Beamforming in multicast communications

Abstract

The present disclosure provides methods, apparatus and systems for beamforming in wireless communications. Some implementations more specifically relate to beamforming configurations for multicast communications. A transmitting device may simultaneously send multicast data to multiple receiving devices via a physical downlink shared channel (PDSCH). A physical downlink control channel (PDCCH) may precede 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. A receiving device may determine that the PDSCH contains multicast data based on an indication in the PDCCH. In order 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 the delay between the PDCCH and the PDSCH.

Description

Technical Field

[0001]

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

[0002] Wireless communication systems are widely deployed to provide a variety of telecommunication services, such as telephony, video, data, messaging, and broadcast. Typical wireless communication systems may employ multiple access technologies that are 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.

[0003] 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 Third Generation Partnership Project (3GPP) to meet new requirements associated with latency, reliability, security, scalability (e.g., with the Internet of Things (IoT)), and other requirements. 5G NR includes services associated with enhanced mobile broadband (eMBB), massive machine type 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.

[0004] Improvements in 5G NR 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 from which the transmitting device is transmitting. The focused beam greatly improves the signal-to-interference-and-noise ratio (SINR) of communications between the transmitting device and the receiving device. In mmW communications, beamforming is highly directional to compensate for the extremely high path loss and short distances. 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

[0005] 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.

[0006] An 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 receiving antennas to receive the PDSCH on the first beam or the second beam based on the determined delay between the PDCCH and the PDSCH.

[0007] In some implementations, the method may further include determining that the PDSCH carries multicast data based on a control resource set (CORESET) associated with the PDCCH. 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 that the PDSCH carries multicast data based on determining that the CRC sequence is scrambled with the group identifier.

[0008] In some implementations, the method may further include determining the second beam based on the 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 the MAC CE. In some implementations, the second beam is different from a default beam associated with a unicast transmission to the UE by the base station.

[0009] In some implementations, the tuning of 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 a unicast transmission from a base station. In some other implementations, the threshold duration is different from the duration associated with tuning the receive antennas to receive a unicast transmission from a base station. In some implementations, the method may also 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.

[0010] 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 at least one processor so that the UE performs operations including the following: 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 a first beam or a second beam based on the delay determined between the PDCCH and the PDSCH.

[0011] Another innovative aspect of the subject matter described in the present disclosure can be implemented as a method for wireless communication. The method can be performed by a base station and can include: sending a PDCCH to multiple UEs, wherein the PDCCH carries scheduling information, the scheduling information indicates a first beam associated with a PDSCH to be multicast to multiple UEs and a timing offset between the PDCCH and the PDSCH; based on the timing offset between the PDCCH and the PDSCH, selecting at least one of the first beam or the second beam for sending the PDSCH; and sending the PDSCH to the multiple UEs on the selected at least one beam.

[0012] 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 sent 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.

[0013] 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 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 method may also 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.

[0014] In some implementations, selecting at least one of the first beam or the second beam includes: 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, selecting the second beam is based on determining that the timing offset does not exceed the duration determined for a first UE of the plurality of UEs, wherein the second beam is a default beam associated with a unicast transmission 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 of the durations determined for the plurality of UEs.

[0015] 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 at least one processor so that the base station performs operations including: sending a PDCCH to multiple UEs, wherein the PDCCH carries scheduling information, the scheduling information indicates a first beam associated with a PDSCH to be multicast to multiple UEs and a timing offset between the PDCCH and the PDSCH; based on the timing offset between the PDCCH and the PDSCH, selecting at least one of the first beam or the second beam for sending the PDSCH; and sending the PDSCH to multiple UEs on the selected at least one beam. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A diagram of an example wireless communication system and access network is shown.

[0017] 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.

[0018] Figure 3 A block diagram of an example base station and user equipment (UE) in an access network is shown.

[0019] Figure 4A An example wireless communication system configured for unicast transmissions is shown.

[0020] Figure 4BA timing diagram illustrating example unicast communications between a base station and a UE is shown.

[0021] Figure 5A

[0013] An example wireless communication system configured for multicast transmissions in accordance with some implementations is shown.

[0022] Figure 5B

[0013] Another example wireless communication system configured for multicast transmissions in accordance with some implementations is shown.

[0023] Figure 5C

[0013] Another example wireless communication system configured for multicast transmissions in accordance with some implementations is shown.

[0024] Figure 6 A timing diagram illustrating example multicast communications between a base station and a group of UEs according to some implementations is shown.

[0025] 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.

[0026] 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.

[0027] Fig. 9 A flow chart illustrating an example process for wireless communications supporting beamforming in multicast communications according to some implementations.

