from a UE (as part of the RA procedure), and / or process one or more instances of the first RA message. For example, the msgA processing component 352 may receive at least one preamble part and at least one payload part of the first RA message sent by the UE 104, and in the case of receiving at least one of each, the msgA processing component 352 may decode and / or process the first RA message and continue the RA procedure. In one example, the msgA processing component 352 may receive the preamble part of one of the multiple instances, but may not receive the payload part.

[0090] In method 500, at block 508, multiple beams to be used when sending messages during the RA procedure may be determined. In one aspect, the msgB generation component 354, e.g., in conjunction with the processor 312, the memory 316, the transceiver 302, the configuration component 342, etc., may determine multiple beams to be used when sending messages during the RA procedure. For example, the msgB generation component 354 may determine the multiple beams based on the beam from which the first RA message was received from the UE, based on the RS beam sent to the UE (e.g., at block 502), based on the beam indicated by the UE, etc. For example, the msgB generation component 354 may determine the beam to be sent from each of the multiple TRPs providing the cell. In one example, the msgB generation component 354 may determine the multiple beams based on determining the beam associated with the first RA message (e.g., the beam indicated by the time or frequency resource of receiving one or more instances of the first RA message, the beam indicated by the RA preamble of one or more instances of the first RA message, the beam indicated as a beam identifier in one or more instances of the first RA message, etc.).

[0091] In one example, when determining the plurality of beams at block 508, optionally at block 510, for one TRP, the plurality of beams can be determined to include at least a first beam from a first beam pool index and a second beam from a second beam pool index. In one aspect, the msgB generation component 354, in combination with, for example, the processor 312, the memory 316, the transceiver 302, the configuration component 342, etc., can determine, for one TRP, the plurality of beams to include at least a first beam from a first beam pool index and a second beam from a second beam pool index. For example, the msgB generation component 354 can determine the plurality of beams for a given TRP to include beams from different beam pool indices. In this example, the msgB generation component 354 can determine at least one beam (and associated beam pool index) from the first beam pool and at least one beam (and associated beam pool index) from the second pool for transmitting the random access message. For example, the msgB generation component 354 can determine a first beam index indicated by a first instance of the first RA message, and can determine at least one beam from the first beam pool as the beam corresponding to the first beam index in the first beam pool, and the msgB generation component 354 can determine a second beam index indicated by a second instance of the first RA message, and can determine at least one beam from the second beam pool as the beam corresponding to the second beam index in the second beam pool, and so on.

[0092] In one example, when determining the plurality of beams at block 508, optionally at block 512, the plurality of beams can be determined to include a first beam from a first TRP and a second beam from a second TRP. In one aspect, the msgB generation component 354, in combination with, for example, the processor 312, the memory 316, the transceiver 302, the configuration component 342, etc., can determine the plurality of beams to include a first beam from a first TRP and a second beam from a second TRP. For example, the msgB generation component 354 can determine the plurality of beams to include beams from different TRPs. For example, each TRP can broadcast beams from one or more beam pools by sending a plurality of beams (e.g., four beams) from the first TRP, and then sending a plurality of beams from the second TRP, and so on. In this example, the msgB generation component 354 can determine at least one beam from the first TRP and at least one beam from the second TRP for transmitting the random access message based on one or more received instances of the first RA message. For example, the msgB generation component 354 can determine the first beam indicated by a first instance of the first RA message as corresponding to the beam of the first TRP, and the msgB generation component 354 can determine the second beam indicated by a second instance of the first RA message as corresponding to the beam of the second TRP.

[0093] In another example, in method 500, optionally at block 514, an indication of the plurality of beams can be received from the UE. In one aspect, the msgB generation component 354, for example in combination with the processor 312, the memory 316, the transceiver 302, the configuration component 342, etc., can receive an indication of the plurality of beams from the UE. As described above, for example, the UE can indicate a set of desired beams based on receiving and measuring beams from multiple TRPs. In one example, the indication of the beams can be indicated in a first RA message received from UE 104, or can be indicated in other signaling from the UE. In any case, in response to the first RA message, the msgB generation component 354 can determine the plurality of beams for generating a second RA message to be sent to UE 104.

[0094] For example, UE 104 can send a measurement report that can indicate desired beams or measurements of RSs received based on the plurality of beams. In this example, the msgB generation component 354 can determine the plurality of beams based on the measurement report. In one example, the msgB generation component 354 can determine the number of most desired beams, which can include: determining one beam from each beam pool of a plurality of beam pools, one beam for each TRP of a plurality of TRPs, etc. In another example, the msgA processing component 352 can determine the beams for receiving multiple instances of msgA based on an RA opportunity during which at least a preamble portion has been received from UE 104 (e.g., where the RA opportunity and / or associated resources can be associated with an RS beam, as described above). In any case, the msgA processing component 352 can accordingly determine when UE 104 sends a portion of msgA based on which beam, etc., as shown above Figure 6 and Figure 7 shown.

