Beamforming reporting and link adaptive enhancements for nr multicast services

Abstract

Methods and systems are disclosed for enhancing multicast beamforming to support PTM multicast service, concurrent multicast and unicast service, MBS or group side link service at the physical layer. A base station or a multicast UE of a wireless communication network may enhance reporting of channel state information for a link between the base station and the UE and adaptation of the link for multicast beamforming. The enhancement of multicast beamforming may include techniques such as CQI table optimization and SSB-based early CQI reporting, taking into account UE preferences (such as a preferred number of retransmissions and frequency hopping preferences for retransmissions) when designing a time-domain or frequency-domain retransmission scheme common to multicast UEs, and multi-layer MIMO beamforming for two-layer multicast transmission on horizontal and vertical polarization and for concurrent multicast transmission and unicast transmission. The enhancement improves multicast service performance and effectively allows the UE to access multicast service.

Description

Technical Field

[0001] The present invention relates generally to the field of wireless communications, and more particularly to systems and methods for operating a communication network using beamforming capabilities when a base station of the communication network transmits simultaneously to multiple wireless communication devices in a multicast configuration. Other aspects are also described. Background Art

[0002] In a wireless communication network, a user equipment (UE) can communicate with a base station of the network by establishing a radio link between the UE and the base station. In a 5G (New Radio or NR) or 4G (LTE) wireless network, the UE can receive signaling and data from a serving base station in a downlink transmit direction or send signaling and data to a serving base station in an uplink transmit direction. Beamforming can be used by the base station, the UE, or both to improve the link budget in the downlink and uplink directions by increasing the antenna gain of the transmit and / or receive antenna beams. This can be particularly beneficial for higher operating frequency bands that experience greater air interface interference. Beamforming can also help reduce inter-cell interference by focusing the transmission into a relatively narrow beam.

[0003] In one operating scenario, a base station may use beamforming to provide signaling and data to multiple UEs simultaneously in time by sending a common beam to the multiple UEs. In this operating scenario, the base station provides a point-to-multipoint (PTM) multicast service at the physical layer and may be referred to as multicast beamforming. In an alternative operating scenario, the base station may generate multicast data at the application layer, but may use a point-to-point (PTP) configuration at the physical layer to send different beams to multiple UEs to provide multicast services. A beamforming design that supports multicast beamforming may rely on the base station determining the quality of the downlink channel to each of the UEs based on uplink transmissions received from the UE and based on an assumption of reciprocity of channel characteristics between the uplink direction and the downlink direction. Alternatively, in order to obtain a more accurate characterization of the downlink channel to the UE, the base station may send a reference signal or synchronization signal on a candidate beam for the UE to estimate the quality of the downlink channel, as in unicast beamforming. The UE may measure the downlink channel quality estimated from the received reference signal or synchronization signal and report it back to the base station for the base station to design the beam for multicast beamforming. The design of multicast beamforming has unique design challenges because a common beam is sent to multiple UEs. The base station may balance different UE capabilities and different downlink channel characteristics for the UE to design the beam. It is desirable to enhance the design of beamforming to more efficiently and effectively support UEs operating in a multicast configuration. Summary of the invention

[0004] Disclosed are methods and systems for UEs to support base stations of wireless networks to transmit in a multicast beamforming configuration. In a network providing multicast services, the network may maintain an admission control policy by authorizing UEs to access the multicast services based on channel characteristics measured by the UEs. For example, a base station of a 4G / 5G network may send a channel state information reference signal (CSI-RS) on physical resources reserved for multicast services. The base station may use one or more multicast beams to send the CSI-RS. A UE that wishes to join a multicast service may measure the channel characteristics of a downlink channel based on the received multicast CSI-RS, and may report the measurement results back to the base station. The base station may grant or deny the UE multicast services based on the reported measurement results. The base station may also send a synchronization signal block (SSB) signal by the UE during a cell search process and during a beam management process through a synchronization signal / physical broadcast channel (SS / PBCH). The UE may measure the channel state information of the downlink channel based on the SSB signal, and may report the best downlink beam during the beam management process. Reporting of channel state information allows fast and responsive beamforming and switching between beams. The measurement results are affected by the downlink beamforming design, including the downlink transmit beam from the base station and the downlink receive beam of the UE. Techniques for UE reporting of channel state information for UE and base station enhanced downlink and adaptation of links for multicast beamforming used to provide multicast PTM or concurrent multicast and unicast services are disclosed. The disclosed techniques can also be applied to 5G beamforming multicast and broadcast services (MBS) or 5G beamforming sidelink multicast services.

[0005] In one aspect, the technology may include simplifying the measurement results of channel characteristics reported by the UE as a channel quality indicator (CQI). The CQI may represent a signal to interference plus noise ratio (SINR), which is calculated as the ratio of the target signal measured using the CSI-RS carried by the multicast beam to the interference level measured when there is no transmission on the physical resources reserved for the multicast service. In unicast beamforming, when measuring channel characteristics, the CQI may be reported for a range of modulation and coding schemes (MCS). Because multicast typically focuses on a limited number of MCS configurations to ensure reliable transmission to multiple UEs, the base station can reduce feedback overhead by limiting the number of MCS configurations used for CQI measurement and reporting. In one aspect, the base station may configure multiple multicast beam candidates for the UE to measure and report the CQI of each beam candidate.

[0006] In one aspect, the technology may include the UE measuring CQI based on a synchronization signal block (SSB) signal and reporting the SSB-based CQI at the beginning of a radio resource control (RRC) connection establishment. For downlink beam management, the base station may send the SSB signal using a less spectrally efficient MCS carried on a relatively wide beam for initial acquisition by the UE. The base station may then send a CSI-RS carried on a more directional beam for beam refinement. Because multicast transmissions typically use a reliable MCS and may not require fine-grained CQI reporting based on CSI-RS, the CQI derived from the SSB signal may be sufficient to indicate the downlink channel quality. The UE may report the SSB-based CQI early during RRC connection establishment during a random access procedure, during a handover procedure from one base station to another, or when transitioning from an RRC inactive state to an RRC connected state.

[0007] In one aspect, when reporting channel characteristics, the UE may report the expected number of multicast retransmissions. In order to support multicast retransmissions when the multicast transmission fails to be received by any of the multicast UEs, the number of retransmissions may be the same for all multicast UEs. In order to facilitate network decisions, the UE may report the expected number of multicast retransmissions to the network or base station based on feedback to determine the final number of retransmissions. In one aspect, the base station may configure multiple multicast beam candidates for measurement, and the UE may report or maintain different numbers of retransmissions for different beam candidates. In one aspect, multicast retransmissions may be implemented in the frequency domain using different frequency subbands (such as by frequency hopping). In one aspect, when the UE is in an RRC inactive state, the UE may report its expected number of multicast retransmissions for a multicast service.

[0008] In one aspect, the base station may use multi-layer beamforming to send multicast beams in more than one layer. For example, the base station may send multicast services in two layers with horizontal polarization and vertical polarization to increase the transmission rate. In another example, the base station may use multi-layer multiple-input multiple-output (MIMO) / beamforming for concurrent multicast and unicast transmissions. Multicast data may be mapped to a first subset of one or more layers, and unicast data may be mapped to a second subset of one or more layers in the multiple layers. The base station may use different downlink transmission beams to simultaneously send multicast data and unicast data. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The present invention is illustrated by way of example and not limitation in the figures of the accompanying drawings in which like references indicate similar elements.

[0010] Figure 1 An exemplary wireless communication system according to one aspect of the present disclosure is shown.

[0011] Figure 2A user equipment is shown in direct communication with a base station (BS) according to one aspect of the present disclosure.

[0012] Figure 3 An exemplary block diagram of a UE according to one aspect of the present disclosure is shown.

[0013] Figure 4 An exemplary block diagram of a BS according to one aspect of the present disclosure is shown.

[0014] Figure 5 An exemplary block diagram of a cellular communication circuit according to one aspect of the present disclosure is shown.

