Beam-Scanning Based Random Access MSG 2

Abstract

A method, computer-readable medium, and apparatus for wireless communication including random access between a base station and a user equipment (UE) are provided. The UE transmits a beam report including beam measurement information to the base station and uses one or more beams based on random access measurements different from the beam measurement information included in the beam report to transmit a first random access message to the base station for reception. The UE monitors a second random access message from the base station using a plurality of beams, and the beams are selected based on the beam report.

Description

[0001] Cross - Reference to Related Applications

[0002] This application claims the benefit of the following applications: U.S. Provisional Application Serial No. 62 / 952,014, filed on December 20, 2019, and entitled "BeamSweep Based Random Access Msg 2"; and U.S. Patent Application No. 17 / 092,679, filed on November 9, 2020, and entitled "Beam Sweep Based Random Access MSG 2", the entire contents of which are hereby incorporated by reference. Technical Field

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

[0004] Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, and broadcasting. A typical wireless communication system may employ a multiple - access technology that is capable of supporting communication with multiple users by sharing 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 a common protocol that enables different wireless devices to communicate at the urban, national, regional, and even global levels. An example telecommunication standard is 5G New Radio (NR). 5G NR is part of the continuous mobile broadband evolution released by the Third Generation Partnership Project (3GPP) to meet new requirements associated with latency, reliability, security, scalability (e.g., with the 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 that employ these technologies. Summary of the Invention

[0006] A brief overview of one or more aspects is given below to provide a basic understanding of such aspects. This overview is not an extensive review of all contemplated aspects and is neither intended to identify key or critical elements of all aspects nor to delineate the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that follows.

[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 a beam report including beam measurement information to a base station. The apparatus uses one or more beams based on random access measurements different from the beam measurement information included in the beam report to transmit a first random access message to the base station for reception. The apparatus uses multiple beams to monitor a second random access message from the base station, and the beams are selected based on the beam report.

[0008] In another aspect of the present disclosure, a method, computer-readable medium, and apparatus for wireless communication at a base station are provided. The apparatus receives a beam report including beam measurement information from a UE. The apparatus uses one or more beams based on random access measurements, which are based on measurements different from the beam measurement information included in the beam report, to receive a first random access message from the UE. Then, the apparatus uses multiple beams to transmit a second random access message to the UE, and the multiple beams are selected based on the beam report from the UE.

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

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

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

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

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

[0014] Figure 2D is a schematic diagram showing examples of UL channels within a subframe according to various aspects of the present disclosure.

[0015] Figure 3 is a schematic diagram showing examples 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 related to random access.

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

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

[0021] Figure 9 is a flowchart of a method of wireless communication.

[0022] Figure 10 is a flowchart of a method of wireless communication.

[0023] Figure 11 is a schematic diagram showing an example of a hardware implementation for an example device.

[0024] Figure 12 is a schematic diagram showing an example of a hardware implementation for an example device. Detailed Description

[0025] The detailed description set forth below in connection with the appended drawings is intended as a description of various configurations and is not intended to represent the only configurations in which the concepts described herein may be practiced. For the purpose of providing a thorough understanding of the various concepts, the detailed description includes specific details. 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.

[0026] 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 by various blocks, components, circuits, processes, algorithms, etc. (collectively referred to as "elements") and illustrated in the accompanying drawings. These elements can be implemented using electronic hardware, computer software, or any combination thereof. Whether such elements are implemented as hardware or software depends on the particular application and the design constraints imposed on the overall system.

[0027] 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 microprocessors, microcontrollers, graphics processing units (GPUs), central processing units (CPUs), application processors, digital signal processors (DSPs), reduced instruction set computing (RISC) processors, system on a chip (SoCs), baseband processors, field programmable gate arrays (FPGAs), programmable logic devices (PLDs), state machines, gated logic, discrete hardware circuits, and other suitable hardware configured to perform the various functions described throughout this disclosure. One or more processors in the processing system can execute software. Software should be broadly interpreted to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software components, applications, software applications, software packages, routines, subroutines, objects, executable files, execution threads, processes, functions, etc., regardless of whether it is referred to as software, firmware, middleware, microcode, hardware description language, or other names.

[0028] Accordingly, in one or more example embodiments, the described functions can be implemented in hardware, software, or any combination thereof. If implemented in software, the functions can be stored or encoded on a computer-readable medium as one or more instructions or code. Computer-readable media 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 can 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 above types of computer-readable media, or any other media capable of storing computer-executable code in the form of instructions or data structures that can be accessed by a computer.

[0029] 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, such as Msg 2, Msg 3, and Msg 4, with the base station. After completing the random access procedure, the UE and the base station may transition to fine beam operation, where the UE may measure CSI-RS from the base station on different beams and may provide a measurement report to the base station for beam selection.

[0030] Aspects presented herein may use multiple beams to provide coverage and / or latency improvements for random access by transmitting / receiving random access messages. The use of multiple beams may help improve the reliability of transmission by providing multiple transmission opportunities for random access transmissions or random access channels (RACH) in the time domain, frequency domain, and / or spatial domain. The additional transmission opportunities may improve the reliability of communication by increasing the likelihood of a successful random access procedure between the UE and the cell, such as in unlicensed spectrum. The increased reliability may help support services such as URLLC services, IoT such as industrial IoT (IIoT) services, NR-based communication in unlicensed spectrum in a controlled environment (e.g., FR1). Random access reliability and robustness may be improved by using beam scanning during random access between the UE and the base station. Aspects presented herein provide different methods for selecting beams for Msg 1 and Msg 2 of the random access procedure. For example, a UE may select one or more beams to transmit a first random access message (e.g., Msg 1) based on random access measurements. The UE may monitor a second random access message (e.g., Msg 2) on multiple beams selected based on a layer 1 / layer 3 beam measurement report provided to the base station. For a UE without a corresponding beam, there may be little or no interaction between the best beam for transmission to the cell and the beam for reception from the cell. Using the latest downlink beam management to select a receive beam for receiving Msg 2 (which may result in the same or a different transmit beam as the transmit beam used for sending Msg 1) may improve reliability and reduce the latency of the random access procedure.

[0031] Figure 1 is a schematic 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)). Referring again to Figure 1, in some aspects, the UE 104 may include a random access message component 198 configured to exchange random access messages with a cell using multiple beams (e.g., beam direction 182”). The base station 102 / 180 may include a random access message component 199 configured to exchange random access messages with the UE 104 using multiple beams (e.g., beam direction 182’). The random access messages may include a first random access message (e.g., Msg 1) containing a preamble, where the UE 104 transmits the first random access message and a second random access message (e.g., Msg 2). As described herein, the base station 102 or the base station 180 and the UE 104 may exchange the first random access message using multiple beams associated with a reference signal during a corresponding number of allocated random access opportunities. The UE 104 may be configured to send a beam report including beam measurement information to the base station 102 / 180. The random access message component 198 may be configured to send the first random access message (e.g., Msg 1) to the base station 102 / 180 for reception using one or more beams based on a random access beam measurement different from the last beam measurement information included in the latest beam report. The random access message component 198 may be configured to monitor or receive the second random access message from the base station using multiple beams, and the beams are selected based on the latest beam report.

[0032] The base station 102 / 180 may be configured to receive a beam report including beam measurement information from the UE 104. The random access message component 199 of the base station 102 / 180 may be configured to receive the first random access message from the UE using one or more beams based on a random access beam measurement, and the random access beam measurement is based on a measurement different from the latest beam measurement information included in the latest beam report. The random access message component 199 may be configured to send the second random access message to the UE using multiple beams, and the multiple beams are selected based on the latest beam report from the UE.

[0033] 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 cells include femtocells, picocells, and microcells.

