Beam-Scanning Based Random Access Msg 1 and Msg 2

Abstract

Methods, computer-readable media, and apparatuses for wireless communication including random access between a base station and a user equipment (UE) are provided. The UE transmits at least two first random access messages (Msg 1) to multiple transmit receive points (TRPs) of at least one cell, and different resources are used for the transmission for the multiple TRPs. The UE monitors at least two second random access messages (Msg 2) from the multiple TRPs of the at least one cell using different resources for the multiple TRPs.

Description

[0001] Cross - Reference to Related Applications

[0002] This application claims the benefit of U.S. Provisional Application No. 62 / 951,894, filed on December 20, 2019, entitled "Beam Sweep Based RandomAccess Msg 1and Msg 2", and U.S. Patent Application No. 17 / 091,352, filed on November 6, 2020, entitled "BEAM SWEEP BASED RANDOM ACCESS MSG 1AND MSG 2", the entire contents of which are hereby incorporated by reference in their entirety. Technical Field

[0003] Broadly speaking, the present disclosure relates to communication systems, and more particularly, to wireless communication including random access. Background Art

[0004] Wireless communication systems are widely deployed to provide various telecommunication services such as voice, video, data, messaging, and broadcasting. A typical wireless communication system may use multiple access technologies that are capable of supporting communication with multiple users by sharing the available system resources. Examples of such multiple access technologies include Code Division Multiple Access (CDMA) systems, Time Division Multiple Access (TDMA) systems, Frequency Division Multiple Access (FDMA) systems, Orthogonal Frequency Division Multiple Access (OFDMA) systems, Single - Carrier Frequency Division Multiple Access (SC - FDMA) systems, and Time Division Synchronous Code Division Multiple Access (TD - SCDMA) systems.

[0005] These multiple access technologies have been adopted in various telecommunication standards to provide common protocols that enable different wireless devices to communicate in cities, countries, regions, and even globally. One example telecommunication standard is 5G New Radio (NR). 5G NR is part of the continuous evolution of mobile broadband published by the Third Generation Partnership Project (3GPP) to meet new requirements associated with latency, reliability, security, scalability (e.g., for Internet of Things (IoT)), and other requirements. 5G NR includes services associated with enhanced mobile broadband (eMBB), massive machine - type communication (mMTC), and ultra - reliable low - latency communication (URLLC). Some aspects of 5G NR may be based on the 4G Long - Term Evolution (LTE) standard. There is a need for further improvement in 5G NR technology. These improvements may also be applicable to other multiple access technologies and telecommunication standards using these technologies. Summary of the Invention

[0006] A simplified summary of one or more aspects is given below to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated aspects and is not 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.

[0007] In one aspect of the present disclosure, a method, computer-readable medium, and apparatus for wireless communication at a user equipment (UE) are provided. The apparatus transmits at least two first random access messages (Msg 1) to multiple transmission reception points (TRPs) of at least one cell, and the transmission uses different resources for the multiple TRPs. The apparatus monitors at least two second random access messages (Msg 2) from the multiple TRPs of the at least one cell using different resources for the multiple TRPs.

[0008] In one aspect of the present disclosure, a method, computer-readable medium, and apparatus for wireless communication at a base station are provided. The apparatus receives at least two first random access messages (Msg 1) from a UE at multiple TRPs of at least one cell based on different resources for the multiple TRPs. The apparatus transmits at least two second random access messages (Msg 2) from the multiple TRPs of the at least one cell to the UE based on the different resources for the multiple TRPs.

[0009] To achieve the foregoing and related purposes, the one or more aspects include the features that are described in detail hereinafter and are particularly pointed out in the claims. The following description and the drawings set forth illustrative features of the one or more aspects. However, these features indicate only some of the various ways in which the principles of the various aspects may be used, and this specification is intended to include all such aspects and their equivalents. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 is a diagram illustrating an example of a wireless communication system and an access network.

[0011] Figure 2A is a diagram illustrating an example of a first frame according to various aspects of the present disclosure.

[0012] Figure 2B is a diagram illustrating an example of DL channels within a subframe according to various aspects of the present disclosure.

[0013] Figure 2C is a diagram illustrating an example of a second frame according to various aspects of the present disclosure.

[0014] Figure 2D is a diagram showing an example of the UL channel within a subframe according to various aspects of the present disclosure.

[0015] Figure 3 is a diagram showing an example of a base station and a user equipment (UE) in an access network.

[0016] Figure 4 shows a communication flow between a UE and a base station including a random access procedure.

[0017] Figure 5 shows an example of communication for a UE to perform random access with a primary-secondary cell (PSCell).

[0018] Figure 6 shows an example of beam usage in combination with random access.

[0019] Figure 7A and 7B shows example aspects of random access between a UE and a cell having a single transmit-receive point (TRP) using multiple beams.

[0020] Figure 8 shows example aspects of random access between a UE and a cell having multiple TRPs using multiple beams.

[0021] Figure 9 shows example aspects of random access between a UE and a cell having a single TRP using multiple beams.

[0022] Figure 10 shows example aspects of random access between a UE and a cell having multiple TRPs using multiple beams.

[0023] Figure 11 shows example aspects of random access between a UE and a cell having multiple TRPs using multiple beams.

[0024] Figure 12 is a flowchart of a wireless communication method.

[0025] Figure 13 is a flowchart of a wireless communication method.

[0026] Figure 14 is a diagram showing an example of a hardware implementation of an example apparatus.

[0027] Figure 15 is a diagram showing an example of a hardware implementation of an example apparatus. Detailed Description

[0028] The following detailed description, presented in conjunction with the accompanying drawings, is intended as a description of various configurations and is not intended to represent the only configurations in which the concepts described herein may be practiced. The detailed description includes specific details for the purpose of providing a thorough understanding of the various concepts. It will be apparent, however, to one of ordinary skill in the art that the concepts may be practiced without these specific details. In some instances, well-known structures and components are shown in block diagram form to avoid obscuring such concepts.

[0029] Certain aspects of a telecommunications system will now be presented with reference to various apparatuses and methods. These apparatuses and methods will be described in the following detailed description and illustrated in the accompanying drawings by various blocks, components, circuits, processes, algorithms, etc. (collectively referred to as “elements”). These elements can be implemented using either electronic hardware, computer software, or any combination thereof. Whether such an element is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system.

[0030] By way of example, an element, or any portion of an element, or any combination of elements can be implemented as a “processing system” that includes one or more processors. Examples of processors include a microprocessor, a microcontroller, a graphics processing unit (GPU), a central processing unit (CPU), an application processor, a digital signal processor (DSP), a reduced instruction set computing (RISC) processor, a system on a chip (SoC), a baseband processor, a field programmable gate array (FPGA), a programmable logic device (PLD), a state machine, a gate logic unit, discrete hardware circuitry, and other suitable hardware configured to perform the various functions described throughout this disclosure. One or more processors in the processing system can execute software. 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, processes, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise.

[0031] Accordingly, in one or more example embodiments, the described functionality may be implemented in hardware, software, or any combination thereof. If implemented in software, the functionality may be stored or encoded as one or more instructions or code on a computer-readable medium. A computer-readable medium includes computer storage media. Storage media can be any available media that can be accessed by a computer. By way of example and not limitation, such computer-readable media may include random access memory (RAM), read only memory (ROM), electrically erasable programmable ROM (EEPROM), optical disk storage, magnetic disk storage, other magnetic storage devices, combinations of the aforementioned types of computer-readable media, or any other medium that can be used to store computer-executable code in the form of instructions or data structures that can be accessed by a computer.

[0032] To perform a random access procedure with a cell, a UE may identify a directional beam. The UE may use the beam identified by the UE to exchange random access messages with the base station, e.g., Msg 2, Msg 3, and Msg 4. After completing the random access procedure, the UE and the base station may transition to an enhanced beam operation, in which the UE may measure CSI-RS on different beams from the base station and may provide a measurement report to the base station for beam selection.

[0033] Aspects presented herein may provide coverage and / or latency improvements for random access. Aspects presented herein may help improve the reliability of transmissions by providing multiple transmission opportunities in the time, frequency, and / or spatial domain for random access transmissions or the random access channel (RACH). The additional transmission opportunities may improve the reliability of communications, e.g., in unlicensed spectrum, by increasing the likelihood of a successful random access procedure between the UE and the cell. The improved reliability may help support services such as URLLC services, IoT such as industrial IoT (IIoT) services, and NR-based communications in unlicensed spectrum in a controlled environment (such as FR1). Aspects may provide improved random access reliability and robustness by using beam scanning during random access between the UE and multiple TRPs associated with at least one base station.

[0034] Figure 1FIG. is a diagram illustrating an example of a wireless communication system and an access network 100. The wireless communication system (also referred to as a wireless wide area network (WWAN)) includes a base station 102, a UE 104, an evolved packet core (EPC) 160, and another core network 190 (e.g., a 5G core (5GC)). The UE 104 may include a random access message component 199 configured to send at least two first random access messages (Msg 1) to multiple TRPs of at least one cell, sending different resources for the multiple TRPs. The apparatus monitors at least two second random access messages (Msg 2) from multiple TRPs of at least one cell using different resources for the multiple TRPs. The base station 102 or 180 may include a random access message component 198 configured to receive at least two first random access messages (Msg 1) from the UE 104 at multiple TRPs of at least one cell based on different resources for the multiple TRPs. The apparatus sends at least two second random access messages (Msg 2) to the UE 104 from multiple TRPs of at least one cell based on different resources for the multiple TRPs.

[0035] The base station 102 may include a macro cell (high-power cellular base station) and / or a small cell (low-power cellular base station). The macro cell includes a base station. The small cell includes a femto cell, a pico cell, and a micro cell.

[0036] The base station 102 configured for 4G LTE (collectively referred to as an evolved universal mobile telecommunications system (UMTS) terrestrial radio access network (E-UTRAN)) may interface with the EPC 160 via a first backhaul link 132 (e.g., an S1 interface). The base station 102 configured for 5G NR (collectively referred to as a next-generation RAN (NG-RAN)) may interface with the core network 190 via a second backhaul link 184. In addition to other functions, the base station 102 may perform one or more of the following functions: transmission of user data, encryption and decryption of wireless 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 distribution of alert messages. The base station 102 may communicate directly or indirectly with each other (e.g., via the EPC 160 or the core network 190) via a third backhaul link 134 (e.g., an X2 interface). The first backhaul link 132, the second backhaul link 184, and the third backhaul link 134 may be wired or wireless.

[0037] Base station 102 can communicate wirelessly with UE 104. Each base station 102 in base station 102 can provide communication coverage for a respective geographical coverage area 110. There can be overlapping geographical coverage areas 110. For example, small cell 102’ can have a coverage area 110’ that overlaps with the coverage areas 110 of one or more macro base stations 102. A network that includes 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 (eNB) (HeNB), and the HeNB can serve a restricted group referred to as 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 reverse link) transmission from UE 104 to base station 102 and / or a downlink (DL) (also referred to as 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 up to a total of Yx MHz (x component carriers) of carrier aggregation with up to Y MHz (e.g., 5, 10, 15, 20, 100, 400, etc. MHz) of bandwidth per carrier allocated for transmission in each direction. The carriers can or can not be 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 to DL than UL). The component carriers can include one 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).

