Unified TCI framework
A user equipment (UE) is configured to receive a command for a transmission configuration indicator (TCI) state change for a joint TCI state including uplink (UL) and downlink (DL) signals, decode the joint ICI state command and performing measurements necessary to receive and transmit with the target TCI state, the measurements including a pathloss (PL) measurement for an UL channel and switch to receive the DL signals and transmit the UL signals with the target TCI state no later than a time duration for a switching delay.
1 . A processor of a base station configured to perform operations, comprising:
generating, for transmission to a user equipment (UE), a beam switch time parameter;
configuring a joint TCI state command for a transmission configuration indicator (TCI) state change for a joint TCI state including uplink (UL) and downlink (DL) signals; and
generating, for transmission to the UE, the joint TCI state command, wherein the command is transmitted via one of a medium access control (MAC) control element (CE) or a downlink control information (DCI), wherein the UE switches to receive DL signals and transmit UL signals with a target TCI state within a time duration for a switching delay, wherein when the command is transmitted via the DCI, the time duration is based on at least the beam switch time parameter, wherein the UE switches from a first pathloss reference signal (PL-RS) to a target PL-RS and the switching from the first PL-RS to the target PL-RS is completed at a same time as the switching to receive the DL signals and transmit the UL signals with the target TCI state.
2 . The processor of claim 1 , wherein, when the command is transmitted via the MAC CE, the time duration includes a MAC CE parsing time and an acknowledgement time for the command.
3 . The processor of claim 1 , wherein the time duration is further based on a time for receive (Rx) beam refinement when the Rx beam of the target TCI state is unknown.
4 . The processor of claim 1 , wherein the time duration is further based on a time for time and frequency offset tracking for DL signals of the target TCI state when the target TCI state is not tracked by the UE.
5 . The processor of claim 1 , wherein the time duration does not include a time for performing a pathloss (PL) measurement.
6 . The processor of claim 1 , wherein a source reference signal (RS) for the target TCI state is a synchronization signal block (SSB) or channel state information (CSI) RS.
7 . A user equipment (UE), comprising:
a transceiver configured to communicate with a network; and
a processor communicatively coupled to the transceiver and configured to perform operations comprising:
receiving a beam switch time parameter from the network;
receiving a command for a transmission configuration indicator (TCI) state change for a separate UL TCI state including uplink (UL) signals and not including downlink (DL) signals, wherein the command is transmitted via one of a medium access control (MAC) control element (CE) or a downlink control information (DCI);
decoding the separate UL TCI state command and performing measurements necessary to receive and transmit with a target TCI state, the measurements including a pathloss (PL) measurement for an UL channel;
switching to transmit the UL signals with the target TCI state within a time duration for a switching delay, wherein when the command is transmitted via the DCI, the time duration is based on at least the beam switch time parameter; and
switching from a first PL reference signal (PL-RS) to a target PL-RS, wherein the switching from the first PL-RS to the target PL-RS is completed at a same time as the switching to transmit the UL signals with the target TCI state.
8 . The UE of claim 7 , wherein a source reference signal (RS) for the target TCI state is a synchronization signal block (SSB) or channel state information (CSI) RS.
9 . A processor of a base station configured to perform operations comprising:
generating, for transmission to a user equipment (UE), a beam switch time parameter;
configuring a separate UL TCI state command for a transmission configuration indicator (TCI) state change for a separate uplink (UL) TCI state including UL signals and not including downlink (DL) signals; and
generating, for transmission to the UE, the separate UL TCI state command, wherein the command is transmitted via one of a medium access control (MAC) control element (CE) or a downlink control information (DCI), wherein the UE switches to transmit the UL signals with the target TCI state within a time duration for a switching delay, wherein when the command is transmitted via the DCI, the time duration is based on at least the beam switch time parameter, wherein the UE switches from a first pathloss reference signal (PL-RS) to a target PL-RS and the switching from the first PL-RS to the target PL-RS is completed at the same time as the switching to transmit the UL signals with the target TCI state.
10 . The processor of claim 9 , wherein, when the command is transmitted via the MAC CE, the time duration includes a MAC CE parsing time and an acknowledgement time for the command.
11 . The processor of claim 9 , wherein the time duration is further based on a time for receive (Rx) beam refinement when the Rx beam of the target TCI state is unknown and a source reference signal (RS) for the target TCI state is a DL RS.
12 . The processor of claim 9 , wherein the time duration does not include a time for receive beam refinement when the Tx beam of the target TCI state is unknown and a source reference signal (RS) for the target TCI state is a UL RS, wherein the UE uses a best known beam without additional Tx beam refinement.
13 . The processor of claim 9 , wherein the time duration does not include a time for performing a pathloss (PL) measurement.