[0015] Figure 6 A scenario is shown in which a base station of a wireless communication network according to one aspect of the present disclosure controls the UE to be granted to receive a multicast service based on the UE measuring a channel characteristic of a downlink channel and reporting the channel characteristic to the base station.

[0016] Figure 7 A flow chart of signaling between a base station and a UE for granting multicast resources based on the UE reporting measured channel quality of a channel state information reference signal (CSI-RS) sent by the base station according to one aspect of the present disclosure is shown.

[0017] Figure 8 A channel quality indicator (CQI) table for a subset of the modulation and coding scheme (MCS) range measured and reported by a UE to reduce overhead associated with reporting channel quality of received CSI-RS according to one aspect of the present disclosure is shown.

[0018] Fig. 9 A flow chart of signaling between a base station and a UE for the UE to measure CQI based on a synchronization signal block (SSB) signal and report SSB-based CQI using a contention-based random access channel (RACH) procedure to allow early reporting of channel characteristics during radio resource control (RRC) connection establishment according to one aspect of the present disclosure is shown.

[0019] Fig.10 A flow chart is shown of signaling between a base station and a UE for the UE to measure CQI based on an SSB signal and report the SSB-based CQI using a two-step RACH procedure to allow early reporting of channel characteristics during RRC connection establishment according to one aspect of the present disclosure.

[0020] Fig.11 A flow chart of a method for a UE to measure and report channel quality of a downlink beam so that a base station can adapt the downlink beam to a multicast beam to provide multicast services to the UE and other UEs of a multicast group according to one aspect of the present disclosure is depicted. DETAILED DESCRIPTION

[0021] Methods and systems for enhancing multicast beamforming to support PTM multicast services, concurrent multicast and unicast services, MBS or group side link services at the physical layer are disclosed. A base station or multicast UE of a wireless communication network may apply the disclosed technology to enhance the reporting of channel state information of a link between a base station and a UE and the adaptation of a link for multicast beamforming to support provisioning services in PTM multicast, concurrent multicast and unicast, MBS or group side link configurations. The enhancement improves multicast service performance and efficiently allows UEs to access multicast services. Multicast beamforming may also be applied to MIMO beamforming to increase diversity gain, array gain or spatial multiplexing gain. Various aspects of the enhancement are explained in the context of 4G LTE and 5G NR networks, but may be applied to other networks such as Wi-Fi.

[0022] Enhancements to multicast beamforming may include techniques such as: CQI table optimization and SSB-based early CQI reporting, consideration of UE preferences (such as preferred number of retransmissions and frequency hopping preference for retransmissions) when designing a time-domain or frequency-domain retransmission scheme common to multicast UEs, and multi-layer MIMO beamforming for two-layer multicast transmissions on horizontal and vertical polarizations and for concurrent multicast and unicast transmissions.

[0023] In the following description, numerous specific details are set forth to provide a thorough explanation of embodiments of the present invention. However, it will be apparent to those skilled in the art that embodiments of the present invention may be implemented without these specific details. In other cases, well-known components, structures, and techniques have not been shown in detail to avoid obscuring the understanding of this description.

[0024] Reference to "some embodiments" or "embodiments" in this specification means that a particular feature, structure, or characteristic described in conjunction with the embodiment may be included in at least one embodiment of the present invention. The phrase "in some embodiments" appearing in various places in this specification does not necessarily refer to the same embodiment.

[0025] In the following description and claims, the terms "coupled" and "connected" and their derivatives may be used. It should be understood that these terms are not intended to be synonymous with each other. "Coupled" is used to indicate that two or more elements that may or may not be in direct physical or electrical contact with each other cooperate or interact with each other. "Connected" is used to indicate the establishment of communication between two or more elements that are coupled to each other.

[0026] The processes shown in the following figures are performed by processing logic, which includes hardware (e.g., circuits, dedicated logic, etc.), software (such as software running on a general-purpose computer system or a dedicated machine), or a combination of both. Although the following describes these processes as certain sequential operations, it should be understood that certain operations described may be performed in a different order. In addition, certain operations may also be performed in parallel rather than in sequence.

[0027] The terms "server," "client," and "device" are intended to refer generally to data processing systems rather than specifically to a particular form factor of a server, client, and / or device.

[0028] Figure 1 A simplified exemplary wireless communication system according to one aspect of the present disclosure is shown. Note that Figure 1 The system is only one example of possible systems, and features of the present disclosure may be implemented in any of a variety of systems as desired.

[0029] As shown, the exemplary wireless communication system includes a base station 102A, which communicates with one or more user equipment 106A, user equipment 106B to user equipment 106N, etc. through a transmission medium. Each of the user equipments may be referred to as a "user equipment" (UE) in this document. Therefore, the user equipment 106 is referred to as a UE or a UE device.

[0030] The base station (BS) 102A may be a base transceiver station (BTS) or a cell site ("cellular base station"), and may include hardware that enables wireless communications with the UEs 106A-106N.

[0031] The communication area (or coverage area) of a base station may be referred to as a "cell". The base station 102A and the UE 106 may be configured to communicate over a transmission medium using any of a variety of radio access technologies (RATs), which are also referred to as wireless communication technologies or telecommunication standards, such as GSM, UMTS (associated with, for example, WCDMA or TD-SCDMA air interfaces), LTE, Advanced LTE (LTE-A), 5G New Radio (5G NR), HSPA, 3GPP2 CDMA2000 (e.g., 1xRTT, 1xEV-DO, HRPD, eHRPD), and the like. Note that if the base station 102A is implemented in the context of LTE, it may alternatively be referred to as an "eNodeB" or "eNB". Note that if the base station 102A is implemented in the context of 5G NR, it may alternatively be referred to as a "gNodeB" or "gNB".

[0032] As shown, base station 102A may also be configured to communicate with network 100 (e.g., a core network of a cellular service provider, a telecommunications network such as a public switched telephone network (PSTN), and / or the Internet, among other possibilities). Thus, base station 102A may facilitate communications between user devices and / or between user devices and network 100. Specifically, cellular base station 102A may provide UE 106 with various communication capabilities, such as voice, SMS, and / or data services.

[0033] Base station 102A and other similar base stations (such as base stations 102B, 102N) operating according to the same or different cellular communication standards may thus provide a network as a cell that can provide continuous or nearly continuous overlapping service to UE 106A to UE 106N and similar devices over a geographic area via one or more cellular communication standards.

[0034] Thus, although base station 102A may function as Figure 1 106A through 106N, each UE 106 may also be capable of receiving signals from (and possibly within communication range of) one or more other cells (which may be provided by base stations 102B-N and / or any other base stations), which may be referred to as "neighboring cells." Such cells may also be capable of facilitating communications between user devices and / or between user devices and network 100. Such cells may include "macro" cells, "micro" cells, "pico" cells, and / or any other variety of other granularity of cell sizes providing a service area. For example, in Figure 1 The base stations 102A-102B shown in FIG. 1 may be macro cells, while the base station 102N may be a micro cell. Other configurations are also possible.

[0035] In some embodiments, base station 102A may be a next generation base station, e.g., a 5G New Radio (5G NR) base station or "gNB". In some embodiments, a gNB may be connected to a legacy evolved packet core (EPC) network and / or to an NR core (NRC) network. In addition, a gNB cell may include one or more transition and reception points (TRPs). In addition, a UE capable of operating in accordance with 5G NR may be connected to one or more TRPs within one or more gNBs.

[0036] Note that the UE 106 is capable of communicating using multiple wireless communication standards. For example, the UE 106 may be configured to communicate using wireless networking (e.g., Wi-Fi) and / or peer-to-peer wireless communication protocols (e.g., Bluetooth, Wi-Fi peer-to-peer, etc.) in addition to at least one cellular communication protocol (e.g., GSM, UMTS (associated with, for example, WCDMA or TD-SCDMA air interfaces), LTE, LTE-A, 5G NR, HSPA, 3GPP2 CDMA2000 (e.g., 1xRTT, 1xEV-DO, HRPD, eHRPD), etc.). If desired, the UE 106 may also or alternatively be configured to communicate using one or more global navigation satellite systems (GNSS, such as GPS or GLONASS), one or more mobile television broadcast standards (e.g., ATSC-M / H or DVB-H), and / or any other wireless communication protocols. Other combinations of wireless communication standards (including more than two wireless communication standards) are also possible.