[0095] In one example, the SCell can send multiple instances of msgB, each instance can include a control channel portion (e.g., PDCCH) and a data channel portion (e.g., PDSCH, which can indicate a successful RAR, a fallback RAR, etc.), and can send msgB in TDM / FDM / SDM mode (with beam scanning from one or more TRPs and one or more beam pool indices, etc.), as described above for msgA. In one example, the RAR window can be extended to 40 ms for a 2-step RACH, and / or can start after the last scan / repeat of msgA. For example, as long as a pair of preamble and payload is successful, the base station 102 can use full beam scanning to send msgB.

[0096] In method 500, at block 516, multiple instances of a second RA message can be sent to a UE using one or more TRPs based on multiple beams and in response to a first RA message. In one aspect, a configuration component 342, e.g., in conjunction with a processor 312, a memory 316, a transceiver 302, etc., can send multiple instances of the second RA message to the UE using one or more TRPs based on multiple beams and in response to the first RA message. For example, the configuration component 342 can send multiple instances of the second RA message such that for each instance, it includes at least one control channel portion (e.g., PDCCH) and at least one data channel portion (e.g., PDSCH, which can include a successful RAR or a fallback RAR), where each instance can be based on one of the multiple beams.

[0097] When sending multiple instances of the second RA message at block 516, optionally at block 518, the second RA message can be sent using the same or different beams as the first RA message. In one aspect, a configuration component 342, e.g., in conjunction with a processor 312, a memory 316, a transceiver 302, etc., can send the second RA message using the same or different beams as the first RA message. In one example, the configuration component 342 can send the msgB PDCCH based on the beam of the best n RSs selected for receiving msgA during RACH measurement. In another example, the configuration component 342 can send the msgB PDCCH based on the beam of one best RS in each RACH resource candidate beam pool for receiving msgA (e.g., the RS index for each beam pool index defined and configured by RRC). Using beams from each beam pool can address potential misalignment issues in the previous example where n best beams were selected. Additionally, this example can apply to both single TRP and mTRP scenarios. In yet another example, the configuration component 342 can send the msgB PDCCH using a beam different from the beam used for receiving msgA.

[0098] In another example, the configuration component 342 may send msgB using different beams configured by the cell or received from the UE 104. For example, method 400 may optionally include, at block 420, sending an indication of one or more different beams to one or more TRPs. In one aspect, the communication component 242, for example in conjunction with the processor 212, the memory 216, the transceiver 202, etc., may send an indication of one or more different beams to one or more TRPs. For example, the communication component 242 may measure the beam between sending the first random access message and receiving the second random access message, and may send an indication of one or more different beams by sending a measurement report. In this example, in method 500, optionally at block 520, an indication of one or more different beams may be received from the UE. In one aspect, the configuration component 342, for example in conjunction with the processor 312, the memory 316, the transceiver 302, etc., may receive an indication of one or more different beams (e.g., in a measurement report) from the UE.

[0099] For example, the msgB generation component 354 may determine that the UE reports a better beam (e.g., a beam with a more desirable corresponding signal measurement at the UE) before msgB transmission, or the PCell instructs the UE to use a better beam. In another example, in the case where the signal strength of the received msgA is low (e.g., does not reach a threshold), the PCell may instruct the SCell to use a different beam. In either case, the msgB generation component 354 may determine to use a different beam for msgB transmission than that used for msgA reception, and may accordingly send msgB based on the different beam. Figure 8 An example is shown in.

[0100] Figure 8An example of a timeline 800 for sending RA messages in accordance with various aspects described herein is shown. In one example, the timeline 800 may correspond to NSA mode CFRA for establishing a connection on the SCG in NR-DC. During the timeline 800, RS beams may be received from the first PSCell TRP and the second PSCell TRP, as described above, and a first RA message may be sent, as described above. Additionally, for example, the second PSCell TRP may, in response to the first RA message, send a control channel portion 802 of a second RA message based on a first beam, and the first PSCell TRP may, in response to the first RA message, send a control channel portion 804 of the second RA message based on a second beam. For example, the first beam may be beam 820, where the second TRP may select beam 820 based on determining that the first RA message received based on the initial beam was not received or based on determining that beam 820 is more preferred / desirable than the initial beam (e.g., based on a report received from the UE, a determination by the TRP, etc., as described above). The second beam may be similar to the beam from which the second RA message is received from the first TRP. Additionally, the second PSCell TRP may send a first transmission of a data channel portion 806 of the second RA message based on the first beam and a second transmission of the data channel portion 808 of the second RA message based on the first beam. The first PSCell TRP may send a data channel portion 810 of the second RA message based on the second beam.

[0101] For example, the SCell may send multiple msgB success / fallback RARs in TDM / FDM / SDM with beam scanning from one or more TRPs and one or more beam pool indices. In one example, the SCell may use the same beam as the msgB PDCCH or may be scheduled via the msgB PDCCH using a different beam or repetition pattern. In one example, each msgB PDCCH may carry resource allocation information for multiple msgB PDSCHs such that in the event that one msgB PDCCH is lost, the remainder of the RACH path may continue without any impact. The same rules may apply to msgB success RARs or fallback RARs.

