# US 11,451,934 B2 · Transport block size and rate matching for multicast communications > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,451,934 B2 - Document ID: US11451934B2 - Status: Granted - Kind: B2 - Application number: 16/937,232 - Filed: 2020-07-23 - Published: 2021-01-28 - Granted: 2022-09-20 - Earliest claimed: 2019-07-25 - Assignees: QUALCOMM Incorporated - Applicants: QUALCOMM Incorporated - Inventors: Alberto Rico Alvarino; Le Liu; Kazuki Takeda - Web page: https://patentgrep.com/patent/US11451934B2 ## CPC - H04L 1/0013: {Rate matching, e.g. puncturing or repetition of code symbols} - H04W 4/06: Selective distribution of broadcast services, e.g. multimedia broadcast multicast service [MBMS]; Services to user groups; One-way selective calling services - H04L 1/0025: {Transmission of mode-switching indication} - H04L 1/0045: {Arrangements at the receiver end} - H04L 1/0067: {Rate matching (H04L1/0013 and H04L1/08 take precedence)} - H04L 5/0044: {Allocation of payload; Allocation of data channels, e.g. PDSCH or PUSCH} - H04L 5/0053: {Allocation of signalling, i.e. of overhead other than pilot signals} - H04W 72/121: for groups of terminals or users - H04W 72/1273: of downlink data flows - H04L 1/0003: {by switching between different modulation schemes} - H04L 1/0009: {by adapting the channel coding (H04L1/1812 takes precedence)} - H04W 72/30: Resource management for broadcast services - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract A base station may transmit a multicast transmission to a group of user equipments (UEs) that are each configured with a group radio network temporary identifier (G-RNTI). The UEs may be configured to receive the transmission using the same modulation and coding scheme (MCS) and transport block size (TBS) such that the group of UEs may receive the same transmission. In particular, a UE may receive one or more configurations for multicast transmissions, each configuration associated with a G-RNTI. The UE may determine a MCS table for the G-RNTI. The UE may determine a TBS for a multicast transmission based on an overhead value for the G-RNTI. The UE may receive the multicast transmission based on the MCS table and the TBS. ## Claims ### Claim 1 A method of wireless communication, comprising: receiving, at a user equipment (UE), one or more configurations for multicast transmissions, each configuration associated with a group radio network temporary identifier (G-RNTI); selecting a modulation and coding scheme (MCS) table for the G-RNTI; receiving downlink control information associated with the G-RNTI; determining a transport block size (TBS) for a multicast transmission based on an overhead value for the G-RNTI and the downlink control information received for the G-RNTI, wherein determining the TBS for the multicast transmission based on the overhead value comprises receiving a configuration of a UE-specific overhead value or a configured overhead value in the one or more configurations for multicast transmissions on a system information block; and decoding the multicast transmission based on the MCS table and the TBS. ### Claim 2 (depends on 1) The method of claim 1, wherein selecting the MCS table for the G-RNTI comprises selecting a default MCS table for all multicast transmissions for the G-RNTI. ### Claim 3 (depends on 1) The method of claim 1, wherein selecting the MCS table for the G-RNTI comprises receiving a configuration of the MCS table for the G-RNTI. ### Claim 4 (depends on 3) The method of claim 3, wherein the configuration of the MCS table for the G-RNTI is received via system information. ### Claim 5 (depends on 3) The method of claim 3, wherein the configuration of the MCS table for the G-RNTI is received via a unicast radio resource configuration message. ### Claim 6 (depends on 1) The method of claim 1, wherein selecting the MCS table for the G-RNTI comprises selecting a UE-specific MCS table for G-RNTI transmissions scheduled in a UE-specific search space and selecting a default or configured MCS table for G-RNTI transmissions scheduled in a common search space. ### Claim 7 (depends on 1) The method of claim 1, wherein each UE receiving the multicast transmission is configured with a same UE-specific overhead value. ### Claim 8 (depends on 1) The method of claim 1, wherein the configuration of the UE-specific overhead value is received via a unicast radio resource configuration message. ### Claim 9 (depends on 1) The method of claim 1, further comprising: determining to apply limited buffer rate matching (LBRM) to the multicast transmission; determining a maximum TBS for the G-RNTI; and applying a LBRM code rate to the maximum TBS to determine a LBRM TBS. ### Claim 10 (depends on 9) The method of claim 9, wherein determining the maximum TBS comprises receiving a signaled maximum TBS. ### Claim 11 (depends on 9) The method of claim 9, wherein determining the maximum TBS comprises determining the maximum TBS based on one or more of a number of layers for the G-RNTI, a maximum modulation order for the G-RNTI, and a number of physical resource blocks for the LBRM based on a bandwidth part for the G-RNTI. ### Claim 12 (depends on 1) The method of claim 1, wherein decoding the multicast transmission based on the MCS table and the TBS comprises rate matching a transport block to physical downlink shared channel (PDSCH) resources based on a rate matching pattern for the G-RNTI. ### Claim 13 (depends on 12) The method of claim 12, wherein the rate matching pattern for the G-RNTI is indicated by the downlink control information. ### Claim 14 (depends on 12) The