Performing a two-step random access channel procedure
Apparatuses, methods, and systems are disclosed for performing a two-step random access channel procedure. One method includes determining whether to perform a two-step random access channel procedure or a four-step random access channel procedure. The method includes, in response to determining to perform the two-step random access channel procedure: in a first step: transmitting a preamble in a first time slot; and transmitting an uplink data transmission via a physical uplink shared channel in a second time slot different from the first time slot; and, in a second step, receiving a response message corresponding to the first step, wherein the response message comprises a radio network temporary identifier.
1. A user equipment (UE), comprising:
a processor; and
a memory coupled with the processor, the memory comprising instructions executable by the processor to cause the UE to:
receive, from a base station, a configuration indicating whether a two-step random access procedure and a four-step random access procedure are allowed to be performed by the UE;
determine whether one or more random access resources are configured for the two-step random access procedure and the four-step random access procedure based at least in part on the received configuration;
determine whether to perform the two-step random access procedure or the four-step random access procedure based on the received configuration and a reference signal received power (RSRP) associated with a pathloss reference satisfying a threshold;
select the two-step random access procedure based at least in part on the received configuration and the RSRP;
transmit a random access message associated with the selected two-step random access procedure, including a first transmission of a random access preamble associated with the random access message at a first time and a second transmission of a payload associated with the random access message at a second time offset from the first time, wherein the offset is based on a subcarrier spacing; and
receive a random access response message during a response window and based at least in part on the transmitted random access message, wherein the random access response message is associated with a radio network temporary identifier (RNTI).
2. The UE of claim 1 , wherein the instructions are further executable by the processor to cause the UE to:
measure the RSRP associated with the pathloss reference based at least in part on the determination,
wherein to select the two-step random access procedure based at least in part on the measured RSRP associated with the pathloss reference.
3. The UE of claim 2 , wherein, to transmit the random access message associated with the selected two-step random access procedure, the instructions are executable by the processor to cause the UE to:
transmit the payload associated with the random access message after the first transmission of the random access preamble associated with the random access message.
4. The UE of claim 3 , wherein the payload comprises a physical uplink shared channel (PUSCH) payload.
5. The UE of claim 4 , wherein the one or more random access resources correspond to one or more physical random access channel (PRACH) occasions, one or more PUSCH occasions, or a combination thereof.
6. The UE of claim 5 , wherein, to transmit the random access message associated with the selected two-step random access procedure, the instructions are executable by the processor to cause the UE to:
transmit the PUSCH payload during a PUSCH occasion and after the first transmission of the random access preamble during a PRACH occasion.
7. The UE of claim 1 , wherein the configuration is associated with a cell.
8. A method of wireless communication at a user equipment (UE), the method comprising:
receiving, from a base station, a configuration indicating whether a two-step random access procedure and a four-step random access procedure are allowed to be performed by the UE;
determining whether one or more random access resources are configured for the two-step random access procedure and the four-step random access procedure based at least in part on the received configuration;
determining whether to perform the two-step random access procedure or the four-step random access procedure based on the received configuration and a reference signal received power (RSRP) associated with a pathloss reference satisfying a threshold;
selecting the two-step random access procedure based at least in part on the received configuration and the RSRP;
transmitting a random access message associated with the selected two-step random access procedure, including a first transmission of a random access preamble associated with the random access message at a first time and a second transmission of a payload associated with the random access message at a second time offset from the first time, wherein the offset is based on a subcarrier spacing; and
receiving a random access response message during a response window and based at least in part on the transmitted random access message, wherein the random access response message is associated with a radio network temporary identifier (RNTI).
9. The method of claim 8 , further comprising:
measuring the RSRP associated with the pathloss reference based at least in part on the determining,
wherein selecting the two-step random access procedure based at least in part on the measured RSRP associated with the pathloss reference.
10. The method of claim 9 , wherein transmitting the random access message associated with the selected two-step random access procedure comprises:
transmitting the payload associated with the random access message after the first transmission of the random access preamble associated with the random access message.
11. The method of claim 10 , wherein the payload comprises a physical uplink shared channel (PUSCH) payload.
12. The method of claim 11 , wherein the one or more random access resources correspond to one or more physical random access channel (PRACH) occasions, one or more PUSCH occasions, or a combination thereof.
13. The method of claim 12 , wherein transmitting the random access message associated with the selected two-step random access procedure comprises:
transmitting the PUSCH payload during a PUSCH occasion and after the first transmission of the random access preamble during a PRACH occasion.
14. A base station, comprising:
a processor; and
a memory coupled with the processor, the memory comprising instructions executable by the processor to cause the base station to:
transmit, to a user equipment (UE), a configuration indicating whether a two-step random access procedure and a four-step random access procedure are allowed, wherein the two-step random access procedure or the four-step random access procedure is performed in accordance with the configuration and a reference signal received power RSRP associated with a pathloss reference satisfying a threshold;
receive a random access message associated with the two-step random access procedure, including a first transmission of a random access preamble associated with the random access message at a first time and a second transmission of a payload associated with the random access message at a second time offset from the first time, wherein the offset is based on a subcarrier spacing, wherein the second transmission of the payload associated with the random access message is received after reception of the first transmission of the random access preamble associated with the random access message; and
transmit a random access response message during a response window and based at least in part on the received random access message, wherein the random access response message is associated with a radio network temporary identifier (RNTI).
15. The base station of claim 14 , wherein the payload comprises a physical uplink shared channel (PUSCH) payload.
16. The base station of claim 15 , wherein one or more resources configured for the two-step random access procedure correspond to one or more physical random access channel (PRACH) occasions, one or more PUSCH occasions, or a combination thereof.
17. The base station of claim 16 , wherein, to receive the random access message associated with the two-step random access procedure, the instructions are executable by the processor to cause the base station to:
receive the PUSCH payload during a PUSCH occasion and after reception of the first transmission of the random access preamble during a PRACH occasion.
18. The base station of claim 14 , wherein the configuration is associated with a cell.
19. A method performed by a base station, the method comprising:
transmitting, to a user equipment (UE), a configuration indicating whether a two-step random access procedure and a four-step random access procedure are allowed, wherein the two-step random access procedure or the four-step random access procedure is performed in accordance with the configuration and a reference signal received power RSRP associated with a pathloss reference satisfying a threshold;
receiving a random access message associated with the two-step random access procedure, including a first transmission of a random access preamble associated with the random access message at a first time and a second transmission of a payload associated with the random access message at a second time offset from the first time, wherein the offset is based on a subcarrier spacing, wherein the second transmission of the payload associated with the random access message is received after reception of the first transmission of the random access preamble associated with the random access message; and
transmitting a random access response message during a response window and based at least in part on the received random access message, wherein the random access response message is associated with a radio network temporary identifier (RNTI).