Default PDSCH beam selection

Abstract

The UE determines a default beam for the Physical Downlink Shared Channel (PDSCH) independent of the beam used for the Physical Downlink Control Channel (PDCCH). The default PDSCH beam may be determined based on information received in a Medium Access Control-Control Element (MAC-CE) or Radio Resource Control (RRC) message, Downlink Control Information (DCI). The default PDSCH beam may be determined based on the state of at least one active Transmission Configuration Indicator (TCI) for the PDSCH.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. Provisional Application Serial No. 62 / 911,194, filed on October 4, 2019, and entitled “DefaultPDSCH Beam Selection,” and U.S. Patent Application Serial No. 17 / 028,714, filed on September 22, 2020, and entitled “DEFAULT PDSCH BEAM SELECTION,” which are hereby expressly incorporated by reference in their entireties. Technical Field

[0003] The present disclosure generally relates to communication systems, and more particularly, to wireless communications including PDSCH beams. Background Art

[0004] Wireless communication systems are widely deployed to provide a variety of telecommunication services such as telephony, video, data, messaging, and broadcasts. Typical wireless communication systems may employ multiple access technologies 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 a city, country, region, and even global level. One example telecommunication standard is 5G New Radio (NR). 5G NR is part of the continued mobile broadband evolution released by the 3rd Generation Partnership Project (3GPP) to meet new requirements associated with latency, reliability, security, scalability (for example, in the case of the Internet of Things (IoT)), and other requirements. 5G NR includes services associated with enhanced mobile broadband (eMBB), massive machine type communications (mMTC), and ultra-reliable low latency communications (URLLC). Some aspects of 5G NR may be based on the 4G Long Term Evolution (LTE) standard. There is a need for further improvements to 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] The following is a simplified summary of one or more aspects in order to provide a basic understanding of such aspects. This summary is not an exhaustive overview 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 will be presented later.

[0007] In one aspect of the present disclosure, a method, a computer-readable medium, and an apparatus are provided. In some examples, the apparatus may be a user equipment (UE). If information is received in a medium access control-control element (MAC-CE), a radio resource control (RRC) message, a downlink control information (DCI), or a message activating at least one transmission configuration indication (TCI) state for a physical downlink shared channel (PDSCH), the apparatus determines a default beam for the PDSCH independent of a beam used for the physical downlink control channel (PDCCH). The apparatus then uses the default beam to receive the PDSCH from a base station.

[0008] In one aspect of the present disclosure, a method, computer-readable medium, and apparatus for wireless communication are provided. In some examples, the apparatus may be a base station. The apparatus receives an indication from a UE of a capability for determining a default beam for a PDSCH independent of a beam for a PDCCH. The apparatus sends information to the UE in a MAC-CE, an RRC message, a DCI, or a message activating at least one TCI state for the PDSCH. The apparatus sends a scheduling DCI that schedules the PDSCH using a scheduling offset that is less than a threshold; and based on the information sent to the UE in the MAC-CE, the RRC message, the DCI, or the message activating at least one TCI state for the PDSCH, sends the PDSCH to the UE using the default beam.

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

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

[0011] Figure 2A 、 2B, 2C and 2D are diagrams showing examples of a first 5G / NR frame, a DL channel within a 5G / NR subframe, a second 5G / NR frame, and a UL channel within a 5G / NR subframe, respectively.

[0012] Figure 3 is a schematic diagram illustrating an example of a base station and a user equipment (UE) in an access network.

[0013] Figure 4A An example of beam-based communication between a UE and a base station is shown.

[0014] Figure 4B An example of DCI scheduling PDSCH transmission is shown.

[0015] Figure 5 An example of a MAC-CE that may be used to determine the TCI state for the default PDSCH is shown.

[0016] Figure 6 An example communication flow between a UE and a base station is shown.

[0017] Figure 7 Flowchart of a method of wireless communication that includes determining a default PDSCH beam independent of a PDCCH beam.

[0018] Figure 8 is a schematic diagram illustrating an example of a hardware implementation for an example apparatus.

[0019] Figure 9 is a flow chart of a method of wireless communication that includes using a default PDSCH beam independent of a PDCCH beam.

[0020] Figure 10 is a schematic diagram illustrating an example of a hardware implementation for an example apparatus. DETAILED DESCRIPTION

[0021] The detailed description set forth below in conjunction with the accompanying drawings is intended as a description of various configurations and is not intended to represent the only configurations in which the concepts described herein may be implemented. The detailed description includes specific details for the purpose of providing a thorough understanding of the various concepts. However, it will be apparent to those skilled in the art that these concepts may be implemented without these specific details. In some instances, well-known structures and components are shown in block diagram form to avoid obscuring such concepts.

[0022] Several aspects of telecommunication systems will now be presented with reference to various apparatuses and methods. These apparatuses and methods will be described in the following detailed description and illustrated in the accompanying drawings by various blocks, components, circuits, processes, algorithms, etc. (collectively referred to as "elements"). These elements may be implemented using electronic hardware, computer software, or any combination thereof. Whether these elements are implemented as hardware or software depends on the specific application and the design constraints imposed on the overall system.

[0023] For example, an element or any part of an element or any combination of elements can be implemented as a "processing system", which includes one or more processors. The example of a processor includes: a microprocessor, a microcontroller, a graphics processing unit (GPU), a central processing unit (CPU), an application processor, a digital signal processor (DSP), a reduced instruction set operation (RISC) processor, a system on a chip (SoC), a baseband processor, a field programmable gate array (FPGA), a programmable logic device (PLD), a state machine, a gated logic, a discrete hardware circuit, and other suitable hardware configured to perform the various functions described throughout this disclosure. One or more processors in a processing system can execute software. Whether referred to as software, firmware, middleware, microcode, hardware description language or other names, software should be broadly interpreted as meaning an instruction, an instruction set, a code, a code segment, a program code, a program, a subroutine, a software component, an application, a software application, a software package, a routine, a subroutine, an object, an executable file, a thread of execution, a process, a function etc.

[0024] Accordingly, in one or more exemplary embodiments, the described functions can be implemented with hardware, software or any combination thereof. If implemented with software, the functions can be stored on a computer-readable medium or encoded as one or more instructions or codes on a computer-readable medium. Computer-readable media include computer storage media. Storage media can be any available medium 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, a combination of the aforementioned types of computer-readable media, or any other medium that can be used to store computer-executable code in the form of instructions or data structures that can be accessed by a computer.

[0025] Figure 11 is a schematic diagram illustrating an example of a wireless communication system and access network 100. The wireless communication system (also referred to as a wireless wide area network (WWAN)) includes a base station 102, a UE 104, an evolved packet core (EPC) 160, and another core network 190 (e.g., a 5G core (5GC)). The base station 102 may include a macro cell (a high-power cellular base station) and / or a small cell (a low-power cellular base station). A macro cell includes a base station. Small cells include femto cells, pico cells, and micro cells.

[0026] Base stations 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., an S1 interface). Base stations 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. Among other functions, the base stations 102 can perform one or more of the following functions: transmission of user data, radio channel encryption and decryption, 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, RAN information management (RIM), paging, positioning, and transmission of warning messages. The base stations 102 can communicate with each other directly or indirectly (eg, through the EPC 160 or the core network 190) via a third backhaul link 134 (eg, an X2 interface). The third backhaul link 134 can be wired or wireless.

[0027] Base stations 102 can communicate wirelessly with UEs 104. Each of base stations 102 can provide communication coverage for a corresponding geographic coverage area 110. There can be overlapping geographic coverage areas 110. For example, a small cell 102′ can have a coverage area 110′ that overlaps with the coverage area 110 of one or more macro base stations 102. A network that includes both small cells and macro cells can be referred to as a heterogeneous network. A heterogeneous network can also include home evolved Node Bs (eNBs) (HeNBs), which can provide services to a restricted group known as a closed subscriber group (CSG). The communication link 120 between base station 102 and UE 104 can include uplink (UL) (also known as reverse link) transmissions from UE 104 to base station 102 and / or downlink (DL) (also known as forward link) transmissions 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 spectrum with a bandwidth of up to Y MHz (e.g., 5, 10, 15, 20, 100, 400, etc. MHz) per carrier allocated in a carrier aggregation of up to a total of Yx MHz (x component carriers) for transmission in each direction. The carriers may be adjacent to each other or may not be adjacent to each other. The allocation of carriers may be asymmetric with respect to DL and UL (e.g., more or fewer carriers may be allocated for DL ​​than for UL). Component carriers may include a primary component carrier and one or more secondary component carriers. The primary component carrier may be referred to as a primary cell (PCell), and the secondary component carrier may be referred to as a secondary cell (SCell).

