Beamforming in multicast communications

Abstract

The present disclosure provides a method, apparatus and system for beamforming in wireless communications. Some implementations are more particularly directed to beamforming configurations for multicast communications. A transmitting device may simultaneously transmit multicast data to a plurality of receiving devices via a physical downlink shared channel (PDSCH). A physical downlink control channel (PDCCH) may be prior to the PDSCH. The PDCCH may provide scheduling information to the PDSCH, including a multicast beam associated with the PDSCH and a timing offset or delay between the PDCCH and the PDSCH. The receiving device may determine that the PDSCH contains multicast data based on the indication in the PDCCH. To receive the PDSCH, each receiving device may tune its antenna in the direction of a predetermined multicast beam or a default beam based on a delay between the PDCCH and the PDSCH.

Description

[0001] This application is a divisional application of the invention patent application with the application date of November 17, 2020, application number 202080076496.4, and name “Beamforming in Multicast Communications”. Technical Field

[0002]

[0002] The present disclosure relates generally to wireless communications and, more particularly, to beamforming configurations for transmitting and receiving multicast communications. Background Art

[0003] 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 communications 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.

[0004] These multiple access technologies have been used in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate across cities, countries, regions, and even the globe. An example telecommunication standard is 5G New Radio (NR), which is part of the continued mobile broadband evolution promulgated by the 3rd Generation Partnership Project (3GPP) to meet new requirements associated with latency, reliability, security, scalability (e.g., with the Internet of Things (IoT)), and other requirements. 5G NR includes services associated with enhanced mobile broadband (eMBB), massive machine type 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.

[0005] 5G NR improvements include beamforming and the use of extremely high frequency (EHF) or millimeter wave (mmW) spectrum (30-300GHz). The transmitting device uses transmit (TX) beamforming technology to concentrate the energy of the wireless signal in the direction of one or more receiving devices. The receiving device uses receive (RX) beamforming technology to tune its receiving antenna in the direction of the beam transmitted by the transmitting device. The focused beam greatly improves the signal-to-interference-and-noise ratio (SINR) of the communication between the transmitting device and the receiving device. In mmW communication, beamforming is highly directional to compensate for the extremely high path loss and short distance. In other words, each beam can be narrowly focused in a given direction. Therefore, TX beamforming needs to be precisely configured in conjunction with RX beamforming to establish a communication channel between the transmitting device and the receiving device. Summary of the Invention

[0006] The systems, methods, and devices of the present disclosure each have several innovative aspects, no single one of which is solely responsible for the desirable attributes disclosed herein.

[0007] One innovative aspect of the subject matter described in the present disclosure can be implemented as a method of wireless communication. The method can be performed by a user equipment (UE) and can include: receiving a physical downlink control channel (PDCCH) from a base station, wherein the PDCCH carries scheduling information for a physical downlink shared channel (PDSCH) to be multicast to multiple UEs including the UE; determining a first beam associated with the PDSCH and a delay between the PDCCH and the PDSCH based on the scheduling information; and tuning multiple receive antennas to receive the PDSCH on the first beam or the second beam based on the determined delay between the PDCCH and the PDSCH.

[0008] In some implementations, the method may further include determining, based on a control resource set (CORESET) associated with the PDCCH, that the PDSCH carries multicast data. In some other implementations, the method may further include: identifying a cyclic redundancy check (CRC) sequence in the PDCCH; determining that the CRC sequence is scrambled with a group identifier associated with a plurality of UEs; and determining, based on determining that the CRC sequence is scrambled with the group identifier, that the PDSCH carries multicast data.

[0009] In some implementations, the method may further include determining a second beam based on a CORESET associated with the PDCCH. In some other implementations, the method may further include: receiving a radio resource control (RRC) message or a medium access control (MAC) control element (CE) from the base station before receiving the PDCCH; and determining the second beam based on information carried in the RRC message or MAC CE. In some implementations, the second beam is different from a default beam associated with unicast transmissions to the UE by the base station.

[0010] In some implementations, tuning the multiple receive antennas may include determining whether a delay between a PDCCH and a PDSCH exceeds a threshold duration, wherein based on determining that the delay exceeds the threshold duration, the multiple receive antennas are tuned to a first beam, and wherein based on determining that the delay does not exceed the threshold duration, the multiple receive antennas are tuned to a second beam. In some implementations, the threshold duration is based on a duration associated with tuning the multiple receive antennas to receive unicast transmissions from a base station. In some other implementations, the threshold duration is different from a duration associated with tuning the receive antennas to receive unicast transmissions from the base station. In some implementations, the method may further include: receiving at least one of an RRC message or a downlink control information (DCI) message from the base station; and determining the threshold duration based on information carried in the RRC message or the DCI message.

[0011] Another innovative aspect of the subject matter described in the present disclosure can be implemented in a UE. In some implementations, the UE may include: at least one modem; at least one processor communicatively coupled to the at least one modem; and at least one memory communicatively coupled to the at least one processor and storing processor-readable code. In some implementations, the processor-readable code is executed by the at least one processor so that the UE performs operations including: receiving a physical downlink control channel (PDCCH) from a base station, wherein the PDCCH carries scheduling information for a physical downlink shared channel (PDSCH) to be multicast to multiple UEs including the UE; determining a first beam associated with the PDSCH and a delay between the PDCCH and the PDSCH based on the scheduling information; and tuning multiple receive antennas to receive the PDSCH on the first beam or the second beam based on the delay determined between the PDCCH and the PDSCH.

[0012] Another innovative aspect of the subject matter described in the present disclosure can be implemented as a method of wireless communication. The method can be performed by a base station and can include: transmitting a PDCCH to multiple UEs, wherein the PDCCH carries scheduling information, the scheduling information indicating a first beam associated with a PDSCH to be multicast to the multiple UEs and a timing offset between the PDCCH and the PDSCH; selecting at least one of the first beam or the second beam for transmitting the PDSCH based on the timing offset between the PDCCH and the PDSCH; and transmitting the PDSCH to the multiple UEs on the selected at least one beam.

[0013] In some implementations, the method may further include: generating a CRC sequence associated with the PDCCH; and scrambling the CRC sequence with a group identifier associated with the plurality of UEs, wherein the scrambled CRC sequence is transmitted in the PDCCH. In some implementations, the method may further include determining a second beam based on a CORESET associated with the PDCCH. In some implementations, the second beam is different from a default beam associated with a unicast transmission to any UE in the plurality of UEs.

[0014] In some implementations, selecting at least one of the first beam or the second beam may include determining whether a timing offset exceeds a multicast scheduling threshold associated with a plurality of UEs, wherein the first beam is selected based on determining that the timing offset exceeds the multicast scheduling threshold, and wherein the second beam is selected based on determining that the timing offset does not exceed the multicast scheduling threshold. In some implementations, the method may further include: determining, for each of the plurality of UEs, a respective duration associated with tuning the plurality of receive antennas to receive a unicast transmission from the base station; and configuring the multicast scheduling threshold to be at least equal to a longest duration of the durations determined for the plurality of UEs.

[0015] In some implementations, selecting at least one of the first beam or the second beam includes: determining, for each of a plurality of UEs, a respective duration associated with tuning a plurality of receive antennas to receive a unicast transmission from a base station; and determining whether a timing offset exceeds the duration determined for each of the plurality of UEs, wherein at least the first beam is selected based on determining that the timing offset exceeds the duration determined for at least one of the plurality of UEs. In some implementations, selecting the second beam is based on determining that the timing offset does not exceed the duration determined for a first UE in the plurality of UEs, wherein the second beam is a default beam associated with unicast transmissions from the base station to the first UE. In some implementations, the method may further include configuring the timing offset to be at least equal to a longest duration among the durations determined for the plurality of UEs.

[0016] Another innovative aspect of the subject matter described in the present disclosure can be implemented in a base station. In some implementations, the base station may include: at least one modem; at least one processor communicatively coupled to the at least one modem; and at least one memory communicatively coupled to the at least one processor and storing processor-readable code. In some implementations, the processor-readable code is executed by the at least one processor, causing the base station to perform operations including: transmitting a PDCCH to a plurality of UEs, wherein the PDCCH carries scheduling information, the scheduling information indicating a first beam associated with a PDSCH to be multicast to the plurality of UEs and a timing offset between the PDCCH and the PDSCH; selecting at least one of the first beam or the second beam for transmitting the PDSCH based on the timing offset between the PDCCH and the PDSCH; and transmitting the PDSCH to the plurality of UEs on the selected at least one beam. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A diagram of an example wireless communication system and access network is shown.

