Random access channel procedure type selection
Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may receive, from a base station, one or more downlink reference signals. The UE may transmit, to the base station, a random access channel (RACH) message associated with a RACH procedure using a first RACH configuration that is associated with repetitions or a second RACH configuration that is not associated with repetitions based at least in part on whether a measurement of the one or more downlink reference signals satisfies a measurement threshold, wherein a selection of a RACH configuration is evaluated by the UE prior to a transmission of an initial message associated with the RACH procedure. Numerous other aspects are described.
1. A method of wireless communication performed by a user equipment (UE), comprising:
receiving one or more downlink reference signals; and
transmitting a random access channel (RACH) message associated with a RACH procedure using a first RACH configuration or a second RACH configuration based at least in part on whether a measurement of the one or more downlink reference signals satisfies a measurement threshold,
wherein the first RACH configuration is associated with repetitions during the RACH procedure and the second RACH configuration is not associated with repetitions during the RACH procedure, and
wherein a selection of a RACH configuration, of the first RACH configuration or the second RACH configuration, is evaluated by the UE prior to a transmission of an initial message associated with the RACH procedure.
2. The method of claim 1 , wherein the selection of a RACH configuration, of the first RACH configuration or the second RACH configuration, is evaluated by the UE prior to each retransmission of the initial message or based at least in part on a quantity of transmissions of the initial message satisfying another threshold.
3. The method of claim 1 , further comprising:
receiving RACH configuration information indicating the first RACH configuration and the second RACH configuration.
4. The method of claim 1 , further comprising:
performing the RACH procedure using the first RACH configuration or the second RACH configuration based at least in part on the measurement of the one or more downlink reference signals, wherein performing the RACH procedure includes transmitting the RACH message.
5. The method of claim 1 , wherein transmitting the RACH message comprises:
transmitting the RACH message using the first RACH configuration based at least in part on the measurement not satisfying the measurement threshold; or
transmitting the RACH message using the second RACH configuration based at least in part on the measurement satisfying the measurement threshold.
6. The method of claim 1 , wherein the RACH configuration, of the first RACH configuration and the second RACH configuration, used to transmit the RACH message is used for the RACH procedure until a completion criterion is detected.
7. The method of claim 1 , wherein the measurement is evaluated by the UE prior to transmitting the initial message associated with the RACH procedure and prior to each retransmission of the initial message to select a RACH configuration to be associated with an iteration of the RACH procedure.
8. The method of claim 1 , wherein transmitting the RACH message comprises:
transmitting the RACH message using the second RACH configuration based at least in part on the measurement satisfying the measurement threshold.
9. The method of claim 8 , wherein an iteration of the RACH procedure associated with the second RACH configuration is not successfully completed, the method further comprising:
measuring the one or more downlink reference signals to obtain another measurement; and
transmitting a retransmission of the initial message associated with the RACH procedure using the first RACH configuration or the second RACH configuration based at least in part on whether the other measurement satisfies the measurement threshold.
10. The method of claim 9 , wherein the retransmission of the initial message uses the first RACH configuration, and wherein the first RACH configuration is used by the UE until a completion criterion is detected.
11. The method of claim 8 , wherein the RACH procedure is performed for a quantity of iterations using the second RACH configuration without being successfully completed, the method further comprising:
transmitting a retransmission of the initial message associated with the RACH procedure using the first RACH configuration based at least in part on the quantity of iterations satisfying another threshold.
12. The method of claim 8 , wherein the RACH procedure is performed for a quantity of iterations using the second RACH configuration without being successfully completed, the method further comprising:
measuring the one or more downlink reference signals to obtain another measurement based at least in part on the quantity of iterations satisfying another threshold; and
transmitting a retransmission of the initial message associated with the RACH procedure using the first RACH configuration or the second RACH configuration based at least in part on whether the other measurement satisfies the measurement threshold.
13. A method of wireless communication performed by a network entity, comprising:
transmitting one or more downlink reference signals intended for a user equipment (UE); and
receiving a random access channel (RACH) message associated with a RACH procedure from the UE using a first RACH configuration or a second RACH configuration based at least in part on whether a measurement of the one or more downlink reference signals satisfies a measurement threshold, wherein the first RACH configuration is associated with repetitions during the RACH procedure and the second RACH configuration is not associated with repetitions during the RACH procedure, and
wherein receiving the RACH message comprises:
receiving the RACH message using the first RACH configuration based at least in part on the measurement not satisfying the measurement threshold; or
receiving the RACH message using the second RACH configuration based at least in part on the measurement satisfying the measurement threshold.
14. The method of claim 13 , further comprising:
transmitting RACH configuration information intended for the UE indicating the first RACH configuration and the second RACH configuration.