[0034] The base station 102 configured for 4G LTE (collectively referred to as the evolved universal mobile telecommunications system (UMTS) terrestrial radio access network (E-UTRAN)) can interface with the EPC 160 via a first backhaul link 132 (e.g., the S1 interface). The base station 102 configured for 5G NR (collectively referred to as the next-generation RAN (NG-RAN)) can interface with the core network 190 via a second backhaul link 184. In addition to other functions, the base station 102 can also perform one or more of the following functions: transmission of user data, encryption and decryption of radio channels, integrity protection, header compression, mobility control functions (e.g., handover, dual connectivity), inter-cell interference coordination, connection establishment and release, load balancing, distribution of non-access stratum (NAS) messages, NAS node selection, synchronization, radio access network (RAN) sharing, multimedia broadcast multicast service (MBMS), user and device tracking, radio access network information management (RIM), paging, positioning, and delivery of warning messages. The base stations 102 can communicate directly or indirectly (e.g., via the EPC 160 or the core network 190) with each other via a third backhaul link 134 (e.g., the X2 interface). The first backhaul link 132, the second backhaul link 184, and the third backhaul link 134 can be wired or wireless.

[0035] Base station 102 can communicate wirelessly with UE 104. Each base station in base station 102 can provide communication coverage for a corresponding 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 including both small cells and macro cells can be referred to as a heterogeneous network. The heterogeneous network can also include a home evolved Node B (eNB) (HeNB), which can provide services to a restricted group called a closed subscriber group (CSG). The communication link 120 between base station 102 and UE 104 can include an uplink (UL) (also referred to as a reverse link) transmission from UE 104 to base station 102 and / or a downlink (DL) (also referred to as a forward link) transmission from base station 102 to UE 104. The communication link 120 can use multiple-input multiple-output (MIMO) antenna technology, including spatial multiplexing, beamforming, and / or transmit diversity. The communication link can be over one or more carriers. Base station 102 / UE 104 can use a spectrum with a bandwidth of up to Y MHz (e.g., 5, 10, 15, 20, 100, 400, etc. MHz) per carrier allocated in carrier aggregation for transmission in each direction, with a total of up to Yx MHz (x component carriers). The carriers can be adjacent to each other or can be non-adjacent to each other. The allocation of carriers can be asymmetric with respect to DL and UL (e.g., more or fewer carriers can be allocated for DL compared to UL). The component carriers can include a primary component carrier and one or more secondary component carriers. The primary component carrier can be referred to as the primary cell (PCell), and the secondary component carriers can be referred to as secondary cells (SCell).

[0036] Certain UEs 104 can communicate with each other using device-to-device (D2D) communication link 158. The D2D communication link 158 can use DL / UL WWAN spectrum. The D2D communication link 158 can use one or more sidelink channels, such as the physical sidelink broadcast channel (PSBCH), the physical sidelink discovery channel (PSDCH), the physical sidelink shared channel (PSSCH), and the physical sidelink control channel (PSCCH). D2D communication can be through various wireless D2D communication systems, such as, for example, WiMedia, Bluetooth, ZigBee, Wi-Fi based on the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standards, LTE, or NR.

[0037] The wireless communication system may also include a Wi-Fi access point (AP) 150 that communicates with a Wi-Fi station (STA) 152 via a communication link 154, e.g., in a 5 GHz unlicensed spectrum. When communicating in an unlicensed spectrum, the STA 152 / AP 150 may perform a Clear Channel Assessment (CCA) before communication to determine whether the channel is available.

[0038] The small cell 102' may operate in licensed and / or unlicensed spectrums. When operating in an unlicensed spectrum, the small cell 102' may adopt NR and use the same unlicensed spectrum (e.g., 5 GHz, etc.) as that used by the Wi-Fi AP 150. The small cell 102' adopting NR in an unlicensed spectrum may enhance the coverage of the access network and / or increase the capacity of the access network.

[0039] The electromagnetic spectrum is generally subdivided into various categories, frequency bands, channels, etc. based on frequency / wavelength. In 5G NR, two initial operating frequency bands have been identified as the frequency range name FR1 (410 MHz - 7.125 GHz) and FR2 (24.25 GHz - 52.6 GHz). The frequencies between FR1 and FR2 are generally referred to as intermediate band frequencies. Although a part of FR1 is greater than 6 GHz, FR1 is generally (interchangeably) referred to as the "below 6 GHz" band in various documents and articles. Similar naming issues sometimes occur with respect to FR2. Although different from the extremely high frequency (EHF) band (30 GHz - 300 GHz) identified by the International Telecommunication Union (ITU) as the "millimeter wave" band, FR2 is generally (interchangeably) referred to as the "millimeter wave" band in documents and articles.

[0040] Considering the above aspects, unless otherwise specifically stated, it should be understood that if the term "below 6 GHz" etc. is used herein, it may generally represent a frequency that may be less than 6 GHz, may be within FR1, or may include intermediate band frequencies. Additionally, unless otherwise specifically stated, it should be understood that if the term "millimeter wave" etc. is used herein, it may generally represent a frequency that may include intermediate band frequencies, may be within FR2, or may be within the EHF band.

[0041] Base station 102 (whether small cell 102' or large cell (e.g., macro base station)) may include and / or be referred to as an eNB, a next generation node B (gNodeB, gNB), or another type of base station. Some base stations (such as gNB 180) may operate in traditional sub-6 GHz spectrum, at millimeter wave frequencies, and / or near millimeter wave frequencies to communicate 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. Millimeter wave base station 180 may utilize beamforming 182 with UE 104 to compensate for path loss and short distances. Base station 180 and UE 104 may each include multiple antennas, such as antenna elements, antenna panels, and / or antenna arrays to facilitate beamforming.

[0042] 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. The transmission direction and reception direction for base station 180 may be the same or may be different. The transmission direction and reception direction for UE 104 may be the same or may be different.

[0043] The EPC 160 may include a Mobility Management Entity (MME) 162, other MMEs 164, a Serving Gateway 166, a Multimedia Broadcast Multicast Service (MBMS) Gateway 168, a Broadcast Multicast Service Center (BM-SC) 170, and a Packet Data Network (PDN) Gateway 172. The MME 162 may communicate with a Home Subscriber Server (HSS) 174. The MME 162 is a control node that processes signaling between the UE 104 and the EPC 160. Generally, the MME 162 provides bearer and connection management. All user Internet Protocol (IP) packets are transported through the Serving Gateway 166, which itself is connected to the PDN Gateway 172. The PDN Gateway 172 provides IP address allocation to the UE, as well as other functions. The PDN Gateway 172 and the BM-SC 170 are connected to an IP service 176. The IP service 176 may include the Internet, an intranet, an IP Multimedia Subsystem (IMS), a PS streaming service, and / or other IP services. The BM-SC 170 may provide functions for MBMS user service provision and delivery. The BM-SC 170 may serve as an entry point for content provider MBMS 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 particular service being broadcast, and may be responsible for session management (start / stop) and collecting charging information related to eMBMS.

[0044] 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, 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 UE IP address allocation, 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.

[0045] A base station 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. Base station 102 provides an access point to EPC 160 or core network 190 for UE 104. Examples of UE 104 include cellular phones, smart phones, session initiation protocol (SIP) phones, laptop computers, personal digital assistants (PDAs), satellite radio units, global positioning systems, multimedia devices, video devices, digital audio players (e.g., MP3 players), cameras, game consoles, tablet devices, smart devices, wearable devices, vehicles, electricity meters, gas pumps, large or small kitchen appliances, healthcare devices, implants, sensors / actuators, displays, or any other device with similar functionality. Some of the UEs 104 in UE104 may be referred to as IoT devices (e.g., parking meters, gas pumps, ovens, vehicles, cardiac monitors, etc.). 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, radio communication device, remote device, mobile user station, access terminal, mobile terminal, radio terminal, remote terminal, handheld device, user agent, mobile client, client, or some other suitable term.

[0046] Although this specification may focus on 5G NR, the concepts described herein may be applicable to other similar areas, such as LTE, LTE-A, CDMA, GSM, and other wireless technologies.