[0102] In one example, when sending a second RA message at block 516, optionally at block 522, a successful RAR or a fallback RAR may be sent. In one aspect, the configuration component 342, e.g., in conjunction with the processor 312, the memory 316, the transceiver 302, etc., may send a successful RAR or a fallback RAR. For example, in the case where the msgA processing component 352 receives and processes the preamble and payload portions of one or more instances of the first RA message, the msgB generation component 354 may generate a second RA message to include a successful RAR, and the configuration component 342 may accordingly send the successful RAR. In one example, when the msgA processing component 352 receives and processes the preamble portion rather than the payload portion of one or more instances of the first RA message (e.g., receives and processes at least one preamble portion but does not receive or process the payload portion), the msgB generation component 354 may generate a second RA message to include a fallback RAR, and the configuration component 342 may accordingly send the fallback RAR. The fallback RAR may be similar to the MAC RAR of the four-step RACH and may include parameters for retransmitting at least the payload portion of the first RA message to one or more TRPs, etc. (e.g., resources for transmission, beams to be used for transmission, beam patterns for transmitting beams, etc.). The UE may accordingly retransmit at least the payload portion of the first RA message and may monitor the contention resolution from one or more TRPs. The successful RAR may include what has been described above, such as the UE contention resolution identifier, TPC, HARQ feedback timing indicator (e.g., as described herein for sending feedback for msgB), PUCCH resource indicator, TA command, C-RNTI, etc.

[0103] In method 400, at block 422, the UE may receive one or more instances of a second RA message from at least one TRP among one or more TRPs and in response to the first RA message. In one aspect, the msgB processing component 254, e.g., in conjunction with the processor 212, the memory 216, the transceiver 202, the communication component 242, etc., may receive one or more instances of a second RA message from at least one TRP among one or more TRPs and in response to the first RA message. As described above, the msgB processing component 254 may receive and process the control channel portion and / or the data channel portion of msgB, and may receive one or more instances of the control channel portion and / or one or more instances of the data channel portion based on one or more beams.

[0104] When receiving the second RA message at block 422, optionally at block 424, the UE may receive the second RA message based on a different beam that is not included in the plurality of beams. In one aspect, the msgB processing component 254, in combination with, for example, the processor 212, the memory 216, the transceiver 202, the communication component 242, etc., may receive the second RA message based on a different beam that is not included in the plurality of beams used for transmitting the first RA message. For example, the cell may configure a different beam for transmitting msgB based on UE reporting or other means, as described above. In one example, the msgB processing component 254 may receive an indication of the different beam from the cell or may otherwise determine the different beam for receiving msgB.

[0105] In addition, when receiving the second RA message at block 422, optionally at block 426, the UE may receive a successful RAR or a fallback RAR. In one aspect, the msgB processing component 254, in combination with, for example, the processor 212, the memory 216, the transceiver 202, the communication component 242, etc., may receive the successful RAR or the fallback RAR as the second RA message from the cell.

[0106] In method 400, optionally at block 428, at least the payload portion of the first RA message may be retransmitted. In one aspect, the communication component 242, in combination with, for example, the processor 212, the memory 216, the transceiver 202, etc., may retransmit at least the payload portion of the first RA message. For example, the communication component 242 may retransmit at least the payload portion of the first RA message for which a fallback RAR is received. In one example, the communication component 242 may retransmit multiple instances of the payload portion based on the plurality of beams used for transmitting the first RA message at block 412 or based on another set of a plurality of beams (e.g., which may be specified in the fallback RAR, etc.). In addition, the communication component 242 may also adjust the uplink timing for retransmitting the payload portion.

[0107] In another example, the communication component 242 may also retransmit the preamble portion (e.g., retransmit all of msgA) in the case where no RAR is received. In this example, the communication component 242 may retransmit msgA after a backoff and MAC processing delay.

[0108] In another example, in method 400, optionally at block 430, feedback for a second RA message can be sent to one or more TRPs based on multiple feedback beams. In one aspect, feedback component 256, for example in conjunction with processor 212, memory 216, transceiver 202, communication component 242, etc., can send feedback for a second RA message to one or more TRPs based on multiple feedback beams. For example, the feedback can include HARQ feedback (e.g., acknowledgement (ACK) or negative ACK (NACK)) regarding whether the second RA message was successfully received and / or decoded. In one example, feedback component 256 can also use beam scanning to send the feedback, which can be based on the multiple beams used to send the first RA message or another set of beams (e.g., the set of beams indicated in a successful RAR). For example, for the UE to use beam scanning to send multiple HARQ-ACKs in FDM / TDM / SDM, the successful RAR (msgB PDSCH) can also signal a PUCCH resource index via 4 bits for sending the feedback. Additionally, in one example, the successful RAR can contain a beam scanning pattern for HARQ-ACK, which can be the same or different from msgA. For example, if the signal strength of msgA is low, the successful RAR can enable (more) beam repetitions or different beams for HARQ-ACK to improve reliability. In another example, if the base station 102 receives a most recent report indicating a better beam than msgA, the successful RAR can change the scanning beam for HARQ-ACK (similar to the second RA message as described above). In Figure 9 an example is shown.