[0028] Fig.10 A flow chart illustrating an example process for wireless communications supporting beamforming in multicast communications according to some other implementations is shown.

[0029] Fig.11 A block diagram of an example wireless communication device is shown in accordance with some implementations.

[0030] Fig.12 A block diagram of an example wireless communication device is shown in accordance with some implementations. DETAILED DESCRIPTION

[0031] 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 of this document 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 the Bluetooth Special Interest Group (SIG) defined by the Bluetooth 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 networks in 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.

[0032] Improvements in 5G NR include beamforming and the use of extremely high frequency (EHF) or millimeter wave (mmW) spectrum (30-300GHz). In mmW communications, beamforming is highly directional to compensate for extremely high path losses 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, a beam used in unicast communications between any pair of transmitting and receiving devices may differ in width or directionality from any beam that may 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.

[0033] In summary, various aspects relate to beamforming configurations for multicast communications. Some aspects more specifically relate to scheduling multicast data to be transmitted 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 a PDSCH, and the PDCCH provides scheduling information for the PDSCH, including an identification of a 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. In order to receive a multicast PDSCH, the UE can tune its multiple antennas in the direction of a scheduled multicast beam or in the direction of a default beam based on a delay between the PDCCH and the PDSCH. For example, if the delay between PDCCH and PDSCH exceeds the 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.

[0034] Specific implementations of the subject matter described in the present 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 the scheduled PDSCH to carry multicast data via the PDCCH, various aspects of the present disclosure enable each UE in the group to tune its receiving 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 the default beam used by any individual UE for unicast communications with the base station. In some aspects, when 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 receiving 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 receiving 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.

[0035] Several aspects of telecommunication systems will now be described with reference to various apparatus and methods. These apparatus and methods will be described in the following detailed description and illustrated in the accompanying drawings by various blocks, components, circuits, processes, algorithms, etc. (collectively referred to as "elements"). These elements may be implemented using electronic hardware, computer software, or any combination thereof. Whether these elements are implemented as hardware or software depends on the specific application and design constraints on the overall system.

[0036] For example, an element or any part of an element or any combination of elements may be implemented as a "processing system" including 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 may execute software. Whether or not it is 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.

[0037] Therefore, in one or more example embodiments, the functions may be implemented in hardware, software, or any combination thereof. If implemented in software, the 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 computer-readable media of the above types, 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.

[0038] Figure 1A schematic diagram of an example wireless communication system and access network 100 is shown. The wireless communication system (also referred to as a wireless wide area network (WWAN)) includes a base station 102, a UE 104, an evolved packet core (EPC) 160, and another core network 190 (e.g., a 5G core (5GC)). The base station 102 may include a macro cell (a high-power cellular base station) and / or a small cell (a low-power cellular base station). A macro cell includes a base station. A small cell includes a femto cell, a pico cell, and a micro cell.

[0039] A base station 102 configured for 4G LTE (collectively referred to as 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 Next Generation RAN (NG-RAN)) may interface with the core network 190 via a backhaul link 184. The base station 102 may perform, among other functions, one or more of the following functions: user data transmission, 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.

[0040] Base stations 102 may communicate wirelessly with UE 104. Each base station 102 may 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 including 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 services to a restricted group referred to as a closed subscriber group (CSG). A communication link 120 between a base station 102 and a UE 104 may include an uplink (UL) (also referred to as a reverse link) transmission from the UE 104 to the base station 102 and / or a downlink (DL) (also referred to as a forward link) transmission 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 through one or more carriers. The base station 102 / UE 104 may use spectrum of up to Y MHz (e.g., 5, 10, 15, 20, 100, 400, etc. MHz) bandwidth for each carrier allocated in a carrier aggregation for transmission in each direction for a total of up to Yx MHz (x component carriers). The 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).

[0041] Some UEs 104 may communicate with each other using a device-to-device (D2D) communication link 158. The D2D communication link 158 may use DL / UL WWAN spectrum. The D2D communication link 158 may use one or more sidelink channels, such as a physical sidelink broadcast channel (PSBCH), a physical sidelink discovery channel (PSDCH), a physical sidelink shared channel (PSSCH), and a physical sidelink control channel (PSCCH). The D2D communication may be through various wireless D2D communication systems, such as FlashLinQ, WiMedia, Bluetooth, ZigBee, Wi-Fi based on IEEE 802.11 standards, LTE, or NR.

[0042] 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.

[0043] The small cell 102' may operate in a licensed and / or unlicensed spectrum. When operating in an unlicensed spectrum, the small cell 102' may 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 may expand the coverage of the access network and / or increase the capacity of the access network.