[0038] Particular 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 via a variety of wireless D2D systems such as, for example, WiMedia, Bluetooth, ZigBee, WiFi based on the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standards, LTE, or NR.

[0039] The wireless communication system may further include a Wi-Fi access point (AP) 150 that communicates with a Wi-Fi station (STA) 152 via a communication link 154, for example, in an unlicensed spectrum such as the 5 GHz unlicensed spectrum. When communicating in the unlicensed spectrum, the STA 152 / AP 150 may perform a Clear Channel Assessment (CCA) before communicating to determine whether the channel is available.

[0040] The small cell 102’ may operate in licensed and / or unlicensed spectrum. When operating in the unlicensed spectrum, the small cell 102’ may use NR and use the same unlicensed spectrum (e.g., 5 GHz, etc.) as the spectrum used by the Wi-Fi AP 150. The small cell 102’ using NR in the unlicensed spectrum may enhance the coverage of the access network and / or increase the capacity of the access network.

[0041] The electromagnetic spectrum is generally subdivided into various levels, bands, channels, etc. based on frequency / wavelength. In 5G NR, two initial operating bands have been identified as the frequency range name FR1 (410 MHz - 7.125 GHz) and FR2 (24.25 GHz - 52.6 GHz). The frequency between FR1 and FR2 is generally referred to as the intermediate band frequency. Although a part of FR1 is greater than 6 GHz, FR1 is generally (interchangeably) referred to as the “sub-6 GHz” band in various documents and articles. A similar naming issue sometimes occurs for FR2, which is generally (interchangeably) referred to as the “millimeter wave” band in documents and articles, although it is different from the extremely high frequency (EHF) band (30 GHz - 300 GHz) identified as the “millimeter wave” band by the International Telecommunication Union (ITU).

[0042] In view of the above aspects, unless otherwise specifically stated, it should be understood that the term “sub-6 GHz” etc., if used in this document, may broadly represent frequencies that may be less than 6 GHz, may fall within FR1, or may include the intermediate band frequency. Further, unless otherwise specifically stated, it should be understood that the term “millimeter wave” etc., if used in this document, may broadly represent frequencies that may include the intermediate band frequency, may fall within FR2, or may fall within the EHF band.

[0043] Base station 102 (whether it is a small cell 102' or a large cell (e.g., a macro base station)) may include and / or be referred to as an eNB, a g-node B (gNB), or another type of base station. Some base stations (such as gNB 180) may operate in the traditional sub-6 GHz spectrum, at millimeter wave (mmW) frequencies, and / or near mmW frequencies in communication with UE 104. When gNB 180 operates at millimeter wave or near millimeter wave frequencies, gNB 180 may be referred to as a millimeter wave base station. The millimeter wave base station 180 may use beamforming 182 with UE 104 to compensate for path loss and short distances. Base station 180 and UE 104 may each include a plurality of antennas (such as antenna elements, antenna panels, and / or antenna arrays) to facilitate beamforming.

[0044] Base station 180 may transmit a beamformed signal to UE 104 in one or more transmission directions 182'. UE 104 may receive the beamformed signal from base station 180 in one or more reception directions 182". UE 104 may also transmit a beamformed signal to base station 180 in one or more transmission directions. Base station 180 may receive the beamformed signal from UE 104 in one or more reception directions. Base station 180 / UE 104 may perform beam training to determine the optimal reception and transmission directions for each of base station 180 / UE 104 in base station 180 / UE 104. The transmission and reception directions for base station 180 may or may not be the same. The transmission and reception directions for UE 104 may or may not be the same.

[0045] 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 speaking, the MME 162 provides bearer and connection management. All user Internet Protocol (IP) packets are transmitted through the Serving Gateway 166, which is itself connected to the PDN Gateway 172. The PDN Gateway 172 provides IP address allocation for 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 configuration and distribution. The BM-SC 170 may act as an entry point for content provider MBMS transmissions, may be used to authorize and initiate MBMS bearer services within a Public Land Mobile Network (PLMN), and may be used to schedule MBMS transmissions. 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 specific broadcast service, and may be responsible for session management (start / stop) and collecting charging information related to eMBMS.

[0046] The core network 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 core network 190. Generally speaking, the AMF 192 provides QoS flow and session management. All user Internet Protocol (IP) packets are transmitted through the UPF 195. The UPF 195 provides IP address allocation for the UE, 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 Packet Switched (PS) Streaming (PSS) service, and / or other IP services.

[0047] The base station 102 may include and / or be referred to as a gNB, Node B, eNB, access point, base station transceiver, radio base station, radio transceiver, transceiver function, basic service set (BSS), extended service set (ESS), transmission reception point (TRP), or some other suitable term. The base station 102 provides an access point to the EPC 160 or the core network 190 for the UE 104. Examples of the UE 104 include cellular phones, smart phones, session initiation protocol (SIP) phones, laptop devices, personal digital assistants (PDAs), satellite radios, 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, air pumps, large or small kitchen appliances, health care devices, implants, sensors / actuators, displays, or any other similar functioning devices. Some of the UEs 104 in the UE 104 may be referred to as IoT devices (e.g., parking meters, air pumps, toasters, vehicles, heart monitors, etc.). The UE 104 may also be referred to as a station, mobile station, user station, mobile unit, user unit, radio unit, remote unit, mobile device, radio device, wireless communication device, remote device, mobile user station, access terminal, mobile terminal, wireless terminal, remote terminal, cell phone, user agent, mobile client, client, or some other suitable term.

[0048] Although the following description may focus on 5G NR, the concepts described herein may be applicable to other similar fields (such as LTE, LTE-A, CDMA, GSM, and other wireless technologies).

[0049] Figure 2A FIG. 200 is an example showing a first subframe within the 5G NR frame structure. Figure 2B FIG. 230 is an example showing a DL channel within the 5G NR subframe. Figure 2C FIG. 250 is an example showing a second subframe within the 5G NR frame structure. Figure 2D FIG. 280 is an example showing a UL channel within the 5G NR subframe. The 5G NR frame structure may be frequency division duplexing (FDD), where, for a specific set of subcarriers (carrier system bandwidth), the subframes within the set of subcarriers are dedicated to DL or UL; or it may be time division duplexing (TDD), where, for a specific set of subcarriers (carrier system bandwidth), the subframes within the set of subcarriers are dedicated to both DL and UL. In Figure 2A 、 2CIn the provided example, it is assumed that the 5G NR frame structure is TDD. Among them, subframe 4 is configured to have a slot format 28 (where the majority is DL), where D is DL, U is UL, and F is a flexible symbol used between DL / UL, and subframe 3 is configured to have a slot format 1 (where all are UL). Although subframes 3 and 4 are shown to have slot formats 1 and 28 respectively, any specific subframe can be configured to have any one of the various available slot formats 0 - 61. Slot formats 0 and 1 are all DL and UL respectively. The other slot formats 2 - 61 include a mixture of DL, UL, and flexible symbols. The UE is configured to have a slot format through the received slot format indicator (SFI) (dynamically through downlink control information (DCI) or semi-statically / statically through radio resource control (RRC) signaling). It should be noted that the following description also applies to the TDD 5G NR frame structure.

[0050] Other wireless communication technologies may have different frame structures and / or different channels. A frame (10 ms) can be divided into 10 equal-sized subframes (1 ms). Each subframe can include one or more slots. A subframe can also include mini-slots, and a mini-slot can include 7, 4, or 2 symbols. Depending on the slot configuration, each slot can include 7 or 14 symbols. For slot configuration 0, each slot can include 14 symbols, and for slot configuration 1, each slot can include 7 symbols. The symbols on the DL can be cyclic prefix (CP) orthogonal frequency division multiplexing (OFDM) (CP-OFDM) symbols. The symbols on the UL can be CP-OFDM symbols (for high-throughput scenarios) or discrete Fourier transform (DFT) spread OFDM (DFT-s-OFDM) symbols (also known as single-carrier frequency division multiple access (SC-FDMA) symbols) (for power-limited scenarios; limited to single-stream transmission). The number of slots within a subframe is based on the slot configuration and the numerology. For slot configuration 0, different numerologies μ0 to 4 allow 1, 2, 4, 8, and 16 slots per subframe respectively. For slot configuration 1, different numerologies 0 to 2 allow 2, 4, and 8 slots per subframe respectively. Accordingly, for slot configuration 0 and numerology μ, there are 14 symbols / slot and 2 μ slots / subframe. The subcarrier spacing and symbol length / duration are functions of the numerology. The subcarrier spacing can be equal to 2 μ *15kKz, where μ is the numerology from 0 to 4. Thus, numerology μ = 0 has a subcarrier spacing of 15 kHz, and numerology μ = 4 has a subcarrier spacing of 240 kHz. The symbol length / duration is inversely related to the subcarrier spacing. Figure 2A - 2DAn example of slot configuration 0 with 14 symbols per time slot and digital scheme μ = 2 with 4 time slots per subframe is provided. The slot duration is 0.25 ms, the subcarrier spacing is 60 kHz, and the symbol duration is approximately 16.67 μs. Within a set of frames, there may be one or more different bandwidth parts (BWPs) multiplexed in frequency (see Figure 2B ). Each BWP may have a specific digital scheme.

[0051] A resource grid can be used to represent the frame structure, with each time slot including a resource block (RB) (also referred to as a physical RB (PRB)), and one RB spanning 12 consecutive subcarriers. The resource grid is divided into multiple resource elements (REs). The number of bits carried by each RE depends on the modulation scheme.

[0052] As illustrated in Figure 2A , some of the REs carry reference (pilot) signals (RS) for the UE. The RS may include demodulation RS (DM-RS) (designated as R for a specific configuration, but other DM-RS configurations are possible) and channel state information reference signals (CSI-RS) for channel estimation at the UE. The RS may also include beam measurement RS (BRS), beam refinement RS (BRRS), and phase-tracking RS (PT-RS).

[0053] Figure 2BShows an example of various DL channels within a subframe of a frame. The Physical Downlink Control Channel (PDCCH) carries DCI within one or more Control Channel Elements (CCEs) (e.g., 1, 2, 4, 8, or 16 CCEs), each CCE including six Resource Element Groups (REGs), and each REG including 12 consecutive Resource Elements (REs) in one OFDM symbol of one Resource Block (RB). The PDCCH within a Bandwidth Part (BWP) can be referred to as a Control Resource Set (CORESET). The UE is configured to monitor PDCCH candidates in the PDCCH search space (e.g., common search space, UE-specific search space) during PDCCH monitoring occasions on the CORESET, where the PDCCH candidates have different DCI formats and different aggregation levels. Additional BWPs can be located at higher and / or lower frequencies across the channel bandwidth. The Primary Synchronization Signal (PSS) can be in symbol 2 of a specific subframe of a frame. The PSS is used by the UE104 to determine subframe / symbol timing and the physical layer identity. The Secondary Synchronization Signal (SSS) can be in symbol 4 of a specific subframe of a frame. The SSS is used by the UE to determine the physical layer cell identity group number and the radio frame timing. Based on the physical layer identity and the physical layer cell identity group number, the UE can determine the Physical Cell Identifier (PCI). Based on the PCI, the UE can determine the location of the aforementioned DM-RS. The Physical Broadcast Channel (PBCH) carrying the Master Information Block (MIB) can be logically grouped with the PSS and SSS to form a Synchronization Signal (SS) / PBCH block (also referred to as an SS block (SSB)). The MIB provides the number of RBs in the system bandwidth and the System Frame Number (SFN). The Physical Downlink Shared Channel (PDSCH) carries user data, broadcast system information not sent via the PBCH (such as System Information Blocks (SIBs)), and paging messages.