[0109] Figure 9 An example of a timeline 900 for sending RA message feedback in accordance with aspects described herein is shown. During timeline 900, RS beams can be received from a first PSCell TRP and a second PSCell TRP, and a first RA message and a second RA message can be sent, as described above. Additionally, for example, the UE can send a first transmission of feedback at 902 based on a first beam (e.g., the beam on which the second RA message was received from the second TRP), and a second transmission of feedback at 904 based on the first beam, which the second TRP may not have successfully received, as shown. The UE can also send a first transmission of feedback at 906 based on a second beam (e.g., the beam on which the second RA message was received from the first TRP), and a second transmission of feedback at 908 based on the second beam. The first TRP can successfully receive the feedback. As described above, the RA procedure can be completed in the case where at least one TRP receives the feedback.

[0110] In method 500, optionally at block 524, one or more instances of feedback for a second RA message may be received from a UE. In one aspect, a feedback processing component 356, e.g., in conjunction with a processor 312, a memory 316, a transceiver 302, a configuration component 342, etc., may receive and / or process one or more instances of feedback for a second RA message from a UE. For example, the feedback processing component may receive the feedback and may accordingly determine whether to retransmit the second RA message.

[0111] Figure 10 is a block diagram of a MIMO communication system 1000 including a base station 102 and a UE 104. The MIMO communication system 1000 may illustrate aspects of the wireless communication access network 100 described with reference to Figure 1 The base station 102 may be an example of aspects of the base station 102 described with reference to Figure 1 The base station 102 may be equipped with antennas 1034 and 1035, and the UE 104 may be equipped with antennas 1052 and 1053. In the MIMO communication system 1000, the base station 102 may be capable of simultaneously transmitting data over multiple communication links. Each communication link may be referred to as a “layer,” and the “rank” of a communication link may indicate the number of layers used for communication. For example, in a 2x2 MIMO communication system (where the base station 102 transmits two “layers”), the rank of the communication link between the base station 102 and the UE 104 is two.

[0112] At the base station 102, a transmit (Tx) processor 1020 may receive data from a data source. The transmit processor 1020 may process the data. The transmit processor 1020 may also generate control symbols or reference symbols. A transmit MIMO processor 1030 may perform spatial processing (e.g., precoding) on the data symbols, control symbols, or reference symbols (if applicable), providing an output symbol stream to transmit modulators / demodulators 1032 and 1033. Each modulator / demodulator 1032 to 1033 may process its respective output symbol stream (e.g., for OFDM, etc.) to obtain an output sample stream. Each modulator / demodulator 1032 to 1033 may further process (e.g., convert to an analog signal, amplify, filter, and up-convert) the output sample stream to obtain a DL signal. In one example, the DL signals from modulators / demodulators 1032 and 1033 may be transmitted via antennas 1034 and 1035, respectively.

[0113] The UE 104 may be the one described with reference to Figure 1-2Examples of aspects of the described UE 104. At the UE 104, UE antennas 1052 and 1053 may receive DL signals from the base station 102 and may respectively provide the received signals to modulators / demodulators 1054 and 1055. Each modulator / demodulator 1054 to 1055 may condition (e.g., filter, amplify, down-convert, and digitize) the respective received signals to obtain input samples. Each modulator / demodulator 1054 to 1055 may also further process these input samples (e.g., for OFDM, etc.) to obtain received symbols. The MIMO detector 1056 may obtain the received symbols from the modulators / demodulators 1054 and 1055, perform MIMO detection on the received symbols (if applicable), and provide the detected symbols. The receive (Rx) processor 1058 may process (e.g., demodulate, de-interleave, and decode) the detected symbols, provide decoded data for the UE 104 to the data output, and provide the decoded control information to the processor 1080 or the memory 1082.

[0114] In some cases, the processor 1080 may execute stored instructions to instantiate the communication component 242 (e.g., see Figure 1 and Figure 2 ).

[0115] On the uplink (UL), at the UE 104, the transmit processor 1064 may receive and process data from a data source. The transmit processor 1064 may also generate reference symbols for reference signals. The symbols from the transmit processor 1064 may be precoded (if applicable) by the transmit MIMO processor 1066, further processed (e.g., for SC-FDM, etc.) by the modulators / demodulators 1054 and 1055, and sent back to the base station 102 according to communication parameters received from the base station 102. At the base station 102, the UL signal from the UE 104 may be received by antennas 1034 and 1035, processed by modulators / demodulators 1032 and 1033, detected (if applicable) by the MIMO detector 1036, and further processed by the receive processor 1038. The receive processor 1038 may provide the decoded data to the data output and to the processor 1040 or the memory 1042.

[0116] In some cases, the processor 1040 may execute stored instructions to instantiate the configuration component 342 (e.g., see Figure 1 and Figure 3 ).

[0117] The components of UE 104 may be implemented singly or in combination using one or more application-specific integrated circuits (ASICs), where the one or more ASICs are adapted to perform some or all of the applicable functions in hardware. Each of the stated modules may be a unit for performing one or more functions related to the operation of MIMO communication system 1000. Similarly, the components of base station 102 may be implemented singly or in combination using one or more application-specific integrated circuits (ASICs), where the one or more ASICs are adapted to perform some or all of the applicable functions in hardware. Each of the stated components may be a unit for performing one or more functions related to the operation of MIMO communication system 1000.

[0118] The following aspects are merely illustrative, and aspects thereof may be combined with aspects of other embodiments or teachings described herein, but are not limited thereto.