[0047] Figure 2A FIG. 200 is a schematic diagram showing an example of a first subframe within a 5G NR frame structure. Figure 2B FIG. 230 is a schematic diagram showing an example of a DL channel within a 5GNR subframe. Figure 2C FIG. 250 is a schematic diagram showing an example of a second subframe within a 5G NR frame structure. Figure 2D FIG. 280 is a schematic diagram showing an example of a UL channel within a 5G NR subframe. The 5G NR frame structure may be frequency division duplexing (FDD) (wherein, for a specific set of subcarriers (carrier system bandwidth), the subframes within the set of subcarriers are dedicated to DL or UL), or may be time division duplexing (TDD) (wherein, for a specific set of subcarriers (carrier system bandwidth), the subframes within the set of subcarriers are dedicated to both DL and UL). In passing through Figure 2A 、 2CIn the provided example, the 5G NR frame structure is assumed to be TDD, where subframe 4 is configured with slot format 28 (with most being DL), where D is DL, U is UL, and F is flexibly usable between DL / UL, and subframe 3 is configured with slot format 1 (with most being UL). Although subframes 3 and 4 are shown as having slot formats 1 and 28 respectively, any particular subframe can be configured with any of the various available slot formats 0 - 61. Slot formats 0 and 1 are all-DL and all-UL respectively. The other slot formats 2 - 61 include a mixture of DL, UL, and flexible symbols. The UE is configured with a slot format via the received Slot Format Indicator (SFI) (configured dynamically via Downlink Control Information (DCI) or semi-statically / statically via Radio Resource Control (RRC) signaling). Note that the following description also applies to the 5G NR frame structure as TDD.

[0048] Other wireless communication technologies may have different frame structures and / or different channels. A frame (e.g., 10 ms) can be divided into 10 equally sized subframes (1 ms). Each subframe can include one or more slots. A subframe can also include mini-slots, which 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-constrained scenarios; limited to single stream transmission). The number of slots within a subframe is based on the slot configuration and 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 2μ * 15 kilohertz (kHz), where μ is numerology 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. Figures 2A - 2DProvide an example of time slot configuration 0 (with 14 symbols per time slot) and digital scheme μ = 2 (with 4 time slots per subframe). The time slot duration is 0.25 ms, the subcarrier spacing is 60 kHz, and the symbol duration is approximately 16.67 μs. Within a frame set, there can be one or more different bandwidth parts (BWPs) that are frequency division multiplexed (see Figure 2B ). Each BWP can have a specific digital scheme.

[0049] A resource grid can be used to represent the frame structure. Each time slot includes resource blocks (RBs) (also referred to as physical RBs (PRBs)), where a PRB spans 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.

[0050] As shown in Figure 2A , some of the REs carry reference (pilot) signals (RSs) for the UE. The RS can include demodulation RS (DM-RS) for channel estimation at the UE (indicated as R for a specific configuration, but other DM-RS configurations are possible) and channel state information reference signal (CSI-RS). The RS can also include beam measurement RS (BRS), beam refinement RS (BRRS), and phase tracking RS (PT-RS).

[0051] 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 the OFDM symbols of a 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 UE 104 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 position of the above-mentioned 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.

[0052] As shown in Figure 2C Some of the REs carry Demodulation Reference Signals (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 previous one or two symbols of the PUSCH. The PUCCH DM-RS can be transmitted in different configurations according to whether a short PUCCH or a long PUCCH is transmitted and according to the specific PUCCH format used. The UE can transmit a Sounding Reference Signal (SRS). The SRS can be transmitted in the last symbol of a subframe. The SRS can have a comb structure, and the UE can transmit the SRS on one of the combs in the comb. The SRS can be used by the base station for channel quality estimation to enable frequency-dependent scheduling on the UL.

[0053] Figure 2D An example of various UL channels within a subframe of a frame is shown. The PUCCH can be located as indicated in one configuration. The PUCCH carries uplink control information (UCI), such as a scheduling request, a channel quality indicator (CQI), a precoding matrix indicator (PMI), a rank indicator (RI), and hybrid automatic repeat request (HARQ) acknowledgement (ACK) (HARQ-ACK) information (ACK / negative acknowledgement (NACK)) feedback. The PUSCH carries data and can additionally be used to carry a buffer status report (BSR), a power headroom report (PHR), and / or UCI.

[0054] Figure 3 is a block diagram of a base station 310 communicating 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 a radio resource control (RRC) layer, and layer 2 includes a service data adaptation protocol (SDAP) layer, a packet data convergence protocol (PDCP) layer, a radio link control (RLC) layer, and a media access control (MAC) layer. The controller / processor 375 provides: RRC layer functions associated with: broadcasting 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: transfer 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: 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.

[0055] The transmit (TX) processor 316 and the receive (RX) processor 370 implement the 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) encoding / decoding on 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 processes 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 shift keying (M-PSK), M-order quadrature amplitude modulation (M-QAM)). The encoded and modulated symbols can then be divided into parallel streams. Each stream can then be mapped to OFDM subcarriers, multiplexed with reference signals (e.g., pilots) in the time domain and / or frequency domain, and then combined together using an inverse fast Fourier transform (IFFT) to generate a physical channel carrying a time-domain OFDM symbol stream. The OFDM stream is space precoded to generate multiple spatial streams. Channel estimates from the channel estimator 374 can be used to determine the encoding and modulation schemes and for spatial processing. The channel estimates can be derived based on reference signals transmitted by the UE 350 and / or channel status feedback. Each spatial stream can then be provided to a different antenna 320 via a separate transmitter 318TX. Each transmitter 318TX can modulate an RF carrier with the corresponding spatial stream for transmission.

[0056] At the UE 350, each receiver 354RX receives signals via its corresponding 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 the layer 1 functions associated with various signal processing functions. The RX processor 356 can perform spatial processing on the information to recover any spatial streams destined for the UE 350. If multiple spatial streams are destined for the UE 350, they can be combined by the RX processor 356 into a single OFDM symbol stream. 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 signals on each subcarrier are recovered and demodulated by determining the most likely signal constellation points transmitted by the base station 310. These soft decisions can be based on the channel estimates calculated by the channel estimator 358. The soft decisions are then decoded and deinterleaved to recover the data and control signals originally transmitted by the base station 310 on the physical channel. The data and control signals are then provided to the controller / processor 359, which implements layer 3 and layer 2 functions.

[0057] 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, packet reassembly, decryption, header decompression, and control signal processing between the transport channel and the logical channel 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.

[0058] 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) acquisition, 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: transfer of upper layer PDUs, error correction via ARQ, concatenation, segmentation, and reassembly of RLC SDUs, re-segmentation of RLC data PDUs, and re-ordering of RLC data PDUs; and MAC layer functions associated with: mapping between logical channels 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.

[0059] Channel estimates derived by the channel estimator 358 based on reference signals or feedback transmitted by the base station 310 may be used by the TX processor 368 to select an appropriate modulation and coding scheme 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 using the corresponding spatial stream for transmission.

[0060] UL transmissions are processed at the base station 310 in a manner similar to that described in connection with the receiver function at the UE 350. Each receiver 318RX receives signals via its corresponding antenna 320. Each receiver 318RX recovers the information modulated onto the RF carrier and provides the information to the RX processor 370.

[0061] The controller / processor 375 may be associated with a memory 376 that stores program code and data. The memory 376 may be referred to as a computer-readable medium. In the UL, the controller / processor 375 provides demultiplexing, packet reassembly, decryption, header decompression, control signal processing between the transport channel and the logical channel to recover IP packets from the UE 350. The IP packets from the controller / processor 375 may 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.

[0062] At least one of the TX processor 368, the RX processor 356, and the controller / processor 359 may be configured to perform aspects related to Figure 1 the random access message component 199.

[0063] At least one of the TX processor 316, the RX processor 370, and the controller / processor 375 may be configured to perform aspects related to Figure 1 the random access message component 198.