[0054] As illustrated in Figure 2C Some of the REs carry DM-RS for channel estimation at the base station (indicated as R for a specific configuration, but other DM-RS configurations are possible). The UE can transmit DM-RS for the Physical Uplink Control Channel (PUCCH) and DM-RS for the Physical Uplink Shared Channel (PUSCH). The PUSCH DM-RS can be transmitted in the first one or two symbols of the PUSCH. Depending on whether a short or long PUCCH is transmitted and depending on the specific PUCCH format used, the PUCCH DM-RS can be transmitted in different configurations. The UE can transmit a Sounding Reference Signal (SRS). The SRS can be transmitted in the last symbol of the subframe. The SRS can have a comb structure, and the UE can transmit the SRS on one of the combs. The SRS can be used by the base station for channel quality estimation to enable frequency-dependent scheduling on the UL.

[0055] Figure 2D Shows an example of various UL channels within a subframe of a frame. The PUCCH can be positioned as indicated in one configuration. The PUCCH carries uplink control information (UCI) (such as, scheduling request, channel quality indicator (CQI), precoding matrix indicator (PMI), rank indicator (RI), and hybrid automatic repeat request (HARQ) acknowledgement (ACK) (HARQ-ACK) information (ACK / negative ACK (NACK)) feedback). The PUSCH carries data and can additionally be used to carry buffer status report (BSR), power headroom report (PHR), and / or UCI.

[0056] Figure 3 Is a block diagram of a base station 310 that communicates with a UE 350 in an access network. In the DL, IP packets from the EPC 160 can be provided to a controller / processor 375. The controller / processor 375 implements layer 3 and layer 2 functions. Layer 3 includes the radio resource control (RRC) layer, and layer 2 includes the service data adaptation protocol (SDAP) layer, the packet data convergence protocol (PDCP) layer, the radio link control (RLC) layer, and the media access control (MAC) layer. The controller / processor 375 provides RRC layer functions associated with the broadcast of system information (e.g., MIB, SIB), RRC connection control (e.g., RRC connection paging, RRC connection establishment, RRC connection modification, and RRC connection release), inter-radio access technology (RAT) mobility, and measurement configuration for UE measurement reporting; PDCP layer functions associated with header compression / decompression, security (encryption, decryption, integrity protection, integrity verification), and handover support functions; RLC layer functions associated with the transmission of upper layer packet data units (PDUs), error correction via ARQ, concatenation, segmentation, and reassembly of RLC service data units (SDUs), re-segmentation of RLC data PDUs, and re-ordering of RLC data PDUs; and MAC layer functions associated with the mapping between logical channels and transport channels, multiplexing of MAC SDUs onto transport blocks (TBs), demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction via HARQ, priority handling, and logical channel prioritization.

[0057] The transmit (TX) processor 316 and the receive (RX) processor 370 implement layer 1 functions associated with various signal processing functions. Layer 1, which includes the physical (PHY) layer, may include error detection on the transport channel, forward error correction (FEC) coding / decoding of the transport channel, interleaving, rate matching, mapping to the physical channel, modulation / demodulation of the physical channel, and MIMO antenna processing. The TX processor 316 handles the mapping to the signal constellation based on various modulation schemes (e.g., binary phase shift keying (BPSK), quadrature phase shift keying (QPSK), M-phase phase shift keying (M-PSK), M-order quadrature amplitude modulation (M-QAM)). The encoded and modulated symbols may then be split into parallel streams. Each stream may then be mapped to an OFDM subcarrier, multiplexed with a reference signal (e.g., a pilot) in the time and / or frequency domain, and then combined together using an inverse fast Fourier transform (IFFT) to generate a physical channel carrying a stream of time-domain OFDM symbols. The OFDM stream is precoded spatially to generate multiple spatial streams. The channel estimate from the channel estimator 374 may be used to determine the coding and modulation schemes and for spatial processing. The channel estimate may be derived from the reference signal and / or channel condition feedback sent by the UE 350. Each spatial stream may then be provided to a different antenna 320 via a separate transmitter 318TX. Each transmitter 318TX may modulate an RF carrier with a respective spatial stream for transmission.

[0058] At the UE 350, each receiver 354RX receives signals via its respective antenna 352. Each receiver 354RX recovers the information modulated onto the RF carrier and provides the information to the receive (RX) processor 356. The TX processor 368 and the RX processor 356 implement layer 1 functions associated with various signal processing functions. The RX processor 356 may perform spatial processing on the information to recover any spatial streams intended for the UE 350. If multiple spatial streams are intended for the UE 350, they may be combined into a single OFDM symbol stream by the RX processor 356. The RX processor 356 then uses a fast Fourier transform (FFT) to convert the OFDM symbol stream from the time domain to the frequency domain. The frequency-domain signal includes a separate OFDM symbol stream for each subcarrier of the OFDM signal. The symbols and reference signal on each subcarrier are recovered and demodulated by determining the most likely signal constellation points sent by the base station 310. These soft decisions may be based on the channel estimate computed by the channel estimator 358. The soft decisions are then decoded and deinterleaved to recover the data and control signals originally sent by the base station 310 on the physical channel. The data and control signals are then provided to the controller / processor 359 that implements layer 3 and layer 2 functions.

[0059] The controller / processor 359 may be associated with a memory 360 that stores program code and data. The memory 360 may be referred to as a computer-readable medium. In the UL, the controller / processor 359 provides demultiplexing between transport and logical channels, packet reassembly, decryption, header decompression, and control signal processing to recover IP packets from the EPC 160. The controller / processor 359 is also responsible for error detection using the ACK and / or NACK protocols to support HARQ operations.

[0060] Similar to the functions described in connection with DL transmissions performed by the base station 310, the controller / processor 359 provides RRC layer functions associated with system information (e.g., MIB, SIB) capture, RRC connection, and measurement reporting; PDCP layer functions associated with header compression / decompression and security (encryption, decryption, integrity protection, integrity verification); RLC layer functions associated with the transmission of upper layer PDUs, error correction via ARQ, concatenation, segmentation, and reassembly of RLC SDUs, resegmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functions associated with the mapping between logical and transport channels, multiplexing of MAC SDUs onto TBs, demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction via HARQ, priority handling, and logical channel prioritization.

[0061] Channel estimates derived by the channel estimator 358 from reference signals or feedback sent by the base station 310 may be used by the TX processor 368 to select appropriate coding and modulation schemes and to facilitate spatial processing. The spatial streams generated by the TX processor 368 may be provided to different antennas 352 via a separate transmitter 354TX. Each transmitter 354TX may modulate an RF carrier with a respective spatial stream for transmission.

[0062] UL transmissions are processed at the base station 310 in a manner similar to that described in connection with the receiver functions at the UE 350. Each receiver 318RX receives signals via its respective antenna 320. Each receiver 318RX recovers the information modulated onto the RF carrier and provides the information to the RX processor 370.

[0063] The controller / processor 375 can be associated with a memory 376 that stores program code and data. The memory 376 can be referred to as a computer-readable medium. In the UL, the controller / processor 375 provides demultiplexing between transport and logical channels, packet reassembly, decryption, header decompression, and control signal processing to recover IP packets from the UE 350. The IP packets from the controller / processor 375 can be provided to the EPC 160. The controller / processor 375 is also responsible for error detection using the ACK and / or NACK protocols to support HARQ operations.

[0064] At least one of the TX processor 368, RX processor 356, and controller / processor 359 can be configured to perform aspects in conjunction with Figure 1 the random access message component 199.

[0065] At least one of the TX processor 316, RX processor 370, and controller / processor 375 can be configured to perform aspects in conjunction with Figure 1 the random access message component 198.

[0066] A UE can use a random access procedure to communicate with a base station. For example, a UE can use a random access procedure to request an RRC connection, re-establish an RRC connection, resume an RRC connection, etc. Figure 4 Example aspects of a random access procedure 400 between a UE 402 and a base station 404 are shown. The UE 402 can initiate a random access message exchange by sending a first random access message 403 (e.g., Msg 1) including a preamble to the base station 404. Before sending the first random access message 403, the UE can obtain random access parameters such as preamble format parameters, time and frequency resources, parameters for determining a root sequence, and / or cyclic shifts for random access preambles, for example, in the system information 401 from the base station 404. The preamble can be sent together with an identifier such as a random access RNTI (RA-RNTI). The UE 402 can randomly select a random access preamble sequence from a set of preamble sequences, for example. In some examples, a preamble sequence can be assigned to the UE 402.

[0067] The base station responds to the first random access message 403 by using the PDSCH to send a second random access message 405 (e.g., Msg 2) and including a random access response (RAR). The RAR may include, for example, an identifier of a random access preamble sent by the UE, a timing advance (TA), an uplink grant for the UE to send data, a cell radio network temporary identifier (C-RNTI), or other identifiers and / or a fallback indicator. When receiving the RAR 405, the UE 402 may, for example, use the PUSCH to send a third random access message 407 (e.g., Msg 3) to the base station 404. Depending on the trigger for initiating the random access procedure, the third random access message 407 may include an RRC connection request, an RRC connection reestablishment request, or an RRC connection resume request. The base station 404 may then complete the random access procedure by sending a fourth random access message 409 (e.g., Msg 4) to the UE 402 by using, for example, the PDCCH for scheduling and the PDSCH for the message. The fourth random access message 409 may include a random access response message, and the random access response message includes timing advance information, contention resolution information, and / or RRC connection establishment information. The UE402 may monitor, for example, the PDCCH with the C-RNTI. If the PDCCH is successfully decoded, the UE 402 may also decode the PDSCH. The UE 402 may send HARQ feedback for any data carried in the fourth random access message. The fourth message may be referred to as a contention resolution message. The fourth random access message 409 may complete the random access procedure. Thus, the UE 402 may then send uplink communication with the base station 404 and / or receive downlink communication with the base station 404 based on the RAR and the fourth random access message 409.