[0018] Figure 2A 、 Figure 2B 、 Figure 2C and Figure 2D Examples of a first 5G / NR frame, a downlink (DL) channel within a 5G / NR time slot, a second 5G / NR frame, and an uplink (UL) channel within a 5G / NR time slot are shown, respectively.

[0019] Figure 3 A block diagram of an example base station and user equipment (UE) in an access network is shown.

[0020] Figure 4A An example wireless communication system configured for unicast transmissions is shown.

[0021] Figure 4B A timing diagram illustrating example unicast communications between a base station and a UE is shown.

[0022] Figure 5A

[0014] An example wireless communication system configured for multicast transmissions in accordance with some implementations is shown.

[0023] Figure 5B

[0014] Another example wireless communication system configured for multicast transmissions in accordance with some implementations is shown.

[0024] Figure 5C

[0014] Another example wireless communication system configured for multicast transmissions in accordance with some implementations is shown.

[0025] Figure 6 Shown is a timing diagram illustrating example multicast communications between a base station and a group of UEs according to some implementations.

[0026] Figure 7 Shown is a timing diagram illustrating another example multicast communication between a base station and a group of UEs according to some implementations.

[0027] Figure 8 Shown is a timing diagram illustrating another example multicast communication between a base station and a group of UEs according to some implementations.

[0028] Figure 9 A flow chart illustrating an example process for wireless communications supporting beamforming in multicast communications according to some implementations is shown.

[0029] Figure 10 A flow chart illustrating an example process for wireless communications supporting beamforming in multicast communications according to some other implementations is shown.

[0030] Figure 11 A block diagram of an example wireless communication device is shown in accordance with some implementations.

[0031] Figure 12 A block diagram of an example wireless communication device is shown in accordance with some implementations. DETAILED DESCRIPTION

[0032] For the purpose of describing the innovative aspects of the present disclosure, the following description is directed to some specific implementations. However, one of ordinary skill in the art will readily recognize that the teachings herein can be applied in a variety of different ways. The described implementations can be implemented in any device, system, or network capable of sending and receiving radio frequency (RF) signals in accordance with one or more of the following standards: Long Term Evolution (LTE), 3G, 4G, or 5G (New Radio (NR)) standards promulgated by the Third Generation Partnership Project (3GPP), the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard, the IEEE 802.15 standard, or any standard defined by the Bluetooth Special Interest Group (SIG). Standards, etc. The described implementations may be implemented in any device, system, or network capable of sending and receiving RF signals according to one or more of the following technologies or techniques: code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), single carrier FDMA (SC-FDMA), single user (SU) multiple input multiple output (MIMO), and multi-user (MU) MIMO. The described implementations may also be implemented using other wireless communication protocols or RF signals suitable for use in one or more of a wireless wide area network (WWAN), a wireless personal area network (WPAN), a wireless local area network (WLAN), or an Internet of Things (IoT) network.

[0033] Improvements in 5G NR include beamforming and the utilization of extremely high frequency (EHF) or millimeter wave (mmW) spectrum (30-300GHz). In mmW communications, beamforming is highly directional to compensate for the extremely high path loss and short distances. In addition to being used for unicast communications, beamforming can also be used for multicast (also known as "groupcast") or broadcast communications. For example, a transmitting device can use one or more directional beams to simultaneously send multicast data to a group (two or more) of receiving devices. A beamforming configuration used for unicast communications may not be suitable for multicast communications. For example, the width or directionality of a beam used in unicast communications between any pair of transmitting and receiving devices can be different from any beam that can be used in multicast communications between the same pair of devices. Therefore, TX beamforming needs to be precisely configured in conjunction with RX beamforming to enable multicast communications between a transmitting device and a group of receiving devices.

[0034] In summary, various aspects relate to beamforming configurations for multicast communications. Some aspects more specifically relate to scheduling multicast data for transmission on a default beam or a specific beam configured for multicast transmission (referred to herein as a "multicast beam"). In various aspects, a transmitting device (such as a base station) can use beamforming to simultaneously send multicast data to multiple devices via a physical downlink shared channel (PDSCH). A physical downlink control channel (PDCCH) can precede the PDSCH, and the PDCCH provides scheduling information for the PDSCH, including an identification of the multicast beam associated with the PDSCH and a timing offset or delay between the PDCCH and the PDSCH. A receiving device (such as a user equipment (UE)) can determine that the PDSCH contains multicast data based at least in part on an indication in the PDCCH. To receive the multicast PDSCH, the UE can tune its multiple antennas in the direction of the scheduled multicast beam or in the direction of the default beam based on the delay between the PDCCH and the PDSCH. For example, if the delay between PDCCH and PDSCH exceeds a scheduling threshold, the UE may tune its antenna to the scheduled multicast beam. On the other hand, if the delay between PDCCH and PDSCH does not exceed the scheduling threshold, the UE may tune its antenna to the default beam. The scheduling threshold may correspond to the duration required for the UE to configure (or tune) multiple receive antennas to receive a given beam.

[0035] Specific implementations of the subject matter described in this disclosure can be implemented to achieve one or more of the following potential advantages. In some implementations, the described techniques can be used to send multicast data to multiple UEs simultaneously. By signaling via the PDCCH that a scheduled PDSCH carries multicast data, aspects of the present disclosure enable each UE in the group to tune its receive antenna in the direction of a multicast beam (indicated in the PDCCH) or a common default beam associated with the multicast communication. For example, a common default beam may be more suitable for multicast communications between a base station and the group of UEs than a default beam that any individual UE uses for unicast communications with the base station. In some aspects, upon determining that the scheduled PDSCH carries multicast data, each UE in the group can compare the delay between the PDCCH and the PDSCH with a common (or multicast) scheduling threshold to determine whether to tune its receive antenna in the direction of the multicast beam or in the direction of the common default beam. For example, the common scheduling threshold may be longer than the amount of time required for any individual UE to tune its receive antenna in the direction of the multicast beam. This enables the group of UEs to jointly receive PDSCH (carrying multicast data) on a multicast beam or a common default beam.

[0036] Several aspects of telecommunications systems will now be described with reference to various apparatuses and methods. These apparatuses and methods are described in the detailed description that follows and are illustrated in the accompanying drawings by various blocks, components, circuits, processes, algorithms, etc. (collectively, "elements"). These elements can 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.

[0037] For example, an element or any part of an element or any combination of elements may be implemented as a "processing system" comprising one or more processors. Examples of processors include microprocessors, microcontrollers, graphics processing units (GPUs), central processing units (CPUs), application processors, digital signal processors (DSPs), reduced instruction set computing (RISC) processors, systems on chip (SoCs), baseband processors, field programmable gate arrays (FPGAs), programmable logic devices (PLDs), state machines, gating logic, discrete hardware circuits, and other suitable hardware configured to perform the various functions described in this disclosure. One or more processors in a processing system can execute software. Whether referred to as software, firmware, middleware, microcode, hardware description language, etc., software should be broadly interpreted as representing instructions, instruction sets, codes, code segments, program codes, programs, subroutines, software components, applications, software applications, software packages, routines, subroutines, objects, executable programs, execution threads, processes, functions, etc.

[0038] Therefore, in one or more example embodiments, the functions may be implemented in hardware, software, or any combination thereof. If implemented in software, these functions may 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 may be any available medium accessible by a computer. By way of example and not limitation, such computer-readable media may include random access memory (RAM), read-only memory (ROM), electrically erasable programmable ROM (EEPROM), optical disk storage, magnetic disk storage, other magnetic storage devices, a combination of the above-mentioned types of computer-readable media, or any other medium that may be used to store computer-executable code in the form of instructions or data structures accessible to a computer.

[0039] Figure 1 A schematic diagram of an example wireless communication system and access network 100 is shown. The wireless communication system (also known 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.

[0040] A base station 102 configured for 4G LTE (collectively referred to as the Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN)) may interface with the EPC 160 via a backhaul link 132 (e.g., an S1 interface). A base station 102 configured for 5G NR (collectively referred to as the Next Generation RAN (NG-RAN)) may interface with the core network 190 via a backhaul link 184. The base station 102 may perform one or more of the following functions, among other things: 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 delivery of warning messages. The base stations 102 may communicate with each other via a backhaul link 134 (eg, an X2 interface) directly or indirectly (eg, via the EPC 160 or the core network 190). The backhaul link 134 may be wired or wireless.

