Reference signal resource configuration
Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may transmit, using a random access channel transmission and when operating in an idle mode or inactive mode, a request for information identifying a reference signal configuration; and selectively receive, as a response to the request and based at least in part on a mode of the UE, the information identifying the reference signal configuration for reception of a reference signal, wherein the reference signal is a channel state information reference signal or a tracking reference signal. Numerous other aspects are provided.
1. A method of wireless communication performed by a user equipment (UE), comprising:
transmitting, using a random access channel transmission and when operating in an idle mode or an inactive mode, a request for information identifying a reference signal configuration;
selectively receiving, as a response to the request and based at least in part on a mode of the UE, the information identifying the reference signal configuration for reception of a reference signal, wherein the reference signal is a channel state information reference signal or a tracking reference signal;
receiving, when operating in the idle mode or the inactive mode, the reference signal based at least in part on receiving the information identifying the reference signal configuration; and
monitoring, when operating in the idle mode or the inactive mode, for a paging message in a paging occasion based at least in part on receiving the information identifying the reference signal configuration.
2. The method of claim 1 , wherein transmitting the request comprises:
transmitting the request using a configured set of random access channel resources.
3. The method of claim 2 , wherein the configured set of random access channel resources is a dedicated set of random access channel resources for requesting the information identifying the reference signal configuration.
4. The method of claim 2 , wherein the configured set of random access channel resources includes at least one of:
a configured time resource for a random access channel occasion,
a configured frequency resource for the random access channel occasion, or
a random access channel preamble sequence for the random access channel transmission.
5. The method of claim 1 , wherein transmitting the request for information identifying a reference signal configuration comprises:
transmitting the request using a message-3 transmission associated with a random access procedure.
6. The method of claim 1 , wherein the random access channel transmission does not trigger a radio resource control resume or connection re-establishment procedure.
7. The method of claim 1 , wherein the random access channel transmission comprises a reference signal transmission request.
8. A method of wireless communication performed by a user equipment (UE), comprising:
transmitting, when operating in a connected mode, a request for information identifying a reference signal configuration;
selectively receiving, as a response to the request, the information identifying the reference signal configuration for reception of a reference signal, wherein the reference signal is a channel state information reference signal or a tracking reference signal;
receiving, when operating in an idle mode or an inactive mode, the reference signal based at least in part on receiving the information identifying the reference signal configuration; and
monitoring, when operating in the idle mode or the inactive mode, for a paging message in a paging occasion based at least in part on receiving the information identifying the reference signal configuration.
9. The method of claim 8 , wherein transmitting the request comprises:
transmitting the request using at least one of:
a radio resource control message,
a medium access control control element,
an uplink control information message,
a tracking area update message, or
a radio access network based notification area update message.
10. The method of claim 8 , further comprising:
transitioning from the idle mode or the inactive mode to the connected mode to perform a tracking area update or a radio access network based notification area update; and
wherein transmitting the request comprises:
transmitting the request based at least in part on transitioning from the idle mode or the inactive mode to the connected mode.
11. The method of claim 8 , further comprising:
determining to transmit the request;
transitioning from the idle mode or the inactive mode to the connected mode based at least in part on determining to transmit the request; and
wherein transmitting the request comprises:
transmitting the request based at least in part on transitioning from the idle mode or the inactive mode to the connected mode.
12. A method of wireless communication performed by a base station (BS), comprising:
receiving, from a user equipment (UE), a request for information identifying a reference signal configuration;
selectively transmitting, as a response to the request and to the UE, the information identifying the reference signal configuration for reception of a reference signal, wherein the reference signal is a channel state information reference signal or a tracking reference signal;
transmitting, when the UE is in an idle mode or an inactive mode, the reference signal based at least in part on transmitting the information identifying the reference signal configuration; and
transmitting, when the UE is in the idle mode or the inactive mode, a paging message in a paging occasion based at least in part on transmitting the information identifying the reference signal configuration.
13. The method of claim 12 , wherein the request is received when the UE is in the idle mode or the inactive mode, and
wherein the request is conveyed via a random access channel transmission.
14. The method of claim 12 , wherein the request is received when the UE is in a connected mode, and
wherein the request is conveyed via at least one of:
a radio resource control message,
a medium access control control element,
an uplink control information message,
a tracking area update message, or
a radio access network based notification area update message.
15. The method of claim 12 , further comprising:
determining a set of resources for the reference signal configuration; and
wherein selectively transmitting the information identifying the reference signal configuration comprises:
transmitting the information identifying the reference signal configuration based at least in part on determining the set of resources for the reference signal configuration.
16. The method of claim 15 , wherein the set of resources are a configured set of resources for connected mode UEs; and
wherein transmitting the information identifying the reference signal configuration comprises:
transmitting, to an idle mode or inactive mode UE, an indicator of the configured set of resources for the connected mode UEs.
17. The method of claim 15 , further comprising:
determining that a configured set of resources is unavailable; and
wherein transmitting the information identifying the reference signal configuration comprises:
transmitting, to an idle mode or inactive mode UE, an indicator of a new set of resources based at least in part on determining that the configured set of resources is unavailable.
18. A user equipment (UE) for wireless communication, comprising:
a memory; and
one or more processors coupled to the memory, the one or more processors configured to:
transmit, using a random access channel transmission and when operating in an idle mode or inactive mode, a request for information identifying a reference signal configuration;
selectively receive, as a response to the request and based at least in part on a mode of the UE, the information identifying the reference signal configuration for reception of a reference signal, wherein the reference signal is a channel state information reference signal or a tracking reference signal;
receive, when operating in the idle mode or the inactive mode, the reference signal based at least in part on receiving the information identifying the reference signal configuration; and
monitor, when operating in the idle mode or the inactive mode, for a paging message in a paging occasion based at least in part on receiving the information identifying the reference signal configuration.
19. The UE of claim 18 , wherein the one or more processors, when transmitting the request, are configured to:
transmit the request using a configured set of random access channel resources.
20. The UE of claim 19 , wherein the configured set of random access channel resources is a dedicated set of random access channel resources for requesting the information identifying the reference signal configuration.
21. The UE of claim 19 , wherein the configured set of random access channel resources includes at least one of:
a configured time resource for a random access channel occasion,
a configured frequency resource for the random access channel occasion, or
a random access channel preamble sequence for the random access channel transmission.
22. The UE of claim 18 , wherein the one or more processors, when transmitting the request for information identifying a reference signal configuration, are configured to:
transmit the request using a message-3 transmission associated with a random access procedure.
23. The UE of claim 18 , wherein the random access channel transmission does not trigger a radio resource control resume or connection re-establishment procedure.
24. The UE of claim 18 , wherein the random access channel transmission comprises a reference signal transmission request.