15. The method of claim 13 , wherein the measurement is evaluated by the UE prior to a transmission of an initial message associated with the RACH procedure.
16. A user equipment (UE) for wireless communication, comprising:
one or more memories; and
one or more processors, coupled to the one or more memories, configured to:
receive one or more downlink reference signals; and
transmit a random access channel (RACH) message associated with a RACH procedure using a first RACH configuration or a second RACH configuration based at least in part on whether a measurement of the one or more downlink reference signals satisfies a measurement threshold, wherein the first RACH configuration is associated with repetitions during the RACH procedure and the second RACH configuration is not associated with repetitions during the RACH procedure, and wherein a selection of a RACH configuration, of the first RACH configuration or the second RACH configuration, is evaluated by the UE prior to a transmission of an initial message associated with the RACH procedure.
17. The UE of claim 16 , wherein the one or more processors are further configured to:
receive RACH configuration information indicating the first RACH configuration and the second RACH configuration.
18. The UE of claim 16 , wherein the one or more processors are further configured to:
perform the RACH procedure using the first RACH configuration or the second RACH configuration based at least in part on the measurement of the one or more downlink reference signals, wherein performing the RACH procedure includes transmitting the RACH message.
19. The UE of claim 16 , wherein the one or more processors, to transmit the RACH message, are configured to:
transmit the RACH message using the first RACH configuration based at least in part on the measurement not satisfying the measurement threshold; or
transmit the RACH message using the second RACH configuration based at least in part on the measurement satisfying the measurement threshold.
20. The UE of claim 16 , wherein the measurement is evaluated by the UE prior to transmitting the initial message associated with the RACH procedure and prior to each retransmission of the initial message to select a RACH configuration to be associated with an iteration of the RACH procedure.
21. The UE of claim 16 , wherein the one or more processors, to transmit the RACH message, are configured to:
transmit the RACH message using the first RACH configuration based at least in part on the measurement not satisfying the measurement threshold, wherein the first RACH configuration is used by the UE until a completion criterion is detected.
22. The UE of claim 16 , wherein the one or more processors, to transmit the RACH message, are configured to:
transmit the RACH message using the second RACH configuration based at least in part on the measurement satisfying the measurement threshold.
23. The UE of claim 22 , wherein an iteration of the RACH procedure associated with the second RACH configuration is not successfully completed, and wherein the one or more processors are further configured to:
measure the one or more downlink reference signals to obtain another measurement; and
transmit a retransmission of the initial message associated with the RACH procedure using the first RACH configuration or the second RACH configuration based at least in part on whether the other measurement satisfies the measurement threshold.
24. The UE of claim 23 , wherein the retransmission of the initial message uses the first RACH configuration, and wherein the first RACH configuration is used by the UE until a completion criterion is detected.
25. The UE of claim 22 , wherein the RACH procedure is performed for a quantity of iterations using the second RACH configuration without being successfully completed, and wherein the one or more processors are further configured to:
measure the one or more downlink reference signals to obtain another measurement based at least in part on the quantity of iterations satisfying another threshold; and
transmit a retransmission of the initial message associated with the RACH procedure using the first RACH configuration or the second RACH configuration based at least in part on whether the other measurement satisfies the measurement threshold.
26. The UE of claim 16 , wherein the first RACH configuration is associated with repetitions of a message 3 (msg3) of the RACH procedure during each iteration of the RACH procedure.
27. A network entity for wireless communication, comprising:
one or more memories; and
one or more processors, coupled to the one or more memories, configured to:
transmit, to a user equipment (UE), one or more downlink reference signals; and
receive, from the UE, a random access channel (RACH) message associated with a RACH procedure using a first RACH configuration or a second RACH configuration based at least in part on a measurement threshold configured by the network entity, wherein the first RACH configuration is associated with repetitions during the RACH procedure and the second RACH configuration is not associated with repetitions during the RACH procedure.
28. The network entity of claim 27 , wherein the one or more processors are further configured to:
perform the RACH procedure using the first RACH configuration or the second RACH configuration based at least in part on a measurement of the one or more downlink reference signals, wherein performing the RACH procedure includes receiving the RACH message.
29. The network entity of claim 27 , wherein a measurement of the one or more downlink reference signals is evaluated by the UE prior to a transmission of an initial message associated with the RACH procedure, and wherein the one or more processors, to receive the RACH message, are configured to:
receive the RACH message using the first RACH configuration based at least in part on the measurement not satisfying the measurement threshold; or
receive the RACH message using the second RACH configuration based at least in part on the measurement satisfying the measurement threshold.
30. The network entity of claim 27 , wherein a RACH configuration, of the first RACH configuration and the second RACH configuration, used to receive the RACH message is used for the RACH procedure until the RACH procedure is completed.