[0037] Figure 2 A UE 106 is shown that directly communicates with a base station 102 through uplink and downlink communications according to one aspect of the present disclosure. The UE 106 may be a device with cellular communication capabilities, such as a mobile phone, a handheld device, a computer or a tablet computer, or in fact any type of wireless device. The UE 106 may include a processor configured to execute program instructions stored in a memory. The UE 106 may perform any of the method embodiments described herein by executing such stored instructions. Alternatively or in addition, the UE 106 may include a programmable hardware element, such as a field programmable gate array (FPGA) configured to perform any of the method embodiments described in the present invention or any part of any of the method embodiments described in the present invention.

[0038] UE 106 may include one or more antennas for communicating using one or more wireless communication protocols or technologies. In some embodiments, UE 106 may be configured to communicate using, for example, CDMA2000 (1xRTT, 1xEV-DO, HRPD, eHRPD) or LTE using a single shared radio component and / or GSM or LTE using a single shared radio component. The shared radio component may be coupled to a single antenna, or may be coupled to multiple antennas (e.g., for MIMO) for performing wireless communications. Typically, the radio component may include any combination of a baseband processor, an analog RF signal processing circuit (e.g., including filters, mixers, oscillators, amplifiers, etc.), or a digital processing circuit (e.g., for digital modulation and other digital processing). Similarly, the radio component may use the aforementioned hardware to implement one or more receive chains and transmit chains. For example, UE 106 may share one or more portions of a receive chain and / or a transmit chain between multiple wireless communication technologies such as those discussed above.

[0039] In some embodiments, UE 106 may include a separate transmit chain and / or receive chain (e.g., including separate antennas and other radio components) for each wireless communication protocol configured to communicate with it. As another possibility, UE 106 may include one or more radio components shared between multiple wireless communication protocols, and one or more radio components used uniquely by a single wireless communication protocol. For example, UE 106 may include a shared radio component for communicating using either LTE or 5GNR (or LTE or 1xRTT, or LTE or GSM), and a separate radio component for communicating using each of Wi-Fi and Bluetooth. Other configurations are also possible.

[0040] Figure 3 1 shows an exemplary simplified block diagram of a communication device 106 according to one aspect of the present disclosure. Note that Figure 3 The block diagram of the communication device is only an example of a possible communication device. According to an embodiment, the communication device 106 can be a user equipment (UE) device, a mobile device or mobile station, a wireless device or wireless station, a desktop computer or computing device, a mobile computing device (such as a laptop, a notebook or a portable computing device), a tablet computer and / or a combination of devices, in addition to other devices. As shown, the communication device 106 may include a group of components 300 configured to perform core functions. For example, the group of components can be implemented as a system on a chip (SOC), which can include parts for various purposes. Alternatively, the group of components 300 can be implemented as a separate component or a group of components for various purposes. This group of components 300 can be coupled to various other circuits of the communication device 106 (e.g., communicatively; directly or indirectly).

[0041] For example, the communication device 106 may include various types of memory (e.g., including NAND flash memory 310), input / output interfaces such as a connector I / F 320 (e.g., for connecting to a computer system; a docking station; a charging station; an input device such as a microphone, a camera, a keyboard; an output device such as a speaker; etc.), a display 360 that may be integrated with the communication device 106 or external to the communication device, and cellular communication circuits 330 such as for 5G NR, LTE, GSM, etc., and short-range to medium-range wireless communication circuits 329 (e.g., Bluetooth ™ and WLAN circuitry). In some embodiments, the communication device 106 may include wired communication circuitry (not shown), such as, for example, a network interface card for Ethernet.

[0042] Cellular communication circuitry 330 may be (e.g., communicatively; directly or indirectly) coupled to one or more antennas, such as antennas 335 and 336 as shown. Short-range to medium-range wireless communication circuitry 329 may also be (e.g., communicatively; directly or indirectly) coupled to one or more antennas, such as antennas 337 and 338 as shown. Alternatively, short-range to medium-range wireless communication circuitry 329 may be (e.g., communicatively; directly or indirectly) coupled to antennas 335 and 336 in addition to or in lieu of being (e.g., communicatively; directly or indirectly) coupled to antennas 337 and 338. Short-range to medium-range wireless communication circuitry 329 and / or cellular communication circuitry 330 may include multiple receive chains and / or multiple transmit chains for receiving and / or transmitting multiple spatial streams, such as in a multiple-input multiple-output (MIMO) configuration.

[0043] In some embodiments, as further described below, the cellular communication circuit 330 may include dedicated receive chains (including and / or coupled to (e.g., communicatively; directly or indirectly) dedicated processors and / or radio components) for multiple RATs (e.g., a first receive chain for LTE and a second receive chain for 5G-NR). In addition, in some embodiments, the cellular communication circuit 330 may include a single transmit chain that can switch between radio components dedicated to specific RATs. For example, a first radio component can be dedicated to a first RAT, such as LTE, and can communicate with a dedicated receive chain and a transmit chain shared with an additional radio component, such as a second radio component that can be dedicated to a second RAT (e.g., 5G NR) and can communicate with the dedicated receive chain and the shared transmit chain.

[0044] The communication device 106 may also include and / or be configured for use with one or more user interface elements. The user interface elements may include various elements such as a display 360 (which may be a touch screen display), a keyboard (which may be a separate keyboard or may be implemented as part of a touch screen display), a mouse, a microphone and / or a speaker, one or more cameras, one or more buttons, and / or any of a variety of other elements capable of providing information to a user and / or receiving or interpreting user input.

[0045] The communication device 106 may also include one or more smart cards 345 having SIM (Subscriber Identity Module) functionality, such as one or more UICC cards (Universal Integrated Circuit Cards) 345 .

[0046] As shown, the SOC 300 may include a processor 302 that may execute program instructions for the communication device 106 and a display circuit 304 that may perform graphics processing and provide display signals to a display 360. The processor 302 may also be coupled to a memory management unit (MMU) 340 (which may be configured to receive addresses from the processor 302 and convert those addresses to locations in a memory (e.g., memory 306, read-only memory (ROM) 350, NAND flash memory 310)) and / or to other circuits or devices (such as display circuit 304, short-range wireless communication circuit 229, cellular communication circuit 330, connector I / F 320, and / or display 360). The MMU 340 may be configured to perform memory protection and page table translation or setup. In some embodiments, the MMU 340 may be included as part of the processor 302.

[0047] As described above, the communication device 106 may be configured to communicate using wireless and / or wired communication circuits. The communication device 106 may also be configured to determine physical downlink shared channel scheduling resources for user equipment devices and base stations. In addition, the communication device 106 may be configured to select and group CCs (component carriers) from the wireless link, and determine virtual CCs from the selected CC group. The wireless device may also be configured to perform physical downlink resource mapping based on an aggregated resource matching pattern of a CC group.

[0048] As described herein, the communication device 106 may include hardware and software components for implementing the above-described features for determining physical downlink shared channel scheduling resources for the communication device 106 and the base station. The processor 302 of the communication device 106 may be configured to implement some or all of the features described herein, for example, by executing program instructions stored on a memory medium (e.g., a non-transitory computer-readable memory medium). Alternatively (or in addition), the processor 302 may be configured as a programmable hardware element, such as an FPGA (field programmable gate array) or an ASIC (application-specific integrated circuit). Alternatively (or in addition), in combination with one or more of the other components 300, 304, 306, 310, 320, 329, 330, 340, 345, 350, 360, the processor 302 of the communication device 106 may be configured to implement some or all of the features described herein.

[0049] In addition, as described in the present invention, the processor 302 may include one or more processing elements. Therefore, the processor 302 may include one or more integrated circuits (ICs) configured to perform the functions of the processor 302. In addition, each integrated circuit may include a circuit (e.g., a first circuit, a second circuit, etc.) configured to perform the functions of one or more processors 302.