[0044] The base station 102 (whether a small cell 102' or a large cell (e.g., a macro base station)) may include an eNB, a gNodeB (gNB), or another type of base station. Some base stations (e.g., gNB 180) may communicate with the UE 104 in the traditional sub-6 GHz spectrum, in millimeter wave (mmW) frequencies, and / or in near mmW frequencies. When the gNB 180 operates in mmW or near mmW frequencies, the gNB 180 may be referred to as a millimeter wave or mmW base station. Extremely high frequency (EHF) is a portion of the RF in the electromagnetic spectrum. The range of EHF is 30 GHz to 300 GHz, with wavelengths between 1 mm and 10 mm. Radio waves in the frequency band may be referred to as millimeter waves. Near mmW may extend down to frequencies of 3 GHz with wavelengths of 100 mm. The super high frequency (SHF) band extends between 3 GHz and 30 GHz and is also referred to as centimeter waves. Communications using the mmW / near mmW radio frequency bands (e.g., 3 GHz-300 GHz) have extremely high path losses and short distances. The mmW base station 180 may utilize beamforming 182 with the UE 104 to compensate for the extremely high path loss and short range.

[0045] The base station 180 may send beamformed signals in one or more transmit directions 182' to the UE 104. The UE 104 may receive beamformed signals from the base station 180 in one or more receive directions 182". The UE 104 may also send beamformed signals to the base station 180 in one or more transmit directions. The base station 180 may receive beamformed signals from the UE 104 in one or more receive directions. The 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 the base station 180 may be the same or different. The transmit and receive directions of the UE 104 may be the same or different.

[0046] The EPC 160 may include a mobility management entity (MME) 162, other MMEs 164, a serving gateway 166, a multimedia broadcast multicast service (MBMS) gateway 168, a broadcast multicast service center (BM-SC) 170, and a packet data network (PDN) gateway 172. The MME 162 may communicate with a home subscriber server (HSS) 174. The MME 162 is a control node that handles signaling between the UE 104 and the EPC 160. Typically, the MME 162 provides bearer and connection management. All user Internet Protocol (IP) packets are transmitted through the serving gateway 166, which itself is connected to the PDN gateway 172. The PDN gateway 172 provides UE IP address allocation and other functions. The PDN gateway 172 and the BM-SC 170 are connected to IP services 176. The IP services 176 may include the Internet, an intranet, an IP multimedia subsystem (IMS), a PS streaming service, and / or other IP services. The BM-SC 170 may provide functions for MBMS user service provisioning and delivery. The BM-SC 170 may be used as an entry point for content provider MBMS transmissions, may be used to authorize and initiate MBMS bearer services within a public land mobile network (PLMN), and may be used to schedule MBMS transmissions. The MBMS Gateway 168 may be used to distribute MBMS services to base stations 102 belonging to a multicast broadcast single frequency network (MBSFN) area that broadcasts specific services, and may be responsible for session management (start / stop) and collecting charging information related to eMBMS.

[0047] 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. Typically, the AMF 192 provides QoS flow and session management. All user Internet Protocol (IP) packets are transmitted through the UPF 195. The UPF 195 provides UE IP address allocation and other functions. The UPF 195 is connected to an IP service 197. The IP service 197 may include the Internet, an intranet, an IP multimedia subsystem (IMS), a PS streaming service, and / or other IP services.

[0048] A base station may also be referred to as a gNB, a Node B, an evolved Node B (eNB), an access point, a base transceiver station, a radio base station, a radio transceiver, a transceiver function, a basic service set (BSS), an extended service set (ESS), a transmit receive point (TRP), or some other suitable term. Base station 102 provides an access point to EPC 160 or core network 190 for UE 104. Examples of UE 104 include a cellular phone, a smart phone, 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 similar functional device. Some UEs 104 may be referred to as IoT devices (e.g., parking meters, gas pumps, toasters, vehicles, heart monitors, etc.). UE 104 may also be referred to as a station, a mobile station, a user station, a mobile unit, a user unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communication device, a remote device, a mobile user 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.

[0049] Reference again Figure 1 In some aspects, the base station 102 / 180 can utilize beamforming 182 to simultaneously send 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. The physical downlink control channel (PDCCH) can precede the PDSCH. In some implementations, the base station 102 / 180 and the UE 104 can configure beamforming 182 (198) for multicasting 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 send 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 required for the UE 104 to configure (or tune) multiple receive antennas to receive a given beam.