[0028] Certain UEs 104 may communicate with each other using device-to-device (D2D) communication links 158. The D2D communication links 158 may use the DL / UL WWAN spectrum. The D2D communication links 158 may use one or more sidelink channels, such as a physical sidelink broadcast channel (PSBCH), a physical sidelink discovery channel (PSDCH), a physical sidelink shared channel (PSSCH), and a physical sidelink control channel (PSCCH). D2D communication may be performed over a variety of wireless D2D communication systems, such as FlashLinQ, WiMedia, Bluetooth, ZigBee, Wi-Fi based on the IEEE 802.11 standard, LTE, or NR.

[0029] The wireless communication system may also include a Wi-Fi access point (AP) 150 that communicates with a Wi-Fi station (STA) 152 via a communication link 154 in the 5 GHz unlicensed spectrum. When communicating in the unlicensed spectrum, the STA 152 / AP 150 may perform a clear channel assessment (CCA) before communicating to determine whether the channel is available.

[0030] The small cell 102' can operate in licensed and / or unlicensed spectrum. When operating in the unlicensed spectrum, the small cell 102' can employ NR and use the same 5 GHz unlicensed spectrum as the 5 GHz unlicensed spectrum used by the Wi-Fi AP 150. The small cell 102' employing NR in the unlicensed spectrum can improve coverage and / or increase capacity of the access network.

[0031] Base station 102 (whether a small cell 102' or a large cell (e.g., a macro base station)) may include and / or be referred to as an eNB, gNodeB (gNB), or another type of base station. Some base stations 180 (such as gNBs) may operate in the traditional sub-6 GHz spectrum, in millimeter wave (mmW) frequencies, and / or near-mmW frequencies to communicate with UE 104. When base station 180 operates in mmW or near-mmW frequencies, base station 180 may be referred to as a mmW base station. Extremely high frequency (EHF) is a portion of the RF spectrum in the electromagnetic spectrum. EHF has a range of 30 GHz to 300 GHz and has a wavelength between 1 mm and 10 mm. Radio waves in this band may be referred to as millimeter waves. Near-mmW can extend down to frequencies of 3 GHz and have a wavelength of 100 mm. Super high frequency (SHF) bands extend between 3 GHz and 30 GHz and are also referred to as centimeter waves. Communications using the mmW / near-mmW radio frequency bands (e.g., 3 GHz–300 GHz) have extremely high path loss and short range. A mmW base station (e.g., base station 180) may utilize beamforming 182 with UE 104 to compensate for the extremely high path loss and short range. Base station 180 and UE 104 may each include multiple antennas (such as antenna elements, antenna panels, and / or antenna arrays) to facilitate beamforming.

[0032] Base station 180 may transmit beamformed signals in one or more transmit directions 182′ to UE 104. UE 104 may receive beamformed signals from base station 180 in one or more receive directions 182″. UE 104 may also transmit beamformed signals in one or more transmit directions to base station 180. Base station 180 may receive beamformed signals in one or more receive directions from UE 104. Base station 180 / UE 104 may perform beam training to determine the best receive direction and transmit direction for each of base station 180 / UE 104. The transmit direction and receive direction for base station 180 may be the same or different. The transmit direction and receive direction for UE 104 may be the same or different.

[0033] 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. MME 162 may communicate with a Home Subscriber Server (HSS) 174. MME 162 is a control node that handles signaling between UE 104 and EPC 160. Generally, MME 162 provides bearer and connection management. All user Internet Protocol (IP) packets are transmitted through Serving Gateway 166, which itself is connected to PDN Gateway 172. PDN Gateway 172 provides UE IP address allocation and other functions. PDN Gateway 172 and BM-SC 170 are connected to IP Services 176. IP Services 176 may include the Internet, an intranet, an IP Multimedia Subsystem (IMS), PS streaming services, and / or other IP services. The BM-SC 170 may provide functionality for MBMS user service provisioning 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 broadcasting a specific service, and may be responsible for session management (start / stop) and collecting eMBMS-related billing information.

[0034] 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 unit (UDM) 196. The AMF 192 is a control node that handles signaling between the UE 104 and the core network 190. Typically, the AMF 192 provides QoS flow and session management. All user Internet Protocol (IP) packets are transported through the UPF 195. The UPF 195 provides UE IP address allocation and other functions. The UPF 195 is connected to the IP service 197. The IP service 197 may include the Internet, an intranet, an IP multimedia subsystem (IMS), a PS streaming service, and / or other IP services.

[0035] A base station may include and / or be referred to as a gNB, Node B, eNB, access point, base transceiver station, radio base station, wireless transceiver, transceiver functional unit, basic service set (BSS), extended service set (ESS), transmit receive point (TRP), or some other appropriate terminology. Base station 102 provides an access point to EPC 160 or core network 190 for UE 104. Examples of UE 104 include a cellular phone, a smartphone, a Session Initiation Protocol (SIP) phone, a laptop, a personal digital assistant (PDA), a satellite radio unit, a global positioning system, a multimedia device, a video device, a digital audio player (e.g., an MP3 player), a camera, a game console, a tablet device, a smart device, a wearable device, a vehicle, an electric meter, a gas pump, a large or small kitchen appliance, a healthcare device, an implant, a sensor / actuator, a display, or any other similarly functional device. Some of UE 104 may be referred to as IoT devices (e.g., a parking meter, a gas pump, an oven, a vehicle, a heart monitor, etc.). UE 104 may also be referred to as a station, a mobile station, a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communication device, a remote device, a mobile subscriber station, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, a user agent, a mobile client, a client, or some other appropriate terminology.

[0036] Refer again Figure 1In certain aspects, the UE 104 may include a default PDSCH beam component 198 configured to select a TCI state for a default PDSCH beam. The TCI state for the default PDSCH beam may be selected based on a medium access control-control element (MAC-CE). If no MAC-CE is received, the UE may use a different rule or mechanism to determine the default PDSCH beam. For example, the default PDSCH beam may be determined based on the previous rule. Alternatively, the default PDSCH beam may be determined based on the QCL of the CORESET with the lowest ID.

[0037] The default PDSCH beam may be different from any of the PDCCH beams used for the UE. The default PDSCH beam may be selected based on the activated PDSCH TCI state with the lowest TCI state ID. The default PDSCH beam may be different from any PDCCH beam. If there is no activated PDSCH TCI state, a different rule or mechanism may be used to determine the default PDSCH beam. For example, the default PDSCH beam may be determined based on the previous rule. Alternatively, the default PDSCH beam may be determined based on the QCL of the CORESET with the lowest ID.

[0038] The base station 102 or 180 may include a default PDSCH beam component 199 configured to receive an indication of a capability for determining a default beam for the PDSCH independent of a beam for the PDCCH from the UE 104. The default PDSCH beam component 199 may be configured to send information to the UE in a MAC-CE, an RRC message, a DCI, or a message activating at least one TCI state for the PDSCH, and to transmit the PDSCH to the UE using the default beam based on the information sent to the UE in the MAC-CE, the RRC message, the DCI, or the message activating at least one TCI state for the PDSCH.

[0039] Although the following description 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.

[0040] Figure 2A is a diagram 200 illustrating an example of a first subframe within a 5G / NR frame structure. Figure 2B is a diagram 230 showing an example of DL channels within a 5G / NR subframe. Figure 2C is a diagram 250 illustrating an example of a second subframe within a 5G / NR frame structure. Figure 2Dis a diagram 280 showing an example of UL channels within a 5G / NR subframe. The 5G / NR frame structure can be frequency division duplex (FDD) (wherein, for a particular set of subcarriers (carrier system bandwidth), subframes within that subcarrier set are dedicated to either DL or UL), or can be time division duplex (TDD) (wherein, for a particular set of subcarriers (carrier system bandwidth), subframes within that subcarrier set are dedicated to both DL and UL). Figure 2A 、 2C In the example provided, the 5G / NR frame structure is assumed to be TDD, where subframe 4 is configured with slot format 28 (most of which are DL), where D is DL, U is UL, and F is flexible between DL / UL, and subframe 3 is configured with slot format 1 (all of which are UL). Although subframes 3 and 4 are shown using 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. Other slot formats 2-61 include a mix of DL, UL, and flexible symbols. The UE is configured with the slot format (dynamically configured by DL control information (DCI) or semi-statically / statically controlled by radio resource control (RRC) signaling) via the received slot format indicator (SFI). It should be noted that the following description also applies to the 5G / NR frame structure as TDD.