[0041] Base stations 102 can communicate wirelessly with UEs 104. Each base station 102 can provide communication coverage for a corresponding geographic coverage area 110. There may be overlapping geographic coverage areas 110. For example, a small cell 102' may have a coverage area 110' that overlaps with the coverage area 110 of one or more macro base stations 102. A network that includes small cells and macro cells may be referred to as a heterogeneous network. A heterogeneous network may also include a home evolved Node B (eNB) (HeNB), which may provide service to a restricted group called a closed subscriber group (CSG). The communication link 120 between the base station 102 and the UE 104 may include uplink (UL) (also known as reverse link) transmissions from the UE 104 to the base station 102 and / or downlink (DL) (also known as forward link) transmissions from the base station 102 to the UE 104. The communication link 120 may use multiple-input multiple-output (MIMO) antenna technology, including spatial multiplexing, beamforming, and / or transmit diversity. The communication link may be over one or more carriers. For each carrier allocated in the carrier aggregation for a total of up to Yx MHz (x component carriers) for transmission in each direction, the 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). These carriers may be adjacent to each other or not. 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). The 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).

[0042] Some UEs 104 can communicate with each other using device-to-device (D2D) communication links 158. The D2D communication links 158 can use the DL / UL WWAN spectrum. The D2D communication links 158 can 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). The D2D communication can be carried out through various wireless D2D communication systems, such as FlashLinQ, WiMedia, Bluetooth, ZigBee, Wi-Fi based on the IEEE 802.11 standard, LTE, or NR.

[0043] 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) prior to communication to determine whether the channel is available.

[0044] 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 used by the Wi-Fi AP 150. The small cell 102′ using NR in the unlicensed spectrum can expand the coverage and / or increase the capacity of the access network.

[0045] Base station 102 (whether a small cell 102′ or a large cell (e.g., a macro base station)) may include an eNB, a gNodeB (gNB), or another type of base station. Some base stations (e.g., gNB 180) can communicate with UE 104 in the traditional sub-6 GHz spectrum, in millimeter wave (mmW) frequencies, and / or in near-mmW frequencies. When gNB 180 operates in mmW or near-mmW frequencies, gNB 180 may be referred to as a mmW or mmW base station. Extremely high frequency (EHF) is a portion of the RF spectrum in the electromagnetic spectrum. EHF ranges from 30 GHz to 300 GHz, with wavelengths 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, with wavelengths of 100 mm. Super high frequency (SHF) bands extend between 3 GHz and 30 GHz and are also known as centimeter waves. Communications using mmW / near-mmW radio frequency bands (e.g., 3 GHz-300 GHz) have extremely high path loss and short range. The mmW base station 180 may utilize beamforming 182 with the UE 104 to compensate for the extremely high path loss and short range.

[0046] 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 and transmit directions for each base station 180 / UE 104. The transmit and receive directions of base station 180 may be the same or different. The transmit and receive directions of UE 104 may be the same or different.

[0047] 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 routed 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, Intranet, IP Multimedia Subsystem (IMS), PS streaming services, and / or other IP services. BM-SC 170 may provide functionality for MBMS user service provisioning and delivery. The BM-SC 170 may serve as the 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 that broadcasts a specific service, and may be responsible for session management (start / stop) and collecting charging information related to eMBMS.

[0048] The core network 190 may include an access and mobility management function (AMF) 192, other AMFs 193, a session management function (SMF) 194, and a user plane function (UPF) 195. The AMF 192 may communicate with a unified data management (UDM) 196. The AMF 192 is a control node that handles signaling between the UE 104 and the core network 190. Generally, the AMF 192 provides QoS flow and session management. All user Internet Protocol (IP) packets are transported through the UPF 195. The UPF 195 provides UE IP address allocation and other functions. The UPF 195 is connected to the IP services 197. The IP services 197 may include the Internet, an intranet, an IP multimedia subsystem (IMS), PS streaming services, and / or other IP services.

[0049] A base station may also be referred to as a gNB, Node B, evolved Node B (eNB), access point, base transceiver station, radio base station, radio transceiver, transceiver functionality, basic service set (BSS), extended service set (ESS), transmit receive point (TRP), or some other suitable terminology. Base station 102 provides an access point for UE 104 to EPC 160 or core network 190. 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, 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, 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 UEs 104 may be referred to as IoT devices (e.g., a parking meter, a gas pump, a toaster, 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 suitable terminology.

[0050] Reference again Figure 1 In some aspects, the base station 102 / 180 can utilize beamforming 182 to simultaneously transmit the same downlink (DL) data to a group of UEs 104. The DL data can be included in a physical downlink shared channel (PDSCH) that is multicast to each UE 104 in the group. A physical downlink control channel (PDCCH) can precede the PDSCH. In some implementations, the base station 102 / 180 and the UEs 104 can configure beamforming 182 (198) for multicasting the PDSCH based at least in part on a delay between the PDCCH and the PDSCH. More specifically, depending on whether the delay between the PDCCH and the PDSCH exceeds a scheduling threshold associated with one or more UEs 104 in the group, the base station 102 / 180 can selectively transmit the PDSCH on a scheduled multicast beam or one or more default beams. Similarly, each UE 104 may tune its antenna to receive the PDSCH on a scheduled multicast beam or a default beam, depending on whether the delay between the PDCCH and the PDSCH exceeds its scheduling threshold. The scheduling threshold may correspond to the duration for which the UE 104 needs to configure (or tune) multiple receive antennas to receive a given beam.

[0051] Figure 2A An example of a first time slot 200 within a 5G / NR frame structure is shown. Figure 2BAn example of a DL channel 230 within a 5G / NR timeslot is shown. Figure 2C An example of a second time slot 250 within a 5G / NR frame structure is shown. Figure 2D An example of a UL channel 280 within a 5G / NR timeslot is shown. The 5G / NR frame structure may be FDD, where for a particular set of subcarriers (carrier system bandwidth), the timeslots within the subcarrier set are dedicated to either DL or UL. In other cases, the 5G / NR frame structure may be TDD, where for a particular set of subcarriers (carrier system bandwidth), the timeslots within the subcarrier set are dedicated to both DL and UL. Figure 2A and Figure 2C In the example shown, the 5G / NR frame structure is configured for TDD, where slot 4 is configured with slot format 28 (primarily DL), where D indicates DL, U indicates UL, and X indicates that the slot is flexibly used between DL / UL, and slot 3 is configured with slot format 34 (primarily UL). Although slots 3 and 4 are shown with slot formats 34 and 28, respectively, any particular slot can be configured with any of the various available slot formats 0-61. Slot formats 0 and 1 are full DL and full 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 through DL control information (DCI), or semi-statically / statically through radio resource control (RRC) signaling) via a received slot format indicator (SFI). This format can also be applied to a 5G / NR frame structure that is FDD.

[0052] 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. Depending on the slot configuration, each slot may include 7 or 14 symbols. For slot configuration 0, each slot may include 14 symbols, and for slot configuration 1, each 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 situations) 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 situations; limited to only one stream transmission). The number of slots within a subframe is based on the slot configuration and the digital scheme. For slot configuration 0, different digital schemes μ0 through 5 allow for 1, 2, 4, 8, 16, and 32 slots per subframe, respectively. For slot configuration 1, different digital schemes 0 through 2 allow for 2, 4, and 8 slots per subframe, respectively. Thus, for slot configuration 0 and digital scheme μ, there are 14 symbols per slot and 2μ slots per subframe. 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 number of digital schemes 0 through 5. Thus, digital scheme μ=0 has a subcarrier spacing of 15kHz, and digital scheme μ=5 has a subcarrier spacing of 480kHz. The symbol length / duration is inversely proportional 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 = 0 with 1 slot per subframe. The subcarrier spacing is 15 kHz and the symbol duration is approximately 66.7 μs.

[0053] The resource grid can be used to represent the frame structure. Each time slot consists of a resource block (RB) (also called a physical RB (PRB)), which spans 12 consecutive subcarriers and multiple symbols. The intersection of the subcarriers and symbols of an RB defines multiple resource elements (REs). The number of bits carried by each RE depends on the modulation scheme.

[0054] like Figure 2AAs shown, some REs carry reference (pilot) signals (RS) for the UE. In some configurations, one or more REs may carry demodulation RS (DM-RS) (denoted as Rx for one specific configuration, where 100x is the port number, but other DM-RS configurations are also possible). In some configurations, one or more REs may carry channel state information reference signals (CSI-RS) for channel measurement at the UE. REs may also include beamforming RS (BRS), beam refinement RS (BRRS), and phase tracking RS (PT-RS).

