# US 12,010,730 B2 · Retransmission of MsgB in two-step random access procedure > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,010,730 B2 - Document ID: US12010730B2 - Status: Granted - Kind: B2 - Application number: 18/334,933 - Filed: 2023-06-14 - Published: 2023-10-12 - Granted: 2024-06-11 - Earliest claimed: 2023-06-14 - Assignees: Apple Inc. - Applicants: Apple Inc. - Inventors: Chunhai Yao; Clive E. Rodgers; Dawei Zhang; Fangli Xu; Haijing Hu; Haitong Sun; Wei Zeng; Yuqin Chen; Yushu Zhang; Zhibin Wu - Web page: https://patentgrep.com/patent/US12010730B2 ## CPC - H04W 72/1268: of uplink data flows - H04W 72/0446: Resources in time domain, e.g. slots or frames - H04W 72/232: the control data signalling from the physical layer, e.g. DCI signalling - H04W 74/006: {in the downlink, i.e. towards the terminal} - H04W 74/0836: with 2-step access - H04W 74/0833: Random access procedures, e.g. with 4-step access - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract A wireless user equipment (UE) device may transmit a random access preamble to a base station, using a physical resource on an uplink signal. After failing to receive an initial transmission of a response message from the base station (BS), the UE device may monitor for one or more retransmissions of the response message. Each of the retransmission may include a corresponding transmission number. As an alternative, each of the retransmissions may be at least partially scrambled using a corresponding Radio Network Temporary Identifier (RNTI). As another alternative, a window for monitoring and RNTI calculation may be extended to include the one or more retransmissions. The successive retransmissions may include the same set of UE-specific payloads, or, a decreasing set of payloads over time as UE devices acknowledge successful receipt of their respective payloads. ## Claims ### Claim 1 A method, comprising: receiving a configuration message from a base station, wherein the configuration message indicates a time duration of a window for monitoring a physical downlink control channel (PDCCH); monitoring the PDCCH for one or more transmissions of a downlink message, wherein the one or more transmissions of the downlink message are part of a two-step random access procedure; decoding downlink control information (DCI) in a first of the one or more transmissions of the downlink message within the window using a message B (MSGB) Radio Network Temporary Identity (RNTI), wherein the MSGB-RNTI is based on location parameters of a physical uplink resource that was used by a user equipment (UE) to transmit a random access preamble of the two-step random access procedure; and determining, based on a field in the decoded DCI indicating a time sub-window number, that the decoded DCI is intended for the UE. ### Claim 2 (depends on 1) The method of claim 1, wherein the time sub-window number is associated with a time of the random access preamble transmission. ### Claim 3 (depends on 1) The method of claim 1, wherein the time sub-window number resolves DCI transmissions relating to random access preamble transmissions in different radio frames using a same MSGB-RNTI. ### Claim 4 (depends on 3) The method of claim 3, wherein the window for monitoring the PDCCH is larger than a sub-window. ### Claim 5 (depends on 1) The method of claim 1, wherein said monitoring includes: recovering a transmission number from the first of the one or more transmissions; and comparing the transmission number with a current window number of the UE device in order to determine whether the first of the one or more transmissions includes random access response (RAR) information targeted for the UE device. ### Claim 6 (depends on 1) The method of claim 1, wherein the time duration is sufficiently large to include up to N transmissions of the downlink message, and wherein N is greater than one. ### Claim 7 (depends on 1) The method of claim 1, further comprising: transmitting, in response to successfully receiving the first of the one or more transmissions, an acknowledge message. ### Claim 8 (depends on 1) The method of claim 1, wherein the downlink message includes at least one grant of transmission resources and at least one contention resolution identity. ### Claim 9 An apparatus, comprising: at least one processor configured to cause a user equipment (UE) to: receive a configuration message from a base station, wherein the configuration message indicates a time duration of a window for monitoring a physical downlink control channel (PDCCH); and monitor the PDCCH for one or more transmissions of a downlink message, wherein the one or more transmissions of the downlink message are part of a two-step random access procedure; decode downlink control information, DCI, in a first of the one or more transmissions of the downlink message within the window using a message B (MSGB) Radio Network Temporary Identity (RNTI), wherein the MSGB-RNTI is based on location parameters of a physical uplink resource that was used by the UE to transmit a random access preamble of the two-step random access procedure; and determine, based on a field in the decoded DCI that resolves DCI transmissions relating to random access preamble transmissions in different radio frames using a same MSB-RNTI, whether to accept or reject the decoded DCI. ### Claim 10 (depends on 9) The apparatus of claim 9, wherein the field that resolves DCI transmissions relating to random access preamble transmissions in different radio frames using a same MSGB-RNTI indicates a time sub-window number. ### Claim 11 (depends on 10) The apparatus of claim 10, wherein the time sub-window number is associated with a time of the random access preamble transmission. ### Claim 12 (depends on 10) The apparatus of claim 10, wherein the time sub-window number resolves DCI transmissions relating to random access preamble transmissions in different radio frames using a same MSGB-RNTI. ### Claim 13 (depends on 9) The apparatus of claim 9, wherein the window for monitoring the PDCCH is larger than a sub-window. ### Claim 14 (depends on 9) The apparatus of claim 9, wherein, as part of the monitoring of the PDCCH, the at least one processor is further configured to cause the UE to: recover a transmission number from the first of the one or more transmissions; and compare the transmission number with a current window number of the UE device in order to determine whether the first of the one or more transmissions includes random access response (RAR) information targeted for the UE device. ### Claim 15 (depends on 9) The apparatus of claim 9, wherein the downlink message includes at least one grant of transmission resources and at least one contention resolution identity. ### Claim 16 (depends on 9) The apparatus of claim 9, further comprising: a radio operably coupled to the at least one processor. ### Claim 17 A non-transitory computer readable storage medium storing program instructions executable by one or more processors to cause a user equipment (UE) to: receive a configuration message from a base station, wherein the configuration message indicates a time duration of a window for monitoring a physical downlink control channel (PDCCH); monitor the PDCCH for one or more transmissions of a downlink message, wherein the one or more transmissions of the downlink message are part of a two-step random access procedure; decode downlink control information (DCI) in a first of the one or more transmissions of the downlink message within the window using a message B (MSGB) Radio Network Temporary Identity (RNTI), wherein the MSGB-RNTI is based on location parameters of a physical uplink resource that was used by a user equipment (UE) to transmit a random access preamble of the two-step random access procedure; and determine, based on a field in the decoded DCI indicating a time sub-window number, that the decoded DCI is intended for the UE. ### Claim 18 (depends on 17) The non-transitory computer readable storage medium of claim 17, wherein the time sub-window number is associated with a time of the random access preamble transmission. ### Claim 19 (depends on 17) The non-transitory computer readable storage medium of claim 17, wherein the time sub-window number resolves DCI transmissions relating to random access preamble transmissions in different radio frames using a same MSGB-RNTI. ### Claim 20 (depends on 17) The non-transitory computer readable storage medium of claim 17, wherein the window for monitoring the PDCCH is larger than a sub-window.