[0050] 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 time slot is shown. The 5G / NR frame structure may be FDD, where, for a particular set of subcarriers (carrier system bandwidth), a time slot within a subcarrier set is 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), a time slot within a subcarrier set is 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 a 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.

[0051] 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 a microslot, which may include 7, 4, or 2 symbols. Depending on the slot configuration, each time slot may include 7 or 14 symbols. For slot configuration 0, each time slot may include 14 symbols, and for slot configuration 1, each time slot may include 7 symbols. The symbol on the DL may be a cyclic prefix (CP) OFDM (CP-OFDM) symbol. The symbol on the UL may be a CP-OFDM symbol (for high throughput situations) or a discrete Fourier transform (DFT) spread OFDM (DFT-s-OFDM) symbol (also known as a single carrier frequency division multiple access (SC-FDMA) symbol) (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 to 5 allow 1, 2, 4, 8, 16 and 32 slots per subframe, respectively. For slot configuration 1, different digital schemes 0 to 2 allow 2, 4 and 8 slots per subframe, respectively. Therefore, for slot configuration 0 and digital scheme μ, there are 14 symbols / slot and 2μ slots / subframe. The subcarrier spacing and symbol length / duration are functions of the digital scheme. The subcarrier spacing can be equal to 2^μ*15kKz, where μ is the digital scheme 0 to 5. Therefore, 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. Figure 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.

[0052] A 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 spans 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.

[0053] like Figure 2AAs shown, some REs carry reference (pilot) signals (RS) for UEs. In some configurations, one or more REs may carry demodulation RS (DM-RS) (denoted as Rx for one particular 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 beam measurement RS (BRS), beam refinement RS (BRRS), and phase tracking RS (PT-RS).

[0054] 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 including nine RE groups (REGs), and each REG including 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 location of the aforementioned DM-RS. The physical broadcast channel (PBCH) carrying the master information block (MIB) can be logically grouped with the PSS and SSS to form a synchronization signal (SS) / PBCH block. 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.

[0055] 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.

[0056] Figure 2DExamples of various UL channels within a subframe of a frame are shown. The PUCCH may be positioned as shown in one configuration. The PUCCH carries uplink control information (UCI), such as scheduling requests, channel quality indicator (CQI), precoding matrix indicator (PMI), rank indicator (RI), and HARQ ACK / NACK feedback. The PUSCH carries data and may additionally be used to carry a buffer status report (BSR), a power headroom report (PHR), and / or UCI.

[0057] Figure 3 A block diagram of an example base station 310 and 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 functions. Layer 3 includes a radio resource control (RRC) layer, and layer 2 includes a service data adaptation protocol (SDAP) layer, a packet data convergence protocol (PDCP) layer, a radio link control (RLC) layer, and a 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 (encryption, decryption, 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), re-segmentation 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.

[0058] The transmit (TX) processor 316 and the receive (RX) processor 370 implement layer 1 functions related to various signal processing functions. Layer 1 including the physical (PHY) layer may 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 processes the mapping to the signal constellation based on various modulation schemes (e.g., binary phase shift keying (BPSK), quadrature phase shift keying (QPSK), M-phase shift keying (M-PSK), M-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., pilot) in the time domain and / or frequency domain, and then combined together using an inverse fast Fourier transform (IFFT) to produce a physical channel carrying a time domain OFDM symbol stream. The OFDM stream is spatially precoded to produce multiple spatial streams. Channel estimates from a channel estimator 374 may be used to determine coding and modulation schemes and for spatial processing. The channel estimates may be derived from a reference signal and / or channel condition feedback sent by the UE 350. Each spatial stream may then be provided to a different antenna 320 via a separate transmitter 318TX. Each transmitter 318TX may modulate an RF carrier with a corresponding spatial stream for transmission.

[0059] At the UE 350, each receiver 354RX receives a signal through its corresponding antenna 352. Each receiver 354RX recovers the information modulated on the RF carrier and provides the information to the receive (RX) processor 356. The TX processor 368 and the RX processor 356 implement layer 1 functions associated with various signal processing functions. The RX processor 356 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 only one 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 sent 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 the base station 310. The data and control signals are then provided to the controller / processor 359, which implements layer 3 and layer 2 functions.

[0060] 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, packet reassembly, decryption, header decompression, and control signal processing between transport and logical channels 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.

[0061] 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 processing, and logical channel prioritization.

[0062] 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.

[0063] 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 a RX processor 370.