[0064] The UE may use a random access procedure to communicate with the base station. For example, the UE may use the 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 may 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 may obtain random access parameters from the base station 404, such as including preamble format parameters, time and frequency resources, parameters for determining the root sequence and / or cyclic shift for the random access preamble, etc., e.g., in the system information 401. The preamble may be sent with an identifier, such as a random access RNTI (RA-RNTI). The UE 402 may randomly select a random access preamble sequence from a set of preamble sequences, for example. In some examples, a preamble sequence may be assigned to the UE 402.

[0065] 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 can 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. Upon receiving the RAR 405, the UE 402 can send a third random access message 407 (e.g., Msg 3) to the base station 404 using, for example, the PUSCH. This message can include an RRC connection request, an RRC connection re-establishment request, or an RRC connection resume request, depending on the trigger used to initiate the random access procedure. Then, the base station 404 can complete the random access procedure by sending a fourth random access message 409 (e.g., Msg 4) to the UE 402 (e.g., scheduling using the PDCCH and scheduling the message using the PDSCH). The fourth random access message 409 can include a random access response message that includes timing advance information, contention resolution information, and / or RRC connection establishment information. The UE 402 can monitor the PDCCH using, for example, the C-RNTI. If the PDCCH is successfully decoded, the UE 402 can also decode the PDSCH. The UE 402 can send HARQ feedback for any data carried in the fourth random access message. The fourth message can be referred to as a contention resolution message. The fourth random access message 409 can complete the random access procedure. Thus, the UE 402 can subsequently send uplink communications and / or receive downlink communications with the base station 404 based on the RAR and the fourth random access message 409.

[0066] Figure 5 An example communication flow 500 including a UE 502 is shown. The UE 502 performs a random access procedure with a secondary cell 506 (such as a PSCell) based on a configuration received from a PCell 504 serving the UE 502. As Figure 5As shown, the PCell 504 may configure the UE 502 at 501 to perform layer 3 (L3) measurements on another cell (e.g., the PSCell 506). The PCell may be a cell operating as the primary cell of the primary cell group. The PSCell is a cell belonging to the secondary cell group (SCG). One of the cells belonging to the SCG may operate as the primary SCell and may be referred to as the PSCell. An SCF may have one PSCell and one or more secondary secondary cells (SSCells). Although aspects are shown for the PSCell, these aspects may apply to other cells. In some examples, these aspects may apply to any SCell. The UE 502 may use the configuration 501 received from the PCell 504 to measure the synchronization signal from the PSCell 506. The UE may perform the measurement in the corresponding SS / PBCH block measurement time configuration (SMTC) window 503. The SMTC window 503 may be configured by the PCell 504 (e.g., via 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 (e.g., an L1 or L3 beam report) 507 about the PSCell 506 to the PCell 504. In some examples, 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 periodically provide the beam report 507 to the PCell 504.

[0067] The PCell 504 may initiate a PSCell addition procedure 509 for the UE 502 using the L3 beam report 507 on the PSCell 506 received from the UE 502. The PCell 504 may send a PSCell RACH configuration 511 to the UE 502. At 515, the UE 502 may indicate to the PCell 504 the completion of the RRC reconfiguration, and at 517, the PCell 504 may indicate to the PSCell 506 the completion of the PSCell reconfiguration. The UE 502 may identify, for example based on the RS 513, the best downlink RS beam for the PSCell 506, and may perform a random access procedure 519 with the PSCell 506 using the identified beam. For example, the UE 502 may send a first random access message (e.g., Msg 1 403) to the PSCell 506 during a corresponding RACH occasion. After sending Msg 1, the PSCell 506 and the 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 of the random access procedure 519, such as Msg 2, Msg 3, and Msg 4, may be exchanged between the UE 502 and the PSCell 506 using the same beam as Msg 1. Msg 1, Msg 2, Msg 3, and Msg 4 may include aspects described in the random access messages described in conjunction with Figure 4 aspects described in the random access messages described in conjunction with

[0068] After completion of the random access procedure 519, the UE 502 and the PSCell 506 may transition to CSI-RS-based fine beam operation 521. The UE 502 may measure the CSI-RS from the PSCell 506 on different beams and may provide a measurement report to the PSCell 506 for beam selection.

[0069] Figure 6 An example of the RAR window 600 for multiple Msg 1 transmissions during a portion 602 of the RAR window 600, e.g., a time window for receiving the RAR or Msg 2, is shown. UEs with beam correspondences may obtain multi-beam diversity during random access transmissions 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 can correspond to the reference signal for beam 604a, beam 608b can correspond to the reference signal for beam 604b, and 608c can correspond to the reference signal for beam 604c. The UE can send Msg 1 multiple times using different beams, which can be referred to as scanning the beams of Msg1 over multiple beams. With beam correspondence, the uplink transmission beam can be the same as the downlink reception beam for the UE. The UE can perform uplink beam scanning and can select an uplink transmission beam for Msg 1 beam scanning. In some examples, a UE with beam correspondence can be fully flexible in using any uplink transmission beam (e.g., beams 608a, 608b, 608c) to send multiple Msg 1 random access transmissions corresponding to different SSB / CSI-RS. The RAR window 600 can be interleaved for different transmission beams. As shown, the UE can use parts 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 can be synchronized so that the base station determines the beam that the UE will use to monitor Msg 2 within different parts 602 of the RAR window using a specific beam. For example, during a specific part 602a of the RAR window 600, the base station can determine that the UE will use the reception beam 608a corresponding to the reference signal for the transmit beam 604a. The base station can use beam 604a to send Msg2 during part 602a. The base station can send Msg 2 multiple times, e.g., send RARs using different beams during different parts 602 of the RAR window 600.

[0070] Aspects presented herein can provide coverage and / or latency improvements during time period 523 in the examples in Figure 5 Aspects presented herein can help improve the reliability of transmissions by providing multiple transmission opportunities for uplink transmissions or channels (e.g., random access transmissions or random access channel (RACH)) in the time domain and / or frequency domain. The additional transmission opportunities can improve the reliability of communication 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), e.g., in unlicensed spectrum. The increased reliability may help support services such as URLLC services, IoT such as industrial IoT (IIoT) services, NR-based communication in unlicensed spectrum (e.g., FR1) in a controlled environment, etc.

[0071] The present disclosure provides increased random access reliability and robustness by using beam sweeping during random access between a UE and a base station. Aspects may be applied to random access with a PCell, SCell, PSCell, etc. For example, aspects may be applied to random access with a secondary cell, e.g., for a new radio dual connection (NR-DC) where a UE is connected to a PCell and an SCell, as described in conjunction with Figure 5 above.

[0072] A UE may use beam sweeping to exchange Msg 1 and / or Msg 2 during random access with a cell, such as described in conjunction with Figure 6 below. A UE may exchange random access messages with a single transmit receive point (TRP) or multiple TRPs of a serving cell. In some aspects, the random access procedure may include simultaneous transmission / reception. In other aspects, the random access procedure may not include simultaneous transmission / reception. For example, transmission and reception may be based on TDM rather than simultaneous. As given herein, a candidate beam pool may be provided for random access. A beam pool index may be used to avoid potential beam pair misalignment that may occur with a single TRP or multiple TRPs. When random access involves multiple TRPs, different pool indexes may help a UE select a random access beam from different TRPs with a large transmission angle, which may help improve uplink interference diversity. Also, for multiple TRPs, using a beam pool index may help balance the load of the TRPs. For example, a TRP with less urgent traffic may be selected to exchange random access message 1 and / or message 2. Also, joint random access across beam sweeping may improve reliability and reduce latency by enabling the random access to be successfully completed even if some messages are not accurately received. Beam sweeping during random access may help avoid blocking during the initial access procedure with a cell. The added transmission of beam sweeping may help avoid failures due to uplink or downlink inter-cell interference bursts. For example, random access using beam sweeping for Msg1 / Msg 2 may reduce random access latency and provide a faster PSCell setup procedure with reduced failures or retransmissions.

