# US 12,120,748 B2 · Two-step random access channel configuration > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,120,748 B2 - Document ID: US12120748B2 - Status: Granted - Kind: B2 - Application number: 17/608,650 - Filed: 2020-05-14 - Published: 2022-07-28 - Granted: 2024-10-15 - Earliest claimed: 2019-05-15 - Assignees: QUALCOMM Incorporated - Applicants: Qualcomm Incorporated - Inventors: Yiqing Cao; Jing Lei; Ruiming Zheng - Web page: https://patentgrep.com/patent/US12120748B2 ## CPC - H04L 5/0048: {Allocation of pilot signals, i.e. of signals known to the receiver (allocation of control signalling H04L5/0053; use of control signalling H04L5/0091)} - H04L 5/0051: {of dedicated pilots, i.e. pilots destined for a single user or terminal} - H04L 5/0007: {the frequencies being orthogonal, e.g. OFDM(A) or DMT} - H04W 74/004: {in the uplink, i.e. towards network} - H04W 74/006: {in the downlink, i.e. towards the terminal} - H04W 74/0836: with 2-step access - 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 Methods, systems, and devices for wireless communications are described. A wireless device may receive a configuration for a first random access message of a two-step random access channel procedure. The wireless device may select a subcarrier spacing and a number of demodulation reference signal occurrences for transmitting the first random access message based at least in part on the configuration and a speed of the wireless device. The wireless device may transmit the first random access message of the two-step random access channel procedure using the subcarrier spacing and the number of demodulation reference signal occurrences. ## Claims ### Claim 1 A method for wireless communications at a wireless device, comprising: receiving a configuration for a first random access message of a two-step random access channel procedure; selecting a subcarrier spacing and a number of demodulation reference signal occurrences for transmitting the first random access message based at least in part on the configuration and a speed of the wireless device; and transmitting the first random access message of the two-step random access channel procedure using the subcarrier spacing and the number of demodulation reference signal occurrences. ### Claim 2 (depends on 1) The method of claim 1, wherein the configuration comprises a set of combinations for the subcarrier spacing and the number of demodulation reference signal occurrences. ### Claim 3 (depends on 2) The method of claim 2, wherein the selecting comprises: selecting a configuration identification corresponding to a combination of the set of combinations for the subcarrier spacing and the number of demodulation reference signal occurrences. ### Claim 4 (depends on 1) The method of claim 1, wherein the configuration comprises a first parameter for the subcarrier spacing and a second parameter for the number of demodulation reference signal occurrences. ### Claim 5 (depends on 4) The method of claim 4, wherein the selecting comprises: independently selecting the subcarrier spacing based at least in part on the first parameter and the number of demodulation reference signal occurrences based at least in part on the second parameter. ### Claim 6 (depends on 1) The method of claim 1, further comprising: selecting the subcarrier spacing and the number of demodulation reference signal occurrences based at least in part on the speed of the wireless device exceeding a threshold. ### Claim 7 (depends on 1) The method of claim 1, further comprising: transmitting an indication of the selected subcarrier spacing and the number of demodulation reference signal occurrences. ### Claim 8 (depends on 7) The method of claim 7, wherein the indication is included in a physical uplink shared channel (PUSCH) of the first random access message, in uplink control information on a physical uplink control channel, or both. ### Claim 9 (depends on 7) The method of claim 7, wherein the indication comprises a first parameter for the selected subcarrier spacing and a second parameter for the number of demodulation reference signal occurrences. ### Claim 10 (depends on 7) The method of claim 7, wherein the indication comprises a configuration identification to indicate the subcarrier spacing and the number of demodulation reference signal occurrences. ### Claim 11 (depends on 7) The method of claim 7, wherein the indication comprises sequences, frequency position information, or both, for demodulation reference signals corresponding to the number of demodulation reference signal occurrences. ### Claim 12 (depends on 1) The method of claim 1, wherein the configuration is received in a system information message. ### Claim 13 (depends on 12) The method of claim 12, further comprising: transmitting a request for the system information message, wherein the system information message is received based at least in part on the request. ### Claim 14 (depends on 1) The method of claim 1, further comprising: determining the speed of the wireless device is below a threshold; and registering to another cell based at least in part on the determining. ### Claim 15 (depends on 1) The method of claim 1, wherein the number of demodulation reference signal occurrences comprises occurrences for a front loaded demodulation reference signal and at least one additional demodulation reference signal. ### Claim 16 (depends on 15) The method of claim 15, wherein the at least one additional demodulation reference signal uses a same sequence, frequency location, or both, as the front loaded demodulation reference signal or a different sequence, frequency location, or both, than the front loaded demodulation reference signal. ### Claim 17 (depends on 1) The method of claim 1, wherein the wireless device is a user equipment (UE) or a relay node. ### Claim 18 A method for wireless communications, comprising: transmitting, to a first wireless device, a configuration for a first random access message of a two-step random access channel procedure; and receiving the first random access message of the two-step random access channel procedure using a subcarrier spacing and a number of demodulation reference signal occurrences, wherein the subcarrier spacing and the number of demodulation reference signal occurrences are based at least in part on the configuration and a speed of the first wireless device. ### Claim 19 (depends on 18) The method of claim 18, wherein the configuration comprises a set of combinations for the subcarrier spacing and the number of demodulation reference signal occurrences. ### Claim 20 (depends on 18) The method of claim 18, wherein the configuration comprises a first parameter for the subcarrier spacing and a second parameter for the number of demodulation reference signal occurrences. ### Claim 21 (depends on 18) The method of claim 18, wherein the subcarrier spacing and the number of demodulation reference signal occurrences are based at least in part on the speed of the first wireless device exceeding a threshold. ### Claim 22 (depends on 18) The method of claim 18, further comprising: receiving an indication of the selected subcarrier spacing and the number of demodulation reference signal occurrences. ### Claim 23 (depends on 22) The method of claim 22, wherein the indication is received in a physical uplink shared channel (PUSCH) of the first random access message, in uplink control information on a physical uplink control channel, or both. ### Claim 24 (depends on 22) The method of claim 22, wherein the indication comprises a first parameter for the selected subcarrier spacing and a second parameter for the number of demodulation reference signal occurrences. ### Claim 25 (depends on 22) The method of claim 22, wherein the indication comprises a configuration identification indicating the subcarrier spacing and the number of demodulation reference signal occurrences. ### Claim 26 (depends on 22) The method of claim 22, wherein the indication comprises sequences, frequency position information, or both, for demodulation reference signals corresponding to the number of demodulation reference signal occurrences. ### Claim 27 (depends on 18) The method of claim 18, wherein the configuration is transmitted in a system information message. ### Claim 28 (depends on 18) The method of claim 18, wherein the first wireless device is a user equipment (UE) or a relay node. ### Claim 29 An apparatus for wireless communications at a wireless device, comprising: a processor, memory in electronic communication with the processor; and instructions stored in the memory and executable by the processor to cause the apparatus to: receive a configuration for a first random access message of a two-step random access channel procedure; select a subcarrier spacing and a number of demodulation reference signal occurrences for transmitting the first random access message based at least in part on the configuration and a speed of the wireless device; and transmit the first random access message of the two-step random access channel procedure using the subcarrier spacing and the number of demodulation reference signal occurrences. ### Claim 30 An apparatus for wireless communications, comprising: a processor, memory in electronic communication with the processor; and instructions stored in the memory and executable by the processor to cause the apparatus to: transmit, to a first wireless device, a configuration for a first random access message of a two-step random access channel procedure; and receive the first random access message of the two-step random access channel procedure using a subcarrier spacing and a number of demodulation reference signal occurrences, wherein the subcarrier spacing and the number of demodulation reference signal occurrences are based at least in part on the configuration and a speed of the first wireless device.