[0050] In addition, as described herein, both the cellular communication circuit 330 and the short-range wireless communication circuit 329 may include one or more processing elements. In other words, one or more processing elements may be included in the cellular communication circuit 330, and similarly, one or more processing elements may be included in the short-range wireless communication circuit 329. Therefore, the cellular communication circuit 330 may include one or more integrated circuits (ICs) configured to perform the functions of the cellular communication circuit 330. In addition, each integrated circuit may include a circuit (e.g., a first circuit, a second circuit, etc.) configured to perform the functions of the cellular communication circuit 230. Similarly, the short-range wireless communication circuit 329 may include one or more ICs configured to perform the functions of the short-range wireless communication circuit 32. In addition, each integrated circuit may include a circuit (e.g., a first circuit, a second circuit, etc.) configured to perform the functions of the short-range wireless communication circuit 329.

[0051] Figure 4 1 shows an exemplary block diagram of a base station 102 according to one aspect of the present disclosure. Note that Figure 4The base station of is only one example of a possible base station. As shown, the base station 102 may include a processor 404 that may execute program instructions for the base station 102. The processor 404 may also be coupled to a memory management unit (MMU) 440 or other circuit or device, which may be configured to receive addresses from the processor 404 and convert these addresses to locations in memory (e.g., memory 460 and read-only memory (ROM) 450).

[0052] Base station 102 may include at least one network port 470. Network port 470 may be configured to couple to a telephone network and provide access to the telephone network described above. Figure 1 and Figure 2 Multiple devices such as UE 106 of the telephone network described in.

[0053] The network port 470 (or an additional network port) may also or alternatively be configured to couple to a cellular network, such as a core network of a cellular service provider. The core network may provide mobility-related services and / or other services to a plurality of devices, such as the UE 106. In some cases, the network port 470 may be coupled to a telephone network via the core network, and / or the core network may provide a telephone network (e.g., in other UEs served by the cellular service provider).

[0054] In some embodiments, base station 102 may be a next generation base station, e.g., a 5G New Radio (5G NR) base station, or "gNB". In such embodiments, base station 102 may be connected to a legacy evolved packet core (EPC) network and / or to an NR core (NRC) network. Furthermore, base station 102 may be considered a 5G NR cell and may include one or more transition and reception points (TRPs). Furthermore, a UE capable of operating in accordance with 5G NR may be connected to one or more TRPs within one or more gNBs.

[0055] The base station 102 may include at least one antenna 434 and possibly multiple antennas. The at least one antenna 434 may be configured to function as a wireless transceiver and may be further configured to communicate with the UE 106 via the radio 430. The antenna 434 communicates with the radio 430 via a communication chain 432. The communication chain 432 may be a receive chain, a transmit chain, or both. The radio 430 may be configured to communicate via various wireless communication standards, including but not limited to 5G NR, LTE, LTE-A, GSM, UMTS, CDMA2000, Wi-Fi, and the like.

[0056] The base station 102 may be configured to perform wireless communications using multiple wireless communication standards. In some cases, the base station 102 may include multiple radio components that enable the base station 102 to communicate according to multiple wireless communication technologies. For example, as one possibility, the base station 102 may include an LTE radio component for performing communications according to LTE and a 5G NR radio component for performing communications according to 5G NR. In this case, the base station 102 may be able to operate as both an LTE base station and a 5G NR base station. As another possibility, the base station 102 may include a multimode radio component that can perform communications according to any of a plurality of wireless communication technologies (e.g., 5G NR and Wi-Fi, LTE and Wi-Fi, LTE and UMTS, LTE and CDMA2000, UMTS and GSM, etc.).

[0057] As further described later herein, BS 102 may include hardware and software components for implementing or supporting a specific implementation of the features described herein. The processor 404 of base station 102 may be configured to implement or support a specific implementation of part or all of the methods described herein, for example, by executing program instructions stored on a memory medium (e.g., a non-transitory computer-readable memory medium). Alternatively, processor 404 may be configured as a programmable hardware element such as an FPGA (field programmable gate array), or as an ASIC (application-specific integrated circuit) or a combination thereof. Alternatively (or in addition), in combination with one or more of the other components 430, 432, 434, 440, 450, 460, 470, the processor 404 of BS 102 may be configured to implement or support a specific implementation of part or all of the features described herein.

[0058] In addition, as described herein, processor 404 may be composed of one or more processing elements. In other words, one or more processing elements may be included in processor 404. Therefore, processor 404 may include one or more integrated circuits (ICs) configured to perform the functions of processor 404. In addition, each integrated circuit may include circuits (e.g., first circuits, second circuits, etc.) configured to perform the functions of one or more processors 404.

[0059] Additionally, as described herein, radio 430 may be comprised of one or more processing elements. In other words, one or more processing elements may be included in radio 430. Thus, radio 430 may include one or more integrated circuits (ICs) configured to perform the functions of radio 430. Furthermore, each integrated circuit may include circuits (e.g., a first circuit, a second circuit, etc.) configured to perform the functions of radio 430.

[0060] Figure 5An exemplary simplified block diagram of a cellular communication circuit according to one aspect of the present disclosure is shown. Note that Figure 5 The block diagram of the cellular communication circuitry of is only one example of possible cellular communication circuitry. According to an embodiment, the cellular communication circuitry 330 may be included in a communication device such as the communication device 106 described above. As described above, the communication device 106 may be a user equipment (UE) device, a mobile device or mobile station, a wireless device or wireless station, a desktop computer or computing device, a mobile computing device (e.g., a laptop, notebook, or portable computing device), a tablet computer, and / or a combination of devices, among other devices.

[0061] Cellular communication circuitry 330 may be (eg, communicatively; directly or indirectly) coupled to one or more antennas, such as ( Figure 3 In some embodiments, the cellular communication circuit 330 may include dedicated receive chains (including and / or coupled to (e.g., communicatively; directly or indirectly) dedicated processors and / or radio components) for multiple RATs (e.g., a first receive chain for LTE and a second receive chain for 5G NR). For example, Figure 5 As shown, cellular communication circuitry 330 may include modem 510 and modem 520. Modem 510 may be configured for communication according to a first RAT (e.g., such as LTE or LTE-A), and modem 520 may be configured for communication according to a second RAT (e.g., such as 5G NR).

[0062] As shown, the modem 510 may include one or more processors 512 and a memory 516 in communication with the processor 512. The modem 510 may communicate with a radio frequency (RF) front end 530. The RF front end 530 may include circuits for sending and receiving radio signals. For example, the RF front end 530 may include a receiving circuit (RX) 532 and a transmitting circuit (TX) 534. In some embodiments, the receiving circuit 532 may communicate with a downlink (DL) front end 550, which may include circuits for receiving radio signals via an antenna 335a.

[0063] Similarly, the modem 520 may include one or more processors 522 and a memory 526 in communication with the processor 522. The modem 520 may communicate with the RF front end 540. The RF front end 540 may include circuits for sending and receiving radio signals. For example, the RF front end 540 may include a receiving circuit 542 and a transmitting circuit 544. In some embodiments, the receiving circuit 542 may communicate with the DL front end 560, which may include circuits for receiving radio signals via the antenna 335b.

[0064] In some embodiments, the switch 570 may couple the transmit circuit 534 to an uplink (UL) front end 572. In addition, the switch 570 may couple the transmit circuit 544 to the UL front end 572. The UL front end 572 may include circuitry for transmitting radio signals via the antenna 336. Thus, when the cellular communication circuit 330 receives an instruction to transmit according to a first RAT (e.g., via a transmit chain including the transmit circuit 534 and the UL front end 572) supported by the modem 510, the switch 570 may be switched to a first state that allows the modem 510 to transmit signals according to the first RAT (e.g., via a transmit chain including the transmit circuit 534 and the UL front end 572). Similarly, when the cellular communication circuit 330 receives an instruction to transmit according to a second RAT (e.g., via a transmit chain including the transmit circuit 544 and the UL front end 572) supported by the modem 520, the switch 570 may be switched to a second state that allows the modem 520 to transmit signals according to the second RAT (e.g., via a transmit chain including the transmit circuit 544 and the UL front end 572).