[0041] Other wireless communication technologies may have different frame structures and / or different channels. A frame (10ms) may be divided into 10 equally sized subframes (1ms). Each subframe may include one or more time slots. A subframe may also include mini-slots, which may include 7, 4, or 2 symbols. Each time slot may include 7 or 14 symbols, depending on the time slot configuration. For time slot configuration 0, each time slot may include 14 symbols, while for time slot configuration 1, each time slot may include 7 symbols. The symbols on the DL may be cyclic prefix (CP) OFDM (CP-OFDM) symbols. The symbols on the UL may be CP-OFDM symbols (for high throughput scenarios) or discrete Fourier transform (DFT) spread OFDM (DFT-s-OFDM) symbols (also known as single carrier frequency division multiple access (SC-FDMA) symbols) (for power-limited scenarios; limited to single stream transmission). The number of time slots within a subframe may be based on the time slot configuration and numerology. For slot configuration 0, different digital schemes μ0 to 4 allow 1, 2, 4, 8, and 16 slots per subframe, respectively. For slot configuration 1, different digital schemes 0 to 2 allow 2, 4, and 8 slots per subframe, respectively. Accordingly, for slot configuration 0 and digital scheme μ, there are 14 symbols / slot and 2 μtime slots / subframes. The subcarrier spacing and symbol length / duration are functions of the digital scheme. The subcarrier spacing can be equal to 2 μ *15kHz, where μ is the digital scheme 0 to 4. Thus, digital scheme μ=0 has a subcarrier spacing of 15kHz, and digital scheme μ=4 has a subcarrier spacing of 240kHz. Symbol length / duration is inversely related to the subcarrier spacing. Figures 2A-2D An example is provided for slot configuration 0 with 14 symbols per slot and a digital scheme μ=2 with 4 slots per subframe. The 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 may be one or more different bandwidth parts (BWPs) that are frequency-division multiplexed (see Figure 2B ). Each BWP can have a specific number scheme.

[0042] The resource grid can be used to represent the frame structure. Each time slot includes a resource block (RB) (also known as a physical RB (PRB)), which extends over 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.

[0043] like Figure 2A As shown in , some of the REs carry reference (pilot) signals (RS) for the UE. The RS may include a demodulation RS (DM-RS) (indicated as R for a specific configuration, but other DM-RS configurations are possible) and a channel state information reference signal (CSI-RS) for channel estimation at the UE. The RS may also include a beam measurement RS (BRS), a beam refinement RS (BRRS), and a phase tracking RS (PT-RS).

[0044] Figure 2BExamples of various DL channels within a subframe of a frame are shown. 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 comprising six RE groups (REGs), each REG comprising 12 consecutive REs in an OFDM symbol of an RB. The PDCCH within a BWP may be referred to as a control resource set (CORESET). The UE is configured to monitor PDCCH candidates in a PDCCH search space (e.g., common search space, UE-specific search space) during a PDCCH monitoring opportunity on the CORESET, where the PDCCH candidates have different DCI formats and different aggregation levels. Additional BWPs may be located at higher and / or lower frequencies across the channel bandwidth. The primary synchronization signal (PSS) may be within symbol 2 of a particular subframe of the frame. The PSS is used by the UE 104 to determine subframe / symbol timing and physical layer identification. The secondary synchronization signal (SSS) may be within symbol 4 of a particular subframe of the 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 aforementioned DM-RS. The physical broadcast channel (PBCH) (which carries 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 that is not sent through the PBCH (e.g., system information block (SIB)), and paging messages.

[0045] like Figure 2C As shown in , some of the REs carry DM-RSs for channel estimation at the base station (indicated as R for one specific configuration, but other DM-RS configurations are possible). The UE may send DM-RSs for the physical uplink control channel (PUCCH) and DM-RSs for the physical uplink shared channel (PUSCH). The PUSCH DM-RS may be sent in the first one or two symbols of the PUSCH. The PUCCH DM-RS may be sent in different configurations depending on whether a short PUCCH or a long PUCCH is sent and depending on the specific PUCCH format used. The UE may send a sounding reference signal (SRS). The SRS may be sent in the last symbol of the subframe. The SRS may have a comb structure, and the UE may send the SRS on one of the combs. The SRS may be used by the base station for channel quality estimation to enable frequency-dependent scheduling on the UL.

[0046] Figure 2DExamples of various UL channels within a subframe of a frame are shown. The PUCCH may be positioned as indicated in one configuration. The PUCCH carries uplink control information (UCI), such as scheduling requests, channel quality indicator (CQI), precoding matrix indicator (PMI), rank indicator (RI), and hybrid automatic repeat request (HARQ) ACK / NACK feedback. The PUSCH carries data and may additionally be used to carry buffer status reports (BSRs), power headroom reports (PHRs), and / or UCI.

[0047] Figure 3 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 may be provided to the controller / processor 375. The controller / processor 375 implements layer 3 and layer 2 functions. Layer 3 includes the radio resource control (RRC) layer, and layer 2 includes the service data adaptation protocol (SDAP) layer, the packet data convergence protocol (PDCP) layer, the radio link control (RLC) layer, and the medium access control (MAC) layer. The controller / processor 375 provides: RRC layer functions associated with the following: broadcast of system information (e.g., MIB, SIB), RRC connection control (e.g., RRC connection paging, RRC connection establishment, RRC connection modification, and RRC connection release), inter-radio access technology (RAT) mobility, and measurement configuration for UE measurement reporting; PDCP layer functions associated with the following: header compression / decompression, security (ciphering, deciphering, integrity protection, integrity verification), and handover support functions; RLC layer functions associated with the following: transmission of upper layer packet data units (PDUs), error correction through ARQ, concatenation, segmentation and reassembly of RLC service data units (SDUs), resegmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functions associated with the following: 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 through HARQ, priority handling, and logical channel prioritization.

[0048] The transmit (TX) processor 316 and receive (RX) processor 370 implement layer 1 functions associated with various signal processing functions. Layer 1 (which includes the physical (PHY) layer) can include error detection on the transmission channel, forward error correction (FEC) encoding / decoding of the transmission channel, interleaving, rate matching, mapping to the physical channel, modulation / demodulation of the physical channel, and MIMO antenna processing. The TX processor 316 handles the mapping to the signal constellation based on various modulation schemes (e.g., binary phase shift keying (BPSK), quadrature phase shift keying (QPSK), M-phase shift keying (M-PSK), M-quadrature amplitude modulation (M-QAM)). The coded and modulated symbols can then be split into parallel streams. Each stream can then be mapped to an OFDM subcarrier, multiplexed with a reference signal (e.g., a pilot) in the time and / or frequency domain, and then combined together using an inverse fast Fourier transform (IFFT) to produce a physical channel carrying a time-domain OFDM symbol stream. The OFDM stream is spatially precoded to generate multiple spatial streams. Channel estimates from a channel estimator 374 may be used to determine the coding and modulation schemes, as well as for spatial processing. The channel estimates may be derived based on a reference signal and / or channel condition feedback transmitted by the UE 350. Each spatial stream may then be provided to a different antenna 320 via a separate transmitter 318TX. Each transmitter 318TX may modulate an RF carrier with a corresponding spatial stream for transmission.

[0049] At the UE 350, each receiver 354RX receives a signal via its respective antenna 352. Each receiver 354RX recovers the information modulated onto the RF carrier and provides the information to a receive (RX) processor 356. The TX processor 368 and the RX processor 356 implement layer 1 functions associated with various signal processing functions. The RX processor 356 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 into a single OFDM symbol stream by the RX processor 356. The RX processor 356 then transforms the OFDM symbol stream from the time domain to the frequency domain using a fast Fourier transform (FFT). 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 point transmitted by the base station 310. These soft decisions can be based on channel estimates calculated by the channel estimator 358. The soft decisions are then decoded and deinterleaved to recover the data and control signals originally sent on the physical channel by the base station 310. The data and control signals are then provided to the controller / processor 359, which implements layer 3 and layer 2 functionality.

[0050] The controller / processor 359 may be associated with a memory 360 that stores program codes and data. The memory 360 may be referred to as a computer-readable medium. In the UL, the controller / processor 359 provides demultiplexing between transport and logical channels, packet reassembly, decryption, header decompression, and control signal processing to recover IP packets from the EPC 160. The controller / processor 359 is also responsible for error detection using ACK and / or NACK protocols to support HARQ operations.

[0051] Similar to the functions described for DL ​​transmissions performed in conjunction with 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: transmission of upper layer PDUs, error correction through ARQ, concatenation, segmentation and reassembly of RLC SDUs, resegmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functions associated with: mapping between logical channels and transport channels, multiplexing of MAC SDUs onto TBs, demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction through HARQ, priority handling, and logical channel prioritization.