[0064] 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, packet reassembly, decryption, header decompression, control signal processing between transport and logical channels to recover IP packets from the UE 350. The IP packets from the controller / processor 375 may be provided to the EPC 160. The controller / processor 375 is also responsible for error detection using ACK and / or NACK protocols to support HARQ operations. The wirelessly transmitted information (e.g., for LTE or NR-based communications) is encoded and mapped to one or more radio channels at the PHY layer for transmission.

[0065] 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, which provides scheduling information for the PDSCH, including an identification of a 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, at least in part, that the PDSCH contains multicast data based on an indication in the PDCCH. In order to receive a multicast PDSCH, the UE can tune its multiple antennas in the direction of a scheduled multicast beam or in the direction of a default beam based on the delay between the PDCCH and the PDSCH. For example, if the delay between PDCCH and PDSCH exceeds the 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.

[0066] In some implementations, the default beam may be the default beam that the UE 104 uses to receive unicast transmissions. For example, different UEs 104 may have different default beams. In some other implementations, the default beam may be different from the default beam that the UE 104 uses to receive unicast transmissions. For example, the default beam may be specifically configured for multicast communications and may be common to all UEs 104 in a multicast group. In some aspects, the default beam may correspond to the beam on which scheduling information for the PDSCH is sent. In some other aspects, the default beam may be determined by the base station and signaled to the UE 104 before transmitting the PDSCH.

[0067] In some implementations, the scheduling threshold may be a scheduling threshold implemented by the UE 104 when receiving a unicast transmission. 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 a unicast transmission. 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 before transmitting the PDSCH.

[0068] Specific implementations of the subject matter described in the present 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 the scheduled PDSCH to carry multicast data via the PDCCH, various aspects of the present disclosure enable each UE in the group to tune its receiving 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 this group of UEs than the default beam used by any individual UE for unicast communications with the base station. In some aspects, when 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 receiving 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 receiving 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.

[0069] 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 any of base stations 102 / 180 and 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.

[0070] 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 probing. Therefore, the TX beam 401 can be optimized for the channel conditions associated with the UE 404. In order to receive 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.

[0071] Tuning or configuration of the receive antenna consumes time and resources. In some cases, after identifying TX beam 401, UE 404 may not have enough time to tune its receive antenna in the direction of TX beam 401. When UE 404 cannot configure (or reconfigure) its antenna in time to receive TX beam 401, UE 404 may tune its receive antenna to default beam 403 instead. Before sending DL data, base station 402 and UE 404 may both know the direction of default beam 403. Therefore, if base station 402 determines that UE 404 cannot tune its receive antenna to 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.

[0072] 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 FIG. 4 , scheduling information 412 is sent on a scheduling (SC) beam 405. The scheduling beam 405 can be the same as or different from the TX beam 401 or the default beam 403. The scheduling information 412 can identify the TX beam 401 and indicate the delay or timing offset (k0) between the PDCCH and the PDSCH. The UE 404 compares the timing offset k0 with the scheduling threshold 416 to determine whether to tune its receive antenna to the TX beam 401 or the default beam 403.

[0073] 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 of , 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 of 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 send the PDSCH on the TX beam 401.

[0074] 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. 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.

[0075] 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 send DL data to UEs 504 and 506 via multicast (MC) beam 501. Figure 5A In the example of , 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 by probing. Therefore, the MC beam 501 can be optimized for the channel conditions associated with the group of UEs 504 and 506. In order to receive the DL data, each of the UEs 504 and 506 can tune its receiving 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).

[0076] Figure 5B Another example wireless communication system 510 configured for multicast transmissions according to some implementations is shown. 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 MC beams 512 and 514 based on CSI acquired from each of UEs 504 and 506 by probing. Therefore, MC beam 512 can be optimized for channel conditions associated with UE 506, and MC beam 514 can be optimized for channel conditions associated with UE 504. In order to receive DL data, UE 506 can tune its receive antenna in the direction of MC beam 512, and UE 504 can tune its receive antenna in the direction of MC beam 514.

[0077] 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 transmits 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 the CSI obtained from the UEs 506 and 504, respectively, by probing. 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. In order 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.

[0078] As described above, tuning or configuration of 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 scheduling threshold of the UE). 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 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 be different in width and direction from the MC beam 524 sent to UE 504 for multicast communication. In addition, different UEs 504 and 506 may have different scheduling thresholds. Therefore, although UE 506 may be able to receive MC beam 522, UE 504 may not be able to receive MC beam 524.

[0079] 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. Therefore, the base station may schedule DL transmissions to each UE individually. In some cases, one or more UEs may receive MC beams, while other UEs may receive 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 multicast scheduling threshold may be specifically configured for multicast communication and may be common to all UEs in the multicast group. Therefore, the base station may schedule DL transmissions to the UEs as a group. As a result, all UEs in the multicast group will receive MC beams or default beams.