[0055] Figure 2B Examples 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), each CCE includes nine RE groups (REGs), and each REG includes four consecutive REs in an OFDM symbol. The primary synchronization signal (PSS) can be within symbol 2 of a specific subframe of the frame. The UE 104 uses the PSS to determine the subframe or symbol timing and the physical layer identification. The secondary synchronization signal (SSS) can be within symbol 4 of a specific subframe of the frame. The UE uses the SSS to determine the physical layer cell identification group number and the radio frame timing. Based on the physical layer identification and the physical layer cell identification 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) carrying the master information block (MIB) can be logically grouped with the PSS and SSS to form a synchronization signal (SS) / PBCH block. The MIB provides multiple RBs in the system bandwidth and a system frame number (SFN). The Physical Downlink Shared Channel (PDSCH) carries user data, broadcast system information (eg, System Information Block (SIB)) that is not transmitted through the PBCH, and paging messages.

[0056] like Figure 2C As shown, some REs carry DM-RS (indicated as R for one specific configuration, but other DM-RS configurations are also possible) for channel estimation at the base station. The UE can send DM-RS for the physical uplink control channel (PUCCH) and DM-RS for the physical uplink shared channel (PUSCH). The PUSCH DM-RS can be sent in the first one or two symbols of the PUSCH. Depending on whether a short PUCCH or a long PUCCH is sent, and depending on the specific PUCCH format used, the PUCCH DM-RS can be sent in different configurations. Although not shown, the UE can send a sounding reference signal (SRS). The base station can use the SRS for channel quality estimation to achieve frequency-dependent scheduling on the UL.

[0057] Figure 2DAn example of various UL channels within a subframe of a frame is shown. The PUCCH may be positioned as shown in one configuration. The PUCCH carries uplink control information (UCI), such as scheduling requests, channel quality indicators (CQI), precoding matrix indicators (PMI), rank indicators (RI), and HARQ ACK / NACK feedback. The PUSCH carries data and may also be used to carry buffer status reports (BSRs), power headroom reports (PHRs), and / or UCI.

[0058] Figure 3 A block diagram of an example base station 310 and a UE 350 in an access network is shown. In the DL, IP packets from the EPC 160 may be provided to a controller / processor 375. The controller / processor 375 implements layer 3 and layer 2 functionality. Layer 3 includes a radio resource control (RRC) layer, and layer 2 includes a service data adaptation protocol (SDAP) layer, a packet data convergence protocol (PDCP) layer, a radio link control (RLC) layer, and a medium access control (MAC) layer. The controller / processor 375 provides RRC layer functions associated with broadcasting of system information (e.g., MIB, SIB), RRC connection control (e.g., RRC connection paging, RRC connection establishment, RRC connection modification, and RRC connection release), inter-radio access technology (RAT) mobility, and measurement configuration for UE measurement reporting; PDCP layer functions related to header compression / decompression, security (ciphering, deciphering, integrity protection, integrity verification), and handover support functions; RLC layer functions associated with 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 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.

[0059] The transmit (TX) processor 316 and receive (RX) processor 370 implement layer 1 functions related to various signal processing functions. Layer 1, including 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 divided 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 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 produce multiple spatial streams. Channel estimates from a channel estimator 374 may be used to determine the coding and modulation schemes and for spatial processing. The channel estimates may be derived from 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.

[0060] At the UE 350, each receiver 354RX receives a signal via its corresponding 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, these spatial streams can be combined by the RX processor 356 into a single OFDM symbol stream. The RX processor 356 then converts 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. By determining the most likely signal constellation point transmitted by the base station 310, the symbols and reference signals on each subcarrier are recovered and demodulated. 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 base station 310. The data and control signals are then provided to controller / processor 359, which implements layer 3 and layer 2 functionality.

[0061] 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 an ACK and / or NACK protocol to support HARQ operations.

[0062] Similar to the functions described in conjunction with the DL transmission of 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.

[0063] 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 to different antennas 352 via separate transmitters 354TX. Each transmitter 354TX may modulate an RF carrier with a corresponding spatial stream for transmission.

[0064] The base station 310 processes the UL transmission in a manner similar to that described in conjunction with the receiver functionality of 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.

[0065] 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 an ACK and / or NACK protocol to support HARQ operations. The PHY layer encodes and maps wirelessly transmitted information (e.g., for LTE or NR-based communications) to one or more radio channels for transmission.

[0066] In summary, various aspects relate to beamforming configurations for multicast communications. Some aspects more specifically relate to scheduling multicast data for transmission on a default beam or a specific beam configured for multicast transmission (referred to herein as a "multicast beam"). In various aspects, a transmitting device (such as a base station) can use beamforming to send multicast data to multiple devices simultaneously via a physical downlink shared channel (PDSCH). The PDSCH can be preceded by a physical downlink control channel (PDCCH) that provides scheduling information for the PDSCH, including an identification of the multicast beam associated with the PDSCH and a timing offset or delay between the PDCCH and the PDSCH. A receiving device (such as a user equipment (UE)) can determine that the PDSCH contains multicast data based at least in part on an indication in the PDCCH. To receive the multicast PDSCH, the UE can tune its multiple antennas in the direction of the scheduled multicast beam or in the direction of the default beam based on the delay between the PDCCH and the PDSCH. For example, if the delay between the PDCCH and PDSCH exceeds a scheduling threshold, the UE may tune its antenna to the scheduled multicast beam. On the other hand, if the delay between the PDCCH and PDSCH does not exceed the scheduling threshold, the UE may tune its antenna to the default beam. The scheduling threshold may correspond to the duration required for the UE to configure (or tune) multiple receive antennas to receive a given beam.

[0067] In some implementations, the default beam can be the default beam that the UE 104 uses to receive unicast transmissions. For example, different UEs 104 can have different default beams. In some other implementations, the default beam can be different from the default beam that the UE 104 uses to receive unicast transmissions. For example, the default beam can be specifically configured for multicast communications and can be common to all UEs 104 in a multicast group. In some aspects, the default beam can correspond to the beam on which scheduling information for the PDSCH is transmitted. In some other aspects, the default beam can be determined by the base station and signaled to the UE 104 before transmitting the PDSCH.

[0068] In some implementations, the scheduling threshold may be a scheduling threshold implemented by the UE 104 when receiving unicast transmissions. For example, different UEs 104 may have different scheduling thresholds. In some other implementations, the scheduling threshold may be different from the scheduling threshold implemented by the UE 104 when receiving unicast transmissions. For example, the scheduling threshold may be specifically configured for multicast communications and may be common to all UEs 104 in the multicast group. In some aspects, the scheduling threshold may be a predefined value (e.g., a value defined by the 3GPP standard) supported by any UE capable of multicast beamforming. In some other aspects, the scheduling threshold may be determined by the base station and signaled to the UE 104 prior to transmitting the PDSCH.

[0069] Specific implementations of the subject matter described in this disclosure can be implemented to achieve one or more of the following potential advantages. In some implementations, the described techniques can be used to send multicast data to multiple UEs simultaneously. By signaling via the PDCCH that a scheduled PDSCH carries multicast data, aspects of the present disclosure enable each UE in the group to tune its receive antenna in the direction of a multicast beam (indicated in the PDCCH) or a common default beam associated with the multicast communication. For example, a common default beam may be more suitable for multicast communications between a base station and the group of UEs than a default beam that any individual UE uses for unicast communications with the base station. In some aspects, upon determining that the scheduled PDSCH carries multicast data, each UE in the group can compare the delay between the PDCCH and the PDSCH with a common (or multicast) scheduling threshold to determine whether to tune its receive antenna in the direction of the multicast beam or in the direction of the common default beam. For example, the common scheduling threshold may be longer than the amount of time required for any individual UE to tune its receive antenna in the direction of the multicast beam. This enables the group of UEs to jointly receive PDSCH (carrying multicast data) on a multicast beam or a common default beam.

[0070] Figure 4AAn example wireless communication system 400 configured for unicast transmission is shown. The wireless communication system 400 includes a base station 402 and a UE 404. The wireless communication system 400 may be Figure 1 Thus, base station 402 and UE 404 may be example implementations of either base station 102 / 180 or UE 104, respectively. Figure 4A In the example shown in FIG. 4 , only one base station 402 and one UE 404 are shown. However, in actual implementation, the wireless communication system 400 may include any number of base stations and any number of UEs.