[0119] Aspect 1 is a method for wireless communication, the method comprising: determining a plurality of beams to be used when transmitting a message during a random access procedure with one or more transmission and reception points (TRPs) of a cell; and transmitting a plurality of instances of a first random access message to the one or more TRPs of the cell based on the plurality of beams, wherein each instance of the plurality of instances of the first random access message includes a preamble portion and a payload portion.

[0120] In aspect 2, the method according to aspect 1 includes, wherein the cell is a secondary cell (SCell) for the UE or a primary cell (PSCell) for the UE.

[0121] In aspect 3, the method according to any one of aspects 1 or 2 includes, wherein for one TRP of the cell, the plurality of beams includes at least a first beam from a first beam pool index and a second beam from a second beam pool index.

[0122] In aspect 4, the method according to any one of aspects 1 to 3 includes, wherein the plurality of beams includes a first beam from a first TRP index of the cell and a second beam from a second TRP index of the cell.

[0123] In aspect 5, the method according to any one of aspects 1 to 4 includes, wherein transmitting the plurality of instances of the first random access message includes: using at least one of time-division multiplexing, frequency-division multiplexing, or space-division multiplexing to separate the plurality of beams and transmitting the plurality of instances of the first random access message based on the plurality of beams.

[0124] In aspect 6, the method according to any one of aspects 1 to 5 includes, wherein the preamble part of each instance of the plurality of instances of the first random access message includes a plurality of preamble transmissions.

[0125] In aspect 7, the method according to any one of aspects 1 to 6 includes, wherein the payload part of each instance of the plurality of instances of the first random access message includes a plurality of payload transmissions.

[0126] In aspect 8, the method according to any one of aspects 1 to 7 includes, wherein determining the plurality of beams includes: determining a set of beams based on reference signals received from the one or more TRPs.

[0127] In aspect 9, the method according to any one of aspects 1 to 8 includes, wherein transmitting the plurality of instances of the first random access message includes: transmitting the preamble part of each instance of the plurality of instances of the first random access message, and subsequently transmitting the payload part of each instance of the plurality of instances of the first random access message based on the plurality of beams.

[0128] In aspect 10, the method according to aspect 9 includes, wherein the plurality of beams include a plurality of transmission beams for a plurality of reference signals, the plurality of transmission beams corresponding to a plurality of reception beams from the cell during a corresponding number of allocated random access opportunities, wherein each random access opportunity is associated with one of the plurality of reference signals for receiving the preamble part.

[0129] In aspect 11, the method according to aspect 10 includes, wherein the plurality of reference signals include at least one of SSB or CSI-RS from the cell.

[0130] In aspect 12, the method according to any one of aspects 9 to 11 includes, wherein transmitting the plurality of instances of the first random access message includes: transmitting the preamble part of each instance of the plurality of instances of the first random access message according to a first beam scanning pattern, and transmitting the payload part of each instance of the plurality of instances of the first random access message according to a second beam scanning pattern.

[0131] In aspect 13, the method according to any one of aspects 1 to 12 includes, wherein transmitting the plurality of instances of the first random access message includes: for each instance of the plurality of instances of the first random access message, transmitting the preamble part followed by the payload part.

[0132] In aspect 14, the method according to aspect 13 includes, wherein, for each instance of the plurality of instances of the first random access message, transmitting the preamble part followed by a payload part includes: transmitting the preamble part according to a first beam scanning pattern, and transmitting the payload part according to a second beam scanning pattern.

[0133] In aspect 15, the method according to any one of aspects 1 to 14 includes receiving one or more instances of a second random access message from at least one of the one or more TRPs and in response to the first random access message.

[0134] In aspect 16, the method according to aspect 15 includes, wherein the one or more instances of the second random access message are received based on at least one beam among the plurality of beams.

[0135] In aspect 17, the method according to any one of aspects 15 or 16 includes, wherein the one or more instances of the second random access message are received based on a different beam not included in the plurality of beams, wherein the different beam is reported to at least one of the one or more TRPs or configured by the one or more TRPs.

[0136] In aspect 18, the method according to any one of aspects 15 to 17 includes, wherein the second random access message includes at least a control channel part, and the control channel part indicates resources for a shared channel part.

[0137] In aspect 19, the method according to aspect 18 includes, wherein the shared channel part includes a random access response indicating a successful random access response or a fallback random access response.

[0138] In aspect 20, the method according to any one of aspects 15 to 19 includes, wherein the second random access message indicates uplink control channel resources for transmitting feedback for receiving the second random access message, and further includes: transmitting the feedback on the uplink control channel resources.

[0139] In aspect 21, the method according to aspect 20 includes, wherein transmitting the feedback includes: transmitting multiple instances of the feedback based on multiple feedback beams.

[0140] In aspect 22, the method according to aspect 21 includes, wherein the second random access message indicates at least one feedback beam among the multiple feedback beams or a beam pattern for transmitting the multiple feedback beams.

[0141] In aspect 23, the method according to any one of aspects 21 or 22 includes determining that the plurality of feedback beams are the same as the plurality of beams.