[0080] In some implementations, the 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. Therefore, 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. Therefore, 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.

[0081] 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. Figure 5A-Figure 5C , a multicast communication 600 may be performed between a base station 502 (or a TRP 508) and a group of UEs 504 and 506. Figure 6 In the example of FIG. 5 , the base station 502 may be configured to transmit 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 may be Figure 5A-Figure 5C An example implementation of any MC beam 501, 512, 514, 522, or 524.

[0082] 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 may be the same as or different from the MC beam 601 or any default beam 603. The scheduling information 602 may 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 may 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 may 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 particular UE).

[0083] Each of 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 MC beam 601 or default beam 603. As described above, the scheduling thresholds 604 and 606 may correspond to the amount of time required for UEs 504 and 506, respectively, to tune their receive antennas to MC beam 601. Figure 6 In the example of , 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 receiving antenna to MC beam 601, while UE 506 can tune its receiving antenna to default beam 603. Base station 502 can determine the scheduling thresholds 604 and 606 of UE 504 and 506 based on the information carried in the corresponding capability report received before the transmission of PDCCH. Therefore, the base station can also determine that UE 504 can receive PDSCH on MC beam 601, while UE 506 cannot receive PDSCH on MC beam 601. Therefore, base station 502 can use beamforming to send PDSCH on MC beam 601 and default beam 603 simultaneously.

[0084] 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. Figure 5A-Figure 5C , a multicast communication 700 may be performed between a base station 502 (or a TRP 508) and a group of UEs 504 and 506. Figure 7 In the example of FIG. 5 , the base station 502 may be configured to send DL data to the group of UEs 504 and 506 on the MC beam 701 or the common default beam 703 used by the group of UEs for multicast (MC) communication. The MC beam 701 may be Figure 5A-Figure 5C An example implementation of any MC beam 501, 512, 514, 522, or 524.

[0085] 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).

[0086] Each of the UEs 504 and 506 compares the timing offset k0 with the 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 is capable of tuning its receive antenna to the MC beam 701 at the end of the MC scheduling threshold 704. In some aspects, the base station 502 may 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 may 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 duration. The base station 502 may 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 may be a predefined value. For example, the MC scheduling threshold 704 may be defined by a wireless standard (e.g., a 3GPP standard). Therefore, any wireless device (including UE and base station) supporting multicast beamforming needs to comply with the MC scheduling threshold 704 .

[0087] 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 MC scheduling threshold 704), so UEs 504 and 506 can each tune their receive antennas to MC beam 701. Similarly, base station 502 can send PDSCH on only MC beam 701 using beamforming.

[0088] 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. Figure 5A-Figure 5C , a multicast communication 800 may be performed between a base station 502 (or a TRP 508) and a group of UEs 504 and 506. Figure 8 In the example of FIG. 5 , the base station 502 may be configured to send 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 Figure 5A-Figure 5C An example implementation of any MC beam 501, 512, 514, 522, or 524.

[0089] 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 sent. 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.

[0090] Each of the UEs 504 and 506 compares the timing offset k0 with 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 is 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 is 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).

[0091] 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 send PDSCH on only MC beam 801 using beamforming.

[0092] Fig. 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 described above with reference to Figure 1 , Figure 4A and Figure 5A-Figure 5C One of the UEs 104, 404, or 504 and 506 depicted.

[0093] In some implementations, process 900 begins at block 902, where a PDCCH is received from a base station, wherein the PDCCH includes scheduling information for a PDSCH to be multicast to a plurality of UEs including the UE. In some implementations, it may be determined that the PDSCH carries multicast data based on a CORESET associated with the PDCCH. In some other implementations, it may be determined that the PDSCH carries multicast data based on determining that a CRC sequence included in the PDCCH is scrambled with a group identifier associated with the plurality of UEs.

[0094] In block 904, process 900 continues to determine a first beam associated with the PDSCH and a delay between the PDCCH and the PDSCH based on the scheduling information. In block 906, process 900 continues to tune 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 a unicast transmission 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.

[0095] 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.

[0096] Fig.10 A flowchart of an example process 1000 for wireless communication supporting beamforming in multicast communication according to some other implementations is shown. In some implementations, the process 1000 may be performed by a wireless communication device operating as a network node or within a network node, for example, as described above with reference to Figure 1 , Figure 4A and Figure 5A-Figure 5C One of base stations 102 / 180, 402 or 502 and 508 is depicted.

