# US 2021/0243815 A1 · Multiple message types and procedure for selection of a message type for a random access message in a 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 2021/0243815 A1 - Document ID: US20210243815A1 - Status: Published application - Kind: A1 - Application number: 17/247,206 - Filed: 2020-12-03 - Published: 2021-08-05 - Earliest claimed: 2020-01-31 - Assignees: QUALCOMM Incorporated - Applicants: QUALCOMM Incorporated - Inventors: Mahmoud TAHERZADEH BOROUJENI; Tao LUO; Juan MONTOJO; Peter GAAL; Jelena DAMNJANOVIC; Yan ZHOU - Web page: https://patentgrep.com/patent/US20210243815A1 ## CPC - H04B 17/318: Received signal strength - H04L 1/0003: {by switching between different modulation schemes} - H04L 1/0007: {by modifying the frame length} - H04W 24/10: Scheduling measurement reports {; Arrangements for measurement reports} - H04W 56/001: {Synchronization between nodes} - H04W 74/002: {Transmission of channel access control information} - H04W 74/0836: with 2-step access - H04W 74/0833: Random access procedures, e.g. with 4-step access - H04B: TRANSMISSION - 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 Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment may determine a message type for a random access message associated with a two-step random access channel procedure. The message type may be either a first message type or a second message type that is different from the second message type. The message type may be determined based at least in part on whether a signal strength satisfies a signal strength threshold. The user equipment may transmit the random access message based at least in part on the determined message type. Numerous other aspects are provided. ## Claims ### Claim 1 A method of wireless communication performed by a user equipment (UE), comprising: determining a message type for a random access message associated with a two-step random access channel (RACH) procedure, wherein the message type is either a first message type or a second message type, the first message type being different from the second message type, and wherein the message type is determined based at least in part on whether a signal strength satisfies a signal strength threshold; and transmitting the random access message based at least in part on the determined message type. ### Claim 2 (depends on 1) The method of claim 1, wherein the message type is determined to be the first message type when the signal strength satisfies the signal strength threshold, and is determined to be the second message type when the signal strength does not satisfy the signal strength threshold. ### Claim 3 (depends on 1) The method of claim 1, wherein the first message type includes a message type of a first message in the two-step RACH procedure and the second message type includes a coverage enhanced message type of the first message in the two-step RACH procedure. ### Claim 4 (depends on 1) The method of claim 1, wherein the random access message is msgA. ### Claim 5 (depends on 1) The method of claim 1, further comprising receiving system information from the base station, wherein the signal strength threshold is identified in the system information received by the UE. ### Claim 6 (depends on 1) The method of claim 1, further comprising receiving the signal strength threshold in system information comprising remaining minimum system information. ### Claim 7 (depends on 1) The method of claim 1, wherein transmitting the random access message comprises transmitting with a physical random access channel (PRACH) format, wherein the PRACH format when the first message type is determined is different from the PRACH format when the second message type is determined. ### Claim 8 (depends on 1) The method of claim 1, wherein transmitting the random access message comprises applying physical uplink shared channel (PUSCH) repetition if the first message type is determined and not applying PUSCH repetition if the second message type is determined. ### Claim 9 (depends on 1) The method of claim 1, wherein transmitting the random access message comprises transmitting with a modulation and coding scheme (MCS), wherein the MCS when the first message type is determined is different from the MCS when the second message type is determined. ### Claim 10 (depends on 1) The method of claim 1, wherein transmitting the random access message comprises transmitting with a payload size, wherein the payload size when the first message type is determined is different from the payload size when the second message type is determined. ### Claim 11 (depends on 1) The method of claim 1, wherein transmitting the random access message comprises transmitting with a physical uplink shared channel (PUSCH) resource allocation, wherein the PUSCH resource allocation when the first message type is determined is different from the PUSCH resource allocation when the second message type is determined. ### Claim 12 (depends on 1) The method of claim 1, wherein transmitting the random access message comprises applying preamble repetition if the first message type is determined and not applying preamble repetition if the second message type is determined. ### Claim 13 (depends on 1) The method of claim 1, wherein transmitting the random access message comprises transmitting with a preamble length, wherein the preamble length when the first message type is determined is different from the preamble length when the second message type is determined. ### Claim 14 (depends on 1) The method of claim 1, wherein transmitting the random access message comprises transmitting using a preamble sequence, wherein the preamble sequence indicates whether physical uplink shared channel (PUSCH) repetition was applied when transmitting the random access message, the preamble sequence being one of a set of preamble sequences associated with indicating application of PUSCH repetition. ### Claim 15 (depends on 1) The method of claim 1, wherein transmitting the random access message comprises transmitting with a format of a preamble that indicates whether physical uplink shared channel repetition was applied when transmitting the random access message. ### Claim 16 (depends on 1) The method of claim 1, wherein transmitting the random access message comprises transmitting with a format of a preamble that indicates a modulation and coding scheme for a physical uplink shared channel included in the random access message. ### Claim 17 (depends on 1) The method of claim 1, further comprising determining whether the signal strength satisfies the signal strength threshold, wherein a resource allocation of a physical uplink shared channel (PUSCH) occasion and a selection of a