[0142] Aspect 24 is a method for wireless communication, the method including: as part of a random access procedure, receiving, by one or more TRPs from a UE, one or more instances of a first random access message, where each instance of the one or more instances of the first random access message includes a preamble portion and a payload portion; determining a plurality of beams used when sending a message during the random access procedure; and sending, by one or more TRPs, based on the plurality of beams, a plurality of instances of a second random access message to the UE and in response to the first random access message.

[0143] In aspect 25, the method according to aspect 24 includes, wherein, for one TRP, the plurality of beams includes at least a first beam from a first beam pool index and a second beam from a second beam pool index.

[0144] In aspect 26, the method according to any one of aspects 24 or 25 includes, wherein the plurality of beams includes a first beam corresponding to a first TRP index of the one or more TRPs and a second beam corresponding to a second TRP index of the one or more TRPs, and wherein sending the plurality of instances of the second random access message includes: sending, by the first TRP, a first instance of the second random access message based on at least the first beam, and sending, by the second TRP, a second instance of the second random access message based on at least the second beam.

[0145] In aspect 27, the method according to any one of aspects 24 to 27 includes, wherein sending the plurality of instances of the second random access message includes: using at least one of time division multiplexing, frequency division multiplexing, or spatial division multiplexing to separate the plurality of beams and sending the plurality of instances based on the plurality of beams.

[0146] In aspect 28, the method according to any one of aspects 24 to 28 includes, wherein the plurality of beams corresponds to a plurality of receive beams through which the one or more instances of the first random access message are received from the UE.

[0147] In aspect 29, the method according to any one of aspects 24 to 29 includes, wherein the plurality of beams corresponds to at least a first receive beam from a first beam pool and at least a second beam from a second beam pool, receiving a first instance of the first random access message from the UE on the first beam pool, and receiving a second instance of the first random access message from the UE on the second beam pool.

[0148] In aspect 30, the method according to any one of aspects 24 to 30 includes, wherein the plurality of beams are different from the plurality of receiving beams of the one or more instances on which the first random access message is received from the UE.

[0149] In aspect 31, the method according to aspect 30 includes at least one of the following: receiving a report indicating the plurality of beams from the UE, or indicating the plurality of beams to the UE.

[0150] In aspect 32, the method according to any one of aspects 24 to 31 includes, wherein the second random access message includes a control channel portion and a data channel portion, and the control channel portion indicates resources for the data channel portion.

[0151] In aspect 33, the method according to aspect 32 includes, wherein the data channel portion includes a random access response indicating a successful random access response or a fallback random access response.

[0152] In aspect 34, the method according to any one of aspects 32 or 33 includes, wherein the control channel portion indicates resources for all data channel portions in the data channel portion for each instance of the plurality of instances of the second random access message.

[0153] In aspect 35, the method according to any one of aspects 32 to 24 includes, wherein transmitting the plurality of instances of the second random access message includes: for each instance of the plurality of instances, transmitting the data channel portion using the same beam as the control channel portion.

[0154] In aspect 36, the method according to any one of aspects 32 to 25 includes, wherein transmitting the plurality of instances of the second random access message includes, for each instance of the plurality of instances, transmitting the data channel portion using a beam different from the control channel portion.

[0155] In aspect 37, the method according to aspect 36 includes, wherein the control channel portion indicates the beam for transmitting the data channel portion.

[0156] In aspect 38, the method according to any one of aspects 24 to 37 includes receiving one or more instances of feedback for the second random access message from the UE.

[0157] In aspect 39, the method according to aspect 38 includes, wherein the second random access message indicates the resources of the one or more instances on which the feedback is sent.

[0158] In aspect 40, the method according to any one of aspects 38 or 39 includes, wherein the second random access message indicates at least one of the following: a plurality of feedback beams used when sending the feedback of the one or more instances, or a beam pattern for sending the plurality of feedback beams.

[0159] Aspect 41 is a device for wireless communication, which includes a transceiver, a memory configured to store instructions, and one or more processors coupled to the memory and the transceiver, wherein the one or more processors are configured to execute one or more of the methods according to any one of aspects 1 to 40.

[0160] Aspect 42 is a device for wireless communication, which includes units for executing one or more of the methods according to any one of aspects 1 to 40.

[0161] Aspect 43 is a computer-readable medium, which includes code for wireless communication executable by one or more processors, and the code includes code for executing one or more of the methods according to any one of aspects 1 to 40.

[0162] The above specific implementations described above in conjunction with the accompanying drawings are examples, and do not represent the only examples that can be implemented or within the scope of the claims. As used in this specification, the term "example" means "serving as an example, instance, or illustration", and not "preferred" or "superior to other examples". For the purpose of providing an understanding of the described technology, the specific implementations include specific details. However, these technologies can be implemented without these specific details. In some instances, well-known structures and devices are shown in block diagram form to avoid obscuring the concepts of the described examples.

[0163] Information and signals can be represented using any of a variety of different processes and technologies. For example, the data, instructions, commands, information, signals, bits, symbols, and chips referred to throughout the above specification can be represented by voltage, current, electromagnetic waves, magnetic fields or particles, optical fields or particles, computer-executable code or instructions stored on a computer-readable medium, or any combination thereof.