[0097] In some implementations, process 1000 begins at block 1002, sending 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 with selecting at least one of the first beam or the second beam for sending 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 a unicast transmission to any of the plurality of UEs. In block 1006, process 1000 continues with sending the PDSCH to the plurality of UEs on the selected at least one beam.

[0098] 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 the 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 of durations associated with tuning multiple receive antennas by any UE to receive a unicast transmission from a base station.

[0099] 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 of the plurality of UEs, wherein the second beam is a default beam associated with a unicast transmission 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.

[0100] Fig.11 1 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 reference Fig. 9 The wireless communication device 1100 may be the wireless communication device 1100 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 may 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).

[0101] 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 at least partially implemented 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 components.

[0102] 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 a wireless communication device. The sending 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 receiving antennas based on the delay determined between the PDCCH and the PDSCH to receive the PDSCH on the first beam or the second beam.

[0103] Fig.12 1 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 Fig.10 The wireless communication device 1200 may be the wireless communication device 1200 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).

[0104] 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 may 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 may 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.

[0105] 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 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.

[0106] As used herein, phrases referring to "at least one" or "one or more" of a list of items refer 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.

[0107] 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 design constraints on the overall system.

[0108] Various modifications to the implementations described in this disclosure may be apparent to those of ordinary skill in the art, and the general principles defined herein may be applied to other implementations without departing from the spirit or scope of the disclosure. Therefore, the claims are not intended to be limited to the implementations shown herein, but are to be accorded the broadest scope consistent with the disclosure, the principles and novel features disclosed herein.

[0109] In addition, various features described in this specification in the context of independent 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. Likewise, 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 the combination, and a claimed combination may be directed to a subcombination or a variation of a subcombination.

[0110] Similarly, although the operations are depicted in a particular order in the figure, it should not be understood as requiring such operations to be performed in the particular order shown or in a sequential order, or requiring the execution of all the operations shown to achieve the desired result. In addition, the accompanying drawings can schematically depict one or more exemplary processes in the form of a flow chart or a job diagram. However, other operations not described can be incorporated into the schematically illustrated exemplary processes. For example, one or more additional operations can 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 various system components in the above implementations should not be understood as requiring such separation in all implementations, and it should be understood that the described program components and systems can usually 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 a plurality of 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; as well as Tuning a plurality of receive antennas to receive the PDSCH on the first beam or the second beam based on a comparison of the determined delay between the PDCCH and the PDSCH and a multicast threshold duration associated with the plurality of UEs, wherein the multicast threshold duration is at least equal to a longest duration of corresponding durations associated with any UE among the plurality of UEs tuning a plurality of receive antennas to receive unicast transmissions from the base station.

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

3. 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 plurality of UEs; as well as Based on determining that the CRC sequence is scrambled with the group identifier, determining that the PDSCH carries multicast data.

4. The method according to claim 1, further comprising: The second beam is determined based on a CORESET associated with the PDCCH.

5. The method according to claim 1, further comprising: receiving a radio resource control (RRC) message or a medium access control (MAC) control element (CE) from the base station before receiving the PDCCH; as well as The second beam is determined based on information carried in the RRC message or the MAC CE.

6. The method according to claim 1, wherein: The second beam is different from a default beam associated with unicast transmissions from the base station to the UE.

7. The method according to claim 1, wherein: The tuning of the plurality of receive antennas comprises: determining whether the delay between the PDCCH and the PDSCH exceeds the multicast threshold duration, tuning the multiple receive antennas to the first beam based on determining that the delay exceeds the multicast threshold duration, and tuning the multiple receive antennas to the second beam based on determining that the delay does not exceed the multicast threshold duration.

8. The method according to claim 7, further comprising: receiving at least one of an RRC message or a downlink control information (DCI) message from the base station; as well as The multicast threshold duration is determined based on information carried in the RRC message or the DCI message.

9. A user equipment (UE), comprising: at least one modem; at least one processor communicatively coupled to the at least one modem; as well as at least one memory communicatively coupled to the at least one processor and storing processor-readable code that, when executed by the at least one processor in conjunction with the at least one modem, is configured to: 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 a plurality of 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; as well as Tuning a plurality of receive antennas to receive the PDSCH on the first beam or the second beam based on a comparison of the determined delay between the PDCCH and the PDSCH and a multicast threshold duration associated with the plurality of UEs, wherein the multicast threshold duration is at least equal to a longest duration of corresponding durations associated with any UE among the plurality of UEs tuning a plurality of receive antennas to receive unicast transmissions from the base station.

10. The UE according to claim 9, wherein: Execution of the processor readable code is further configured to: The PDSCH carries multicast data based on a control resource set (CORESET) associated with the PDCCH.