[0071] like Figure 4A As shown, the base station 402 and the UE 404 can be configured to use beamforming for unicast communication. For example, the base station 402 can send DL data to the UE 404 via a transmit (TX) beam 401. In some aspects, the TX beam 401 can be narrowly focused in the direction of the UE 404 to compensate for the high path loss and short distance of mmW communication. The base station 402 can configure the TX beam 401 based on the channel state information (CSI) obtained from the UE 404 by sounding. Therefore, the TX beam 401 can be optimized for the channel conditions associated with the UE 404. In order to receive the DL data, the UE 404 can tune multiple receive antennas in the direction of the TX beam 401. For example, depending on the width and directivity of the TX beam 401, the signal received by each antenna can be amplified by different weights.

[0072] Tuning or configuring the receive antenna consumes time and resources. In some cases, after identifying TX beam 401, UE 404 may not have sufficient time to tune its receive antenna in the direction of TX beam 401. When UE 404 is unable to configure (or reconfigure) its antenna in time to receive TX beam 401, UE 404 may instead tune its receive antenna to default beam 403. Before sending DL data, both base station 402 and UE 404 may know the direction of default beam 403. Therefore, if base station 402 determines that UE 404 is unable to tune its receive antenna in the direction of TX beam 401 in time to receive DL data, base station 402 may send DL data on default beam 403. Unlike TX beam 401, default beam 403 may not be optimized for the channel conditions of wireless communication system 400.

[0073] Figure 4B A timing diagram illustrating an example unicast communication 410 between a base station and a UE is shown. Figure 4A, unicast communication 410 may be performed between base station 402 and UE 404. At time t0, base station 402 transmits a PDCCH to UE 404. The PDCCH includes scheduling information 412 for a subsequent PDSCH carrying DL data 414 for UE 404. Figure 4B In the example of FIG4 , scheduling information 412 is sent on a scheduling (SC) beam 405. Scheduling beam 405 can be the same as or different from TX beam 401 or default beam 403. Scheduling information 412 can identify TX beam 401 and indicate the delay or timing offset (k0) between the PDCCH and PDSCH. UE 404 compares the timing offset k0 to a scheduling threshold 416 to determine whether to tune its receive antenna to TX beam 401 or default beam 403.

[0074] As described above, the scheduling threshold 416 may correspond to the amount of time required for the UE 404 to tune its receive antenna to the TX beam 401. Thus, if the timing offset k0 exceeds the scheduling threshold 416 (such as where the PDSCH arrives at time t2), the UE 404 may tune its receive antenna to the TX beam 401. If the timing offset k0 does not exceed the scheduling threshold 416 (such as where the PDSCH arrives at time t1), the UE 404 may tune its receive antenna to the default beam 403. Figure 4B In the example shown in FIG4 , the PDSCH is scheduled to arrive at time t2 (after the scheduling threshold 416), so the UE 404 can tune its receive antenna to the TX beam 401. The base station 402 can determine the scheduling threshold 416 for the UE 402 based on the information carried in the capability report received before the transmission of the PDCCH, and can also determine that the UE 404 is capable of receiving the PDSCH on the TX beam 401. Therefore, the base station 402 can use beamforming to transmit the PDSCH on the TX beam 401.

[0075] Figure 5A An example wireless communication system 500 configured for multicast transmission according to some implementations is shown. The wireless communication system 500 includes a base station 502 and a plurality of UEs 504 and 506. The wireless communication system 500 may be Figure 1 Thus, base station 502 may be an example implementation of any base station 102 / 180, and each UE 504 and 506 may be an example implementation of any UE 104. Although Figure 5A In the example shown in FIG. 5 , only one base station 502 and two UEs 504 and 506 are shown. However, in actual implementation, the wireless communication system 500 may include any number of base stations and any number of UEs.

[0076] like Figure 5AAs shown, base station 502 and UEs 504 and 506 may be configured for multicast (or broadcast) communication using beamforming. For example, base station 502 may transmit DL data to UEs 504 and 506 via multicast (MC) beam 501. Figure 5A In the example of FIG, a relatively wide MC beam 501 is used to focus DL data in a wide direction of both UEs 504 and 506. In some implementations, the base station 502 can configure the MC beam 501 based on the CSI obtained from each of the UEs 504 and 506 through sounding. Therefore, the MC beam 501 can be optimized for the channel conditions associated with the group of UEs 504 and 506. To receive the DL data, each of the UEs 504 and 506 can tune its receive antenna in the direction of the MC beam 501. Using the MC beam to multicast DL data to the group of UEs 504 and 506 simultaneously significantly reduces the signaling overhead of the wireless communication system 500 (compared to unicast transmission to each of the UEs 504 and 506 separately).

[0077] Figure 5B Another example wireless communication system 510 is shown configured for multicast transmissions according to some implementations. Figure 5B In the example of , a "composite beam" is used to focus DL data in different directions. The composite beam includes a first MC beam 512 and a second MC beam 514. The first MC beam 512 is narrowly focused in the direction of UE 506, and the second MC beam 514 is narrowly focused in the direction of UE 504. In some implementations, the base station 502 can configure the MC beams 512 and 514 based on the CSI obtained from each of the UEs 504 and 506 by sounding. Therefore, the MC beam 512 can be optimized for the channel conditions associated with the UE 506, and the MC beam 514 can be optimized for the channel conditions associated with the UE 504. In order to receive the DL data, the UE 506 can tune its receive antenna in the direction of the MC beam 512, and the UE 504 can tune its receive antenna in the direction of the MC beam 514.

[0078] Figure 5C Another example wireless communication system 520 configured for multicast transmissions according to some implementations is shown. Figure 5CIn the example of , an additional transmit receive point (TRP) 508 is used to provide coordinated multicast transmission to the group of UEs 504 and 506. More specifically, the base station 502 can transmit a narrowly focused MC beam 522 in the direction of the UE 506, and the TRP 508 can transmit a narrowly focused MC beam 524 in the direction of the UE 504. In some implementations, the base station 502 and the TRP 508 can configure the MC beams 522 and 524 based on CSI obtained from the UEs 506 and 504, respectively, through sounding. Therefore, the MC beam 522 can be optimized for the channel conditions associated with the UE 506, and the MC beam 524 can be optimized for the channel conditions associated with the UE 504. To receive DL data, the UE 506 can tune its receive antenna in the direction of the MC beam 522, and the UE 504 can tune its receive antenna in the direction of the MC beam 524.

[0079] As described above, tuning or configuring the receive antenna consumes time and resources. In some cases, the UE may not have enough time to tune its receive antenna in the direction of a particular MC beam (depending on the UE's scheduling threshold). In this case, it may be desirable for the UE to tune its antenna to a pre-configured default beam. However, existing 3GPP standards define a default beam configuration for unicast communications only. Aspects of the present disclosure recognize that a beamforming configuration used for unicast communications may not be suitable for multicast communications. For example, Figure 5C As shown, the default beam 523 used by UE 504 for unicast communication may differ in width and direction from the MC beam 524 sent to UE 504 for multicast communication. Furthermore, different UEs 504 and 506 may have different scheduling thresholds. Thus, while UE 506 may be able to receive MC beam 522, UE 504 may not be able to receive MC beam 524.

[0080] In some implementations, the UE may use its scheduling threshold for unicast communication as the scheduling threshold for multicast communication. For example, different UEs belonging to the same multicast group may have different scheduling thresholds. Thus, the base station may schedule DL transmissions to each UE individually. In some cases, one or more UEs may receive an MC beam, while other UEs may receive a default beam. In some other implementations, the UE may use a scheduling threshold for multicast communication that is different from the scheduling threshold for unicast communication. For example, the multicast scheduling threshold may be specifically configured for multicast communication and may be common to all UEs in the multicast group. Thus, the base station may schedule DL transmissions to the UEs as a group. As a result, all UEs in the multicast group will receive an MC beam or a default beam.

[0081] In some implementations, a UE may use its default beam for unicast communication as the default beam for multicast communication. For example, different UEs belonging to the same multicast group may have different default beams. Thus, the base station may send DL transmissions to one or more UEs individually. In some cases, the base station may be configured to send DL data on multiple different default beams. In some other implementations, the UE may use a scheduling threshold for multicast communication that is different from the scheduling threshold for unicast communication. For example, the default beam may be specifically configured for multicast communication and may be common to all UEs in the multicast group. Thus, the base station may send DL transmissions to the UEs as a group. As a result, all UEs in the multicast group will receive the same MC beam or default beam.