[0164] The various illustrative blocks and components described in connection with the disclosure herein can be implemented or performed with a specially programmed device designed to perform the functions described herein, such as but not limited to a processor, digital signal processor (DSP), ASIC, field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof. A specially programmed processor can be a microprocessor, but in the alternative, the processor can be any conventional processor, controller, microcontroller, or state machine. A specially programmed processor can also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors cooperating with a DSP core, or any other such configuration.

[0165] The functions described herein can be implemented in hardware, software (e.g., executed by a processor), or any combination thereof. Whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise, software should be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software components, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, or functions, etc. If implemented in software executed by a processor, the functions can be stored on a computer-readable medium or transmitted via a computer-readable medium as one or more instructions or code. Other examples and implementations are within the scope and spirit of the present disclosure and the appended claims. For example, due to the nature of software, the functions described above can be implemented using software (e.g., executed by a specially programmed processor), hardware, hardwiring, or any combination of these items. The features implementing the functions can also be physically located at various positions, including being distributed such that portions of the functions can be implemented at different physical locations. Additionally, as used herein, including in the claims, "or" (e.g., as used in a list of items beginning with "at least one of") indicates a disjunctive list, such that a list of "at least one of A, B, or C" means A or B or C or AB or AC or BC or ABC (i.e., A and B and C). Additionally, as used herein, the phrase "based on" should not be construed as a reference to a closed set of conditions. For example, without departing from the scope of the present disclosure, an example step described as "based on condition A" can be based on both condition A and condition B. In other words, as used herein, the phrase "based on" should be construed in the same manner as the phrase "at least partially based on". As used herein, when used in a list of two or more items, the term "and / or" means any combination of two or more of the listed items that can be taken. For example, if a composition is described as including components A, B, and / or C, the composition can include only A; only B; only C; a combination of A and B; a combination of A and C; a combination of B and C; or a combination of A, B, and C.

[0166] A computer-readable medium includes both computer storage media and communication media, where the communication media includes any medium that facilitates the transfer of a computer program from one place to another. The storage media can be any available media that can be accessed by a general-purpose or special-purpose computer. By way of example and not limitation, a computer-readable medium can include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store the desired program code units in the form of instructions or data structures and that can be accessed by a general-purpose or special-purpose computer or a general-purpose or special-purpose processor. Additionally, any connection is properly termed a computer-readable medium. For example, if software is transmitted from a website, server, or other remote source using coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of the medium. As used herein, disk and optical disks include compact disk (CD), laser disk, optical disk, digital versatile disk (DVD), floppy disk, and Blu-ray disk, where disks typically reproduce data magnetically, while optical disks utilize lasers to optically reproduce data. Combinations of the above are also included within the scope of computer-readable media.

[0167] The foregoing description of the disclosure is provided to enable a person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other variations without departing from the spirit or scope of the disclosure. In addition, while the elements of the described aspects and / or embodiments may be described or claimed in the singular, the plural form is contemplated unless expressly stated to the contrary. Additionally, unless otherwise stated, all or a portion of any aspect and / or embodiment may be utilized in conjunction with all or a portion of any other aspect and / or embodiment. Therefore, the disclosure is not limited to the examples and designs described herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A device for wireless communication, comprising: a transceiver; a memory configured to store instructions; and one or more processors coupled to the memory and the transceiver, wherein the one or more processors are configured to perform the following operations: select a plurality of beams to be used when transmitting a message during a random access procedure with one or more transmit / receive points (TRPs) of a cell; and transmit a plurality of instances of a first random access message to the one or more TRPs of the cell based on the plurality of beams, the first random access message including a preamble portion and a payload portion, wherein each instance of transmitting the first random access message includes: transmitting the preamble portion of the corresponding instance of the first random access message based on one of the plurality of beams; and transmitting the payload portion of the corresponding instance of the first random access message based on the one of the plurality of beams and after a transmission gap from the preamble portion in time.

2. The device according to claim 1, wherein The cell is a secondary cell (SCell) for the device, or a primary-secondary cell (PSCell) for the device.

3. The device according to claim 1, wherein, For one TRP of the cell, the plurality of beams at least include a first beam from a first beam pool index and a second beam from a second beam pool index.

4. The device according to claim 1, wherein, The plurality of beams include a first beam from a first TRP index of the cell and a second beam from a second TRP index of the cell.

5. The apparatus according to claim 1, wherein The one or more processors are configured to use at least one of time-division multiplexing, frequency-division multiplexing, or space-division multiplexing to separate the plurality of beams and transmit the plurality of instances of the first random access message based on the plurality of beams.

6. The device according to claim 1, wherein, The preamble portion of each instance of the first random access message includes a plurality of preamble transmissions.

7. The apparatus according to claim 1, wherein The payload portion of each instance of the first random access message includes a plurality of payload transmissions.

8. The apparatus according to claim 1, wherein, The one or more processors are configured to: select the plurality of beams as a set of beams based on a reference signal received from the one or more TRPs.

9. The apparatus according to claim 1, wherein The plurality of beams include a plurality of transmit beams for a plurality of reference signals, the plurality of transmit beams corresponding to a plurality of receive beams from the cell during a corresponding number of allocated random access opportunities, wherein each random access opportunity is associated with one of the plurality of reference signals for receiving the preamble portion.

