Phase tracking reference signal transmission in a radio resource control connection request message
Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may receive, from a network node and prior to transmission of a radio resource control (RRC) connection request message, a phase tracking reference signal (PTRS) indication that indicates a presence of a PTRS. The UE may transmit the RRC connection request message comprising the PTRS based at least in part on the PTRS indication. Numerous other aspects are described.
1. A method of wireless communication performed by a user equipment (UE), comprising:
receiving, from a network node and prior to transmission of a radio resource control (RRC) connection request message, a phase tracking reference signal (PTRS) indication that indicates a presence of a PTRS; and
transmitting the RRC connection request message comprising the PTRS based at least in part on the PTRS indication.
2. The method of claim 1 , wherein receiving the PTRS indication comprises receiving a random access response (RAR) that includes the PTRS indication.
3. The method of claim 2 , wherein receiving the PTRS indication comprises interpreting a bitfield of the RAR to identify the PTRS indication.
4. The method of claim 1 , wherein receiving the PTRS indication comprises receiving a physical downlink control channel (PDCCH) transmission that includes the PTRS indication, wherein the PDCCH transmission schedules a random access response.
5. The method of claim 4 , wherein receiving the PTRS indication comprises interpreting a bitfield of a downlink control information transmission corresponding to the PDCCH to identify the PTRS indication.
6. The method of claim 1 , wherein receiving the PTRS indication comprises receiving a physical downlink control channel (PDCCH) that includes the PTRS indication, wherein the PDCCH schedules a retransmission of the RRC connection request message.
7. The method of claim 6 , wherein receiving the PTRS indication comprises interpreting a bitfield of a downlink control information transmission corresponding to the PDCCH to identify the PTRS indication.
8. The method of claim 1 , wherein receiving the PTRS indication comprises receiving an indication of an RRC connection request message repetition.
9. The method of claim 1 , wherein receiving the PTRS indication comprises receiving an indication of a number of repetitions of the RRC connection request message.
10. The method of claim 1 , wherein receiving the PTRS indication comprises determining that an indicating condition is satisfied.
11. The method of claim 10 , wherein determining that the indicating condition is satisfied comprises determining that a consecutive pair of RRC connection request message repetitions include a first repetition associated with a first uplink slot and a second repetition associated with a second uplink slot, wherein at least one third uplink slot is disposed between the first uplink slot and the second uplink slot.
12. The method of claim 1 , further comprising receiving a PTRS indication configuration that indicates one or more rules for implicit indication of the presence of the PTRS.
13. The method of claim 12 , wherein receiving the PTRS indication configuration comprises receiving remaining minimum system information (RMSI).
14. The method of claim 13 , wherein receiving the RMSI comprises receiving a system information block (SIB) that indicates the RMSI.
15. The method of claim 1 , further comprising obtaining a PTRS repetition configuration that indicates at least one parameter associated with transmitting a plurality of repetitions of the PTRS.
16. The method of claim 15 , wherein the at least one parameter indicates at least one of a transmission time or a repetition frequency density.
17. The method of claim 15 , wherein obtaining the PTRS repetition configuration comprises receiving system information that indicates the PTRS repetition configuration.
18. The method of claim 15 , wherein the PTRS repetition configuration is indicated by a wireless communication standard.
19. The method of claim 15 , wherein the at least one parameter associated with transmitting the plurality of repetitions of the PTRS is based at least in part on at least one parameter associated with transmission of the RRC connection request message.
20. The method of claim 19 , wherein the at least one parameter associated with transmission of the RRC connection request message indicates at least one of:
a number of repetitions of the RRC connection request message,
a modulation and coding scheme, or
a bandwidth.
21. A method of wireless communication performed by a network node, comprising:
transmitting, to a user equipment (UE) and prior to transmission of a radio resource control (RRC) connection request message, a phase tracking reference signal (PTRS) indication that indicates a presence of a PTRS; and
receiving the RRC connection request message comprising the PTRS based at least in part on the PTRS indication.
22. The method of claim 21 , wherein transmitting the PTRS indication comprises transmitting a random access response (RAR) that includes the PTRS indication, and wherein the PTRS indication is based at least in part on an interpretation of a bitfield of the RAR.
23. The method of claim 21 , wherein transmitting the PTRS indication comprises transmitting a physical downlink control channel (PDCCH) transmission that includes the PTRS indication, wherein the PDCCH transmission schedules a random access response, and wherein the PTRS indication is based at least in part on an interpretation of a bitfield of a downlink control information transmission corresponding to the PDCCH.
24. The method of claim 21 , wherein transmitting the PTRS indication comprises transmitting a physical downlink control channel (PDCCH) that includes the PTRS indication, wherein the PDCCH schedules a retransmission of the RRC connection request message, and wherein the PTRS indication is based at least in part on an interpretation of a bitfield of a downlink control information transmission corresponding to the PDCCH.
25. The method of claim 21 , wherein transmitting the PTRS indication comprises transmitting an indication of an RRC connection request message repetition.
26. The method of claim 21 , wherein transmitting the PTRS indication comprises transmitting an indication of a number of repetitions of the RRC connection request message.
27. The method of claim 21 , wherein the PTRS indication is based at least in part on a determination that an indicating condition is satisfied, wherein the determination that the indicating condition is satisfied is based at least in part on a determination that a consecutive pair of RRC connection request message repetitions include a first repetition associated with a first uplink slot and a second repetition associated with a second uplink slot, and wherein at least one third uplink slot is disposed between the first uplink slot and the second uplink slot.
28. The method of claim 21 , wherein a PTRS repetition configuration indicates at least one parameter associated with transmitting a plurality of repetitions of the PTRS, and wherein the at least one parameter indicates at least one of a transmission time or a repetition frequency density.
29. 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 cause the UE to:
receive, from a network node and prior to transmission of a radio resource control (RRC) connection request message, a phase tracking reference signal (PTRS) indication that indicates a presence of a PTRS; and
transmit the RRC connection request message comprising the PTRS based at least in part on the PTRS indication.
30. A network node for wireless communication, comprising:
one or more memories; and
one or more processors, coupled to the one or more memories, configured to cause the network node to:
transmit, to a user equipment (UE) and prior to transmission of a radio resource control (RRC) connection request message, a phase tracking reference signal (PTRS) indication that indicates a presence of a PTRS; and
receive the RRC connection request message comprising the PTRS based at least in part on the PTRS indication.