[0052] The TX processor 368 may select an appropriate coding and modulation scheme and facilitate spatial processing using channel estimates derived by the channel estimator 358 from a reference signal or feedback transmitted by the base station 310. The spatial streams generated by the TX processor 368 may be provided via separate transmitters 354TX to different antennas 352. Each transmitter 354TX may modulate an RF carrier with a corresponding spatial stream for transmission.

[0053] At the base station 310, the UL transmission is processed in a manner similar to that described in conjunction with the receiver functionality at the UE 350. Each receiver 318RX receives a signal through its respective antenna 320. Each receiver 318RX recovers information modulated onto an RF carrier and provides the information to an RX processor 370.

[0054] The controller / processor 375 may be associated with a memory 376 that stores program codes and data. The memory 376 may be referred to as a computer-readable medium. In the UL, the controller / processor 375 provides demultiplexing between transport and logical channels, packet reassembly, decryption, header decompression, and control signal processing to recover IP packets from the UE 350. The IP packets from the controller / processor 375 may be provided to the EPC 160. The controller / processor 375 is also responsible for error detection using ACK and / or NACK protocols to support HARQ operations.

[0055] At least one of the TX processor 368, the RX processor 356, and the controller / processor 359 may be configured to perform operations related to Figure 1 Various aspects related to the default PDSCH beam selection component 198.

[0056] At least one of the TX processor 316, the RX processor 370, and the controller / processor 375 may be configured to perform operations related to Figure 1 Various aspects related to the default PDSCH beam component 199.

[0057] Figure 4A An example of beamforming communication 400 between a base station 402 and a UE 404 is shown. The base station 402 and the UE 404 may each include multiple antennas (such as antenna elements, antenna panels, and / or antenna arrays) to facilitate beamforming. The base station 402 may use one or more directional beams to transmit communications to the UE. The UE may use one or more directional beams to receive communications from the base station. Similarly, the UE 404 may use one or more directional beams to transmit communications to the base station 402, and the base station may use one or more directional beams to receive communications from the UE 404. The base station 402 or the UE 404 may perform beam training to determine the optimal receive and transmit directions for each of the base station 402 or the UE 404. The transmit and receive directions for the base station 402 may be the same or different. The transmit and receive directions for the UE 404 may be the same or different.

[0058] The UE may need to determine the beam to be used to receive communications from the base station. The beam may be different for different channels. The UE may determine one or more beams for monitoring or receiving the PDCCH from the base station. The UE may determine the beam for receiving the PDSCH from the base station. The base station may indicate the beam for the UE to use to receive the PDSCH from the base station. For example, the base station may indicate the beam for the UE to use in downlink control information (DCI), which schedules PDSCH transmission for the UE. The base station may configure one or more TCI states for the UE, for example, one or more PDSCH TCI states. The base station may then activate one or more of the configured PDSCH TCI states, for example, by sending a MAC-CE or DCI that activates the TCI state. The base station may configure one or more beams for the UE to monitor the PDCCH. For example, the base station may configure the UE to have one or more control resource sets (CORESETs), where each CORESET configuration includes beam information. Each CORESET may be associated with a CORESET identifier (ID).

[0059] There may be times when the UE does not receive an indication of the PDSCH beam in the DCI and / or does not receive a DCI with sufficient scheduling offset between the scheduling DCI and the scheduled PDSCH. K0 is the offset between the scheduling DCI and the scheduled PDSCH and may be indicated per time slot. For example, K0=0 may mean that the DCI and the scheduled PDSCH are in the same time slot. If K0=1, this means that the PDSCH is in the next time slot. Figure 4B Two examples of DCI and PDSCH transmissions for scheduling PDSCH are shown. In the first example 425, the scheduling offset K0 is less than the threshold offset, and the UE can determine the default beam for receiving PDSCH. In the second example 450, the scheduling offset K0 is greater than the threshold time length, and the UE can have time to determine the PDSCH beam based on the DCI. The threshold length for K0 can be based on the beam switching delay time. If the scheduling offset between the scheduling DCI and the scheduled PDSCH is less than the beam switching delay threshold, the UE can determine the default PDSCH beam to be used for receiving PDSCH from the base station. For example, the UE can use the default PDSCH beam to receive a PDSCH with K0=0, for example, which is scheduled in the same time slot as the DCI.

[0060] In other examples, the UE may not receive an indication of a PDSCH beam in the DCI and may determine a default PDSCH beam to use for receiving PDSCH from the base station.

[0061] Therefore, if the UE does not receive an indication of the PDSCH beam in the DCI, and / or the scheduling offset between the scheduling DCI and the scheduled PDSCH is less than the beam switching delay threshold, the UE can determine the default PDSCH beam for receiving PDSCH.

[0062] The default PDSCH beam may follow the QCL assumption of the CORESET with the lowest control resource set (CORESET) ID in the most recently monitored timeslot. To improve robustness to UE mobility, wide beams may be used to transmit / receive PDCCH, for example, both the base station and the UE may use wide beams. For example, the PDCCH beam may be wider than the beam used to transmit / receive PDSCH. However, if the default PDSCH beam follows the PDCCH wide beam, the throughput of PDSCH may be degraded. Table 1 shows example UE throughput results for a group of cells in Table 1, where there are multiple UEs per cell. The table is used to illustrate that using level 3 narrow beams at both the UE and the base station improves the intermediate UE throughput compared to using wider (or coarser) level 2 and level 1 beams at both the UE and the base station.

[0063] Table 1

[0064]

[0065] The present disclosure provides various ways for a UE to determine a default PDSCH beam independent of a PDCCH beam. Decoupling the default PDSCH beam for a UE from the PDCCH beam can enable the UE to use a default beam that is narrower than the PDCCH beam and can improve PDSCH throughput, for example, for a configuration where K0=0. In some examples, a UE may only support K0=0 and may repeatedly use the default PDSCH beam to receive PDSCH.

[0066] Determining a default PDSCH beam independently of the PDCCH beam may reduce data delivery latency. The reduction in data delivery latency may be helpful for applications such as URLLC communications or Industrial Internet of Things (IIoT) communications. Determining a default PDSCH beam independently of the PDCCH beam may improve UE power savings, for example, when operating using connected mode discontinuous reception (C-DRX). Determining a default PDSCH beam independently of the PDCCH beam (e.g., based on a CORESET configuration) may enable the UE to receive scheduled PDSCHs more quickly after a scheduled DCI and using a narrower beam that provides better throughput than a wider PDCCH-based beam. The various aspects presented herein may provide greater scheduling flexibility with respect to K0 while maintaining sustained throughput even when using a default PDSCH beam.

[0067] The UE 404 may select a TCI state for a default PDSCH beam. The default PDSCH beam may correspond to the beam used by the UE to receive the PDSCH when the scheduling offset between the scheduling DCI and the scheduled PDSCH is less than the beam switching delay threshold.

[0068] In some examples, the TCI state for the default PDSCH beam may be selected based on a Medium Access Control-Control Element (MAC-CE). The TCI state for the default PDSCH beam selected based on the MAC-CE may be different from any PDCCH beam for the UE.

[0069] If no MAC-CE is received, the UE may use different rules or mechanisms to determine the default PDSCH beam. For example, the default PDSCH beam may be determined based on a fallback rule. An example fallback rule may indicate that if the cell has one or more CORESETs configured, the default PDSCH beam follows the QCL assumption of the CORESET with the lowest CORESET ID in the most recently monitored timeslot. If the cell has no CORESETs configured, the default PDSCH beam may follow the activated PDSCH TCI state with the lowest TCI state ID on that cell.

[0070] Alternatively, the fallback rule may indicate that the default PDSCH beam will be determined based on the QCL of the CORESET with the lowest CORESET ID.

[0071] As an alternative to using MAC-CE to determine the default PDSCH beam, the UE may use information indicated by an RRC message and / or indicated in a DCI from the base station.

[0072] In some examples, the default PDSCH beam may be selected based on the activated PDSCH TCI state with the lowest TCI state ID. For example, even if a CORESET is configured for the UE, the default PDSCH beam may be based on the activated PDSCH TCI state with the lowest TCI state ID. The default PDSCH beam may be different from any PDCCH beam used for the UE. If there is no activated PDSCH TCI state, a different rule or mechanism may be used to determine the default PDSCH beam. For example, the default PDSCH beam may be determined based on a fallback rule. In this example, if the PDSCH TCI state has not been activated for the UE, the UE may determine the default PDSCH beam based on the QCL assumption of the CORESET with the lowest ID.