[0073] Figure 7A FIG. shows an example of a random access 700 of a PSCell 706 using a single TRP. The random access procedure may correspond to the random access procedure 519 in Figure 5 and may include message exchanges as described in conjunction with Figure 4 below. Figure 7A FIG. shows a base station transmitting a reference signal, e.g., transmitting CSI-RS using beam sweeping by using different transmit beams in each CSI-RS resource of a CSI-RS resource set. Figure 7AIllustrated is that the PSCell 706 transmits CSI-RS using CSI-RS resources 1-4 on each of four different beams. The PSCell 706 may continue to transmit CSI-RS using different beams in different CSI-RS resources, e.g., until the PSCell 706 transmits CSI-RS using CSI-RS resources 63-66. The UE 702 may use n selected reference signals from the PSCell 706 to transmit multiple preambles in Msg 1 (e.g., the first random access message corresponding to 403) on n allocated random access occasions. The allocated random access occasions may correspond to n reference signals of the cell, which may be TDM or FDM. Figure 7A Illustrated is an example of TDM random access resources in which the UE 702 transmits Msg1 transmissions 711 and 713 at different times. Figure 7B Illustrated is an FDM example 750 in which Msg 1 transmissions 711 and 713 overlap in time and are transmitted using different frequencies. Although Figure 7A the example in shows the reference signal as CSI-RS, SSB transmitted by the base station using different beams may be similarly applied in various aspects. Although Figure 7A illustrated is transmitting a reference signal from a single TRP and transmitting a Msg 1 transmission to a single TRP, but various aspects may also be applied to multiple TRPs. Although the various aspects are described in conjunction with the PSCell 706, the UE may similarly use beam scanning to perform random access with the PCell 704 or SCell. The PCell 704 may provide a random access configuration to the UE 702, such as that described in conjunction with Figure 5 . As Figure 7A shown, the UE 702 may use a selected beam pair (e.g., a beam pair including a transmit beam from the UE and a receive beam at the base station) to transmit Msg 1 711, and may use a different beam pair to transmit an additional Msg 1 713. For example, the UE may use a transmit beam corresponding to CSI-RS beam n to transmit Msg 1 711, and may use CSI-RS beam m to transmit Msg 1 713.

[0074] Figure 8 Illustrated is an example of random access 800 of a PSCell using multiple TRPs 806 and 808. The random access procedure 800 may correspond to Figure 5 the random access procedure 519 in, and may include an exchange of messages as 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 the random access procedure 750 in Figure 7B . Figure 8Random access with multiple TRPs is shown. The aspects described in conjunction with Figure 8 can also be applied to random access with a single TRP. The UE 802 can select one or more beams to transmit Msg 1 based on random access measurements of reference signals, e.g., as described in conjunction with Figure 5 . For example, the random access measurements can be based on RRC configuration or reconfiguration (e.g., 511), and the UE can perform measurements on the configured reference signal 513. Figure 8 A non-limiting example is shown where the configured reference signal can be CSI-RS. The UE 802 can send Msg 1 811 to the TRP 806 and can send Msg 1 813 to the TRP 808. The receiving beam of the PSCell can be from a different random access resource candidate beam pool of the serving cell, which can correspond to FDM or TDM random access resources. Figure 8 It is shown 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 shown for two TRPs, different beam pools can be associated with a single TRP, e.g., for different random access resources. An index can be provided to the UE for each reference signal. Thus, at the random access resource corresponding to a specific reference signal, the UE can know the corresponding random access candidate beam pool. A single TRP can have 64 beams, which can be separated into different beam pools for random access. For example, the first 8 beams can be associated with beam pool index 1, the next 8 beams can be associated with beam pool index 2, and so on, and the last 8 beams are associated with beam pool index 8. The UE can select a beam from within the beam pool index for a specific transmission of Msg 1.

[0075] In Figure 8 , the serving cell can use the beam selected based on the most recent L1 or L3 report from the UE 802 to transmit Msg2 PDCCH and / or Msg 2 PDSCH. Figure 8 It is shown that an L1 / L3 beam report 830 can be provided to the base station before the UE performs random access measurements on a reference signal (e.g., CSI-RS in Figure 8 ). As described in conjunction with Figure 5As described, the UE can provide L1 or L3 beam reports based on the configuration for L1 / L3 beam reporting. For example, the UE can perform measurements during the SMTC window 503. In other examples, the beam report can be provided closer to Msg 2, e.g., right before receiving Msg 2. The L1 / L3 beam report and the random access beam measurement can be based on different downlink signals, and the timing of the measurements may be different. For example, the cell can select the best beam or the number of best beams based on the measurement of the beam provided by the UE to the cell in the L1 or L3 beam report. The cell can use the latest or last received L1 / L3 beam report from the UE. The UE 802 can use different beams (e.g., beams based on random access measurements) to send Msg 1 transmissions 811 and 813. Selecting the beam for sending Msg 1 and for monitoring or receiving Msg 2 can include one or more of the same beams, but is based on different measurements performed by the UE. The UE can use the beam to receive Msg2 PDCCH / PDSCH based on the L1 or L3 beam report, e.g., 815, 817, 823, 825. As shown, the UE can select a different beam from the beam used to receive Msg 2 PDCCH 815 and / or Msg 2 PDSCH 825 to send Msg 1 813. Figure 8 It shows that in some examples, two ways of selecting beams may cause the UE or the cell to select the same beam. For example, the UE 802 is shown as selecting the same beam as the beam used to monitor Msg 2 PDCCH 817 and / or Msg 2 PDSCH 823 to send Msg 1 811. Different ways of selecting beams for Msg 1 and Msg2 can improve random access between the UE 802 and the cell. For example, for a UE without beam correspondence, there may be little or no reciprocity between the best beam for sending to the cell and the beam for receiving from the cell. Therefore, the UE can use downlink beam management to select the receive beam for receiving Msg 2, and can use random access measurements to determine the transmit beam for sending Msg 1.

[0076] Figure 9FIG. 900 is a flowchart of a method of wireless communication. The method may be performed by a UE or a component of a UE (e.g., UE 104, 350, 402, 502, 702, 802; apparatus 1102; a processing system that may include a memory 360 and may be an 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 in dashed lines. The method may improve random access between a UE and a base station by providing multiple transmission opportunities and applying beam scanning to random access transmissions. Aspects may help avoid failures due to interference, blockage, etc. Aspects of the method may help improve the reliability of random access and reduce the latency of random access.

[0077] At 904, the UE transmits a beam report including beam measurement information to the base station. The beam report may include an L1 beam report and / or an L3 beam report. The UE may perform measurements, e.g., as described in conjunction with Figure 5 to provide an L1 / L3 beam report to the base station. For example, the L1 / L3 beam report may be based on measurements during an SMTC window and / or may be based on an L1 / L3 beam measurement configuration. Transmission of the report may be performed, e.g., by beam report component 1140 and / or cellular RF transceiver 1122 of apparatus 1102 in Figure 11 .

[0078] As shown in Figure 9 , the UE may perform L1 / L3 beam measurements at 902. The beam report transmitted at 904 may be based on the measurements performed at 902. The measurements may be based on an L1 / L3 measurement configuration, e.g., as described in conjunction with Figure 5 . The measurements may be performed, e.g., by measurement component 1142 of apparatus 1102 in Figure 11 .

[0079] As shown at 906, the UE may perform random access measurements based on a reference signal. The random access measurements may be based on a random access configuration or reconfiguration, e.g., as described in conjunction with Figure 5 . In some examples, the reference signal may include CSI-RS, e.g., as shown in Figure 8 . The measurements may be performed, e.g., by measurement component 1142 of apparatus 1102 in Figure 11 .

[0080] As shown at 908, the UE may select one or more beams for transmitting a first random access message (e.g., Msg 1) based on the random access measurements performed at 906. For example, the selection may be performed by beam selection component 1144 of apparatus 1102 in Figure 11 .