[0068] Figure 5 An example communication flow 500 is shown, and the communication flow 500 includes the UE 502 performing a random access procedure with a secondary cell 506 (such as, a PSCell) based on the configuration received from the PCell 504 that serves the UE 502. As shown in Figure 5As shown, the PCell 504 may configure the UE 502 at 501 to perform layer 3 (L3) measurements on another cell, such as the PSCell 506. A PSCell is a cell belonging to a secondary cell group (SCG). An SCG may have one PSCell and one or more secondary secondary cells (SSCells). Although aspects are shown for the PSCell, the aspects may be applied to any SCell. The UE 502 may measure the synchronization signal from the PSCell 506 using the configuration 501 received from the PCell 504. The UE may perform the measurement in the corresponding SS / PBCH block measurement timing configuration (SMTC) window 503. The SMTC window 503 may be configured by the PCell 504, for example, through the configuration 501. Figure 2B An example SS / PBCH block is shown. After performing L3 measurements on the SSB of the PSCell, the UE 502 may send a beam report 507 regarding the PSCell 506 to the PCell 504. The UE 502 may provide the beam report 507 to the PCell 504 in response to an event trigger 505. In another example, the beam report 507 may be a periodic report, and the UE 502 may provide the beam report 507 to the PCell 504 in a periodic manner.

[0069] PCell 504 may initiate a PSCell addition procedure 509 for UE 502 using, for example, an L3 beam report 507 on PSCell 506 received from UE 502. PCell 504 may send a PSCell RACH configuration 511 to UE 502. UE 502 may indicate to PCell 504 at 515 that the RRC reconfiguration is complete, and PCell 504 may indicate to PSCell 506 at 517 that the PSCell reconfiguration is complete. UE 502 may identify, for example, based on RS 513, the best downlink RS beam for PSCell 506 and may perform a random access procedure 519 with PSCell 506 using the identified beam. For example, UE 502 may send a first random access message (e.g., Msg 1 403) to PSCell 506 during a corresponding RACH occasion. After sending Msg 1, PSCell 506 and UE 502 may exchange Msg 2 (e.g., 405), Msg 3 (e.g., 407), and Msg 4 (e.g., 409) of the random access procedure 519. The random access messages (e.g., Msg 2, Msg 3, and Msg 4) of the random access procedure 519 may be exchanged between UE 502 and PSCell 506 using the same beam as Msg 1. Msg1, Msg 2, Msg 3, and Msg 4 may include aspects described in connection with the random access messages described in connection with Figure 4 After completing the random access procedure 519, UE 502 and PSCell 506 may transition to CSI-RS based on improved beam operation 521. UE 502 may measure CSI-RS on different beams from PSCell 506 and may provide a measurement report to PSCell 506 for beam selection.

[0070] Figure 6 FIG. shows an example of a RAR window 600 for multiple Msg 1 transmissions during a portion 602 (such as a time window for receiving a RAR or Msg 2) of, for example, the RAR window 600. A UE having beam correspondences may obtain multi-beam diversity during random access transmission by sending multiple Msg 1 transmissions, each Msg 1 transmission using a different beam. The beams (e.g., 604a, 604b, and 604c) may correspond to different SSBs or different CSI-RSs. Figure 6Shows the correspondence between UE beams 608a, 608b, and 608c and the base station beams for reference signals. For example, beam 608a may correspond to the reference signal of beam 604a, beam 608b may correspond to the reference signal of beam 604b, and 608c may correspond to the reference signal of beam 604c. The UE may transmit Msg 1 multiple times using different beams. Using the beam correspondence, the uplink transmission beam may be the same as the UE's downlink reception beam. The UE may perform uplink beam scanning and may select an uplink transmission beam for Msg 1 beam scanning. In some examples, a UE with beam correspondence may have sufficient flexibility to transmit multiple Msg 1 random access transmissions corresponding to different SSB / CSI-RS using any uplink transmission beam (e.g., beams 608a, 608b, 608c). The RAR window 600 may be interleaved for different transmission beams. As shown, the UE may use portions of the RAR window to monitor Msg 2 from the base station using different reception beams (e.g., beams 608a, 608b, 608c). The UE and the base station may be synchronized so that the base station determines that the UE will use a specific beam within different portions 602 of the RAR window to monitor Msg 2. For example, during a specific portion 602a of the RAR window 600, the base station may determine that the UE will use the reception beam 608a corresponding to the reference signal for transmitting beam 604a. The base station may transmit Msg2 using beam 604a during portion 602a. The base station may transmit Msg 2 multiple times, e.g., transmit the RAR using different beams during different portions 602 of the RAR window 600.

[0071] Aspects presented herein may provide coverage and / or latency during the time period 523 in the example in Figure 5 Aspects presented herein may help improve the reliability of transmission by providing multiple transmission opportunities in the time and / or frequency domain for uplink transmission or channels such as random access transmission or random access channel (RACH). The additional transmission opportunities may improve the reliability of communication in unlicensed spectrum, for example, by increasing the likelihood of a successful random access procedure between the UE and the base station (e.g., a secondary cell such as a PSCell). The improved reliability may help support services such as URLLC services, IoT such as industrial IoT (IIoT) services, and NR-based communication in unlicensed spectrum (such as FR1) in a controlled environment.

[0072] The present disclosure provides improved random access reliability and robustness by using beam scanning during random access between a UE and a base station. Aspects can be applied to random access with a PCell, SCell, PSCell, etc. For example, aspects can be applied to random access with a secondary cell, e.g., applied to a new radio dual connection (NR-DC) such as that described in conjunction with Figure 5 wherein the UE is connected to a PCell and an SCell.

[0073] The UE can exchange Msg 1 and / or Msg 2 with a cell during random access using beam scanning, e.g., as described in conjunction with Figure 6 . The UE can exchange random access messages with a single transmit-receive point (TRP) or with multiple TRPs of a serving cell. In some aspects, the random access procedure can include simultaneous transmission / reception. In other aspects, the random access procedure may not include simultaneous transmission / reception. For example, transmission and reception can be TDM-based and not simultaneous. As presented herein, a candidate beam pool can be provided for random access. A beam pool index can be used to avoid potential beam pairing misalignment, which may occur for a single TRP or multiple TRPs. When random access involves multiple TRPs, different pool indices can help the UE select random access beams from different TRPs with large departure angles, which can help improve uplink interference diversity. Similarly, for multiple TRPs, using a beam pool index can help balance the load of the TRPs. For example, a TRP with less urgent traffic can be selected for the exchange of random access Msg 1 and / or Msg 2. Similarly, joint random access across beam scanning can improve reliability and reduce latency by enabling the random access to be successfully completed even if some of the messages in the messages are not accurately received. Beam scanning during random access can help avoid blockages during the initial access procedure to a cell. The added transmission of beam scanning can help avoid failures due to bursts of uplink or downlink inter-cell interference. For example, using beam scanning for Msg 1 / Msg 2 random access can reduce random access latency and provide a faster PSCell establishment procedure with reduced failures or retransmissions.

[0074] Figure 7A An example of random access 700 of a PSCell 706 using a single TRP is shown. The random access procedure can correspond to the random access procedure in Figure 5 and can include the exchange of messages as described in conjunction with Figure 4 . Figure 7AIllustrated is that the base station uses beam scanning to transmit a reference signal such as CSI-RS by transmitting CSI-RS using different transmit beams in each CSI-RS resource in a set of CSI-RS resources. Figure 7A Illustrated is that the PSCell 706 transmits CSI-RS using the CSI-RS resources 1-4 on each of four different beams. The PSCell 706 can continue to transmit CSI-RS using different beams in different CSI-RS resources, for example until the PSCell 706 transmits CSI-RS using the CSI-RS resources 63-66. The UE 702 can transmit multiple preambles in Msg 1 (e.g., the first random access message corresponding to 403) in n allocated random access opportunities using n selected reference signals from the PSCell706. The allocated random access opportunities can correspond to n reference signals of the cell, and the n reference signals can be TDM or FDM. Figure 7A Illustrated is an example of TDM random access resources, where the Msg 1 transmissions 711 and 713 are sent by the UE 702 at different times. Figure 7B Illustrated is the FDM example 750, where the Msg 1 transmissions 711 and 713 overlap in time and are sent using different frequencies. Although Figure 7A the example in Figure 7A illustrates the reference signal as CSI-RS, but the SSB transmitted by the base station using different beams can be similarly applied in terms of aspects. Although Figure 5 illustrated is that the reference signal is sent from a single TRP and the Msg 1 transmission is sent to a single TRP, but the aspects can also be applied to multiple TRPs. Although the aspects are described in conjunction with the PSCell 706, the UE can similarly perform random access using beam scanning with the PCell 704 or SCell. The PCell 704 can provide a random access configuration to the UE 702 as described in conjunction with Figure 7A As illustrated in

[0075] Figure 8 Illustrated is an example of random access 800 of a PSCell using multiple TRPs 806 and 808. The random access procedure 800 can be the same as Figure 5corresponds to the random access procedure 519 in, and may include the exchange of messages described in conjunction with Figure 4 The random access procedure 800 may include aspects similar to the random access procedure 700 in Figure 7A and 7B However, in Figure 8 the CSI-RS is sent from different TRPs. The UE 802 may send Msg 1 811 to the TRP 806, and may send Msg 1 813 to the TRP 808. The receiving beam of the PSCell may be from a different random access resource candidate beam pool of the serving cell, and the different random access resource candidate beam pools may correspond to FDM or TDM random access resources. Figure 8 shows that the TRP 808 is associated with the random access candidate beam pool j, and uses the receiving beam selected from the beam pool j for random access. The TRP 806 is associated with the random access candidate beam pool i, and uses the receiving beam selected from the beam pool i for random access. Although described for two TRPs, different beam pools for different random access resources may be associated with a single TRP, for example. An index may be provided to the UE for each reference signal. Thus, using the random access resources corresponding to a specific reference signal, the UE can know the corresponding random access candidate beam pool. A single TRP may have 64 beams, and these 64 beams may be divided into different beam pools for random access. For example, the first 8 beams may be associated with the beam pool index 1, the next 8 beams may be associated with the beam pool index 2, and so on, where the last 8 beams are associated with the beam pool index 8. The UE may select a beam from within the beam pool index for a specific transmission of Msg 1.

[0076] For both a single TRP and multiple TRPs, using the beam pool index can help avoid beam pairing misalignment. Figure 9 shows an example random access procedure 900 that may include aspects described in conjunction with any of the examples in Figure 7A , 7B and 8 and in which beam pairing misalignment occurs and that uses beam scanning. In Figure 9In [description], the Msg 1 transmission 911 from UE 902 is not received by PSCell 906, and the Msg 1 transmission 913 is received by PSCell. Since the Msg 1 transmission 911 is not received, PSCell 906 can send Msg 2 PDCCH 915 for the beam pair corresponding to Msg 1 913 during the random access resource 920 when UE 902 is using the receiving beam corresponding to Msg 1 911. As illustrated by the dashed line, when PSCell 906 does not send Msg 2, UE 902 can monitor Msg 2 using the receiving beam based on Msg 1 913 during the random access resource 922. Therefore, the failure of Msg 1 911 can result in misalignment of the beams used by PSCell 906 to send and UE 902 to receive Msg 2 PDCCH 915.