[0073] The MAC-CE used in the first implementation may include a new MAC-CE, for example, a MAC-CE for indicating the TCI state for the default PDSCH beam. Alternatively, the MAC-CE may be based on an existing MAC-CE. Figure 5 An example of a MAC-CE 500 that may be sent from a base station and used by a UE to determine the TCI state for a default PDSCH beam is shown. The MAC-CE may include a control element for indicating the activated PDSCH TCI state. One or more bits in the MAC-CE may indicate to the UE that the PDSCH TCI state is to be used for the default PDSCH beam. One or more bits may be reserved bits. For example, if Figure 5 If the reserved bit “R” in the MAC-CE in the QoS policy is set to 1, the control element may indicate the selection of a single indicated PDSCH TCI state as the default PDSCH beam.

[0074] Figure 6 An example communication flow 600 between a UE 602 and a base station 604 is shown. The first and / or second implementations may be applied when the UE 602 signals the corresponding capabilities to the base station 604 at 601. The base station 604 may send an indication 603 to the UE 602 regarding the use of this implementation to determine the TCI state of the default PDSCH beam independently of the PDCCH beam, for example, by setting a flag in an RRC message sent by the base station to the UE. If the flag is not set in the RRC message, the UE may employ another mechanism to determine the TCI state for the default PDSCH beam.

[0075] The base station may provide the information in any one of MAC-CE 605, DCI 607, or RRC message 609. As described in conjunction with the first implementation, the UE may use the information in MAC-CE 605 to determine, at 611, a default PDSCH beam that is different from any PDCCH beam used for the UE. If the UE does not receive this information in a MAC-CE, the UE may employ a fallback rule to determine the default beam for the PDSCH. The default rule may be based on the PDCCH beam used for the UE.

[0076] The UE may use the information in DCI 607 ​​to determine a default PDSCH beam at 611 that is different from any PDCCH beam used for the UE. If the UE does not receive this information in DCI 607, the UE may employ a fallback rule to determine the default beam for PDSCH. The default rule may be based on the PDCCH beam used for the UE.

[0077] The UE may use the information in the RRC message 609 to determine a default PDSCH beam at 611 that is different from any PDCCH beam used for the UE. If the UE does not receive this information in the RRC message 609, the UE may employ a fallback rule to determine the default beam for PDSCH. The default rule may be based on the PDCCH beam used for the UE.

[0078] As described in conjunction with the second implementation, the UE 602 may receive activation of a TCI state 610 from the base station 604. At 611, the UE may determine a default PDSCH beam based on the activated PDSCH TCI state (e.g., based on the lowest TCI state ID). If the UE does not have any activated TCI states, the UE may employ a fallback rule to determine a default beam for the PDSCH. The default rule may be based on the PDCCH beam for the UE.

[0079] After determining the default PDSCH beam at 611 , the UE may receive PDSCH 613 from the base station 604 using the default PDSCH beam.

[0080] Figure 7 700 is a flow chart of a method for wireless communication. The method may be performed by a UE (e.g., UE 104, 350, 404, 602; apparatus 802). Optional aspects are shown with dashed lines. The method enables the UE to determine a default PDSCH beam in a manner that improves throughput on the default PDSCH beam and increases scheduling flexibility for downlink communications.

[0081] As shown at 702, the UE may optionally transmit an indication of a capability for determining a default beam for PDSCH independent of a beam for PDCCH. This transmission may be performed, for example, by capability component 840 of communication manager 832 of apparatus 802. Figure 6 An example is shown in which UE 602 provides UE capabilities to base station 604.

[0082] As shown at 704, the UE may optionally receive an indicator from the base station, the indicator being used to instruct the UE to determine a default beam for the PDSCH independent of the beam used for the PDCCH. The indicator may be received in RRC signaling from the base station or in a MAC-CE. Receiving the indicator may be performed, for example, by the indicator component 842 of the communication manager 832 of the apparatus 802. Figure 6 An example is shown in which the base station 604 provides an indication to the UE 602 regarding determining a default PDSCH independent of a PDCCH beam (eg, based on the UE's ability to make such a determination).

[0083] At 708, if information is received in a MAC-CE, an RRC message, a DCI, or a message activating at least one TCI state for the PDSCH, the UE determines a default beam for the PDSCH independent of the beam used for the PDCCH. This determination may be performed, for example, by the default beam determination component 844 of the communication manager 832 of the apparatus 802. The UE may receive the information in a MAC-CE and, based on the information received in the MAC-CE, determine a default beam for the PDSCH independent of the beam used for the PDCCH. The MAC-CE may activate the PDSCH TCI state, and the UE may determine a default beam for the PDSCH based on the PDSCH TCI state indicated in the MAC-CE. The UE may receive the information in an RRC message and, based on the information received in the RRC message, determine a default beam for the PDSCH independent of the beam used for the PDCCH. The UE may receive the information in a DCI and, based on the information received in the DCI, determine a default beam for the PDSCH independent of the beam used for the PDCCH. The UE may receive this information in a message activating at least one TCI state for PDSCH and determine a default beam for PDSCH independent of the beam for PDCCH based on the activated TCI state for PDSCH with the lowest index.

[0084] For example, as shown at 706, the UE may determine whether information is received in a MAC-CE, an RRC message, a DCI, or a message activating a TCI state for the PDSCH. This determination may be performed by the information determination component 848 of the communication manager 832 of the apparatus 802. If the UE has received the information, the UE performs a determination of a default beam at 708. Figure 6 An example is shown in which the UE 602 determines the TCI state for the default PDSCH beam.

[0085] If the UE has not received the information, then at 712, the UE determines a default beam for the PDSCH based on a fallback rule. This determination may be performed, for example, by a default beam determination component 844 of the communication manager 832 of the apparatus 802. The fallback rule may include, for example, determining the default beam for the PDSCH based on a QCL relationship with a configured CORESET with a lowest CORESET ID (e.g., in the last slot) if one or more CORESETs are configured for the UE; and determining the default beam for the PDSCH based on an activated PDSCH TCI state with a lowest TCI state ID, for example, if no CORESETs are configured for the UE. For example, if the UE has not received activation of the PDSCH TCI state, then if one or more CORESETs are configured for the UE, the UE may determine the default beam for the PDSCH based on a QCL relationship with a configured CORESET with a lowest CORESET ID.

[0086] At 710, the UE receives a PDSCH from the base station using a default beam. This reception can be performed, for example, by the PDSCH component 846 of the communication manager 832 of the apparatus 802. For example, if the scheduling offset between the PDSCH and the scheduling DCI that schedules the PDSCH is less than a threshold (e.g., shorter than a beam switching threshold, such as if K0=0), the UE can receive the PDSCH from the base station using the default beam. In some examples, the default PDSCH beam can be narrower than the PDCCH beam (e.g., a beam with a QCL relationship with a CORESET).

[0087] Figure 8Schematic diagram 800 illustrates an example of a hardware implementation for an apparatus 802. Apparatus 802 is a UE and includes a cellular baseband processor 804 (also known as a modem) coupled to a cellular RF transceiver 822 and one or more subscriber identity module (SIM) cards 820; an application processor 806 coupled to a secure digital (SD) card 808 and a screen 810; a Bluetooth module 812; a wireless local area network (WLAN) module 814; a global positioning system (GPS) module 816; and a power supply 818. Cellular baseband processor 804 communicates with UE 104 and / or BS 102 / 180 via cellular RF transceiver 822. Cellular baseband processor 804 may include computer-readable media / memory. The computer-readable media / memory may be non-transitory. Cellular baseband processor 804 is responsible for general processing, including the execution of software stored on the computer-readable media / memory. When executed by cellular baseband processor 804, the software enables cellular baseband processor 804 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 804 when executing software. The cellular baseband processor 804 also includes a receive component 830, a communication manager 832, and a transmit component 834. The communication manager 832 includes one or more of the components shown. The components within the communication manager 832 may be stored in the computer-readable medium / memory and / or configured as hardware within the cellular baseband processor 804. The cellular baseband processor 804 may be a component of the UE 350 and may include at least one of the TX processor 368, the RX processor 356, and the controller / processor 359 and / or the memory 360. In one configuration, the apparatus 802 may be a modem chip and include only the baseband processor 804, and in another configuration, the apparatus 802 may be the entire UE (e.g., see Figure 3 350) and includes additional modules of device 802.