[0081] At 910, the UE uses one or more beams based on random access measurements to send a first random access message to the base station for reception, where the random access measurements are based on measurements different from the beam measurement information included in the beam report. For example, the beam measurement information provided to the base station at 904 is based on the measurements performed at 902, while the beam selection for Msg 1 transmission at 910 performed at 908 is based on the random access measurements performed at 906. The first random access message can be Msg 1 and can include, for example, a preamble. Figure 5 and Figure 8 shows an example where the UE uses at least one beam selected based on reference signal-based random access measurements to send Msg 1. FIG. 7 shows additional example aspects of Msg 1 transmission. The transmission can be performed, for example, by Figure 11 the Msg 1 component 1146 of the apparatus 1102 in

[0082] At 914, the UE monitors a second random access message from the base station using multiple beams, where the beams are selected based on the beam report sent at 904. For example, the monitoring can be performed by Figure 11 the Msg 2 component 1148 of the apparatus 1102 in

[0083] As shown at 912, at 904, the UE can select the beam for monitoring Msg 2 based on the measurements performed at 902 and / or the beam measurement information provided in the beam report. For example, the selection can be performed by Figure 11 the beam selection component 1144 of the apparatus 1102 in

[0084] The first random access message can be sent using at least a first beam selected based on random access measurements, and the second random access message can be received using at least a second beam selected based on the beam measurement information included in the beam report. The first beam may be different from the second beam. In some examples, the first beam and the second beam may be the same, but are selected based on different measurement information. For example, as Figure 7A shown, the second random access message can be received from a single TRP. In another example, for example, as Figure 8 shown, the second random access message can be received from multiple TRPs. The second random access message can be time-division multiplexed using multiple beams, for example, as Figure 7A shown. The second random access message can be frequency-division multiplexed using multiple beams, for example, as Figure 7B shown. The second random access message can include a control channel (e.g., PDCCH) sent using multiple beams, for example, as in conjunction with Figure 8As described above. The second random access message may include a shared channel (PDSCH) transmitted using multiple beams, e.g., as described in conjunction with Figure 8 As described above. The second random access message may be received from any one of the PCell, SCell, or PSCell for the UE.

[0085] As shown at 916, the UE may also receive the second random access message (e.g., Msg 2) using at least one beam selected based on beam reporting according to the monitoring performed at 914. In some examples, the UE may receive Msg 2 using multiple beams selected based on beam measurement information included in the most recent beam report. For example, reception may be performed by the receiving component 1130 of the apparatus 1102 in Figure 11 and / or the RF cellular transceiver 1122.

[0086] Figure 10 is a flowchart 1000 of a method of wireless communication. 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; TRPs 806, 808; apparatus 1202; a processing system that may include a memory 376 and that may be the entire base station 310 or a component of base station 310, such as TX processor 316, RX processor 370, and / or controller / processor 375). The method may be performed by a PCell, SCell, or PSCell for the UE. Optional aspects are indicated by dashed lines. The method may improve random access between a base station and a UE by providing multiple transmission opportunities and applying beam sweeping to random access transmissions. Aspects may help avoid failures due to interference, blockage, etc. Aspects of the method may help improve the reliability of random access and reduce the latency of random access.

[0087] At 1002, the base station receives a beam report from the UE that includes beam measurement information. The base station may be a PCell, SCell, or PSCell for the UE. The beam report may include an L1 beam report and / or an L3 beam report. The beam report may be based on an L1 / L3 measurement configuration, such as described in conjunction with Figure 5 For example, reception of the beam report may be performed by the beam reporting component 1240 of the apparatus 1202 in Figure 12 .

[0088] At 1004, the base station receives a first random access message from the UE using one or more beams based on random access measurements that are based on measurements different from the beam measurement information included in the beam report. As described in conjunction with Figure 5 , 8As described in 9, the UE may send Msg 1 to the base station based on one or more beams of random access measurement using reference signals from the base station. The random access measurement may be based on a random access configuration. It may be performed, for example, by the Msg 1 component 1242 of the apparatus 1202 in Figure 12 to receive the first random access message.

[0089] As shown in 1005, the base station may select multiple beams to send a second random access message to the UE based on the beam measurement information received at 1002. At 1004, one or more of the multiple beams (and one or more associated receiver beams of the UE) may be different from the beam on which the base station receives Msg 1 (and which is sent by the UE). For example, the selection may be performed by the beam selection component 1244 of the apparatus 1202 in Figure 12 .

[0090] At 1006, the base station sends the second random access message to the UE using multiple beams, which are selected based on a beam report from the UE (e.g., at 1005). The transmission may be performed, for example, by the Msg 2 component 1246 of the apparatus 1202 in Figure 12 . The first random access message may be received using a first beam selected based on random access measurement, and the second random access message may be sent using a second beam selected based on the beam measurement information included in the beam report. The first beam may be different from the second beam. In some examples, the beams may be the same, but are selected based on different measurement information. The second random access message may be sent using a single TRP, for example, as shown in Figure 7A . In another example, the second random access message may be sent using multiple TRPs, for example, as shown in Figure 8 . Multiple beams may be used for time division multiplexing of the second random access message, for example, as shown in Figure 7A . Multiple beams may be used for frequency division multiplexing of the second random access message, for example, as shown in Figure 7B . The second random access message may include a control channel (e.g., PDCCH) sent using multiple beams, for example, as described in conjunction with Figure 8 . The second random access message may include a shared channel (PDSCH) sent using multiple beams, for example, as described in conjunction with Figure 8 .

[0091] Figure 11FIG. 1100 is a schematic diagram showing an example of a hardware implementation for device 1102. Device 1102 is a UE and includes a cellular baseband processor 1104 (also referred to as a modem) coupled to a cellular RF transceiver 1122 and one or more subscriber identity module (SIM) cards 1120, an application processor 1106 coupled to a secure digital (SD) card 1108 and a screen 1110, a Bluetooth module 1112, a wireless local area network (WLAN) module 1114, a global positioning system (GPS) module 1116, and a power supply 1118. The cellular baseband processor 1104 communicates with UE 104 and / or BS 102 / 180 via the cellular RF transceiver 1122. The cellular baseband processor 1104 may include a computer-readable medium / memory. The computer-readable medium / memory may be non-transitory. The cellular baseband processor 1104 is responsible for general processing, including executing software stored on the computer-readable medium / memory. When executed by the cellular baseband processor 1104, the software causes the cellular baseband processor 1104 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 1104 when executing the software. The cellular baseband processor 1104 further includes a receiving component 1130, a communication manager 1132, and a transmitting component 1134. The communication manager 1132 includes one or more of the components shown. The components within the communication manager 1132 may be stored in the computer-readable medium / memory and / or configured as hardware within the cellular baseband processor 1104. The cellular baseband processor 1104 may be a component of UE350 and may include at least one of a TX processor 368, an RX processor 356, and a controller / processor 359 and / or a memory 360. In one configuration, device 1102 may be a modem chip and include only the baseband processor 1104, and in another configuration, device 1102 may be an entire UE (e.g., see Figure 3 350) and include additional modules of device 1102.

[0092] The communication manager 1132 includes a beam reporting component 1140 configured to send a beam report including beam measurement information to a base station, e.g., as described in conjunction with Figure 9 904 in. The communication manager 1132 further includes a measurement component 1142 configured to perform L1 / L3 beam measurements or perform random access beam measurements, e.g., as described in conjunction with Figure 9as described in 902 and / or 906 thereof. The communication manager 1132 further includes a beam selection component 1144 that receives as input beam measurements in the form of beam measurements from the measurement component 1142 and / or beam measurement information from the beam reporting component 1140, and is configured to select one or more beams for transmitting a first random access message (e.g., Msg 1) based on random access measurements and / or select multiple beams for monitoring a second random access message (e.g., Msg 2) based on beam measurement information reported to the base station (e.g., as described in Figure 9 908 and / or 912 thereof). The communication manager 1132 further includes a Msg 1 component 1146 that receives as input in the form of the selected beams from the beam selection component 1144, and is configured to use one or more beams based on random access measurements to transmit a first random access message to the base station for reception, the random access measurements being based on measurements different from the beam measurement information included in the beam report, e.g., as described in conjunction with Figure 9 910 thereof. The communication manager 1132 further includes a Msg 2 component 1148 that receives as input in the form of the selected beams from the beam selection component 1144, and is configured to use multiple beams to monitor for a second random access message from the base station, the beams being selected based on the beam report, e.g., as described in conjunction with Figure 9 914 thereof.