[0065] As described herein, the modem 510 may include hardware and software components for implementing the above features or for selecting periodic resource portions for user equipment devices and base stations and for various other technologies described herein. For example, by executing program instructions stored on a memory medium (e.g., a non-transitory computer-readable memory medium), the processor 512 may be configured to implement some or all of the features described herein. Alternatively (or in addition), the processor 512 may be configured as a programmable hardware element, such as an FPGA (field programmable gate array) or as an ASIC (application-specific integrated circuit). Alternatively (or in addition), in combination with one or more of the other components 530, 532, 534, 550, 570, 572, 335, and 336, the processor 512 may be configured to implement some or all of the feature parts described herein.

[0066] In addition, as described herein, processor 512 may include one or more processing elements. Thus, processor 512 may include one or more integrated circuits (ICs) configured to perform the functions of processor 512. In addition, each integrated circuit may include circuits (e.g., a first circuit, a second circuit, etc.) configured to perform the functions of processor 512.

[0067] As described herein, the modem 520 may include hardware and software components for implementing the above features or for selecting a periodic resource portion on a wireless link between a UE and a base station and for various other techniques described herein. For example, by executing program instructions stored on a memory medium (e.g., a non-transitory computer-readable memory medium), the processor 522 may be configured to implement part or all of the feature parts described herein. Alternatively (or in addition), the processor 522 may be configured as a programmable hardware element, such as an FPGA (field programmable gate array) or an ASIC (application-specific integrated circuit). Alternatively (or additionally), in combination with one or more of the other components 540, 542, 544, 550, 570, 572, 335, and 336, the processor 522 may be configured to implement part or all of the feature parts described herein.

[0068] In addition, as described herein, the processor 522 may include one or more processing elements. Thus, the processor 522 may include one or more integrated circuits (ICs) configured to perform the functions of the processor 522. In addition, each integrated circuit may include a circuit (e.g., a first circuit, a second circuit, etc.) configured to perform the functions of the processor 522.

[0069] Figure 6 The base station 102 of the wireless communication network according to one aspect of the present disclosure controls the situation that the UE 106 is allowed to receive the multicast service based on the UE measuring the channel characteristics of the downlink channel reserved for the multicast service and reporting the channel characteristics to the base station. In the following description, the terms "base station" and "network" are used interchangeably.

[0070] The base station 102 maintains an admission control policy in which UEs are authorized to multicast services based on the measured channel quality of the UEs. For example, the base station 102 may send a channel state information reference signal (CSI-RS) on physical resources reserved for multicast services, where such CSI-RS may also be referred to as multicast CSI-RS. In one aspect, if the multicast transmission uses only 1 layer transmission, then the multicast CSI-RS may simply be sent using 1 port. In one aspect, the base station 102 may use one or more multicast beams to send the multicast CSI-RS. The base station 102 may send information to inform the UE of the physical resources used to send the CSI-RS and the configuration for reporting the measured channel characteristics.

[0071] A UE 106 that wishes to join a multicast service may measure channel characteristics of a downlink channel based on a received multicast CSI-RS and may report the measurement results back to a base station. In one aspect, the UE 106 may use metrics such as a channel quality indicator (CQI) and / or a precoding matrix indicator (PMI) from the multicast CSI-RS to estimate the channel characteristics. The CQI may represent a signal to interference plus noise ratio (SINR), which is calculated as a ratio of a target signal measured using a CSI-RS carried by a multicast beam to an interference level measured when there is no transmission on a physical resource reserved for the multicast service. The PMI may allow the UE 106 to recommend a precoding matrix for downlink multicast transmission in a closed-loop beamforming scheme. The UE 106 may report the estimated CQI / PMI back to the base station 102. The CQI / PMI measurement results are affected by the downlink beamforming design, including the downlink multicast transmit beam from the base station 102 and the downlink receive beam of the UE (106). Using the CQI / PMI report, the network or base station 102 can grant or deny the UE 106 multicast services. The base station 102 can determine the multicast beam based on the measurement report from the UE that is granted to enter the multicast group. The granted UE 106 can then receive the multicast service based on the connection established by the multicast beam.

[0072] Figure 7 A flow chart of signaling between a base station and a UE of a 4G or 5G wireless network for granting multicast resources to the UE based on the UE reporting the measured channel quality of a CSI-RS sent by the base station according to one aspect of the present disclosure is shown.

[0073] The network may configure the UE for initial connection establishment, including resource configuration for the random access channel (RACH) procedure and system information such as the master information block (MIB) and system information block (SIB) for the UE to access the network. When the UE accesses the network, the network may send a radio resource control (RRC) message to the UE to establish the CSI-RS physical resources used by the base station to send the multicast CSI-RS and the reporting configuration used by the UE to report the measured channel quality based on the multicast CSI-RS. The network may send a medium access control (MAC) control element (CE) on the physical downlink shared channel (PDSCH) to activate CSI-RS measurement by the UE.

[0074] A UE that wishes to receive a multicast service may measure channel characteristics such as CQI / PMI of a multicast CSI-RS and may report the measurement results as uplink control information (UCI) as part of a channel state information (CSI) report carried on a physical uplink control channel (PUCCH) or a physical uplink shared channel (PUSCH). The measurement results are affected by the multicast downlink (DL) beamforming design, including the multicast DL transmit beams of the base station and the DL receive beamforming of the UE. The network may perform multicast beamforming and beam management based on the measurement results reported by UEs that have been admitted to the multicast group and UEs that wish to join the multicast group.

[0075] The network may authorize the UE to receive the multicast resources based on the measured channel characteristics reported by the UE. In one aspect, the network may send an RRC configuration message to the UE, which includes multicast group common signaling to the granted UE to establish a physical downlink control channel (PDCCH) or PDSCH for the UE to receive the multicast service. In one aspect, the multicast group common signaling may include a search space, a control resource set (CORESET), a bandwidth part (BWP), and a group common radio network temporary identifier (RNTI) for multicast reception. The UE may then receive the multicast data via the multicast group common PDCCH or PDSCH.

[0076] The network may simplify the measurement of channel characteristics reported as CQI by the UE. In beamforming associated with the provision of unicast services, a unicast UE may report CQI for a range of modulation and coding schemes (MCS). For example, NR has 3 existing CQI tables corresponding to a set of MCS tables for PDSCH: a 64QAM table with a block error rate (BLER) of 0.1 when 256QAM is not supported by the base station or UE, a 256QAM table with a BLER of 0.1 when 256QAM is allocated, and a low spectral efficiency table with a FLER of 1e-5 for applications that require a lower coding rate for reliable data transmission. 4 bits may be used to signal the CQI value. A high CQI value indicates that the UE is capable of receiving high-order modulation at a high coding rate. Because multicast services typically focus on a limited number of MCS configurations to ensure reliable transmission to multicast UEs, the network can reduce feedback overhead by limiting the number of MCS configurations used for CQI measurement and reporting.

[0077] Figure 8 A CQI table for 64QAM according to one aspect of the present disclosure is shown, where the CQI corresponding to a subset of MCSs can be measured and reported by the UE to reduce the overhead associated with reporting the channel quality of the received multicast CSI-RS. Figure 8The efficiency plot provides a measure of the spectral efficiency (SE) associated with an MCS configuration given by the modulation order multiplied by the code rate.

[0078] In one aspect, the network can reduce the reporting of the CQI table by increasing the step size of the SE. This is because the provision of multicast services is typically focused on a few limited MCS configurations. Therefore, multicast may only be interested in a subset of MCS configurations from the existing CQI table. For example, the network may define a subset CQI table for multicast beamforming based on the existing 64QAM CQI table to reduce the number of bits used for reporting. The subset CQI table can be selected by using a larger step size in the SE. In one aspect, the network can use a bit mask to indicate which subset from the existing CQI table will be used by the UE to report the multicast channel quality. In an extreme example, the network can configure the bit mask so that the UE only reports CQI index 1 (QPSK) with an SE of 0.1523 or CQI index 7 (16QAM) with an SE of 1.4766. Since only 2 MCS configurations are used, the UE may only need 1 bit for reporting.