10. The apparatus according to claim 9, wherein, The plurality of reference signals include at least one of a synchronization signal block (SSB) or a channel state information reference signal (CSI-RS) from the cell.

11. The device according to claim 1, wherein, The one or more processors are further configured to: receive one or more instances of a second random access message from at least one of the one or more TRPs and in response to the first random access message.

12. The apparatus according to claim 11, wherein, The one or more instances of the second random access message are received based on at least one of the plurality of beams.

13. The apparatus according to claim 11, wherein The one or more instances of the second random access message are received based on different beams not included in the plurality of beams, where the different beams are reported to the one or more TRPs or configured by the one or more TRPs, at least one of which.

14. The apparatus according to claim 11, wherein, The second random access message at least includes a control channel portion indicating resources for a shared channel portion.

15. The apparatus according to claim 14, wherein, The shared channel portion includes a random access response indicating a successful random access response or a fallback random access response.

16. The device according to claim 11, wherein, The second random access message indicates uplink control channel resources for transmitting feedback for receiving the second random access message, and wherein the one or more processors are further configured to transmit the feedback on the uplink control channel resources.

17. The apparatus according to claim 16, wherein, The one or more processors are configured to transmit multiple instances of the feedback based on multiple feedback beams.

18. The device according to claim 17, wherein, The second random access message indicates at least one feedback beam among the multiple feedback beams or a beam pattern for transmitting the multiple feedback beams.

19. The device according to claim 17, wherein, The one or more processors are further configured to determine that the multiple feedback beams are the same as the multiple beams.

20. An apparatus for wireless communication, comprising: a transceiver; a memory configured to store instructions; and one or more processors coupled to the memory and the transceiver, wherein the one or more processors are configured to: As part of a random access procedure, receive, using one or more transmit / receive points (TRPs), multiple instances of a first random access message from a user equipment (UE), the first random access message including a preamble portion and a payload portion, wherein each instance of receiving the multiple instances of the first random access message includes: Receiving the preamble portion of the corresponding instance of the first random access message based on one receiving beam among a plurality of receiving beams; and Receiving the payload portion of the corresponding instance of the first random access message based on the one receiving beam among the plurality of receiving beams and after a transmission gap from the preamble portion; Determine a plurality of beams to be used when sending a message in the random access procedure; and Using one or more TRPs, transmit multiple instances of a second random access message to the UE and in response to the first random access message, based on the plurality of beams.

21. The apparatus according to claim 20, wherein, For one TRP, the plurality of beams at least includes a first beam from a first beam pool index and a second beam from a second beam pool index.

22. The device according to claim 20, wherein, The plurality of beams includes a first beam corresponding to a first TRP index of the one or more TRPs and a second beam corresponding to a second TRP index of the one or more TRPs, and wherein the one or more processors are configured to: transmit the multiple instances of the second random access message at least in part by the first TRP transmitting a first instance of the second random access message based on at least the first beam, and by the second TRP transmitting a second instance of the second random access message based on at least the second beam.

23. The apparatus according to claim 20, wherein, The one or more processors are configured to send the multiple instances of the second random access message by, at least in part, separating the multiple beams by using at least one of time division multiplexing, frequency division multiplexing, or space division multiplexing and sending the multiple instances based on the multiple beams.

24. The apparatus according to claim 20, wherein The multiple beams correspond to the multiple receive beams.

25. A method for wireless communication at a user equipment (UE), comprising: selecting multiple beams to be used when sending a message during a random access procedure with one or more transmit / receive points (TRPs) of a cell; and sending multiple instances of a first random access message to the one or more TRPs of the cell based on the multiple beams, the first random access message including a preamble part and a payload part, wherein each instance of sending the first random access message includes: sending the preamble part of the corresponding instance of the first random access message based on one of the multiple beams; and sending the payload part of the corresponding instance of the first random access message based on the one of the multiple beams and after a transmission gap from the preamble part in time.

26. The method according to claim 25, wherein, The cell is a secondary cell (SCell) for the UE or a primary secondary cell (PSCell) for the UE.

27. The method according to claim 25, wherein, For one TRP of the cell, the multiple beams include at least a first beam from a first beam pool index and a second beam from a second beam pool index.

28. The method according to claim 25, wherein, The multiple beams include a first beam from a first TRP index of the cell and a second beam from a second TRP index of the cell.

29. The method according to claim 25, wherein Sending the multiple instances of the first random access message based on the multiple beams includes separating the multiple beams by using at least one of time division multiplexing, frequency division multiplexing, or space division multiplexing.

30. A method for wireless communication, comprising: receiving, as part of a random access procedure, multiple instances of a first random access message from a user equipment (UE) by one or more transmit / receive points (TRPs), the first random access message including a preamble part and a payload part, wherein each instance of receiving the first random access message includes: receiving the preamble part of the corresponding instance of the first random access message based on one of multiple receive beams; and receiving the payload part of the corresponding instance of the first random access message based on the one of the multiple receive beams and after a transmission gap from the preamble part in time; determining multiple beams to be used when sending a message during the random access procedure; and sending, by one or more TRPs, multiple instances of a second random access message to the UE and in response to the first random access message based on the multiple beams.

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