[0077] Figure 10 illustrates aspects that may include any example described in the examples in conjunction with Figure 7A - 9 and include using a random access resource candidate beam pool to avoid beam misalignment described in conjunction with Figure 9 an example random access procedure 1000 between UE 1002 and a cell having multiple TRPs (e.g., TRP 906 and TRP 910). In Figure 10 [description], the Msg 1 transmission 1011 from UE1002 is not received by TRP 1006, and the Msg 1 transmission 1013 is received by TRP 1008. Since the Msg 1 transmission 1011 is not received, Msg 2 PDCCH cannot be sent in response to Msg 1 1011. However, the random access resource 1020 can be reserved for pool i for Msg 11011. Therefore, the cell can skip sending Msg 2 PDCCH 1017. Since the random access resource 1020 is reserved for or associated with beam pool i, the cell does not use the random access resource 1020 to send a different Msg 2 as occurs in Figure 9 [description]. Instead, the cell sends Msg 2 915 during the random access resource 1022 when the UE is using a beam selected based on the corresponding beam pool j to monitor Msg 2. Therefore, the beam pair used by UE1002 to receive Msg 2 PDCCH 1015 and the cell to send Msg 2 PDCCH 1015 is aligned so that UE 1002 can receive Msg 2 PDCCH.

[0078] The cell can use, such as in Figure 9 - 11The beam scans from one or more TRPs shown in the figure send multiple Msg 2 PDCCHs (e.g., 915, 1015, 1017, 1115, 1117) in the TDM mode, FDM mode, or SDM mode. As an example, in the SDM mode, the UE can use two beams from two different antenna panels to send two first random access messages (Msg1) to two TRPs of at least one cell using different spatial resources at the same frequency and time resources. The network can notify the UE that the cell will use Msg 2 PDCCH beam scanning so that the UE can know the potential PDCCH combinations when receiving the Msg 2 transmission from the cell. In the first option, the base station can send Msg2 PDCCH using the beam based on the n best reference signals selected during the RACH measurement (e.g., the n best beams used to receive Msg 1 from the UE). Many times, if the Msg 1 transmission is lost and not received by the cell, this option may involve beam misalignment as described in conjunction with Figure 9 The beam misalignment can be solved by pre-configuring the beam for the random access resource. In the second option, the cell can send Msg2 PDCCH using a single, best reference signal from each random access resource candidate beam pool. The random access resource candidate beam pool can be indicated by RRC signaling and can be configured using the reference signal index according to the beam pool index. Since the best beam from a specific set of beams in the beam pool is used for the specific Msg 2 resource, the UE can select the receiving beam based on the corresponding random access resource candidate beam pool and is more likely to experience beam pair alignment with the base station.

[0079] Figure 11 shows an example random access procedure 1100 that can include aspects described in any of the examples in conjunction with Figure 7A - 10 and includes joint random access message transmission that can improve the reliability and robustness of random access communication. In Figure 11 , the cell can send multiple transmissions of Msg 2 PDSCH using beam scanning. The cell can use a single TRP, for example, as in Figure 7A and 9 , or can use multiple TRPs as illustrated in Figure 11 . Although Figure 9A TDM example is shown, but either TDM or FDM can be used for beam scanning of Msg 2 PDSCH. Msg 2 PDSCH can be sent using the beam corresponding to the Msg 2 PDCCH that schedules the PDSCH (e.g., using the same beam as the corresponding Msg 2 PDCCH). In another example, Msg 2 PDSCH can be sent using a beam different from the Msg 2 PDSCH that schedules Msg 2 PDSCH. In some examples, one Msg 2 PDCCH can carry resource allocation information for multiple Msg 2 PDSCHs. Thus, if one of the Msg 2 PDCCHs in Msg 2 PDCCH is not received, the UE may still be able to receive Msg 2 PDSCH because UE 1102 may be able to determine the corresponding resources based on different Msg 2 PDCCHs.

[0080] In Figure 11 Msg 1 transmission 1111 is not received by the cell (e.g., by TRP 1106). Msg 1 transmission 1113 is received by TRP 1108. As described in conjunction with Figure 9 and 10 TRP 1106 does not send Msg2 PDCCH 1117 corresponding to Msg 1 1111. TRP 1108 that does receive Msg 1 1113 does send Msg2 PDCCH 1115 that schedules Msg 2 PDSCH 1125. However, Msg 2 PDCCH 1115 can include resource allocation information about Msg 2 PDSCH 1123. Thus, even if the corresponding Msg 2 PDCCH 1117 is not sent (or is sent by the cell but not received by UE 1102), UE1102 can receive Msg 2 PDSCH 1123. In some aspects, each Msg 2 PDCCH (e.g., 1115 and 1117, if sent) can carry resource allocation information for multiple Msg 2 PDSCHs (e.g., 1123 and 1125). Thus, even if one beam pair transmission of Msg 2 PDCCH is successful, communication can continue on multiple beam pairs.

[0081] Similarly, each Msg 2 PDSCH (e.g., 1123 and 1125) can carry uplink grant information for multiple Msg 3 transmissions from UE 1102. Thus, even if one or more Msg 2 transmissions are lost and not received by the UE, the UE can send multiple Msg 2 transmissions using different beams.

[0082] Figure 12FIG. 1200 is a flowchart of a wireless communication method. The method may be performed by a UE or a component of the UE (e.g., UE 104, 350, 402, 502, 702, 802, 902, 1002, 1102; apparatus 1402; a processing system that may include a memory 360 and may be the entire UE 350 or a component of UE 350, such as, TX processor 368, RX processor 356, and / or controller / processor 359). Optional aspects are shown using dashed lines. The method may improve random access between a UE and a base station by providing multiple transmission opportunities and applying beam sweeping to random access transmissions. The aspects may help avoid failures due to interference, blocking, etc. Aspects of the method may help improve the reliability of random access and reduce the waiting time of random access.

[0083] At 1204, the UE may receive a configuration for random access to at least one cell. The configuration may be received, for example, in RRC signaling from a base station. The configuration may be, for example, for random access to a cell having multiple TRPs. The reception of the configuration may be performed, for example, by Figure 14 configuration component 1406 and / or cellular RF transceiver 1422 of apparatus 1402 in Figure 5 The UE may receive a configuration for random access from a PCell. The cell may be the PCell of the UE. In another example, such as described in conjunction with

[0084] At 1210, the UE transmits at least two first random access messages (Msg 1) to multiple TRPs of at least one cell using different resources for the multiple TRPs. For example, Figure 8 、 9 、10 and 11 illustrate aspects in which the UE transmits Msg 1 to multiple TRPs using different resources. Different resources may include different spatial resources, such as described in conjunction with any of the figures in Figure 6 - 11 As an example, the UE may use two beams (e.g., from two different UE antenna panels) to transmit two first random access messages (Msg 1) to two TRPs of at least one cell using different spatial resources at the same frequency and time resources. Different resources may include different frequency resources, as illustrated in Figure 7B As an example, the UE may use two beams (e.g., from two different UE antenna panels) to transmit two first random access messages (Msg 1) to two TRPs of at least one cell using different spatial resources, different frequency resources, and the same time resources. Such as described in conjunction with Figure 6 - 11As depicted in any of the accompanying figures, different resources may include different time resources. As an example, a UE may use two beams (e.g., from two different UE antenna panels) to transmit two first random access messages (Msg 1) to two TRPs of at least one cell using different spatial resources at the same frequency resource and different time resources. As another example, a UE may use two beams (e.g., from two different UE antenna panels) to transmit two first random access messages (Msg 1) to two TRPs of at least one cell using different spatial resources at different frequency and time resources. The transmission may be performed, for example, by Figure 14 the Msg 1 component 1440 and / or the cellular RF transceiver 1422 of the apparatus 1402 in

[0085] The first random access message may include a preamble (e.g., such as the first random access message 403 described in conjunction with Figure 4 . The UE may transmit the first random access message using multiple transmit beams corresponding to reference signals for multiple receive beams from the cell during a corresponding number of allocated random access opportunities, where each random access opportunity is associated with a reference signal for receiving the preamble. The reference signal may include the SSB and / or CSI-RS from the cell. As described in conjunction with Figure 8 、 10 and 11, the reference signal may be received from multiple TRPs of the cell. As illustrated in the example in Figure 7A , the first random access message may be time-division multiplexed over multiple transmit beams. As illustrated in the example in Figure 7B , the first random access message may be frequency-division multiplexed over multiple transmit beams.

[0086] As described in conjunction with Figure 8 、 10 and 11, the UE may transmit a first preamble to be received by a first receive beam selected from a first random access resource candidate beam pool at the cell, and may transmit a second preamble to be received by a second receive beam selected from a second random access resource candidate beam pool at the cell. For example, as described in conjunction with Figure 8 、 10 and 11, the first receive beam may be for the first TRP of the cell, and the second receive beam may be for the second TRP of the cell.

[0087] At 1212, the UE monitors at least two second random access messages (Msg 2) from multiple TRPs of at least one cell based on resources different for multiple TRPs. The monitoring may be performed, for example, by Figure 14is performed by the Msg 2 component 1442 and / or the cellular RF transceiver 1422 of the apparatus 1402 in

[0088] As shown at 1206, the UE may receive an indication of a beam sweep for a second random access message destined for the UE from a base station. The receiving indication may be performed, for example, by Figure 14 the beam sweep component 1448 and / or the cellular RF transceiver 1422 of the apparatus 1402 in Figure 9 , 10 and 11 illustrate examples of Msg 2 PDCCHs transmitted using different beams and received using different beams. As shown, for example, in Figure 9 different beams (e.g., multiple beams) may be transmitted from a single TRP. As illustrated, for example, in Figure 10 and 11 different beams (e.g., multiple beams) may be transmitted from multiple TRPs.

[0089] The UE may receive a control channel (e.g., Msg 2 PDCCH) of a second random access message transmitted using a single beam in accordance with a random access beam pool. The UE may receive an indication of each random access beam pool in RRC signaling, and the UE may receive a configuration of reference signal indices in accordance with the random access beam pool. Multiple random access beam pools may be for a single TRP. Multiple random access beam pools may be for multiple TRPs.

[0090] As shown at 1202, the UE may receive an indication of a random access beam pool index from a base station in accordance with a reference signal from the cell. The UE may use the indication to resolve a potential pairing misalignment for the reception of the second random access message when the first random access message is not correctly received by the base station. The receiving may be performed, for example, by Figure 14 the beam pool component 1444 and / or the cellular RF transceiver 1422 of the apparatus 1402 in

[0091] As shown at 1216, the UE may monitor multiple PDSCHs in a second random access message from the cell. The monitoring may be performed, for example, by Figure 14 the Msg 2 component 1442 of the apparatus 1402 in Figure 11Shows an example where two Msg 2 PDSCHs are transmitted at the PSCell using different beams and received at the UE 1102 using different beams. In some examples, each PDSCH may use the same beam as the control channel (e.g., PDCCH) that schedules the respective PDSCH. Alternatively, the PDSCH may use a different beam from the corresponding control channel (e.g., PDCCH) that schedules the PDSCH. The different beams for the Msg 2 PDSCH may be configured by DCI in the corresponding control channel (e.g., Msg 2 PDCCH).