[0079] In one aspect, the network may reduce feedback overhead by using 1-bit feedback reporting for multicast services. For example, the network may configure a given threshold for reporting purposes (e.g., which may be a predefined spectral efficiency requirement). The UE may use 1-bit feedback to indicate whether it can meet the given threshold (value 1) or whether it fails to meet the given threshold (value 0).

[0080] In one aspect, the network may use 2-bit differential feedback for multicast services. Instead of configuring a predefined threshold for reporting purposes, the network may use the current MCS configuration to establish a multicast transmission. The UE may report whether it prefers a better or worse MCS configuration than the current MCS configuration. For example, the UE may use 2 bits to indicate one of the following options: (1) the UE can support a better MCS configuration than the current multicast MCS configuration; (2) the UE is satisfied with the current multicast MCS configuration and therefore does not need to adjust; or (3) the UE can only support a worse MCS configuration than the current multicast MCS configuration.

[0081] In one aspect, the UE may provide early CQI reporting at the beginning of radio resource control (RRC) connection establishment. For downlink beamforming and beam management, the base station may send SSB signals using a less spectrally efficient MCS carried on a relatively wide beam for initial acquisition by the UE. The base station may send CSI-RS carried on more directional beams for beam refinement. Assuming that multicast services primarily use reliable MCS and layer 1 transmissions, it may be possible to derive early CQI using SSB signals and for the UE to quickly report such SSB-based CQI (e.g., via a RACH process). For example, multicast beamforming may not require the fine-grained CQI reporting provided by CSI-RS measurements because multicast services primarily use reliable MCS configurations. Therefore, the CQI derived from the SSB may be sufficient to indicate the channel quality for multicast beamforming.

[0082] Another advantage of early SSB-based CQI reporting is that multicast transmissions are typically targeted to multiple UEs. Multicast transmissions may already exist (due to other concurrently served UEs) before a new UE wishing to join the multicast group can establish an RRC connection. Therefore, the network can reduce latency for new UEs to access existing multicast resources by configuring the UE for early and fast SSB-based CQI reporting. Early CQI reporting during the RACH procedure can also improve the robustness of the RACH procedure and the reliability of further communications between the UE and the base station.

[0083] Fig. 9 A flow chart of signaling between a base station and a UE for the UE to measure CQI based on an SSB signal and report the SSB-based CQI using a contention-based RACH procedure to allow early reporting of channel characteristics during RRC connection establishment according to one aspect of the present disclosure is shown.

[0084] In one aspect, during RRC connection establishment, such as when going from RRC_IDLE to RRC_CONNECTED, the UE may measure and report multicast CQI based on SSB signals. During the contention-based RACH process, the UE may select a random access preamble from a pool of preambles shared with other UEs. The UE may send the selected random access preamble to the network on message 1 (MSG1). The network may send a random access response (RAR) on message 2 (MSG2) in response to detecting MSG1 sent by the UE for further contention resolution. The RAR may provide uplink resource allocation to schedule the transmission of message 3 (MSG3) from the UE.

[0085] The base station may send multiple SSB signals. Each SSB may be sent using a different beam to provide ubiquitous and robust coverage. Each SSB signal may be associated with its corresponding RACH opportunity. The UE will attempt to detect and measure the quality of the SSB signal. In order to reduce delays, the UE may not complete the measurement of all SSB signals before deciding which RACH opportunity the UE can use for MSG1. As long as the SSB quality meets the performance requirements, the UE may use the RACH opportunity corresponding to the SSB signal for MSG1, and further communications with the network may be based on the beam of the SSB signal until the UE can report the best beam. The network may then reconfigure the beam used for communication after the RRC connection is established. Therefore, in order to reduce RACH delays, the UE may attempt to establish an RRC connection with the network on the RACH opportunity corresponding to the first SSB signal that meets the performance requirements, and continue the RACH process based on the first SSB beam. If the UE finds a better SSB signal, the UE may use message 3 of the RACH process to report a better SSB-based CQI to the network.

[0086] The network may complete contention resolution by sending message 4 (MSG4) to the UE for the UE to determine that it has successfully completed the RACH process. The network may authorize the UE to receive multicast resources based on the SSB-based CQI reported by the UE. The network may then send an RRC configuration message to the UE containing multicast group common signaling to establish a PDCCH or PDSCH for the UE to receive multicast services. Advantageously, early SSB-based CQI reporting allows the UE to update the network with the best beam as early as MSG3 during the RACH process. If there is a significant delay between MSG1 and MSG3, it also allows the UE to update the network with the latest channel.

[0087] Fig.10 A flow chart is shown of signaling between a base station and a UE for the UE to measure CQI based on an SSB signal and report the SSB-based CQI using a two-step RACH procedure to allow early reporting of channel characteristics during RRC connection establishment according to one aspect of the present disclosure.

[0088] In a two-step RACH process, the UE may send a random access preamble and a PUSCH payload together in one round. The UE may measure the multicast CQI based on the SSB signal and report the SSB-based CQI to the network as part of message A (MSGA) for both the random access preamble and the PUSCH payload. In one aspect, the UE may measure the multicast CQI when it determines whether the SSB signal of the beam providing the dedicated random access preamble has sufficient strength. The network may send a random access response to the UE on message B (MSGB) to indicate the completion of the RACH process. As in a contention-based RACH process, the network may authorize the UE to receive multicast resources based on the SSB-based CQI reported by the UE. The network may then send an RRC configuration message to the UE containing multicast group common signaling to establish a PDCCH or PDSCH for the UE to receive multicast services.

[0089] In one aspect, the RACH process associated with the handover process may similarly use early SSB-based CQI reporting. For example, the UE may use MSG3 to report SSB-based CQI to the network during a handover process using a contention-based RACH process, or use MSGA to report SSB-based CQI to the network during a handover process using a two-step RACH process.

[0090] In one aspect, during RRC connection establishment, such as when transitioning from RRC_INACTIVE to RRC_CONNECTED, the UE may report multicast CQI based on SSB signals. For example, when the UE is in RRC_INACTIVE, the network may configure the UE to track and measure multicast CQI based on SSB signals. When the UE transitions from RRC_INACTIVE to RRC_CONNECTED, the UE may report SSB-based CQI. In one aspect, when the UE triggers reselection of a new cell during RRC_INACTIVE, the UE may attach an SSB-based CQI report to the reselected new cell in a RACH procedure.

[0091] In one aspect, the retransmission strategy can be enhanced to support retransmission of previously transmitted PCSCH for multicast services. Since different UEs experience different channel conditions, it is likely that more than 1 UE in a multicast group will need retransmission. It would be extremely inefficient to: (1) schedule MBS retransmissions to all UEs, even though some UEs may have successfully decoded the PDSCH, or (2) independently schedule multiple unicast PDSCHs to each MBS UE that needs retransmission. Retransmission enhancement can help reduce retransmission overhead and improve diversity during retransmissions.

[0092] To support multicast retransmissions when a multicast transmission fails to be received by any of the multicast UEs, the number of retransmissions may be the same for all multicast UEs. To facilitate network decisions, each UE may report a desired number of multicast retransmissions for the network or base station based on feedback from the UE to determine a final number of retransmissions. In one aspect, the base station may configure multiple multicast beam candidates for measurement. The UE may measure the quality of each multicast beam candidate and the preferred number of retransmissions for each beam candidate. The UE may maintain different preferred numbers of retransmissions for different beam candidates and may select which preferred number of retransmissions to report later.

[0093] Multicast retransmissions may use the same frequency band. In one aspect, multicast retransmissions may be implemented using different frequency sub-bands, such as by frequency hopping. As part of the UE beam report, the UE may also indicate whether frequency hopping is preferred for multicast retransmissions of beam candidates.

[0094] In one aspect, the UE may report its preferred number of retransmissions for a multicast service in the RRC_INACTIVE state. For example, before transitioning from RRC_CONNECTED to RRC_INACTIVE, the UE (in the RRC_CONNECTED state) may report its preferred number of retransmissions for RRC_INACTIVE. Later, the network may apply the UE's feedback during the RRC_INACTIVE state.