PUSCH resource unit, relative to a RACH occasion, is based at least in part on the determination of whether the signal strength satisfies the signal strength threshold. ### Claim 18 (depends on 17) The method of claim 17, further comprising receiving system information that identifies information associated with the resource allocation of the PUSCH occasion and the selection of the PUSCH resource unit relative to the RACH occasion. ### Claim 19 (depends on 1) The method of claim 1, further comprising: receiving a synchronization signal block (SSB); and determining the signal strength based at least in part on a reference signal received power associated with the SSB. ### Claim 20 (depends on 1) The method of claim 1, further comprising: receiving configuration information associated with the second message type, the configuration information including information associated with at least one of: a physical random access channel (PRACH) format; application of physical uplink shared channel (PUSCH) repetition; a modulation and coding scheme; a payload size; a resource allocation for PUSCH; application of preamble repetition; or a preamble length. ### Claim 21 (depends on 20) The method of claim 20, further comprising receiving the configuration information in at least one of: a synchronization signal block; system information; a physical downlink control channel; or remaining minimum system information. ### Claim 22 (depends on 1) The method of claim 1, further comprising: determining, based at least in part on another signal strength threshold, that the two-step RACH procedure is to be used in association with accessing a wireless communication system. ### Claim 23 A method of wireless communication performed by a base station, comprising: receiving, from a user equipment (UE), a random access message associated with a two-step random access channel (RACH) procedure; determining, based at least in part on the random access message, a message type of the random access message, wherein the message type is either a first message type or a second message type, the first message type being different from the second message type; and processing the random access message based at least in part on determining the message type of the random access message. ### Claim 24 (depends on 23) The method of claim 23, wherein the first message type includes a message type of a first message in the two-step RACH procedure and the second message type includes a coverage enhanced message type of the first message in the two-step RACH procedure. ### Claim 25 (depends on 23) The method of claim 23, further comprising transmitting system information that identifies a signal strength threshold associated with determining to use the second message type. ### Claim 26 (depends on 23) The method of claim 23, wherein processing the random access message comprises at least one of: processing based on a physical random access channel (PRACH) format, wherein the PRACH format when the first message type is determined is different from the PRACH format when the second message type is determined; processing based on a determination of whether physical uplink shared channel (PUSCH) repetition is applied, wherein PUSCH repetition is determined not to be applied if the first message type is determined and PUSCH repetition is determined to be applied if the second message type is determined; processing based on a modulation and coding scheme (MCS), wherein the MCS when the first message type is determined is different from the MCS when the second message type is determined; processing based on a payload size, wherein the payload size when the first message type is determined is different from the payload size when the second message type is determined; processing based on a PUSCH resource allocation, wherein the PUSCH resource allocation when the first message type is determined is different from the PUSCH resource allocation when the second message type is determined; processing based on a determination of whether preamble repetition is applied, wherein preamble repetition is determined not to be applied if the first message type is determined and preamble repetition is determined to be applied if the second message type is determined; or processing based on a preamble length, wherein the preamble length when the first message type is determined is different from the preamble length when the second message type is determined. ### Claim 27 (depends on 23) The method of claim 23, wherein receiving the random access message comprises receiving an indication of whether physical uplink shared channel (PUSCH) repetition was applied when transmitting the random access message, wherein the indication is at least one of a preamble sequence included in the random access message or a format of a preamble of the random access message, the preamble sequence being one of a set of preamble sequences associated with indicating application of PUSCH repetition. ### Claim 28 (depends on 23) The method of claim 23, wherein receiving the random access message comprises receiving an indication of a modulation and coding scheme (MCS) for a physical uplink shard channel included in the random access message, wherein the indication is a format of a preamble of the random access message. ### Claim 29 A user equipment (UE) for wireless communication, comprising: a memory; and one or more processors operatively coupled to the memory, the memory and the one or more processors configured to: determine a message type for a random access message associated with a two-step random access channel (RACH) procedure, wherein the message type is either a first message type or a second message type, the first message type being different from the second message type, and wherein the message type is determined based at least in part on whether a signal strength satisfies a signal strength threshold; and transmit the random access message based at least in part on the determined message type. ### Claim 30 A base station for wireless communication, comprising: a memory; and one or more processors operatively coupled to the memory, the memory and the one or more processors configured to: receive, from a user equipment (UE), a random access message associated with a two-step random access channel (RACH) procedure; determine, based at least in part on the random access message, a message type of the random access message, wherein the message type is either a first message type or a second message type, the first message type being different from the second message type; and process the random access message based at least in part on determining the message type of the random access message.