method of claim 12, wherein the UE monitors a physical downlink control channel (PDCCH) candidate for the G-RNTI with aggregation level 8, and rate matching the transport block comprises rate matching the transport block around resources corresponding to a PDCCH candidate with aggregation level 16. ### Claim 15 (depends on 12) The method of claim 12, wherein the rate matching pattern does not rate match the transport block around resources for a cell specific reference signal. ### Claim 16 (depends on 12) The method of claim 12, wherein the rate matching pattern indicates rate matching around resources for a cell specific reference signal. ### Claim 17 (depends on 16) The method of claim 16, wherein the configuration for the G-RNTI indicates the cell specific reference signal. ### Claim 18 (depends on 12) The method of claim 12, wherein the rate matching pattern indicates rate matching around a configured set of zero power channel status information reference signal (ZP-CSI-RS) for the G-RNTI. ### Claim 19 (depends on 12) The method of claim 12, further comprising: receiving a media access control—control element (MAC-CE) using the G-RNTI with a HARQ process identifier indicating that a semi-persistent ZP-CSI-RS is activated; and rate matching around the semi-persistent ZP-CSI-RS after receiving a PDSCH for the G-RNTI scheduled with the HARQ process identifier and a new data indicator (NDI) being flipped. ### Claim 20 (depends on 19) The method of claim 19, wherein the configuration for the G-RNTI indicates the ZP-CSI-RS. ### Claim 21 (depends on 12) The method of claim 12, wherein the rate matching pattern does not rate match the transport block around resources for a semi-persistent ZP-CSI-RS for the G-RNTI. ### Claim 22 (depends on 1) The method of claim 1, wherein the G-RNTI comprises one of a RNTI for decoding a multicast control channel (MCCH) or a RNTI for decoding a multicast transport channel (MTCH), wherein determining the TBS for the multicast transmission is based on whether the G-RNTI is the RNTI for decoding the MCCH or the RNTI for decoding the MTCH. ### Claim 23 An apparatus for wireless communication, comprising: a memory; and at least one processor coupled to the memory and configured to: receive, at a user equipment (UE), one or more configurations for multicast transmissions, each configuration associated with a group radio network temporary identifier (G-RNTI); select a modulation and coding scheme (MCS) table for the G-RNTI; receive downlink control information associated with the G-RNTI; receive a configuration of a UE-specific overhead value for the G-RNTI or a configured overhead value in the one or more configurations for multicast transmissions on a system information block; determine a transport block size (TBS) for a multicast transmission based on the UE-specific overhead value or the configured overhead value for the G-RNTI and the downlink control information received for the G-RNTI; and decode the multicast transmission based on the MCS table and the TBS. ### Claim 24 (depends on 23) The apparatus of claim 23, wherein the at least one processor is configured to select the MCS table for the G-RNTI as one of: a default MCS table for all multicast transmissions for the G-RNTI; a received configuration of the MCS table for the G-RNTI; or a UE-specific MCS table for G-RNTI transmissions scheduled in a UE-specific search space. ### Claim 25 (depends on 23) The apparatus of claim 23, wherein the at least one processor is configured to: determine to apply limited buffer rate matching (LBRM) to the multicast transmission; determine a maximum TBS for the G-RNTI; and apply a LBRM code rate to the maximum TBS to determine a LBRM TBS. ### Claim 26 A method of wireless communication, comprising: transmitting, by a base station, one or more configurations for multicast transmissions to one or more user equipment (UE), each configuration associated with a group radio network temporary identifier (G-RNTI); transmitting a configured overhead value in the one or more configurations for multicast transmissions on a system information block or a configuration of a UE-specific overhead value for the G-RNTI; selecting a modulation and coding scheme (MCS) table for the G-RNTI; transmitting downlink control information associated with the G-RNTI to the one or more UE; determining a transport block size (TBS) for a multicast transmission based on the configured overhead value or the UE-specific overhead value for the G-RNTI and the downlink control information for the G-RNTI; and transmitting the multicast transmission based on the MCS table and the TBS. ### Claim 27 An apparatus for wireless communication, comprising: a memory; and at least one processor coupled to the memory and configured to: transmit, by a base station, one or more configurations for multicast transmissions to one or more user equipment (UE), each configuration associated with a group radio network temporary identifier (G-RNTI); transmit a configured overhead value in the one or more configurations for multicast transmissions on a system information block or a configuration of a UE-specific overhead value for the G-RNTI; select a modulation and coding scheme (MCS) table for the G-RNTI; transmit downlink control information associated with the G-RNTI to the one or more UE; determine a transport block size (TBS) for a multicast transmission based on the configured overhead value or the UE-specific overhead value for the G-RNTI and the downlink control information for the G-RNTI; and transmit the multicast transmission based on the MCS table and the TBS.