[0082] Figure 6 A timing diagram illustrating an example multicast communication 600 between a base station and a group of UEs according to some implementations is shown. Figures 5A-5C , a multicast communication 600 may be performed between the base station 502 (or TRP 508) and the group of UEs 504 and 506. Figure 6 In the example of FIG, the base station 502 can be configured to send DL data to the group of UEs 504 and 506 on the MC beam 601 or the default beam 603 used by each UE for unicast (UC) communication. The MC beam 601 can be Figures 5A-5C An example implementation of any MC beam 501, 512, 514, 522, or 524.

[0083] At time t0, base station 502 sends a PDCCH to UEs 504 and 506. The PDCCH includes scheduling information 602 for a subsequent PDSCH that carries DL data for the group of UEs 504 and 506. Figure 6 In the example of , scheduling information 602 is sent on a scheduling beam 605. The scheduling beam 605 can be the same as or different from the MC beam 601 or any default beam 603. The scheduling information 602 can identify the MC beam 601 and indicate a delay or timing offset k0 between the PDCCH and the PDSCH. In some implementations, each of the UEs 504 and 506 can identify the PDSCH as a multicast PDSCH for the group of UEs 504 and 506 based on a multicast indication included in the PDCCH. In some aspects, the multicast indication can correspond to a cyclic redundancy check (CRC) of the PDCCH scrambled with a group identifier (ID) associated with the group of UEs 504 and 506 (instead of a UE ID associated with a specific UE).

[0084] Each of the UEs 504 and 506 compares the timing offset k0 to the corresponding scheduling thresholds 604 and 606 to determine whether to tune its receive antenna to the MC beam 601 or the default beam 603. As described above, the scheduling thresholds 604 and 606 may correspond to the amount of time required for the UEs 504 and 506, respectively, to tune their receive antennas to the MC beam 601. Figure 6 In the example shown in FIG5 , the PDSCH is scheduled to arrive at time t1 (after the scheduling threshold 604 of UE 504, but before the scheduling threshold 606 of UE 506), so UE 504 can tune its receive antenna to MC beam 601, while UE 506 can tune its receive antenna to default beam 603. Base station 502 can determine the scheduling thresholds 604 and 606 for UEs 504 and 506 based on information carried in corresponding capability reports received before the transmission of the PDCCH. Therefore, the base station can also determine that UE 504 can receive the PDSCH on MC beam 601, while UE 506 cannot receive the PDSCH on MC beam 601. Therefore, base station 502 can use beamforming to simultaneously transmit the PDSCH on MC beam 601 and default beam 603.

[0085] Figure 7 A timing diagram illustrating another example multicast communication 700 between a base station and a group of UEs according to some implementations is shown. Figures 5A-5C , a multicast communication 700 may be performed between the base station 502 (or TRP 508) and the group of UEs 504 and 506. Figure 7 In the example of FIG, the base station 502 may be configured to transmit DL data to the group of UEs 504 and 506 on a multicast (MC) beam 701 or a common default beam 703 used by the group of UEs for multicast communication. The MC beam 701 may be Figures 5A-5C An example implementation of any MC beam 501, 512, 514, 522, or 524.

[0086] At time t0, base station 502 sends a PDCCH to UEs 504 and 506. The PDCCH includes scheduling information 702 for a subsequent PDSCH that carries DL data for the group of UEs 504 and 506. Figure 7In the example of , scheduling information 702 is sent on scheduling beam 705. Scheduling beam 705 can be the same as or different from MC beam 701 or default beam 703. Scheduling information 702 can identify MC beam 701 and indicate a delay or timing offset k0 between the PDCCH and the PDSCH. In some implementations, each of UEs 504 and 506 can identify the PDCCH as a multicast PDSCH for the group of UEs 504 and 506 based on a multicast indication included in the PDCCH. In some aspects, the multicast indication can correspond to a CRC of the PDCCH scrambled with a group ID associated with the group of UEs 504 and 506 (instead of a UE ID associated with a specific UE).

[0087] Each of the UEs 504 and 506 compares the timing offset k0 to a multicast (MC) scheduling threshold 704 to determine whether to tune its receive antenna to the MC beam 701 or the default beam 703. In some implementations, each of the UEs 504 and 506 can tune its receive antenna to the MC beam 701 at the end of the MC scheduling threshold 704. In some aspects, the base station 502 can determine the MC scheduling threshold 704 based on a separate scheduling threshold reported by each of the UEs 504 and 506. More specifically, the MC scheduling threshold 704 can be configured to be at least equal to (or longer than) the longest scheduling threshold reported by any UE 504 or 506 in the group in terms of duration. The base station 502 can signal the MC scheduling threshold 704 to the UEs 504 and 506 via one or more RRC or DCI messages. In some other aspects, the MC scheduling threshold 704 can be a predefined value. For example, the MC scheduling threshold 704 can be defined by a wireless standard (e.g., a 3GPP standard). Therefore, any wireless device (including UE and base station) that supports multicast beamforming needs to comply with the MC scheduling threshold 704.

[0088] As described above, the MC scheduling threshold 704 may correspond to an amount of time required for each of the UEs 504 and 506 to tune its receive antenna to the MC beam 701. Thus, if the timing offset k0 exceeds the MC scheduling threshold 704 (such as where the PDSCH arrives at time t2), the UEs 504 and 506 may tune their receive antennas to the MC beam 701. If the timing offset k0 does not exceed the MC scheduling threshold 704 (such as where the PDSCH arrives at time t1), the UEs 504 and 506 may tune their receive antennas to the default beam 703. In some implementations, the base station 502 may signal or otherwise indicate the default beam 703 to the UEs 504 and 506 prior to transmission of the PDCCH. For example, the base station 502 may signal the default beam 703 to the UEs 504 and 506 using RRC signaling and a MAC control element (MAC-CE). In Figure 7 In the example of , the PDSCH is scheduled to arrive at time t2 (after the MC scheduling threshold 704), so UEs 504 and 506 can each tune their receive antennas to MC beam 701. Similarly, base station 502 can use beamforming to send PDSCH on only MC beam 701.

[0089] Figure 8 A timing diagram illustrating another example multicast communication 800 between a base station and a group of UEs according to some implementations is shown. Figures 5A-5C , a multicast communication 800 may be performed between the base station 502 (or TRP 508) and the group of UEs 504 and 506. Figure 8 In the example of FIG, the base station 502 may be configured to transmit DL data to the group of UEs 504 and 506 on the MC beam 801 or the common default beam 803 used by the group of UEs for multicast (MC) communication. The MC beam 801 may be Figures 5A-5C An example implementation of any MC beam 501, 512, 514, 522, or 524.

[0090] At time t0, base station 502 sends a PDCCH to UEs 504 and 506. The PDCCH includes scheduling information 802 for a subsequent PDSCH that carries DL data for the group of UEs 504 and 506. Figure 8In the example of , scheduling information 802 is sent on a dedicated MC beam 803. The dedicated MC beam 803 can be associated with a control resource set (CORESET) specifically allocated for multicast or broadcast communications. A CORESET describes a set of time and frequency resources associated with each beam on which a PDCCH is transmitted. In some implementations, the dedicated MC beam 803 can be associated with the CORESET with the lowest CORESET index. The scheduling information 802 can identify the MC beam 801 and indicate the delay or timing offset k0 between the PDCCH and the PDSCH. In some implementations, each of the UEs 504 and 506 can identify the PDSCH as a multicast PDSCH for the group of UEs 504 and 506 by detecting the scheduling information 802 on the dedicated MC beam 803.

[0091] Each of the UEs 504 and 506 compares the timing offset k0 to the multicast (MC) scheduling threshold 804 to determine whether to tune its receive antenna to the MC beam 801 or the default beam. In some implementations, the UEs 504 and 506 may detect the default beam based on the CORESET associated with the PDCCH. For example, each of the UEs 504 and 506 may use the beam on which the PDCCH with scheduling information 802 was received as the default beam. Thus, in some aspects, the default beam may correspond to the dedicated MC beam 803. As described above, each of the UEs 504 and 506 may be able to tune its receive antenna to the MC beam 801 at the end of the MC scheduling threshold 804. In some aspects, the base station 502 may determine the MC scheduling threshold 804 based on a separate scheduling threshold reported by each of the UEs 504 and 506. The base station 502 may signal the MC scheduling threshold 804 to the UEs 504 and 506 via one or more RRC or DCI messages. In some other aspects, the MC scheduling threshold 804 may be a predefined value (such as defined by 3GPP standards).