[0095] In one aspect, the UE preference information may be reported to the network via RRC signaling "UEAssistanceInformation" which is used by the UE to report its various preference information. For multicast beamforming, new elements may be defined within "UEAssistanceInformation". An example of a new element may be:

[0096]

[0097] where "preferredNumRetx" indicates the preferred number of retransmissions in multicast; "freqHopPreferred" indicates whether frequency hopping is preferred for multicast retransmissions; and "preferredNumInactRetx" indicates the preferred number of retransmissions in the RRC_INACTIVE state. A new element may be defined for each beam candidate.

[0098] In one aspect, the base station may use multi-layer beamforming to send multicast beams in more than one layer. For example, in NR, for NR bands above 2.5 GHz in FR1, the UE may support up to 4 PDSCH layers, and up to 2 PDSCH layers for other cases. PDSCH transmission with a higher number of layers may more efficiently utilize the spectrum, reduce communication delays, and improve communication reliability. For multicast services, MIMO layer adaptation enhancements for MBS may allow the network to select the maximum number of layers that can be served among all multicast UEs. MIMO layer adaptation enhancements to support multicast services may include: (1) enhancements to UE capability reporting and (2) enhancements to UE RI / PMI / CQI reporting.

[0099] For example, in FR2, a base station may send multicast services in two layers using horizontal polarization and vertical polarization to increase the transmission rate. In another example, a base station may use multi-layer MIMO / beamforming for concurrent multicast and unicast transmissions. Concurrent multicast and unicast transmissions may come from the same base station or from different base stations, such as in a multiple transmit / receive point (multi-TRP) scenario. The UE may receive multicast and unicast PDSCHs carried on different beams or the same beam simultaneously in time. The UE may use the same hardware resources to receive multicast and unicast PDSCHs, which may be sent using frequency range 2 (FR2 of 24.25 GHz to 52.60 GHz). Multicast data may be mapped to the first layer, and unicast data may be mapped to the second layer. The base station may use different downlink transmit beams to send multicast data and unicast data simultaneously.

[0100] In one aspect, the UE may support up to X layers, with up to X_M layers concurrently in time for multicast transmissions and up to X_U layers for unicast transmissions (X_M+X_U=X). Multicast and unicast transmissions may come from two base stations / TRPs, and each layer may be associated with one DL Tx beam. To support the above features, the UE may indicate its capabilities in the RRC capability report. Traditional RRC signaling for UE capabilities has an element "FeatureSetDownlink" that may be modified to indicate the number of multicast and unicast layers supported by the UE.

[0101] In one aspect, the UE may report its capability information for supporting multi-layer beamforming to the network via traditional RRC signaling "FeatureSetDownlink" used by the UE to report its capabilities. A new element may be defined within "FeatureSetDownlink" to indicate the number of multicast layers and unicast layers supported by the UE. An example of the new element may be:

[0102]

[0103] Where 2M0U indicates that 2 multicast layers do not support concurrent unicast layers; 1M1U indicates that 1 multicast layer and 1 unicast layer can be supported concurrently in time; and 2M2U indicates that 2 multicast layers and 2 unicast layers can be supported concurrently in time. In one aspect, "FeatureSetDownlink" can be refined separately for each frequency band to cover both two-layer multicast transmission and concurrent multicast / unicast transmission using horizontal / vertical polarization.

[0104] Fig.11 A flow chart depicts a method 1100 for a UE to measure and report the channel quality of a downlink beam so that a base station can adapt the downlink beam to a multicast beam to provide multicast services to the UE and other UEs in a multicast group according to one aspect of the present disclosure. The method may be performed by Figure 1 , Figure 2 , Figure 3 , Figure 5 , Figure 6 , Figure 7 , Fig. 9 and Fig.10 UE practice.

[0105] In operation 1101, the UE receives configuration information for measuring and reporting downlink channel characteristics from a base station.

[0106] In operation 1103, the UE measures channel characteristics of a downlink beam from the base station to generate a channel measurement result based on the configuration information.

[0107] In operation 1105, the UE transmits the channel measurement result to the base station so that the base station can adapt the downlink beam to a multicast beam to provide a multicast service to the UE and other UEs of the multicast group.

[0108] In operation 1107, the UE receives the multicast beam to receive the multicast service.

[0109] In one aspect, the described operations for enhancing the reporting of channel state information of a link for multicast downlink transmission and the adaptation of a link for multicast beamforming may be practiced by a UE including at least one antenna, at least one radio component, and at least one processor. The radio component may be configured to communicate with a communication network (e.g., a base station) via the antenna. The processor may be coupled to the radio component and configured to perform the operations. The operations may include the UE receiving configuration information for measuring and reporting downlink channel characteristics from the communication network. The operations may also include the UE measuring the channel characteristics of a downlink beam from the communication network to generate channel measurement results based on the configuration information. The operations may further include the UE reporting the channel measurement results to the communication network so that the communication network can adapt the downlink beam to a multicast beam to provide multicast services to the UE and other UEs in the multicast group. The UE may then receive the multicast beam from the communication network to receive the multicast service.

[0110] In one aspect, the configuration information may include information for the UE to measure channel characteristics of a downlink beam based on a reference signal sent using a subset of MCS configurations reduced compared to an MCS configuration of a reference signal used to measure channel characteristics of a unicast downlink beam.

[0111] In one aspect, the configuration information may include a channel quality threshold.The channel measurement results reported to the communication network may include an indication of whether the channel characteristics of the downlink beam measured by the UE meet the channel quality threshold.

[0112] In one aspect, the configuration information may include a current MCS configuration for the downlink beam.The channel measurement results reported to the communication network may include an indication of whether the UE is capable of supporting an MCS configuration with higher, equal, or lower spectral efficiency than the current MCS configuration.

[0113] In one aspect, the configuration information may include information for the UE to measure channel characteristics of a downlink beam based on a synchronization signal (SSB) sent by the communication network. The UE may measure the synchronization signal used by the UE to establish a connection to the communication network for early reporting of the channel quality of the downlink.

[0114] In one aspect, a UE may report a preferred multicast retransmission number that may be used by the communication network to retransmit previously transmitted multicast payloads that failed to be received by the UE.

[0115] In one aspect, the UE may report the UE's ability to receive multicast services using multiple transmission layers.

[0116] Part of the above content can be realized by using logic circuits such as dedicated logic circuits or by using a microcontroller or other forms of processing cores for executing program code instructions. Thus, the process taught by the above discussion can be performed using program code such as machine executable instructions, which enable the machine to execute these instructions to perform certain functions. In this context, a "machine" can be a machine that converts intermediate form (or "abstract") instructions into processor-specific instructions (e.g., abstract execution environments such as "virtual machines" (e.g., Java virtual machines), interpreters, common language runtimes, high-level language virtual machines, etc.), and / or an electronic circuit that is set on a semiconductor chip (e.g., a "logic circuit" implemented using transistors), which is designed to execute instructions, and the processor is such as a general-purpose processor and / or a dedicated processor. The process taught by the above discussion can also be performed by (as a substitute for a machine or in combination with a machine) an electronic circuit that is designed to execute a process (or a part thereof) without executing program code.

[0117] For example, the described operations may be stored as instructions on a non-transitory computer-readable medium for computer execution. The computer may execute the instructions to receive configuration information for measuring and reporting downlink channel characteristics from a communication network, measure the channel characteristics of a downlink beam from the communication network to generate a channel measurement result based on the configuration information, report the channel measurement result to the communication network so that the communication network can adapt the downlink beam to a multicast beam to provide a multicast service to the UE and other UEs of the multicast group, and receive the multicast beam from the communication network to receive the multicast service.

[0118] The present invention also relates to an apparatus for performing the operations described herein. The apparatus may be specially constructed for the required purposes, or may include a general-purpose computer selectively activated or reconfigured by a computer program stored in the computer. Such a computer program may be stored in a computer-readable storage medium, such as, but not limited to, any type of disk, including floppy disks, optical disks, CD-ROMs and magneto-optical disks, read-only memories (ROMs), RAMs, EPROMs, EEPROMs, magnetic or optical cards, or any type of medium suitable for storing electronic instructions, and each is coupled to a computer system bus.