[0088] The communication manager 832 includes a capability component 840 configured to send an indication of a capability for determining a default beam for PDSCH independent of a beam for PDCCH, e.g., as in conjunction with Figure 7 The communication manager 832 also includes an indicator component 842 configured to receive an indicator from the base station for instructing the UE to determine a default beam for PDSCH independent of a beam for PDCCH, for example, as described in conjunction with Figure 7The communication manager 832 also includes a default beam determination component 844 configured to: determine a default beam for PDSCH independent of a beam for PDCCH if information is received in a MAC-CE, an RRC message, a DCI, or a message activating at least one TCI state of the PDSCH, for example, as combined with Figure 7 The communication manager 832 also includes a PDSCH component 846 that is configured to receive a PDSCH from a base station using a default beam, for example, as described in conjunction with Figure 7 The communication manager 832 also includes an information determination component 848 that is configured to determine whether information is received from a base station, for example, as described in conjunction with Figure 7 706 described in.

[0089] The apparatus may include performing the above Figure 7 Each box in the algorithm's flowchart or in Figure 6 Thus, the above-mentioned components may be performed by the UE. Figure 7 Each box in the flowchart and / or in Figure 6 The process / algorithm may include aspects of the process / algorithm performed by the UE, and the apparatus may include one or more of those 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.

[0090] In one configuration, the apparatus 802 (and specifically, the cellular baseband processor 804) includes: means for determining a default beam for PDSCH independent of a beam used for PDCCH if information is received in a MAC-CE, an RRC message, a DCI, or a message activating at least one TCI state for PDSCH; and means for receiving PDSCH from a base station using the default beam. The apparatus 802 may also include: means for applying a fallback rule to determine the default beam for PDSCH. The apparatus 802 may also include: means for sending an indication of the ability to determine a default beam for PDSCH independent of a beam used for PDCCH. The apparatus 802 may also include: means for receiving an indicator from the base station, the indicator indicating that the UE determines a default beam for PDSCH independent of a beam used for PDCCH. The above-mentioned means may be one or more of the above-mentioned components of the apparatus 802 configured to perform the functions recited by the above-mentioned means. As described above, the apparatus 802 may include the TX processor 368, the RX processor 356, and the controller / processor 359. Thus, in one configuration, the aforementioned means may be the TX processor 368, the RX processor 356, and the controller / processor 359 configured to perform the functions recited by the aforementioned means.

[0091] Figure 9 Flowchart 900 is a method of wireless communication. The method may be performed by a base station (e.g., base station 102, 180, 310, 402, 604; apparatus 1002). Optional aspects are shown with dashed lines. The method enables the base station to indicate or apply a default PDSCH beam in a manner that improves throughput on the default PDSCH beam and increases scheduling flexibility for downlink communications.

[0092] At 902 , a base station receives an indication of a capability from a UE to determine a default beam for a PDSCH independent of a beam for a PDCCH. This reception can be performed, for example, by capability component 1040 of communication manager 1032 of apparatus 1002 . Figure 6 An example is shown in which UE 602 provides UE capabilities to base station 604.

[0093] At 904, the base station may optionally transmit an indicator for instructing the UE to determine a default beam for the PDSCH independent of the beam used for the PDCCH. For example, the base station may transmit the indicator to the UE in RRC signaling or MAC-CE. Transmitting the indicator may be performed, for example, by the indicator component 1042 of the communication manager 1032 of the apparatus 1002. Figure 6An example is shown in which the base station 604 provides an indication to the UE 602 regarding determining a default PDSCH independent of a PDCCH beam (eg, based on the UE's ability to make such a determination).

[0094] At 906, the base station transmits information to the UE in a MAC-CE, an RRC message, a DCI, or a message activating at least one TCI state for the PDSCH. The base station may transmit the information in a MAC-CE. The MAC-CE may activate the PDSCH TCI state, and the default beam for the PDSCH may be based on the PDSCH TCI state indicated in the MAC-CE. The base station may transmit the information in an RRC message. The base station may transmit the information in a DCI. The base station may activate at least one TCI state for the PDSCH, and the default beam for the PDSCH may be based on the activated TCI state for the PDSCH with the lowest index. The transmitting may be performed by the information component 1048 of the communication manager 1032 of the apparatus 1002. Figure 6 Various examples of base station 604 providing this information to UE 602 are shown, such as 605, 607, 609, 610.

[0095] At 908, the base station transmits a scheduling DCI that schedules the PDSCH with a scheduling offset that is less than a threshold. This transmission may be performed, for example, by the DCI component 1044 of the communication manager 1032 of the apparatus 1002. For example, the DCI may indicate that the scheduling offset between the PDSCH and the scheduling DCI that schedules the PDSCH is less than a threshold, for example, shorter than a beam switching threshold, such as K0=0.

[0096] At 910, the base station transmits a PDSCH to the UE using a default beam based on information sent to the UE in a MAC-CE, an RRC message, a DCI, or a message activating at least one TCI state for the PDSCH. This transmission can be performed, for example, by the PDSCH component 1046 of the communication manager 1032 of the apparatus 1002. Figure 6 An example is shown where the base station 604 transmits PDSCH based on a default PDSCH beam that is independent of the PDCCH beam. In some examples, the default PDSCH beam can be narrower than the PDCCH beam (eg, a beam with a QCL relationship to a CORESET).

[0097] Figure 101000 is a schematic diagram illustrating an example of a hardware implementation for apparatus 1002. Apparatus 1002 is a base station and includes a baseband unit 1004. Baseband unit 1004 can communicate with UE 104 via a cellular RF transceiver. Baseband unit 1004 may include computer-readable media / memory. Baseband unit 1004 is responsible for general processing, including the execution of software stored on the computer-readable media / memory. When executed by baseband unit 1004, the software enables baseband unit 1004 to perform the various functions described above. The computer-readable media / memory may also be used to store data manipulated by baseband unit 1004 when executing the software. Baseband unit 1004 also includes a receiving component 1030, a communication manager 1032, and a transmitting component 1034. Communication manager 1032 includes one or more of the components shown. Components within communication manager 1032 may be stored in computer-readable media / memory and / or configured as hardware within baseband unit 1004. The baseband unit 1004 may be a component of the BS 310 and may include at least one of the TX processor 316 , the RX processor 370 , and the controller / processor 375 , and / or the memory 376 .

[0098] The communications manager 1032 includes a capability component 1040 configured to receive an indication of a UE capability for determining a default beam for PDSCH independent of a beam for PDCCH, e.g., as described in conjunction with Figure 9 The communication manager 1032 also includes an indicator component 1042 configured to send an indicator for instructing the UE to determine a default beam for PDSCH independent of a beam for PDCCH, for example, as described in conjunction with Figure 9 The communication manager 1032 also includes a DCI component 1044 configured to send a scheduling DCI that schedules the PDSCH with a scheduling offset less than a threshold, for example, as described in conjunction with Figure 9 The communication manager 1032 also includes a PDSCH component 1046, which is configured to use a default beam to send PDSCH to the UE, for example, as described in conjunction with Figure 9 The communication manager 1032 also includes an information component 1048, which is configured to send information to the UE in a MAC-CE, RRC message, DCI or activation of a PDSCH TCI state, for example, as described in conjunction with Figure 9 As described in 906.

[0099] The apparatus may include performing the above Figure 9 Each box in the algorithm's flowchart or in Figure 6 Thus, the above-mentioned components may be performed by the base station. Figure 9Each box in the flowchart and / or in Figure 6 The present invention relates to various aspects performed by a base station in the process / algorithm, and the apparatus may include one or more of those 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.

[0100] In one configuration, apparatus 1002 (and specifically, baseband unit 1004) includes means for receiving an indication from a UE of an ability to determine a default beam for PDSCH independent of a beam used for PDCCH. Apparatus 1002 may include means for sending information to the UE in a MAC-CE, an RRC message, a DCI, or a message activating at least one TCI state for PDSCH. Apparatus 1002 may include means for sending scheduling DCI that schedules PDSCH with a scheduling offset less than a threshold. Apparatus 1002 may include means for sending PDSCH to the UE using a default beam based on the information sent to the UE in a MAC-CE, an RRC message, a DCI, or a message activating at least one TCI state for PDSCH. Apparatus 1002 may include means for sending an indicator that indicates to the UE to determine a default beam for PDSCH independent of a beam used for PDCCH. The aforementioned means may be one or more of the aforementioned components of apparatus 1002 configured to perform the functions recited by the aforementioned means. As described above, the apparatus 1002 may include the TX processor 316, the RX processor 370, and the controller / processor 375. Thus, in one configuration, the aforementioned means may be the TX processor 316, the RX processor 370, and the controller / processor 375 configured to perform the functions recited by the aforementioned means.