[0092] As described above, the MC scheduling threshold 804 may correspond to the amount of time required for each of the UEs 504 and 506 to tune its receive antenna to the MC beam 801. Thus, if the timing offset k0 exceeds the MC scheduling threshold 804 (such as where the PDSCH arrives at time t2), the UEs 504 and 506 may tune their receive antennas to the MC beam 801. If the timing offset k0 does not exceed the MC scheduling threshold 804 (such as where the PDSCH arrives at time t1), the UEs 504 and 506 may tune their receive antennas to the dedicated MC beam 803. Figure 8In the example of , the PDSCH is scheduled to arrive at time t2 (after MC scheduling threshold 804), so UEs 504 and 506 can each tune their receive antennas to MC beam 801. Similarly, base station 502 can use beamforming to send PDSCH on only MC beam 801.

[0093] Figure 9 A flow chart illustrating an example process 900 for wireless communication supporting beamforming in multicast communications according to some implementations is shown. In some implementations, process 900 may be performed by a wireless communication device operating as a UE or within a UE, such as those described above with reference to Figure 1 、 Figure 4A and Figures 5A-5C One of the UEs 104, 404, or 504 and 506 depicted.

[0094] In some implementations, process 900 begins at block 902 by receiving a PDCCH from a base station, wherein the PDCCH includes scheduling information for a PDSCH to be multicast to multiple UEs including the UE. In some implementations, determining that the PDSCH carries multicast data may be based on a CORESET associated with the PDCCH. In some other implementations, determining that the PDSCH carries multicast data may be based on determining that a CRC sequence included in the PDCCH is scrambled with a group identifier associated with the multiple UEs.

[0095] At block 904, process 900 continues by determining a first beam associated with the PDSCH based on the scheduling information and the delay between the PDCCH and the PDSCH. At block 906, process 900 continues by tuning the multiple receive antennas based on the delay between the PDCCH and the PDSCH to receive the PDSCH on the first beam or the second beam. In some implementations, the second beam may be different from a default beam associated with unicast transmissions from the base station to the UE. In some implementations, the second beam may be determined based on a CORESET associated with the PDCCH. In some other implementations, the second beam may be determined based on information carried in an RRC message or MAC CE received from the base station prior to receiving the PDCCH.

[0096] In some implementations, in block 906, the operation for tuning the multiple receive antennas may include determining whether a delay between the PDCCH and the PDSCH exceeds a threshold duration, wherein based on determining that the delay exceeds the threshold duration, the multiple receive antennas are tuned to a first beam, and wherein based on determining that the delay does not exceed the threshold duration, the multiple receive antennas are tuned to a second beam. In some implementations, the threshold duration may be based on a duration associated with tuning the multiple receive antennas to receive unicast transmissions from a base station. In some other implementations, the threshold duration may be different from a duration associated with tuning the receive antennas to receive unicast transmissions from a base station. In some implementations, the threshold duration may be determined based on information carried in an RRC message or a DCI message received from the base station.

[0097] Figure 10 A flow chart illustrating an example process 1000 for wireless communication supporting beamforming in multicast communications according to some other implementations is shown. In some implementations, process 1000 may be performed by a wireless communication device operating as or within a network node, such as those described above with reference to Figure 1 、 Figure 4A and Figures 5A-5C One of base stations 102 / 180, 402 or 502 and 508 is depicted.

[0098] In some implementations, process 1000 begins at block 1002 by transmitting a PDCCH to a plurality of UEs, wherein the PDCCH carries scheduling information indicating a first beam associated with a PDSCH to be multicast to the plurality of UEs and a timing offset between the PDCCH and the PDSCH. In some implementations, the PDCCH may include a CRC sequence scrambled with a group identifier associated with the plurality of UEs. In block 1004, process 1000 continues by selecting at least one of the first beam or a second beam for transmitting the PDSCH based on the timing offset between the PDCCH and the PDSCH. In some implementations, the second beam may be determined based on a CORESET associated with the PDCCH. In some implementations, the second beam may be different from a default beam associated with unicast transmissions to any of the plurality of UEs. In block 1006, process 1000 continues by transmitting the PDSCH to the plurality of UEs on the selected at least one beam.

[0099] In some implementations, in block 1004, the operation for selecting at least one of the first beam or the second beam may include determining whether a timing offset exceeds a multicast scheduling threshold associated with the plurality of UEs, wherein the first beam is selected based on determining that the timing offset exceeds the multicast scheduling threshold, and wherein the second beam is selected based on determining that the timing offset does not exceed the multicast scheduling threshold. In some implementations, the multicast scheduling threshold may be configured to be at least equal to a longest duration associated with tuning multiple receive antennas by any UE to receive a unicast transmission from a base station.

[0100] In some other implementations, in block 1004, the operation for selecting at least one of the first beam or the second beam may include: determining, for each of the plurality of UEs, a respective duration associated with tuning the plurality of receive antennas to receive a unicast transmission from the base station; and determining whether a timing offset exceeds the duration determined for each of the plurality of UEs, wherein at least the first beam is selected based on determining that the timing offset exceeds the duration determined for at least one of the plurality of UEs. In some implementations, the second beam may be selected based on determining that the timing offset does not exceed the duration determined for a first UE in the plurality of UEs, wherein the second beam is a default beam associated with unicast transmissions from the base station to the first UE. In some implementations, the timing offset may be configured to be at least equal to a longest duration of the durations determined for the plurality of UEs.

[0101] Figure 11 FIG2 shows a block diagram of an example wireless communication device 1100 according to some implementations. In some implementations, the wireless communication device 1100 is configured to perform the above-referenced Figure 9 The wireless communication device 1100 may be the one described above. Figure 1 and Figure 3 An example implementation of any of the described UEs 104 or 350. For example, the wireless communication device 1100 can be a chip, SoC, chipset, package, or device that includes at least one processor and at least one modem (e.g., a Wi-Fi (IEEE 802.11) modem or a cellular modem).

[0102] The wireless communication device 1100 includes a receiving component 1110, a communication manager 1120, and a transmitting component 1130. The communication manager 1120 also includes a PDCCH interpretation component 1122 and an antenna tuning component 1124. Portions of one or more components 1122 and 1124 may be implemented at least in part in hardware or firmware. In some implementations, at least some components 1122 or 1124 are implemented at least in part as software stored in a memory (e.g., memory 360). For example, portions of one or more components 1122 and 1124 may be implemented as non-transitory instructions (or "code") that can be executed by a processor (e.g., controller / processor 359) to perform the functions or operations of the corresponding component.

[0103] The receiving component 1110 is configured to receive an RX signal representing a DL communication from a base station. In some implementations, the RX signal may include a PDCCH carrying scheduling information for a PDSCH to be multicast to multiple UEs including wireless communication devices. The transmitting component 1130 is configured to send a TX signal representing an UL communication to the base station. The communication manager 1120 is configured to control or manage DL and UL communications with the base station. In some implementations, the PDCCH interpretation component 1122 may determine a first beam associated with the PDSCH and a delay between the PDCCH and the PDSCH based on the scheduling information; and the antenna tuning component 1124 may tune multiple receive antennas based on the delay determined between the PDCCH and the PDSCH to receive the PDSCH on the first beam or the second beam.

[0104] Figure 12 FIG2 shows a block diagram of an example wireless communication device 1200 according to some implementations. In some implementations, the wireless communication device 1200 is configured to perform the above-referenced Figure 10 The wireless communication device 1200 may be the one described above. Figure 1 and Figure 3 An example implementation of any of the described base stations 102 or 310. For example, the wireless communication device 1200 can be a chip, SoC, chipset, package, or device that includes at least one processor and at least one modem (e.g., a Wi-Fi (IEEE 802.11) modem or a cellular modem).

[0105] The wireless communication device 1200 includes a receiving component 1210, a communication manager 1220, and a transmitting component 1230. The communication manager 1220 also includes a beam selection component 1222. Portions of the beam selection component 1222 can be implemented at least in part in hardware or firmware. In some implementations, the beam selection component 1222 is implemented at least in part as software stored in a memory (e.g., memory 376). For example, portions of the beam selection component 1222 can be implemented as non-transitory instructions (or "code") executable by a processor (e.g., controller / processor 375) to perform the functions or operations of the corresponding component.