[0092] As shown at 1214, the UE may determine the resource allocation for a first PDSCH among multiple PDSCHs based on the control channel for the second PDSCH. The determination of the resource allocation may be performed, for example, by Figure 14 the resource allocation component 1450 of the apparatus 1402 in. Thus, as described in connection with Figure 11 the Msg 2 PDCCH may carry information for more than one Msg2 PDSCH. For example, each random access Msg 2 PDCCH may carry resource allocation information for multiple PDSCHs of the random access Msg 2. Thus, even if the Msg 2 PDCCH is lost on a particular beam, the UE may still obtain the resource allocation for the Msg 2 PDSCH from another PDCCH on a different beam. Similarly, each Msg2 PDSCH in the Msg 2 PDSCH may carry uplink grant information for multiple random access Msg 3 transmissions. Thus, even if the PDSCH is lost on a particular beam, the UE may still obtain the uplink grant information for Msg 3.

[0093] Figure 13 Is a flowchart 1300 of a wireless communication method. The method may be performed by a base station or a component of a base station (e.g., base stations 102, 180, 310, 404; cells 504, 506, 704, 706, 906; TRPs 806, 808, 1006, 1008, 1106, 1108; apparatus 1502; a processing system that may include a memory 376 and may be the entire base station 310 or a component of the base station 310, such as a TX processor 316, an RX processor 370, and / or a controller / processor 375). In some examples, the method may be performed by the PCell, SCell, or PSCell of the UE. Optional aspects are shown with dashed lines. The method may improve random access between the base station and the UE by providing multiple transmission opportunities and applying beam scanning to random access transmissions. The aspects may help avoid failures due to interference, blockage, etc. The aspects of the method may help improve the reliability of random access and reduce the waiting time of random access.

[0094] At 1302, the base station may send a configuration for random access with the UE. The sending may be performed, for example, by the configuration component 1546 and / or the cellular RF transceiver 1522 of the apparatus 1502 in Figure 15 . For example, if the base station is the PCell of the UE, the base station may send the configuration to the UE. If the base station is an SCell or a PSCell, the base station may be, for example, received from the PCell of the UE and determined based on the configuration received from the PCell.

[0095] At 1310, the base station receives at least two first random access messages (Msg 1) using different resources at multiple TRPs of at least one cell for the multiple TRPs. For example, Figure 8 、 9 、10 and 11 illustrate aspects of Msg 1 sent to multiple TRPs using different resources. For example, as described in connection with any of the figures in Figure 6 - 11 , the different resources may include different spatial resources. As an example, the base station may receive two beams (e.g., from two different UE antenna panels) including two first random access messages (Msg 1) using different spatial resources at the same frequency and time resources at two TRPs of at least one cell. For example, as shown in Figure 7B , the different resources may include different frequency resources. As an example, the base station may receive two beams (e.g., from two different UE antenna panels) including two first random access messages (Msg 1) using different spatial resources and the same time resources with different frequency resources at two TRPs of at least one cell. For example, as described in connection with any of the figures in Figure 6 - 11 , the different resources may include different time resources. As an example, the base station may receive two beams (e.g., from two different UE antenna panels) including the first random access message (Msg 1) using different spatial resources at the same frequency resources and different time resources at two TRPs of at least one cell. As another example, the base station may receive two beams (e.g., from two different UE antenna panels) including two first random access messages (Msg 1) using different spatial resources at different frequency and time resources at two TRPs of at least one cell. The receiving may be performed, for example, by the Msg 1 component 1540 and / or the cellular RF transceiver 1522 of the apparatus 1502 in Figure 15 .

[0096] The first random access message may include a preamble. The base station may receive the first random access message from the UE during a corresponding number of allocated random access opportunities using a plurality of receive beams for reference signals corresponding to a plurality of transmit beams from the UE, where each random access opportunity is associated with one reference signal.

[0097] The reference signal may include SSB and / or CSI-RS from the cell. As described in conjunction with Figure 7A and 9 , the reference signal may be received from a single TRP of the cell. As described in conjunction with Figure 8 , 10 and 11, the reference signal may be received from multiple TRPs of the cell. As shown in the example in Figure 7A , the first random access message may be time-division multiplexed on multiple transmit beams. As shown in the example in Figure 7B , the first random access message may be frequency-division multiplexed on multiple transmit beams.

[0098] As described in conjunction with Figure 8 , 10 and 11, the base station may receive the first preamble using a first beam from a first random access beam pool and receive the second preamble using a second beam from a second random access beam pool. The first preamble may be received using a first receive beam selected from a first random access resource candidate beam pool at the cell, and the second preamble may be received using a second receive beam selected from a second random access resource candidate beam pool at the cell. For example, as described in conjunction with Figure 8 , 10 and 11, the first receive beam may be for the first TRP of the cell, and the second receive beam may be for the second TRP of the cell. As described in conjunction with Figure 7A and 9 , the first receive beam and the second receive beam may be for a single TRP of the cell.

[0099] As described at 1304, the base station may send an indication of the random access beam pool index to the UE according to the reference signal from the cell, for example for the UE to use to resolve potential pairing misalignment for the reception of the second random access message when the first random access message is not correctly received by the base station.

[0100] At 1312, the base station sends at least two second random access messages (Msg 2) to the UE from multiple TRPs of at least one cell based on resources different for multiple TRPs. The transmission may be, for example, by Figure 15is performed by the Msg 2 component 1542 and / or the cellular RF transceiver 1522 of the apparatus 1502 in

[0101] The random access message may include a second random access message transmitted by the cell using multiple beams. Thus, as shown at 1312, the base station may transmit the second random access message to the UE using multiple beams, for example, based on beam scanning. As shown at 1306, the base station may transmit an indication of the beam scanning for the second random access message destined for the UE. The transmission may be performed, for example, by Figure 15 the beam scanning component 1548 and / or the cellular RF transceiver 1522 of the apparatus 1502 in

[0102] As part of transmitting the second random access message at 1312, the base station may transmit a control channel (e.g., Msg 2 PDCCH) of the second random access message using multiple beams based on multiple reference signals. For example, Figure 9 、 10 and 11 illustrate examples of Msg 2 PDCCHs that are transmitted using different beams and received using different beams. Such as in Figure 10 and 11 shown, different beams (e.g., multiple beams) may be transmitted from multiple TRPs. The base station may transmit a control channel (e.g., Msg 2 PDCCH) of the second random access message using a single beam in accordance with a random access beam pool. The base station may transmit an indication of each random access beam pool in RRC signaling and may configure a reference signal index for the UE in accordance with the random access beam pool. Multiple random access beam pools may be for a single TRP. Multiple random access beam pools may be for multiple TRPs. The transmission may be performed, for example, by Figure 15 the beam pool component 1544 and / or the cellular RF transceiver 1522 of the apparatus 1502 in

[0103] As shown at 1314, the base station may transmit multiple PDSCHs for the second random access message, each PDSCH of the multiple PDSCHs using a different beam. The transmission may be performed, for example, by Figure 15 the Msg 2 component 1542 and / or the cellular RF transceiver 1522 of the apparatus 1502 in Figure 11An example is shown in which two Msg 2 PDSCHs are transmitted at the PSCell using different beams and received at the UE 1102 using different beams. In some examples, each PDSCH may use the same beam as the control channel (e.g., PDCCH) that schedules the respective PDSCH. Alternatively, the PDSCH may use a different beam than the corresponding control channel (e.g., PDCCH) that schedules the PDSCH. The different beams for the Msg 2 PDSCH may be configured by DCI in the corresponding control channel (e.g., Msg 2 PDCCH).

[0104] Each control channel of the second random access message may carry resource allocation information for multiple PDSCHs. For example, as described in conjunction with Figure 11 the Msg 2 PDCCH may carry information for more than one Msg 2 PDSCH. For example, each random access Msg 2 PDCCH may carry resource allocation information for multiple PDSCHs of the random access Msg 2. Thus, even if the Msg 2 PDCCH is lost on a particular beam, the base station can still enable the UE to obtain the resource allocation for the Msg 2 PDSCH from another PDCCH on a different beam. Similarly, each Msg 2 PDSCH in the Msg 2 PDSCHs may carry uplink grant information for multiple random access Msg 3 transmissions. Thus, even if the PDSCH is lost on a particular beam, the base station can still enable the UE to obtain the uplink grant information for Msg 3.

[0105] Figure 13 The method in can be performed by an apparatus including components that include each block in the flowchart of the algorithm configured to perform the foregoing Figure 13 and / or aspects described in conjunction with Figure 4 - 11 the base station or cell in. Similarly, each block in the flowchart of the foregoing Figure 13 and / or aspects described in conjunction with Figure 4 - 11 can be performed by components, and the apparatus may include one or more of those components. The components may be one or more hardware components specifically configured to implement the indicated process / algorithm, implemented by a processor configured to perform the indicated process / algorithm, stored in a computer-readable medium for implementation by a processor, or some combination thereof.

[0106] Figure 14FIG. 1400 is an example showing a hardware implementation of apparatus 1402. Apparatus 1402 is a UE and includes a cellular baseband processor 1404 (also referred to as a modem) coupled to a cellular RF transceiver 1422 and one or more subscriber identity module (SIM) cards 1420, an application processor coupled to a secure digital (SD) card 1408 and a screen 1410, a Bluetooth module 1412, a wireless local area network (WLAN) module 1414, a global positioning system (GPS) module 1416, and a power supply 1418. The cellular baseband processor 1404 communicates with the UE 104 and / or the BS 102 / 180 via the cellular RF transceiver 1422. The cellular baseband processor 1404 may include a computer-readable medium / memory. The computer-readable medium / memory may be non-transitory. The cellular baseband processor 1404 is responsible for general processing including executing software stored in the computer-readable medium / memory. The software, when executed by the cellular baseband processor 1404, causes the cellular baseband processor 1404 to perform the various functions described above. The computer-readable medium / memory may also be used to store data manipulated by the cellular baseband processor 1404 when executing the software. The cellular baseband processor 1404 further includes a receiving component 1430, a communication manager 1432, and a transmitting component 1434. The communication manager 1432 includes one or more of the components shown. The components within the communication manager 1432 may be stored in the computer-readable medium / memory and / or configured as hardware within the cellular baseband processor 1404. The cellular baseband processor 1404 may be a component of the UE 350 and may include at least one of a memory 360 and / or a TX processor 368, an RX processor 356, and a controller / processor 359. In one configuration, apparatus 1402 may be a modem chip and include only the baseband processor 1404, and in another configuration, apparatus 1402 may be an entire UE (e.g., see Figure 3 350), and include additional modules of apparatus 1402.