[0101] The following examples are merely illustrative, and aspects thereof may be combined with aspects of other examples or teachings described herein without limitation.

[0102] Example 1 is a method of wireless communication at a UE, comprising: if information is received in a MAC-CE, an RRC message, a DCI, or a message activating at least one TCI state for a PDSCH, determining a default beam for the PDSCH independent of a beam used for the PDCCH; and using the default beam to receive the PDSCH from a base station.

[0103] In Example 2, the method according to Example 1 further includes: if a scheduling offset between the PDSCH and a scheduling DCI that schedules the PDSCH is less than a threshold, the UE uses the default beam to receive the PDSCH from the base station.

[0104] In Example 3, the method according to Example 1 or Example 2 further includes: the UE receives the information in the MAC-CE, and determines the default beam for the PDSCH independent of the beam used for the PDCCH based on the information received in the MAC-CE.

[0105] In Example 4, the method according to any one of Examples 1-3 further includes: the MAC-CE activating a PDSCH TCI state, and the UE determining the default beam for the PDSCH based on the PDSCH TCI state indicated in the MAC-CE.

[0106] In Example 5, the method according to any one of Examples 1-4 further includes: the UE receives the information in the RRC message, and determines the default beam for the PDSCH independent of the beam used for the PDCCH based on the information received in the RRC message.

[0107] In Example 6, the method according to any one of Examples 1-5 further includes: the UE receives the information in the DCI, and determines the default beam for the PDSCH independent of the beam used for the PDCCH based on the information received in the DCI.

[0108] In Example 7, the method according to any one of Examples 1-6 further includes: the UE receives the information in the message of activating the at least one TCI state for the PDSCH, and determines the default beam for the PDSCH independent of the beam for the PDCCH based on the activated TCI state for the PDSCH with the lowest index.

[0109] In Example 8, the method according to any one of Examples 1-7 further includes: if the UE does not receive the information, the UE determines the default beam for the PDSCH based on a fallback rule.

[0110] In Example 9, the method according to any one of Examples 1-8 further includes: the fallback rule includes: if one or more CORESETs are configured for the UE, determining the default beam for the PDSCH based on the QCL relationship with the configured CORESET with the lowest CORESET ID; and determining the default beam for the PDSCH based on the activated PDSCH TCI state with the lowest TCI state ID.

[0111] In Example 10, the method according to any one of Examples 1-9 further includes: if the UE has not received activation of the PDSCH TCI state, then if one or more CORESETs are configured for the UE, the UE determines the default beam for the PDSCH based on a QCL relationship with a configured CORESET with a lowest CORESET ID.

[0112] In Example 11, the method of any one of Examples 1-10 further includes sending an indication of a capability for determining the default beam for the PDSCH independent of the beam for the PDCCH.

[0113] In Example 12, the method according to any one of Examples 1-11 further includes: receiving an indicator from the base station, the indicator being used to instruct the UE to determine the default beam for the PDSCH independent of the beam for the PDCCH.

[0114] In Example 13, the method of any one of Examples 1-12 further includes: the indicator is received in radio resource control (RRC) signaling from the base station.

[0115] Example 14 is a device comprising one or more processors and one or more memories in electronic communication with the one or more processors, the one or more memories storing data executable by the one or more processors to cause the device to implement a method as in any one of Examples 1-13.

[0116] Example 15 is a system or apparatus comprising means for implementing the method or apparatus of any of Examples 1-13.

[0117] Example 16 is a non-transitory computer-readable medium storing instructions, the instructions being executable by one or more processors to cause the one or more processors to implement the method as in any one of Examples 1-13.

[0118] Example 17 is a method of wireless communication at a base station, comprising: receiving an indication from a UE of the ability to determine a default beam for a PDSCH independent of a beam used for a PDCCH; sending information to the UE in a MAC-CE, an RRC message, a DCI, or a message activating at least one TCI state for the PDSCH; sending a scheduling DCI that schedules the PDSCH using a scheduling offset that is less than a threshold; and based on the information sent to the UE in the MAC-CE, the RRC message, the DCI, or the message activating at least one TCI state for the PDSCH, using the default beam to send the PDSCH to the UE.

[0119] In Example 18, the method according to Example 17 further includes: sending an indicator for instructing the UE to determine the default beam for the PDSCH independent of the beam used for the PDCCH.

[0120] In Example 19, the method according to Example 17 or Example 18 further includes: the base station sending an indicator to the UE in RRC signaling to the UE.

[0121] In Example 20, the method according to any one of Examples 17-19 further includes: the base station sending the information in the MAC-CE.

[0122] In Example 21, the method according to any one of Examples 17-20 further includes: the MAC-CE activating a PDSCH HTC I state, and the default beam for the PDSCH is based on the PDSCH HTC I state indicated in the MAC-CE.

[0123] In Example 22, the method according to any one of Examples 17-21 further includes: the base station sending the information in the RRC message.

[0124] In Example 23, the method according to any one of Examples 17-22 further includes: the base station sending the information in the DCI.

[0125] In Example 24, the method according to any one of Examples 17-23 further includes: the base station activating the at least one TCI state for the PDSCH, and the default beam for the PDSCH is based on the activated TCI state for the PDSCH with the lowest index.

[0126] Example 25 is a device comprising one or more processors and one or more memories in electronic communication with the one or more processors, the one or more memories storing data executable by the one or more processors to cause the device to implement a method as in any one of Examples 17-24.

[0127] Example 26 is a system or apparatus comprising means for implementing the method of any of Examples 17-24 or performing the apparatus of any of Examples 17-24.

[0128] Example 27 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 as in any of Examples 17-24.

[0129] It should be understood that the specific order or hierarchy of blocks in the disclosed process / flowchart is illustrative of example methods. It should be understood that the specific order or hierarchy of blocks in the process / flowchart may be rearranged based on design preferences. In addition, some blocks may be combined or omitted. The accompanying method claims present elements of the various blocks in an example order and are not meant to be limited to the specific order or hierarchy presented.

[0130] The foregoing description is provided to enable any person skilled in the art to implement the various aspects described herein. Various modifications to these aspects will be apparent to those skilled in the art, and the general principles defined herein can be applied to other aspects. Therefore, the claims are not intended to be limited to the aspects shown herein, but are given the full scope consistent with the textual claims, wherein, unless explicitly stated otherwise, reference to an element in the singular is not intended to mean "one and only one," but rather "one or more." The word "exemplary" is used herein to mean "as an example, instance, or illustration." Any aspect described herein as "exemplary" is not necessarily to be interpreted as being preferred over or having advantages 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 "A, B, C, or any combination thereof" include any combination of A, B, and / or C, and may 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 "A, B, C, or any combination thereof" may be A only, B only, C only, A and B, A and C, B and C, or A and B and C, wherein any such combination may include one or more members or several members of A, B, or C. All structural and functional equivalents of the elements throughout the various aspects described in this disclosure that are known or later become known to one of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. In addition, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is expressly recited in the claims. The words "module," "mechanism," "element," "device," and the like may not be substitutes for the word "unit." Thus, no claim element is to be construed as unit-plus-function unless the element is expressly recited using the phrase "unit for..."

Claims

1. A method of wireless communication at a user equipment (UE), comprising: transmitting an indication of a capability for determining a default beam for a physical downlink shared channel (PDSCH) independent of a beam of a control resource set (CORESET) for a physical downlink control channel (PDCCH); determining the default beam for the PDSCH independent of the beam of the CORESET used for the PDCCH based on information received in a Medium Access Control-Control Element (MAC-CE), a Radio Resource Control (RRC) message, Downlink Control Information (DCI), or a message activating at least one Transmission Configuration Indication (TCI) state for the PDSCH; as well as In response to a determination that a scheduling offset between the PDSCH and the scheduling DCI that schedules the PDSCH is less than a threshold, the PDSCH is received from the base station using the default beam based on the information received in the MAC-CE, the RRC message, the DCI, or the message activating the at least one TCI state.

2. The method according to claim 1, wherein The UE receives the information in the MAC-CE and determines the default beam for the PDSCH independent of the beam of the CORESET used for the PDCCH based on the information received in the MAC-CE.

3. The method according to claim 2, wherein: The MAC-CE activates a PDSCH TCI state, and the UE determines the default beam for the PDSCH based on the PDSCH TCI state indicated in the MAC-CE.

4. The method according to claim 1, wherein The UE receives the information in the RRC message and determines the default beam for the PDSCH independent of the beam of the CORESET used for the PDCCH based on the information received in the RRC message.

5. The method according to claim 1, wherein The UE receives the information in the DCI and determines the default beam for the PDSCH independent of the beam of the CORESET used for the PDCCH based on the information received in the DCI.