[0093] The apparatus may include additional components that perform each block of the algorithm in the Figure 9 flowchart and / or aspects described in conjunction with the UE in Figures 4 - 8 . Accordingly, Figure 9 each block of the above flowchart and / or aspects described in conjunction with the UE in Figures 4 - 8 may be performed by components, and the apparatus may include one or more of these components. The components may be one or more hardware components specifically configured to perform the process / algorithm, implemented by a processor configured to perform the process / algorithm, stored in a computer-readable medium for implementation by a processor, or some combination thereof.

[0094] In one configuration, device 1102 (particularly cellular baseband processor 1104) includes units for sending a beam report including beam measurement information to a base station. Device 1102 may also include units for sending a first random access message to the base station for reception using one or more beams based on random access measurements, where the random access measurements are based on measurements different from the beam measurement information included in the beam report. The device may further include units for monitoring a second random access message from the base station using multiple beams, where the beams are selected based on the beam report. The above units may be one or more of the above components of device 1102 configured to perform the functions described by the above units. As described above, device 1102 may include TX processor 368, RX processor 356, and controller / processor 359. Accordingly, in one configuration, the above units may be TX processor 368, RX processor 356, and controller / processor 359 configured to perform the functions described by the above units.

[0095] Figure 12 FIG. 1200 is a schematic diagram showing an example of a hardware implementation for device 1202. Device 1202 is a BS and includes a baseband unit 1204. The baseband unit 1204 may communicate with UE 104 via a cellular RF transceiver 1222. The baseband unit 1204 may include a computer-readable medium / memory. The baseband unit 1204 is responsible for general processing, including executing software stored on the computer-readable medium / memory. When executed by the baseband unit 1204, the software causes the baseband unit 1204 to perform the various functions described above. The computer-readable medium / memory may also be used to store data manipulated by the baseband unit 1204 when executing the software. The baseband unit 1204 further includes a receiving component 1230, a communication manager 1232, and a transmitting component 1234. The communication manager 1232 includes one or more of the components shown. The components within the communication manager 1232 may be stored in the computer-readable medium / memory and / or configured as hardware within the baseband unit 1204. The baseband unit 1204 may be a component of BS 310 and may include at least one of TX processor 316, RX processor 370, and controller / processor 375 and / or memory 376.

[0096] The communication manager 1232 includes a beam report component 1240 that receives a beam report including beam measurement information from the UE, e.g., as described in connection with Figure 10 1002 in. The communication manager 1232 also includes a Msg 1 component 1242 configured to receive a first random access message from the UE using one or more beams based on random access measurements, where the random access measurements are based on measurements different from the beam measurement information included in the beam report, e.g., as described in connection with Figure 10as described in 1004. The communication manager 1232 also includes a beam selection component 1244 that receives as input in the form of beam measurement information from the beam reporting component 1240, and is configured to select multiple beams to send a second random access message to the UE based on the beam measurement information, e.g., as described in conjunction with Figure 10 as described in 1005. The communication manager 1232 also includes a Msg 2 component 1246 that is configured to send a second random access message to the UE using multiple beams, the multiple beams being selected based on a beam report from the UE, e.g., as described in conjunction with Figure 10 as described in 1006.

[0097] The apparatus may include performing Figure 10 each block in the algorithm of the flowchart of and / or aspects of the base station or cell description in conjunction with Figures 4 - 8 as described in. Accordingly, Figure 10 each block in the flowchart of and / or aspects of the base station or cell description in conjunction with Figures 4 - 8 as described in may be performed by components, and the apparatus may include one or more of these components. The components may be one or more hardware components specifically configured to perform the process / algorithm, implemented by a processor configured to perform the process / algorithm, stored in a computer-readable medium for implementation by a processor, or some combination thereof.

[0098] In one configuration, the apparatus 1202 (especially the baseband unit 1204) includes units for receiving a beam report from the UE that includes beam measurement information. The apparatus 1202 may also include units for receiving a first random access message from the UE using one or more beams based on random access measurements that are based on measurements different from the beam measurement information included in the beam report. The apparatus 1202 may also include units for sending a second random access message to the UE using multiple beams, the multiple beams being selected based on a beam report from the UE. The above units may be one or more of the above components of the apparatus 1202 configured to perform the functions described by the above units. As described above, the apparatus 1202 may include a TX processor 316, an RX processor 370, and a controller / processor 375. Accordingly, in one configuration, the above apparatus may be the TX processor 316, the RX processor 370, and the controller / processor 375 configured to perform the functions described by the above apparatus.

[0099] The following aspects are illustrative only and may be combined with other aspects or teachings described herein, but are not limited thereto.

[0100] Aspect 1 includes a method for wireless communication at a UE, comprising: sending a beam report including beam measurement information to a base station; using one or more beams based on random access measurement to send a first random access message to the base station for reception, where the random access measurement is different from the beam measurement information included in the beam report; and using multiple beams to monitor a second random access message from the base station, where the beams are selected based on the beam report.

[0101] In aspect 2, the method according to aspect 1 further comprises: the first random access message is sent using a first beam selected based on the random access measurement, and the second random access message is received using a second beam selected based on the beam measurement information included in the beam report.

[0102] In aspect 3, the method according to aspect 2 further comprises: the first beam is different from the second beam.

[0103] In aspect 4, the method according to any one of aspects 1 - 3 further comprises: the beam report includes at least one of an L1 beam report or an L3 beam report.

[0104] In aspect 5, the method according to any one of aspects 1 - 4 further comprises: the second random access message is received from a single TRP.

[0105] In aspect 6, the method according to any one of aspects 1 - 4 further comprises: the second random access message is received from multiple TRPs.

[0106] In aspect 7, the method according to any one of aspects 1 - 6 further comprises: the second random access message is time - division multiplexed using the multiple beams.

[0107] In aspect 8, the method according to any one of aspects 1 - 7 further comprises: the second random access message is frequency - division multiplexed using the multiple beams.

[0108] In aspect 9, the method according to any one of aspects 1 - 8 further comprises: the second random access message includes a control channel sent using the multiple beams.

[0109] In aspect 10, the method according to any one of aspects 1 - 9 further comprises: the second random access message includes a shared channel sent using the multiple beams.

[0110] In aspect 11, the method according to any one of aspects 1 - 10 further comprises: the second random access message is received from the PCell for the UE.

[0111] In aspect 12, the method according to any one of aspects 1 - 10 further comprises: the second random access message is received from a SCell for the UE.

[0112] In aspect 13, the method according to any one of aspects 1 - 10 further comprises: the second random access message is received from a PSCell for the UE.

[0113] Aspect 14 is a device comprising: one or more processors; and one or more memories in electronic communication with the one or more processors storing instructions executable by the one or more processors to cause the device to implement the method in any one of aspects 1 - 13.

[0114] Aspect 15 is a system or apparatus comprising units for implementing the method in any one of aspects 1 - 13 or implementing the apparatus in any one of aspects 1 - 13.

[0115] Aspect 16 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 - 13.

[0116] Aspect 17 is a method of wireless communication at a base station, comprising: receiving, from a UE, a beam report comprising beam measurement information; receiving, from the UE, a first random access message using one or more beams based on random access measurements, the random access measurements being based on measurements different from the beam measurement information included in the beam report; and transmitting, to the UE, a second random access message using a plurality of beams selected based on the beam report from the UE.

[0117] In aspect 18, the method according to aspect 17 further comprises: the first random access message is received using a first beam selected based on the random access measurements, and the second random access message is transmitted using a second beam selected based on the beam measurement information included in the beam report.

[0118] In aspect 19, the method according to aspect 17 or aspect 18 further comprises: the first beam is different from the second beam.

[0119] In aspect 20, the method according to any one of aspects 17 - 19 further comprises: the beam report includes at least one of an L1 beam report or an L3 beam report.