[0107] The communication manager 1432 includes a Msg 1 component 1440, and the Msg 1 component 1440 is configured to, for example, as described in connection with Figure 12 1210 in, send at least two first random access messages (Msg 1) to multiple TRPs of at least one cell using different resources for multiple TRPs. The communication manager 1432 further includes a Msg 2 component 1442, and the Msg 2 component 1442 is configured to, for example, as described in connection with 1212 and / or 1216, monitor at least two second random access messages (Msg 2) from multiple TRPs of at least one cell based on different resources for multiple TRPs. The communication manager 1432 further includes a beam pool component 1444, and the beam pool component 1444 is configured to, for example, as described in connection withFigure 12 As described in 1202, receive an indication of a random access beam pool index from a base station according to a reference signal from a cell. The communication manager 1432 further includes a configuration component 1446 configured to receive, for example, as described in connection with 1204, a configuration for random access to at least one cell. The communication manager 1432 further includes a beam scanning component 1448 configured to receive, for example, as described in connection with Figure 12 1206, an indication of beam scanning for a second random access message to the UE from the base station. The communication manager 1432 further includes a resource allocation component 1450 configured to determine, for example, as described in connection with Figure 12 1214, a resource allocation for a first PDSCH among a plurality of PDSCHs according to a control channel for a second PDSCH.

[0108] The apparatus may include each block in the algorithm in the flowchart of performing Figure 12 and / or additional components of the aspects described in connection with the UE in Figure 4 - 11 . Similarly, each block in the aforementioned Figure 12 flowchart and / or the aspects described in connection with the UE in Figure 4 - 11 may be performed by components, and the apparatus may include one or more of those components. The components may be one or more hardware components specifically configured to implement the indicated process / algorithm, implemented by a processor configured to execute the indicated process / algorithm, stored in a computer-readable medium for implementation by a processor, or some combination thereof.

[0109] In one configuration, apparatus 1402, and specifically the cellular baseband processor 1404, includes: a unit for transmitting at least two first random access messages (Msg 1) to multiple transmission and reception points (TRPs) of at least one cell using different resources for the multiple TRPs; and a unit for monitoring at least two second random access messages (Msg 2) from the multiple TRPs of at least one cell based on different resources for the multiple TRPs. Apparatus 1402 may further include: a unit for receiving a configuration for random access with at least one cell having multiple TRPs. Apparatus 1402 may further include: a unit for receiving an indication of a random access beam pool index from a base station in accordance with a reference signal from the cell. Apparatus 1402 may further include: a unit for receiving an indication of beam scanning for a second random access message to the UE from the base station. Apparatus 1402 may further include: a unit for determining resource allocation for a first physical downlink shared channel (PDSCH) among multiple PDSCHs according to a control channel of a second PDSCH. The foregoing units may be one or more of the foregoing components of apparatus 1402 configured to perform the functions detailed by the foregoing units. As described previously, apparatus 1402 may include a TX processor 368, an RX processor 356, and a controller / processor 359. Similarly, in one configuration, the foregoing units may be the TX processor 368, the RX processor 356, and the controller / processor 359 configured to perform the functions detailed by the foregoing units.

[0110] Figure 15 FIG. 1500 is a diagram illustrating an example of a hardware implementation of apparatus 1502. Apparatus 1502 is a base station (BS) and includes a baseband unit 1504. The baseband unit 1504 may communicate with a UE 104 via a cellular RF transceiver 1522. The baseband unit 1504 may include a computer-readable medium / memory. The baseband unit 1504 is responsible for general processing including executing software stored in the computer-readable medium / memory. The software, when executed by the baseband unit 1504, causes the baseband unit 1504 to perform the various functions described previously. The computer-readable medium / memory may also be used to store data manipulated by the baseband unit 1504 when executing the software. The baseband unit 1504 further includes a receiving component 1530, a communication manager 1532, and a transmitting component 1534. The communication manager 1532 includes one or more of the illustrated components. The components within the communication manager 1532 may be stored in the computer-readable medium / memory and / or configured as hardware within the baseband unit 1504. The baseband unit 1504 may be a component of a base station 310 and may include a memory 376 and / or at least one of a TX processor 316, an RX processor 370, and a controller / processor 375.

[0111] The communication manager 1532 includes a Msg 1 component 1540 that is configured to receive at least two first random access messages (Msg 1) using different resources at multiple TRPs of at least one cell for the multiple TRPs, for example, as described in 1310 in conjunction with Figure 13 . The communication manager 1532 further includes a Msg 2 component 1542 that is configured to send at least two second random access messages (Msg 2) from multiple TRPs of at least one cell based on different resources for the multiple TRPs, for example, as described in conjunction with 1312 and / or 1314. The communication manager 1532 further includes a beam pool component 1544 that is configured to send an indication of a random access beam pool index in accordance with a reference signal from the cell, for example, as described in 1304 in conjunction with Figure 13 . The communication manager 1532 further includes a configuration component 1546 that is configured to receive a configuration for random access with at least one cell, for example, as described in 1302. The communication manager 1532 further includes a beam scan component 1548 that is configured to send an indication of a beam scan for a second random access message to the UE, for example, as described in 1306 in conjunction with Figure 13 .

[0112] The apparatus 1402 may include additional components that perform each block in the algorithms in the flowcharts described above Figure 13 and / or aspects described in conjunction with the base station or cell in Figure 4 - 11 . Similarly, each block in the flowcharts described above Figure 13 and / or aspects described in conjunction with the base station or cell in Figure 4 - 11 may be performed by components, and the apparatus may include one or more of those components. The components may be one or more hardware components specifically configured to implement the indicated processes / algorithms, implemented by a processor configured to perform the indicated processes / algorithms, stored in a computer-readable medium for implementation by a processor, or some combination thereof.

[0113] In one configuration, apparatus 1502, and specifically baseband unit 1504, includes: a unit for receiving at least two first random access messages (Msg 1) from a UE at a plurality of TRPs of at least one cell based on different resources for the plurality of TRPs. Apparatus 1502 may further include: a unit for transmitting at least two second random access messages (Msg 2) to the UE from a plurality of TRPs of at least one cell based on different resources for the plurality of TRPs. Apparatus 1502 may further include: a unit for transmitting an indication of a random access beam pool index to the UE in accordance with a reference signal from the cell. Apparatus 1502 may further include: a unit for transmitting an indication of a beam sweep for a second random access message to the UE. Apparatus 1502 may further include: a unit for transmitting a plurality of PDSCHs for a second random access message, each PDSCH of the plurality of PDSCHs using different resources. The foregoing units may be one or more of the foregoing components of apparatus 1502 configured to perform the functions detailed by the foregoing units. As described previously, apparatus 1502 may include TX processor 316, RX processor 370, and controller / processor 375. Similarly, in one configuration, the foregoing units may be TX processor 316, RX processor 370, and controller / processor 375 configured to perform the functions detailed by the foregoing units.

[0114] The following aspects are illustrative only and may be combined with other aspects or teachings described herein, without limitation thereto.

[0115] Aspect 1 is a wireless communication method at a UE, including: transmitting at least two first random access messages (Msg 1) to a plurality of TRPs of at least one cell, transmitting using different resources for the plurality of TRPs; and monitoring at least two second random access messages (Msg 2) from the plurality of TRPs of at least one cell based on different resources for the plurality of TRPs.

[0116] In aspect 2, the method of aspect 1 further includes: the different resources include different spatial resources.

[0117] In aspect 3, the method of aspect 1 or aspect 2 further includes: the different resources include different frequency resources.

[0118] In aspect 4, the method of any one of aspects 1-3 further includes: the different resources include different time resources.

[0119] In aspect 5, the method of any one of aspects 1-4 further includes: receiving a configuration for random access with at least one cell having a plurality of TRPs.

[0120] In aspect 6, the method of any one of aspects 1 - 5 further includes: at least one cell includes the PCell of the UE, the SCell of the UE, or the PSCell of the UE.

[0121] In aspect 7, the method of any one of aspects 1 - 6 further includes: each of at least two first random access messages includes a preamble, and wherein the UE transmits at least two first random access messages during a corresponding number of allocated random access opportunities using a plurality of transmit beams associated with reference signals corresponding to a plurality of received beams from at least one cell, wherein each random access opportunity is associated with a reference signal for receiving the preamble.

[0122] In aspect 8, the method of aspect 7 further includes: the reference signal includes at least one of SSB or CSI - RS from at least one cell.

[0123] In aspect 9, the method of aspect 7 or 8 further includes: the reference signal is received from a plurality of TRPs of a single cell.

[0124] In aspect 10, the method of any one of aspects 7 - 9 further includes: at least two first random access messages are time - division multiplexed on a plurality of transmit beams.

[0125] In aspect 11, the method of any one of aspects 7 - 10 further includes: at least two first random access messages are frequency - division multiplexed on a plurality of transmit beams.

[0126] In aspect 12, the method of any one of aspects 7 - 11 further includes: the UE transmits a first preamble for reception by a first receive beam selected from a first random access resource candidate beam pool of a cell, and transmits a second preamble for reception by a second receive beam selected from a second random access resource candidate beam pool of the cell, the first receive beam is for a first TRP of the cell, and the second receive beam is for a second TRP of the cell.

[0127] In aspect 13, the method of any one of aspects 12 further includes: receiving an indication of a random access beam pool index from the base station according to a reference signal from the cell.

[0128] In aspect 14, the method of any one of aspects 1 - 13 further includes: receiving an indication of beam scanning for at least two second random access messages going to the UE from the base station.

[0129] In aspect 15, the method of any one of aspects 1-14 further comprises: the UE receiving a control channel for at least two second random access messages transmitted using multiple beams based on multiple reference signals, wherein the multiple beams are transmitted from multiple TRPs.

[0130] In aspect 16, the method of any one of aspects 1-15 further comprises: the UE receiving a control channel for at least two second random access messages transmitted using a single beam according to a random access beam pool, wherein the UE receives an indication of each random access beam pool in RRC signaling, wherein the UE receives a configuration of reference signal indices according to the random access beam pool, and wherein multiple random access beam pools are for multiple TRPs.

[0131] In aspect 17, the method of any one of aspects 1-16 further comprises: the UE monitoring at least two second random access messages from at least one cell in multiple PDSCHs.

[0132] In aspect 18, the method of aspect 17 further comprises: the UE monitoring each PDSCH based on the same beam as the control channel scheduling the respective PDSCH.

[0133] In aspect 19, the method of aspect 17 further comprises: the UE monitoring the PDSCH in the multiple PDSCHs based on a beam different from the control channel corresponding to the scheduling of the PDSCH, wherein the different beam is configured by DCI in the corresponding control channel.

[0134] In aspect 20, the method of aspect 17 further comprises: determining a resource allocation for a first PDSCH in the multiple PDSCHs according to the control channel of the second PDSCH, wherein each control channel of the at least two second random access messages carries resource allocation information for the multiple PDSCHs of the at least two second random access messages.

[0135] In aspect 21, the method of aspect 17 further comprises: each PDSCH in the multiple PDSCHs carrying uplink authorization information for multiple third random access messages.

[0136] Aspect 22 is a device comprising one or more processors and one or more memories electronically communicating with the one or more processors, the one or more memories storing instructions executable by the one or more processors to cause the device to implement the method in any one of aspects 1-21.

[0137] Aspect 23 is a system or apparatus comprising units for implementing the method or apparatus in any one of aspects 1-21.

[0138] Aspect 24 is a non-transitory computer-readable medium storing instructions executable by one or more processors to cause the one or more processors to implement the method in any one of Aspects 1-21.