11. The UE according to claim 9, wherein: Execution of the processor readable code is further configured to: identifying a cyclic redundancy check (CRC) sequence in the PDCCH; determining that the CRC sequence is scrambled with a group identifier associated with the plurality of UEs; and Based on determining that the CRC sequence is scrambled with the group identifier, determining that the PDSCH carries multicast data.

12. The UE according to claim 9, wherein: Execution of the processor readable code is further configured to: The second beam is determined based on a CORESET associated with the PDCCH.

13. The UE according to claim 9, wherein: Execution of the processor readable code is further configured to: 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 The second beam is determined based on information carried in the RRC message or the MAC CE.

14. The UE according to claim 9, wherein: The tuning of the plurality of receive antennas comprises: determining whether the delay between the PDCCH and the PDSCH exceeds the multicast threshold duration, tuning the multiple receive antennas to the first beam based on determining that the delay exceeds the multicast threshold duration, and tuning the multiple receive antennas to the second beam based on determining that the delay does not exceed the multicast threshold duration.

15. A wireless communication method performed by a base station, comprising: transmitting a physical downlink control channel (PDCCH) to a plurality of user equipments (UEs), the PDCCH carrying scheduling information indicating a first beam associated with a physical downlink shared channel (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 a comparison of the timing offset between the PDCCH and the PDSCH and a multicast scheduling threshold associated with the plurality of UEs, wherein the multicast scheduling threshold is at least equal to a longest duration of respective durations associated with any UE of the plurality of UEs tuning a plurality of receive antennas to receive a unicast transmission from the base station; as well as The PDSCH is transmitted to the plurality of UEs on the selected at least one beam.

16. The method according to claim 15, further comprising: generating a cyclic redundancy check (CRC) sequence associated with the PDCCH; as well as The CRC sequence is scrambled with a group identifier associated with the plurality of UEs, and the scrambled CRC sequence is transmitted in the PDCCH.

17. The method according to claim 15, wherein: The selecting at least one of the first beam or the second beam comprises: A determination is made as to whether the timing offset exceeds the multicast scheduling threshold, the first beam is selected based on a determination that the timing offset exceeds the multicast scheduling threshold, and the second beam is selected based on a determination that the timing offset does not exceed the multicast scheduling threshold.

18. The method according to claim 17, further comprising: determining, for each of the plurality of UEs, a respective duration associated with tuning a plurality of receive antennas to receive a unicast transmission from the base station; as well as The multicast scheduling threshold is configured to be at least equal to a longest duration among the durations determined for the plurality of UEs.

19. The method according to claim 15, further comprising: The second beam is determined based on a control resource set (CORESET) associated with the PDCCH.

20. The method according to claim 15, wherein: The second beam is different from a default beam associated with unicast transmission to any UE in the plurality of UEs.

21. A base station, comprising: at least one modem; at least one processor communicatively coupled to the at least one modem; as well as at least one memory communicatively coupled to the at least one processor and storing processor-readable code that, when executed by the at least one processor in conjunction with the at least one modem, is configured to: transmitting a physical downlink control channel (PDCCH) to a plurality of user equipments (UEs), the PDCCH carrying scheduling information indicating a first beam associated with a physical downlink shared channel (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 a comparison of the timing offset between the PDCCH and the PDSCH and a multicast scheduling threshold associated with the plurality of UEs, wherein the multicast scheduling threshold is at least equal to a longest duration of respective durations associated with any UE of the plurality of UEs tuning a plurality of receive antennas to receive a unicast transmission from the base station; as well as The PDSCH is transmitted to the plurality of UEs on the selected at least one beam.

22. The base station according to claim 21, wherein: Execution of the processor readable code is further configured to: generating a cyclic redundancy check (CRC) sequence associated with the PDCCH; and The CRC sequence is scrambled with a group identifier associated with the plurality of UEs, and the scrambled CRC sequence is transmitted in the PDCCH.

23. The base station according to claim 21, wherein: Execution of the processor readable code is further configured to: A determination is made as to whether the timing offset exceeds the multicast scheduling threshold, the first beam is selected based on a determination that the timing offset exceeds the multicast scheduling threshold, and the second beam is selected based on a determination that the timing offset does not exceed the multicast scheduling threshold.

24. The base station according to claim 23, wherein: Execution of the processor readable code is further configured to: determining, for each of the plurality of UEs, a respective duration associated with tuning a plurality of receive antennas to receive a unicast transmission from the base station; as well as The multicast scheduling threshold is configured to be at least equal to a longest duration among the durations determined for the plurality of UEs.

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