6. The method according to claim 1, wherein The UE receives the information in the message activating the at least one TCI state for the PDSCH, and determines the default beam for the PDSCH independent of the beam of the CORESET for the PDCCH based on the activated TCI state for the PDSCH with the lowest index.

7. The method according to claim 1, wherein If the UE does not receive the information, the UE determines the default beam for the PDSCH based on a fallback rule.

8. The method according to claim 7, wherein: The fallback rules include: If one or more CORESETs are configured for the UE, determining the default beam for the PDSCH based on a quasi co-location (QCL) relationship with a configured CORESET having a lowest CORESET identifier (ID); or The default beam for the PDSCH is determined based on an activated PDSCH TCI state with a lowest TCI state ID.

9. The method according to claim 1, wherein: If the UE has not received activation of a PDSCH TCI state, then if one or more CORESETs are configured for the UE, the UE determines the default beam for the PDSCH based on a quasi co-location (QCL) relationship with a configured CORESET with a lowest CORESET identifier (ID).

10. The method according to claim 1, further comprising: An indicator is received from the base station, the indicator instructing the UE to determine the default beam for the PDSCH independent of the beam of the CORESET for the PDCCH.

11. The method according to claim 10, wherein: The indicator is received in radio resource control (RRC) signaling from the base station.

12. The method according to claim 1, wherein The UE determines the default beam for the PDSCH in response to the information received in the MAC-CE, the RRC message, the DCI, or the message activating at least one TCI state for the PDSCH, the default beam for the PDSCH being independent of the beam for the CORESET with the lowest identifier (ID).

13. An apparatus for wireless communication at a user equipment (UE), comprising: Memory; as well as at least one processor coupled to the memory and configured to: transmitting an indication of a capability for determining a default beam for a physical downlink shared channel (PDSCH) independent of a beam of a control resource set (CORESET) for a physical downlink control channel (PDCCH); determining the default beam for the PDSCH independent of the beam of the CORESET used for the PDCCH based on information received in a Medium Access Control-Control Element (MAC-CE), a Radio Resource Control (RRC) message, Downlink Control Information (DCI), or a message activating at least one Transmission Configuration Indication (TCI) state for the PDSCH; as well as In response to a determination that a scheduling offset between the PDSCH and the scheduling DCI that schedules the PDSCH is less than a threshold, the PDSCH is received from the base station using the default beam based on the information received in the MAC-CE, the RRC message, the DCI, or the message activating the at least one TCI state.

14. The device according to claim 13, wherein The at least one processor is configured to receive the information in the MAC-CE and determine the default beam for the PDSCH independent of the beam of the CORESET for the PDCCH based on the information received in the MAC-CE.

15. The device according to claim 14, wherein The MAC-CE activates a PDSCH TCI state, and the at least one processor is configured to determine the default beam for the PDSCH based on the PDSCH TCI state indicated in the MAC-CE.

16. The device according to claim 13, wherein The at least one processor is configured to receive the information in the RRC message and determine the default beam for the PDSCH independent of the beam of the CORESET used for the PDCCH based on the information received in the RRC message.

17. The device according to claim 13, wherein The at least one processor is configured to receive the information in the DCI and determine the default beam for the PDSCH independent of the beam of the CORESET for the PDCCH based on the information received in the DCI.

18. The device according to claim 13, wherein The at least one processor is configured to receive the information in the message activating the at least one TCI state for the PDSCH, and determine the default beam for the PDSCH independent of the beam of the CORESET for the PDCCH based on the activated TCI state for the PDSCH with the lowest index.

19. The device according to claim 13, wherein If the device does not receive the information, the at least one processor is configured to: determine the default beam for the PDSCH based on a fallback rule, the fallback rule comprising: if one or more CORESETs are configured for the UE, determining the default beam for the PDSCH based on a quasi-co-location (QCL) relationship with a configured CORESET with a lowest CORESET identifier (ID); or determining the default beam for the PDSCH based on an activated PDSCH TCI state with a lowest TCI state ID.

20. The apparatus according to claim 13, wherein If the apparatus has not received activation of a PDSCH TCI state, the at least one processor is configured to, if one or more CORESETs are configured for the UE, determine the default beam for the PDSCH based on a quasi co-location (QCL) relationship with a configured CORESET having a lowest CORESET identifier (ID).

21. The apparatus according to claim 13, wherein The at least one processor is further configured to: An indicator is received from the base station, the indicator instructing the UE to determine the default beam for the PDSCH independent of the beam of the CORESET for the PDCCH.

22. The device according to claim 21, wherein The indicator is received in radio resource control (RRC) signaling from the base station.

23. The apparatus according to claim 13, wherein The at least one processor is configured to determine the default beam for the PDSCH in response to the information received in the MAC-CE, the RRC message, the DCI, or the message activating at least one TCI state for the PDSCH, the default beam for the PDSCH being independent of the beam for the CORESET with the lowest identifier (ID).

24. A method of wireless communication at a base station, comprising: receiving, from a user equipment (UE), an indication of a capability for determining a default beam for a physical downlink shared channel (PDSCH) independent of a beam of a control resource set (CORESET) for a physical downlink control channel (PDCCH); sending information to the UE in a medium access control-control element (MAC-CE), a radio resource control (RRC) message, downlink control information (DCI), or a message activating at least one transmission configuration indication (TCI) state for the PDSCH; Sending scheduling downlink control information (DCI), wherein the scheduling DCI schedules the PDSCH using a scheduling offset less than a threshold; as well as Based on the information sent to the UE in the MAC-CE, the RRC message, the DCI, or the message activating the at least one TCI state for the PDSCH, and based on the scheduling offset between the PDSCH and the scheduling DCI being less than the threshold, the PDSCH is sent to the UE using the default beam.

25. The method according to claim 24, further comprising: An indicator is sent, the indicator being used to instruct the UE to determine the default beam for the PDSCH independent of the beam of the CORESET used for the PDCCH.

26. The method according to claim 25, wherein The base station sends the indicator to the UE in radio resource control (RRC) signaling to the UE.

27. The method according to claim 24, wherein The base station sends the information in the MAC-CE.

28. The method according to claim 27, wherein The MAC-CE activates a PDSCH TCI state, and the default beam for the PDSCH is based on the PDSCH TCI state indicated in the MAC-CE.

29. The method according to claim 24, wherein The base station sends the information in the RRC message.

30. The method of claim 24, wherein: The base station sends the information in the DCI.

31. The method of claim 24, wherein: The base station activates the at least one TCI state for the PDSCH, and the default beam for the PDSCH is based on the activated TCI state for the PDSCH having a lowest index.

32. An apparatus for wireless communication at a base station, comprising: Memory; as well as at least one processor coupled to the memory and configured to: receiving, from a user equipment (UE), an indication of a capability for determining a default beam for a physical downlink shared channel (PDSCH) independent of a beam of a control resource set (CORESET) for a physical downlink control channel (PDCCH); sending information to the UE in a medium access control-control element (MAC-CE), a radio resource control (RRC) message, downlink control information (DCI), or a message activating at least one transmission configuration indication (TCI) state for the PDSCH; Sending scheduling downlink control information (DCI), wherein the scheduling DCI schedules the PDSCH using a scheduling offset less than a threshold; as well as Based on the information sent to the UE in the MAC-CE, the RRC message, the DCI, or the message activating the at least one TCI state for the PDSCH, and based on the scheduling offset between the PDSCH and the scheduling DCI being less than the threshold, the PDSCH is sent to the UE using the default beam.

33. The apparatus according to claim 32, wherein The at least one processor is further configured to: An indicator is sent, the indicator being used to instruct the UE to determine the default beam for the PDSCH independent of the beam of the CORESET used for the PDCCH.

34. The apparatus according to claim 33, wherein The at least one processor is further configured to: The indicator is sent to the UE in radio resource control (RRC) signaling.

35. The apparatus of claim 32, wherein: The at least one processor is further configured to: The information is sent in the MAC-CE.

36. The apparatus of claim 35, wherein: The MAC-CE activates a PDSCH TCI state, and the default beam for the PDSCH is based on the PDSCH TCI state indicated in the MAC-CE.

37. The apparatus of claim 32, wherein: The at least one processor is further configured to: The information is sent in the RRC message.

38. The apparatus of claim 32, wherein: The at least one processor is further configured to: The information is sent in the DCI.

39. The apparatus of claim 32, wherein: The at least one processor is further configured to: The at least one TCI state for the PDSCH is activated, wherein the default beam for the PDSCH is based on the activated TCI state for the PDSCH having a lowest index.

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