[0139] Aspect 25 is a wireless communication method at a base station, including: receiving at least two first random access messages (Msg 1) from a UE at multiple TRPs in at least one cell based on resources different for the multiple TRPs; and sending at least two second random access messages (Msg 2) from the multiple TRPs in at least one cell to the UE based on resources different for the multiple TRPs.

[0140] In Aspect 26, the method of Aspect 25 further includes: the different resources include at least one of different spatial resources, different frequency resources, or different time resources.

[0141] In Aspect 27, the method of Aspect 25 or Aspect 26 further includes: each of the at least two first random access messages includes a preamble, and wherein the base station receives the at least two first random access messages from the UE during a corresponding number of allocated random access opportunities using multiple receive beams for reference signals corresponding to multiple transmit beams from the UE, each random access opportunity being associated with one reference signal.

[0142] In Aspect 28, the method of Aspect 27 further includes: the reference signal includes at least one of an SSB or a CSI-RS from the cell, wherein the reference signal is sent using multiple TRPs.

[0143] In Aspect 29, the method of any one of Aspects 25-28 further includes: the at least two first random access messages are time-division multiplexed or frequency-division multiplexed on multiple transmit beams.

[0144] In Aspect 30, the method of any one of Aspects 25-29 further includes: the base station receives a first preamble using a first beam from a first random access beam pool and receives a second preamble using a second beam from a second random access beam pool, wherein the first preamble is received using a first receive beam selected from a first random access resource candidate beam pool at the cell, and wherein the second preamble is received using a second receive beam selected from a second random access resource candidate beam pool at the cell, the first receive beam being for a first TRP of the cell and the second receive beam being for a second TRP of the cell.

[0145] In Aspect 31, the method of Aspect 30 further includes: sending an indication of a random access beam pool index to the UE in accordance with a reference signal from the cell.

[0146] Aspect 32 is a device that includes one or more processors and one or more memories that are electronically communicable with the one or more processors, the one or more memories storing instructions executable by the one or more processors to cause the device to implement the method in any of aspects 25 - 31.

[0147] Aspect 33 is a system or apparatus that includes units for implementing the method or apparatus in any of aspects 25 - 31.

[0148] Aspect 34 is a non - transitory computer - readable medium that stores instructions executable by one or more processors to cause the one or more processors to implement the method in any of aspects 25 - 31.

[0149] It should be understood that the specific order or layering of the blocks in the disclosed process / flowchart is illustrative of the exemplary method. Based on design preferences, it should be understood that the specific order or layering of the blocks in the process / flowchart can be rearranged. Further, some blocks can be combined or omitted. The accompanying method claims present the elements of the various blocks in an exemplary order and will not be limited to the specific order or layering presented.

[0150] The foregoing description is provided to enable a person of ordinary skill in the art to practice the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects. Thus, the claims are not intended to be limited to the aspects shown herein, but are to be accorded the full scope consistent with the language of the claims, where the reference to an element in the singular is not intended to mean "one and only one" but rather "one or more" unless specifically so stated. The term "exemplary" is used herein to mean "serving as an example, instance, or illustration." Any aspect described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other aspects. Unless specifically stated otherwise, the term "some" means one or more. Combinations such as "at least one of A, B, or C," "one or more of A, B, or C," "at least one of A, B, and C," "one or more of A, B, and C," and "A, B, C, or any combination thereof" include any combination of A, B, and / or C, and may include multiple As, multiple Bs, or multiple Cs. Specifically, combinations such as "at least one of A, B, or C," "one or more of A, B, or C," "at least one of A, B, and C," "one or more of A, B, and C," and "A, B, C, or any combination thereof" can be A only, B only, C only, A and B, A and C, B and C, or A and B and C, where any such combination can include one or more members of A, B, or C. All structural and functional equivalents of the elements of the various aspects described throughout this disclosure that are known or later become known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public, whether or not such disclosure is expressly recited in the claims. The terms "module," "mechanism," "element," "device," etc. are not to be used as substitutes for the term "unit." Thus, no claim element should be construed as a means-plus-function unless the element is expressly recited using the phrase "means for."

Claims

1. A wireless communication method at a user equipment (UE), comprising: Transmitting at least two first random access messages (Msg 1) to different transmission reception points (TRPs) among a plurality of TRPs pointing to at least one cell, wherein the transmission uses different resources for the plurality of TRPs, and the different resources include one or more of different time resources or different frequency resources for the plurality of TRPs; And After transmitting the at least two first random access messages, monitoring at least two second random access messages (Msg 2) from the plurality of TRPs of the at least one cell based on the different time resources or the different frequency resources for the plurality of TRPs.

2. The method according to claim 1, wherein The different resources for the plurality of TRPs further include different spatial resources.

3. The method according to claim 1, wherein The different resources for the plurality of TRPs at least include the different frequency resources.

4. The method according to claim 1, wherein The different resources for the plurality of TRPs at least include the different time resources.

5. The method according to claim 1, further comprising: Receiving a configuration for random access with the at least one cell having the plurality of TRPs.

6. The method according to claim 1, wherein The at least one cell includes a primary cell (PCell) of the UE, a secondary cell (SCell) of the UE, or a primary-secondary cell (PSCell) of the UE.

7. The method according to claim 1, wherein Each first random access message includes a preamble, and wherein the UE transmits the at least two first random access messages during a corresponding number of allocated random access opportunities using a plurality of transmit beams associated with reference signals corresponding to a plurality of receive beams from the at least one cell, wherein each random access opportunity is associated with a reference signal for receiving the preamble.

8. The method according to claim 7, wherein, The reference signal includes at least one of a synchronization signal block (SSB) or a channel state information-reference signal (CSI-RS) from the at least one cell.

9. The method according to claim 7, wherein The reference signal is received from the plurality of TRPs of a single cell.

10. The method according to claim 7, wherein, The at least two first random access messages are time-division multiplexed on the plurality of transmit beams.

11. The method according to claim 7, wherein, The at least two first random access messages are frequency-division multiplexed on the plurality of transmit beams.

12. The method according to claim 7, wherein, The UE transmits a first preamble for reception by a first receive beam selected from a first random access resource candidate beam pool of a cell, and transmits a second preamble for reception by a second receive beam selected from a second random access resource candidate beam pool of the cell, wherein the first receive beam is for a first transmission reception point (TRP) of the cell, and the second receive beam is for a second TRP of the cell.

13. The method according to claim 12, further comprising: Receiving an indication of a random access beam pool index from a base station according to a reference signal from the cell.

14. The method according to claim 1, further comprising: Receiving an indication of beam scanning for the at least two second random access messages going to the UE from a base station.

15. The method according to claim 1, wherein The UE receives a control channel of the at least two second random access messages transmitted using multiple beams based on multiple reference signals, wherein the multiple beams are transmitted from the multiple TRPs.

16. The method according to claim 1, wherein, The UE receives a control channel of the at least two second random access messages transmitted using a single beam according to a random access beam pool, wherein the UE receives an indication of each random access beam pool in radio resource control (RRC) signaling, wherein the UE receives a configuration of a reference signal index according to the random access beam pool, and wherein multiple random access beam pools are for the multiple TRPs.

17. The method according to claim 1, wherein, The UE monitors the at least two second random access messages from the at least one cell in multiple physical downlink shared channels (PDSCHs).

18. The method according to claim 17, wherein, The UE monitors each PDSCH based on the same beam as the control channel scheduling the respective PDSCH.

19. The method according to claim 17, wherein, The UE monitors the PDSCHs from the multiple PDSCHs based on a beam different from the control channel corresponding to scheduling the PDSCH, wherein the different beam is configured by DCI in the corresponding control channel.

20. The method according to claim 17, further comprising: Determine a resource allocation for a first PDSCH among the multiple PDSCHs according to a control channel of a second PDSCH, wherein each control channel of the at least two second random access messages carries resource allocation information for the multiple PDSCHs of the at least two second random access messages.

21. The method according to claim 17, wherein, Each PDSCH among the multiple PDSCHs carries uplink grant information for multiple third random access messages.

22. An apparatus for wireless communication at a user equipment (UE), comprising: A memory; And At least one processor coupled to the memory and configured to perform the following operations: Transmit at least two first random access messages (Msg 1) pointing to different transmission and reception points (TRPs) among multiple TRPs of at least one cell, the transmission using different resources for the multiple TRPs, the different resources including one or more of different time resources or different frequency resources for the multiple TRPs; And After transmitting the at least two first random access messages, monitor at least two second random access messages (Msg 2) from the multiple TRPs of the at least one cell based on the different time resources or the different frequency resources for the multiple TRPs.

23. A wireless communication method at a base station, comprising: Receive from a user equipment (UE) at least two first random access messages (Msg 1) pointing to different transmission and reception points (TRPs) among multiple TRPs of at least one cell, the reception being based on different resources for the multiple TRPs, the different resources including one or more of different time resources or different frequency resources for the multiple TRPs; And After receiving the at least two first random access messages, at least two second random access messages (Msg 2) are sent from the multiple transmission and reception points (TRPs) of the at least one cell to the UE based on the different time resources or the different frequency resources for the multiple TRPs.

24. The method according to claim 23, wherein, In addition to one or more of the different time resources or the different frequency resources, the different resources further include different spatial resources.

25. The method according to claim 23, wherein, Each of the at least two first random access messages includes a preamble, and wherein the base station receives the at least two first random access messages from the UE during a corresponding number of allocated random access opportunities using multiple receive beams for reference signals corresponding to multiple transmit beams from the UE, and each random access opportunity is associated with a reference signal.

26. The method according to claim 25, wherein, The reference signal includes at least one of a synchronization signal block (SSB) from a cell or a channel state information - reference signal (CSI - RS), and wherein the reference signal is transmitted using the multiple TRPs.

27. The method according to claim 25, wherein, The at least two first random access messages are time - division multiplexed or frequency - division multiplexed on the multiple transmit beams.

28. The method according to claim 25, wherein, The base station receives a first preamble using a first beam from a first random access beam pool and receives a second preamble using a second beam from a second random access beam pool. wherein the first preamble is received using a first receive beam selected from a first random access resource candidate beam pool at a cell, and wherein the second preamble is received using a second receive beam selected from a second random access resource candidate beam pool at the cell, the first receive beam is for a first transmission and reception point (TRP) of the cell, and the second receive beam is for a second TRP of the cell.

29. The method according to claim 28, further comprising: Sending an indication of a random access beam pool index to the UE in accordance with a reference signal from the at least one cell.

30. An apparatus for wireless communication at a base station, comprising: A memory; At least one processor coupled to the memory and configured to perform the following operations: Receiving from a user equipment (UE) at least two first random access messages (Msg 1) directed to different TRPs among multiple transmission and reception points (TRPs) of at least one cell, the receiving being based on different resources for the multiple TRPs, the different resources including one or more of different time resources or different frequency resources for the multiple TRPs; And After receiving the at least two first random access messages, sending at least two second random access messages (Msg 2) from the multiple TRPs of the at least one cell to the UE based on the different time resources or the different frequency resources for the multiple TRPs.

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