[0106] The receiving component 1210 is configured to receive an RX signal representing UL communication from one or more UEs. The transmitting component 1230 is configured to send a TX signal representing DL communication to one or more UEs. In some implementations, the TX signal may include a PDCCH carrying scheduling information, the scheduling information indicating a first beam associated with a PDSCH to be multicast to multiple UEs and a timing offset between the PDCCH and the PDSCH. The communication manager 1220 is configured to control or manage DL and UL communications with one or more UEs. In some implementations, the beam selection component 1222 may select at least one of the first beam or the second beam for transmitting the PDSCH based on the timing offset between the PDCCH and the PDSCH. In some implementations, the transmission component 1230 may also transmit the PDSCH to multiple UEs on the selected at least one beam.

[0107] As used herein, the phrase "at least one" or "one or more" referring to a list of items refers to any combination of those items, including unique elements. For example, "at least one of a, b, or c" is intended to cover the following possibilities: only a, only b, only c, a combination of a and b, a combination of a and c, a combination of b and c, and a combination of a, b, and c.

[0108] The various illustrative components, logic, logic blocks, modules, circuits, operations, and algorithmic processes described in conjunction with the implementations disclosed herein may be implemented as electronic hardware, firmware, software, or a combination of hardware, firmware, or software, including the structures disclosed in this specification and their structural equivalents. The interchangeability of hardware, firmware, and software has been generally described in terms of functionality and illustrated in the various illustrative components, blocks, modules, circuits, and processes described above. Whether such functionality is implemented in hardware, firmware, or software depends on the specific application and the design constraints imposed on the overall system.

[0109] Various modifications to the implementations described in this disclosure may be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other implementations without departing from the spirit or scope of this disclosure. Accordingly, the claims are not intended to be limited to the implementations shown herein, but are to be accorded the widest scope consistent with this disclosure, the principles, and the novel features disclosed herein.

[0110] Furthermore, various features described in this specification in the context of separate implementations may also be implemented in combination in only one implementation. Conversely, various features described in the context of only one implementation may also be implemented individually in multiple implementations or in any suitable subcombination. Similarly, although features may be described above as functioning in a particular combination and even initially claimed as such, in some cases one or more features from a claimed combination may be deleted from that combination, and the claimed combination may be directed to a subcombination or variant of the subcombination.

[0111] Similarly, although operations are depicted in a particular order in the figures, it should not be understood that such operations must be performed in the particular order shown or in a sequential order, or that all operations shown must be performed to achieve the desired result. In addition, the accompanying drawings may schematically depict one or more exemplary processes in the form of a flow chart or a job diagram. However, other operations not described may be incorporated into the schematically illustrated exemplary processes. For example, one or more additional operations may be performed before, after, simultaneously, or between any illustrated operations. In some cases, multitasking and parallel processing may be advantageous. In addition, the separation of the various system components in the above-described implementations should not be understood as requiring such separation in all implementations, and it should be understood that the described program components and systems may typically be integrated together in only one software product or encapsulated in multiple software products.

Claims

1. A method of wireless communication performed by a user equipment (UE), comprising: receiving a physical downlink control channel (PDCCH) from a base station, the PDCCH carrying scheduling information for a physical downlink shared channel (PDSCH) to be multicast to the UE, the scheduling information indicating a delay between the PDCCH and the PDSCH; determining a multicast beamforming configuration associated with the PDSCH based on the delay between the PDCCH and the PDSCH indicated in the scheduling information; as well as A plurality of receive antennas are tuned according to the multicast beamforming configuration to receive the PDSCH.

2. The method according to claim 1, wherein Determining the multicast beamforming configuration includes: determining whether the delay between the PDCCH and the PDSCH exceeds a threshold duration; and The multicast beamforming configuration is determined in response to determining whether the delay between the PDCCH and the PDSCH exceeds the threshold duration.

3. The method according to claim 2, further comprising: receiving at least one of an RRC message or a downlink control information (DCI) message; as well as The threshold duration is determined according to information carried in the RRC message or the DCI message.

4. The method according to claim 2, wherein: The threshold duration is based on a duration associated with tuning the plurality of receive antennas to receive a unicast transmission.

5. The method according to claim 2, wherein: The threshold duration is different from a duration associated with tuning the plurality of receive antennas to receive unicast transmissions.

6. The method according to claim 1, further comprising: The PDSCH carries multicast data, determined according to a control resource set (CORESET) associated with the PDCCH.

7. The method according to claim 1, further comprising: identifying a cyclic redundancy check (CRC) sequence in the PDCCH; determining that the CRC sequence is scrambled with a group identifier associated with the UE; as well as In response to determining that the CRC sequence is scrambled with the group identifier, it is determined that the PDSCH carries multicast data.

8. A user equipment (UE) for wireless communication, comprising: A processing system comprising one or more processors and one or more memories coupled to the one or more processors, wherein the processing system is configured to cause the UE to perform the following operations: receiving a physical downlink control channel (PDCCH), the PDCCH carrying scheduling information for a physical downlink shared channel (PDSCH) to be multicast to the UE, the scheduling information indicating a delay between the PDCCH and the PDSCH; determining a multicast beamforming configuration associated with the PDSCH based on the delay between the PDCCH and the PDSCH indicated in the scheduling information; as well as A plurality of receive antennas are tuned according to the multicast beamforming configuration to receive the PDSCH.

9. The UE according to claim 8, wherein: In order to enable the UE to determine the multicast beamforming configuration, the processing system is configured to enable the UE to perform the following operations: determining whether the delay between the PDCCH and the PDSCH exceeds a threshold duration; as well as The multicast beamforming configuration is determined in response to determining whether the delay between the PDCCH and the PDSCH exceeds the threshold duration.

10. The UE according to claim 9, wherein: The processing system is further configured to cause the UE to perform the following operations: receiving at least one of an RRC message or a downlink control information (DCI) message; as well as The threshold duration is determined according to information carried in the RRC message or the DCI message.

11. The UE according to claim 9, wherein: The threshold duration is based on a duration associated with tuning the plurality of receive antennas to receive a unicast transmission.

12. The UE according to claim 9, wherein: The threshold duration is different from a duration associated with tuning the plurality of receive antennas to receive unicast transmissions.

13. The UE according to claim 8, wherein: The processing system is further configured to cause the UE to perform the following operations: The PDSCH carries multicast data, determined according to a control resource set (CORESET) associated with the PDCCH.

14. The UE according to claim 8, wherein: The processing system is further configured to cause the UE to perform the following operations: identifying a cyclic redundancy check (CRC) sequence in the PDCCH; determining that the CRC sequence is scrambled with a group identifier associated with the UE; and In response to determining that the CRC sequence is scrambled with the group identifier, it is determined that the PDSCH carries multicast data.

15. An apparatus comprising: means for receiving a physical downlink control channel (PDCCH) from a base station, the PDCCH carrying scheduling information for a physical downlink shared channel (PDSCH) to be multicast to the apparatus, the scheduling information indicating a delay between the PDCCH and the PDSCH; means for determining a multicast beamforming configuration associated with the PDSCH based on the delay between the PDCCH and the PDSCH indicated in the scheduling information; as well as Means for tuning a plurality of receive antennas to receive the PDSCH according to the multicast beamforming configuration.

16. The device according to claim 15, wherein The means for determining the multicast beamforming configuration includes: means for determining whether the delay between the PDCCH and the PDSCH exceeds a threshold duration; and means for determining the multicast beamforming configuration in response to determining whether the delay between the PDCCH and the PDSCH exceeds the threshold duration.

17. The apparatus according to claim 16, further comprising: means for receiving at least one of an RRC message or a downlink control information (DCI) message; as well as A unit configured to determine the threshold duration according to information carried in the RRC message or the DCI message.

18. The device according to claim 16, wherein The threshold duration is based on or different from a duration associated with tuning the plurality of receive antennas to receive unicast transmissions.

19. The apparatus according to claim 15, further comprising: The method further comprises a step of: determining, based on a control resource set (CORESET) associated with the PDCCH, that the PDSCH carries multicast data.

20. The apparatus according to claim 15, further comprising: means for identifying a cyclic redundancy check (CRC) sequence in the PDCCH; means for determining that the CRC sequence is scrambled with a group identifier associated with the device; as well as means for determining, in response to determining that the CRC sequence is scrambled with the group identifier, that the PDSCH carries multicast data.

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