Pre-compensation and quasi co-location for downlink multiple transmission reception point operation
Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a network entity may cause a first transmission reception point (TRP) to transmit a first communication using a first time value derived from a first transmission configuration indicator (TCI) state including a set of first quasi co-location (QCL) parameters of the first TRP. The network entity may cause a second TRP to transmit a second communication using a timing pre-compensation value relative to the first time value. Numerous other aspects are described.
1 . A method of wireless communication performed by a network entity, comprising:
causing a first transmission reception point (TRP) to transmit a first communication using a first time value derived from a first transmission configuration indicator (TCI) state including a set of first quasi co-location (QCL) parameters of the first TRP;
causing a second TRP to transmit a synchronization signal block;
causing the second TRP to transmit a tracking or radio resource management (RRM) measurement reference signal using a timing pre-compensation value relative to the first time value; and
causing a second TRP to transmit a second communication using the timing pre-compensation value; and a frequency pre-compensation value relative to a first frequency offset value derived from the first TCI state.
2 . The method of claim 1 , wherein causing the second TRP to transmit the second communication further comprises causing the second TRP to transmit the second communication using the first time value and not a second time value derived from a second TCI state including one or more second QCL parameters of the second TRP.
3 . The method of claim 1 , wherein causing the second TRP to transmit the second communication further comprises causing the second TRP to transmit the second communication using a second time value derived from a second TCI state including one or more second QCL parameters of the second TRP and the timing pre-compensation value relative to the first time value.
4 . The method of claim 1 , wherein the first time value comprises an average delay derived from the first set of QCL parameters of the first TRP.
5 . The method of claim 1 , wherein causing the first TRP to transmit the first communication further comprises causing the first TRP to transmit the first communication using the first frequency offset value.
6 . The method of claim 5 , wherein the first frequency offset value comprises a Doppler shift and a Doppler spread derived from the first set of QCL parameters of the first TRP.
7 . The method of claim 1 , wherein the timing pre-compensation value shifts a transmission time of the second communication to within a maximum timing difference of a transmission time of the first communication.
8 . The method of claim 7 , wherein the maximum timing difference is, at most, a length of a cyclic prefix of the first communication or the second communication.
9 . The method of claim 1 , further comprising:
receiving information indicating at least one of the first time value or a difference between the first time value and a second time value of the second TRP; and
identifying the timing pre-compensation value based at least in part on the first time value or the difference.
10 . The method of claim 9 , wherein the information indicating the at least one of the first time value or the difference is based at least in part on a first physical random access channel (PRACH) transmission associated with the first TRP and a second PRACH transmission associated with the second TRP.
11 . The method of claim 9 , wherein the difference comprises a reference signal timing difference derived from a downlink reference signal.
12 . The method of claim 1 , wherein the timing pre-compensation value is based at least in part on a location of a user equipment.
13 . The method of claim 1 , further comprising causing the second TRP to transmit a reference signal using the timing pre-compensation value.
14 . The method of claim 1 , wherein the first communication and the second communication correspond to respective layers of a multi-layer transmission.
15 . The method of claim 1 , wherein the first communication and the second communication use a single-frequency network configuration.
16 . The method of claim 1 , further comprising causing the second TRP to transmit a synchronization signal block or a tracking or radio resource management (RRM) measurement reference signal, wherein the timing pre-compensation value is not applied for the synchronization signal block or the tracking or RRM measurement reference signal.
17 . The method of claim 1 , further comprising:
causing the second TRP to transmit, using the timing pre-compensation value and a frequency pre-compensation value, at least one of a, a demodulation reference signal, a physical downlink control channel, or a physical downlink shared channel.
18 . The method of claim 1 , wherein the timing pre-compensation value is an initial timing pre-compensation value, and wherein the timing pre-compensation value is derived from the tracking or RRM measurement reference signal or the initial timing pre-compensation value.
19 . The method of claim 1 , further comprising causing a third TRP to transmit a third communication using another timing pre-compensation value relative to the first time value or relative to the timing pre-compensation value of the second TRP.
20 . A method of wireless communication performed by a user equipment (UE), comprising:
receiving a first communication from a first transmission reception point (TRP), the first communication being associated with a first time value derived from a first transmission configuration indicator (TCI) state including a set of first quasi co-location (QCL) parameters of the first TRP;
receiving a synchronization signal block from a second TRP;
receiving a tracking or radio resource management (RRM) measurement reference signal from the second TRP, the tracking or RRM measurement reference signal being associated with a timing pre-compensation value relative to the first time value; and
receiving a second communication from the second TRP, the second communication being associated with the timing pre-compensation value and a frequency pre-compensation value a first frequency offset value derived from the first TCI state.
21 . The method of claim 20 , wherein the second communication uses the first time value and not a second time value derived from a second TCI state including one or more second QCL parameters of the second TRP.
22 . The method of claim 20 , wherein the second communication uses a second time value derived from a second TCI state including one or more second QCL parameters of the second TRP and the timing pre-compensation value relative to the first time value.
23 . The method of claim 20 , wherein the first time value comprises an average delay derived from the first set of QCL parameters of the first TRP.
24 . The method of claim 20 , wherein the first communication uses the first frequency offset value derived from the first TCI state.
25 . The method of claim 24 , wherein the first frequency offset value comprises a Doppler shift and a Doppler spread derived from the first set of QCL parameters of the first TRP.
26 . The method of claim 20 , wherein the timing pre-compensation value shifts a transmission time of the second communication to within a maximum timing difference of a transmission time of the first communication.
27 . The method of claim 26 , wherein the maximum timing difference is, at most, a length of a cyclic prefix of the first communication or the second communication.
28 . A network entity for wireless communication, comprising:
a memory; and
one or more processors, coupled to the memory, configured to:
cause a first transmission reception point (TRP) to transmit a first communication using a first time value derived from a first transmission configuration indicator (TCI) state including a set of first quasi co-location (QCL) parameters of the first TRP;
cause a second TRP to transmit a synchronization signal block;
cause the second TRP to transmit a tracking or radio resource management (RRM) measurement reference signal using a timing pre-compensation value relative to the first time value; and
cause a second TRP to transmit a second communication using the timing pre-compensation value and a frequency pre-compensation value a first frequency offset value derived from the first TCI state.
29 . A user equipment (UE) for wireless communication, comprising: a memory; and
one or more processors, coupled to the memory, configured to:
receive a first communication from a first transmission reception point (TRP), the first communication being associated with a first time value derived from a first transmission configuration indicator (TCI) state including a set of first quasi co-location (QCL) parameters of the first TRP;
receive a synchronization signal block from a second TRP;
receive a tracking or radio resource management (RRM) measurement reference signal from the second TRP, the tracking or RRM measurement reference signal being associated with a timing pre-compensation value relative to the first time value; and
receive a second communication from the second TRP, the second communication being associated with the timing pre-compensation value and a frequency pre-compensation value a first frequency offset value derived from the first TCI state.
30 . The method of claim 1 , further comprising causing the second TRP to adjust at least one of the timing pre-compensation value or the frequency pre-compensation according to a difference between receipt of an uplink sounding reference signal from a user equipment (UE) and transmission of a reference signal from the second TRP.