[0119] A machine-readable medium includes any mechanism for storing or transmitting information in a form readable by a machine (e.g., a computer). For example, machine-readable media include read-only memory ("ROM"); random access memory ("RAM"); magnetic disk storage media; optical storage media; flash memory devices; and the like.

[0120] Articles of manufacture may be used to store program code. Articles of manufacture storing program code may be implemented as, but not limited to, one or more memories (e.g., one or more flash memories, random access memories (static, dynamic, or other)), optical disks, CD-ROMs, DVD ROMs, EPROMs, EEPROMs, magnetic or optical cards, or other types of machine-readable media suitable for storing electronic instructions. Program code may also be downloaded from a remote computer (e.g., a server) to a requesting computer (e.g., a client) by means of a data signal contained in a propagation medium (e.g., via a communication link (e.g., a network connection)).

[0121] The foregoing detailed description has been presented in terms of algorithms and symbolic representations of operations on data bits within a computer memory. These algorithmic descriptions and representations are tools used by those skilled in the art of data processing, and these tools can also most effectively convey the substance of their work to other technicians in the field. An algorithm is here and generally refers to a self-consistent sequence of operations leading to a desired result. These operations are those that require physical manipulation of physical quantities. Typically, but not necessarily, these quantities are in the form of electrical or magnetic signals that can be stored, transferred, combined, compared, and otherwise manipulated. It has proven convenient to refer to these signals as bits, values, elements, symbols, characters, terms, numbers, etc., primarily for general reasons.

[0122] It should be borne in mind, however, that all of these and similar terms are associated with the appropriate physical quantities and are merely convenient labels applied to these quantities. Unless otherwise specifically stated, it will be apparent from the above discussion that discussions throughout this specification using terms such as "select," "determine," "receive," "form," "group," "aggregate," "generate," "remove," etc., will be understood to refer to actions and processes on a computer system or similar electronic computing device that manipulates data represented as physical (electronic) quantities in the computer system's registers and memories and converts it into other data similarly represented as physical quantities in the computer system's memories or registers or other such information storage, transmission, or display devices.

[0123] The process presented herein and display are not inherently relevant to any particular computer or other device. According to the teaching content of this paper, various general-purpose systems can be used together with programs, or it can be proved that it is convenient to construct a more special-purpose device for performing the operation. According to the description below, the required structure for various these systems will be apparent. In addition, the present invention is not described with reference to any specific programming language. It should be appreciated that multiple programming languages ​​can be used to realize the teaching content of the present invention as described herein.

[0124] The foregoing discussion describes only some exemplary embodiments of the present invention. Those skilled in the art will readily recognize from these discussions, drawings and claims that various modifications can be made without departing from the spirit and scope of the present invention.

Claims

1. A baseband processor of a wireless user equipment (UE) of a communication network, the baseband processor comprising: receiving configuration information for measuring and reporting downlink channel characteristics from a base station of the communication network; measuring a channel characteristic of a downlink beam from the base station to generate a channel measurement result based on the configuration information; sending the channel measurement result to the base station so that the base station can adapt the downlink beam to a multicast beam to provide a multicast service to the UE and at least one other UE of a multicast group; as well as The multicast beam is received from the base station to receive the multicast service.

2. The baseband processor of claim 1 , wherein the configuration information includes information for measuring the channel characteristics of the downlink beam based on a reference signal transmitted using a subset of a plurality of modulation and coding schemes (MCSs) reduced compared to an MCS of a reference signal used to measure the channel characteristics of a unicast downlink beam.

3. The baseband processor of claim 2, wherein measuring the channel characteristics of the downlink beam comprises generating the channel measurements based on the reference signal sent using the reduced subset of the plurality of MCSs.

4. The baseband processor of claim 2, wherein the reduced subset of the plurality of MCSs has a larger step size in spectral efficiency than a step size of spectral efficiency associated with measuring channel characteristics of the unicast downlink beam.

5. The baseband processor of claim 2, wherein the configuration information further comprises a bit mask for selecting the reduced subset of the plurality of MCSs associated with measuring the channel characteristics of the unicast downlink beam.

6. A baseband processor according to claim 1, wherein the configuration information includes a channel quality threshold, and wherein the channel measurement result sent to the base station includes an indication of whether the channel characteristics of the downlink beam measured by the UE meet the channel quality threshold.

7. A baseband processor according to claim 1, wherein the configuration information includes a current modulation and coding scheme (MCS) of the downlink beam, and wherein the channel measurement results sent to the base station include an indication of whether the UE supports a preferred MCS selected to have one of higher, equal or lower spectral efficiency than the current MCS.

8. A baseband processor according to claim 1, wherein the configuration information includes information for measuring the channel characteristics of the downlink beam based on a synchronization signal sent by the base station, wherein the synchronization signal is used by the UE to establish a connection to the communication network.

9. The baseband processor of claim 8, wherein measuring the channel characteristics of the downlink beam comprises generating the channel measurements based on the synchronization signal. 10 . The baseband processor of claim 9 , wherein transmitting the channel measurement result comprises transmitting the channel measurement result based on the synchronization signal when the UE establishes a connection to the base station.

11. The baseband processor of claim 9, wherein sending the channel measurement result comprises sending the channel measurement result based on the synchronization signal when the UE establishes a connection to a second base station of the communication network during a handover process.

12. The baseband processor of claim 9, wherein sending the channel measurement result comprises sending the channel measurement result based on the synchronization signal when the UE reestablishes a connection to the base station when transitioning from an inactive state to an active state.

13. The baseband processor of claim 1, wherein transmitting the channel measurement result comprises transmitting a preferred multicast retransmission number that the base station prefers to use to retransmit a previously transmitted multicast payload that failed to be received by the UE.

14. A baseband processor according to claim 13, wherein measuring the channel characteristics of the downlink beam includes measuring the channel characteristics of a plurality of candidate multicast downlink beams, and wherein the preferred number of multicast retransmissions is associated with each of the plurality of candidate multicast downlink beams. 15 . The baseband processor of claim 13 , wherein the preferred multicast retransmission number indicates a preferred retransmission number when the UE is in an inactive state.

16. The baseband processor of claim 1, wherein sending the channel measurement results comprises sending the UE's preference for receiving multicast retransmissions on a different frequency subband when the base station retransmits a multicast payload previously sent on a first subband.

17. The baseband processor of claim 16, wherein the preference of the UE to receive multicast retransmissions on different frequency sub-bands comprises a preference of the UE to receive the multicast retransmissions using frequency hopping.

18. The baseband processor of claim 1, wherein transmitting the channel measurement result comprises transmitting a capability of the UE to receive the multicast service in a plurality of transmission layers.

19. The baseband processor of claim 18, wherein the plurality of transmission layers comprises two layers of horizontal polarization and vertical polarization of multicast downlink beams.

20. The baseband processor of claim 19, wherein the plurality of transmission layers comprises a multiple-input multiple-output (MIMO) layer for receiving multicast services and unicast services concurrently in time by the UE on one or more multicast beams and one or more unicast beams.

21. The baseband processor of claim 20, wherein the MIMO layers include a maximum number of layers for receiving the multicast service on the one or more multicast beams.

22. The baseband processor of claim 20, wherein the MIMO layers include a maximum number of layers for receiving the unicast service on the one or more unicast beams.

23. A base station of a communication network, the base station comprising: at least one antenna; at least one radio, wherein the at least one radio is configured to communicate with a communication network using the at least one antenna; and at least one processor coupled to the at least one radio, wherein the at least one processor is configured to perform operations comprising: sending configuration information for measuring and reporting downlink channel characteristics to a plurality of wireless user equipments (UEs) of a multicast group; Sending a downlink beam to the multicast group so that the plurality of UEs can generate channel measurement results based on the configuration information; receiving the channel measurement result from at least one UE among the UEs in the multicast group; and The downlink beam is configured as a multicast beam based on the channel measurement result to provide multicast service to the multicast group.

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