[0120] In aspect 21, the method according to any one of aspects 17 - 20 further includes: the second random access message is sent using a single TRP.

[0121] In aspect 22, the method according to any one of aspects 17 - 20 further includes: the second random access message is sent using multiple TRPs.

[0122] In aspect 23, the method according to any one of aspects 17 - 22 further includes: the second random access message is time - division multiplexed using the multiple beams.

[0123] In aspect 24, the method according to any one of aspects 17 - 23 further includes: the second random access message is frequency - division multiplexed using the multiple beams.

[0124] In aspect 25, the method according to any one of aspects 17 - 24 further includes: the second random access message includes a control channel sent using the multiple beams.

[0125] In aspect 26, the method according to any one of aspects 17 - 25 further includes: the second random access message includes a shared channel sent using the multiple beams.

[0126] In aspect 27, the method according to any one of aspects 17 - 26 further includes: the method is executed by the PCell for the UE.

[0127] In aspect 28, the method according to any one of aspects 17 - 26 further includes: the method is executed by the SCell for the UE.

[0128] In aspect 29, the method according to any one of aspects 17 - 26 further includes: the method is executed by the PSCell for the UE.

[0129] Aspect 30 is a device, including: one or more processors; and one or more memories in electronic communication with the one or more processors and storing instructions, the instructions being executable by the one or more processors to cause the device to implement the method according to any one of aspects 17 - 29.

[0130] Aspect 31 is a system or apparatus, including units for implementing the method according to any one of aspects 17 - 29 or implementing the apparatus according to any one of aspects 17 - 29.

[0131] Aspect 32 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 of any one of aspects 17 - 29.

[0132] It is to be understood that the specific order or hierarchy of the blocks in the disclosed process / flowchart is illustrative of example methods. It is to be understood that based on design preferences, the specific order or hierarchy of the blocks in the process / flowchart can be rearranged. Additionally, some blocks can be combined or omitted. The appended method claims present the elements of the various blocks in an example order and are not meant to be limited to the specific order or hierarchy presented.

[0133] The foregoing description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein can 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 reference to a singular element is not intended to mean "one and only one" but "one or more" unless explicitly stated otherwise. The word "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 having an advantage over other aspects. Unless otherwise explicitly stated, the term "some" refers to 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 "any combination of A, B, C, or thereof" include any combination of A, B, and / or C and can include multiples of A, multiples of B, or multiples of C. 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 "any combination of A, B, C, or 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 will be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Additionally, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. The words "module", "mechanism", "element", "device", etc. are not intended to be substitutes for the word "unit". Accordingly, no claim element is to be construed as a functional unit unless the element is expressly recited using the phrase "unit for...".

Claims

1. A method for wireless communication at a user equipment (UE), comprising: Performing a first beam measurement before a first random access message Msg1; Sending a beam report including beam measurement information based on the first beam measurement; Sending the first random access message Msg1 to a base station using one or more beams, separately from the beam report, the one or more beams being based on random access measurements different from the first beam measurement; And Monitoring multiple beams for a second random access message Msg2 from the base station, the multiple beams being selected based on the first beam measurement reported in the beam report.

2. The method according to claim 1, wherein, The UE uses at least a first beam selected based on the random access measurement to send the first random access message Msg1, and the UE monitors the second random access message Msg2 on at least a second beam selected based on the beam measurement information included in the beam report.

3. The method according to claim 1, wherein A first beam for the first random access message Msg1 does not have a corresponding relationship with a second beam for the second random access message Msg2.

4. The method according to claim 1, wherein The beam report includes at least one of a layer 1 (L1) beam report or a layer 3 (L3) beam report.

5. The method according to claim 1, wherein, The second random access message Msg2 is received from a single transmit receive point (TRP).

6. The method according to claim 1, wherein, The second random access message Msg2 is received from multiple transmit receive points (TRP).

7. The method according to claim 1, wherein The second random access message Msg2 is time-division multiplexed using the multiple beams.

8. The method according to claim 1, wherein The second random access message Msg2 is frequency-division multiplexed using the multiple beams.

9. The method according to claim 1, wherein, The second random access message Msg2 includes a control channel transmitted using the multiple beams.

10. The method according to claim 1, wherein, The second random access message Msg2 includes a shared channel transmitted using the multiple beams.

11. The method according to claim 1, wherein, The second random access message Msg2 is received from a primary cell (PCell) for the UE.

12. The method according to claim 1, wherein, The second random access message Msg2 is received from a secondary cell (SCell) for the UE.

13. The method according to claim 1, wherein, The second random access message Msg2 is received from a primary and secondary cell (PSCell) for the UE.

14. 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 cause the apparatus to perform the following operations: Performing a first beam measurement before a first random access message Msg1; Sending a beam report including beam measurement information based on the first beam measurement; Sending the first random access message Msg1 to a base station using one or more beams, separately from the beam report, the one or more beams being based on random access measurements different from the first beam measurement; And Monitoring multiple beams for a second random access message Msg2 from the base station, the multiple beams being selected based on the first beam measurement reported in the beam report.

15. The apparatus according to claim 14, wherein, The at least one processor is configured to: transmit the first random access message Msg 1 using at least a first beam selected based on the random access measurement; and monitor the second random access message Msg 2 on at least a second beam selected based on the beam measurement information included in the beam report.

16. The device according to claim 14, wherein, The first beam for the first random access message Msg 1 and the second beam for the second random access message Msg 2 do not have a corresponding relationship.

17. A method for wireless communication at a base station, comprising: receiving, from a user equipment UE, a beam report including beam measurement information based on a first beam measurement before a first random access message Msg 1; receiving, from the UE, the first random access message Msg 1 on one or more beams based on a random access measurement, the random access measurement being different from the first beam measurement reported in the beam report, separately from the beam report; and transmitting a second random access message Msg 2 to the UE using a plurality of beams, the plurality of beams being selected based on the first beam measurement reported in the beam report from the UE.

18. The method according to claim 17, wherein, The first random access message Msg 1 is received on at least a first beam selected based on the random access measurement, and the second random access message Msg 2 is transmitted using at least a second beam selected based on the beam measurement information included in the beam report.

19. The method according to claim 17, wherein, The first beam for the first random access message Msg 1 and the second beam for the second random access message Msg 2 do not have a corresponding relationship.

20. The method according to claim 17, wherein, The beam report includes at least one of a layer 1 L1 beam report or a layer 3 L3 beam report.

21. The method according to claim 17, wherein The second random access message Msg 2 is transmitted using a single transmit receive point TRP.

22. The method according to claim 17, wherein, The second random access message Msg 2 is transmitted using a plurality of transmit receive points TRP.

23. The method according to claim 17, wherein The second random access message Msg 2 is time division multiplexed using the plurality of beams.

24. The method according to claim 17, wherein, The second random access message Msg 2 is frequency division multiplexed using the plurality of beams.

25. The method according to claim 17, wherein The second random access message Msg 2 includes a control channel transmitted using the plurality of beams.

26. The method according to claim 17, wherein, The second random access message Msg 2 includes a shared channel transmitted using the plurality of beams.

27. The method according to claim 17, wherein The method is performed by a primary cell PCell for the UE.

28. The method according to claim 17, wherein The method is performed by a secondary cell SCell for the UE.

29. The method according to claim 17, wherein, The method is performed by a primary and secondary cell PSCell for the UE.

30. An apparatus for wireless communication at a base station, comprising: a memory; and at least one processor coupled to the memory and configured to cause the apparatus to perform the following operations: receive, from a user equipment UE, a beam report including beam measurement information based on a first beam measurement before a first random access message Msg 1; Receive the first random access message Msg 1 from the UE separately from the beam report on one or more beams based on random access measurements, where the random access measurements are different from the first beam measurements reported in the beam report; And Transmit a second random access message Msg 2 to the UE using multiple beams, where the multiple beams are selected based on the first beam measurements reported in the beam report from the UE.

Images