Techniques for updating reference signals
Methods, systems, and devices for wireless communications are described. The described techniques provide for dynamic updates to beam failure detection (BFD) reference signals (RSs) and path loss RS using medium access control-control element (MAC-CE) or downlink control information (DCI). For example, the quasi co-location (QCL) of periodic CSI-RS may be dynamically updated by the MAC-CE or DCI when the periodic CSI-RS is for BFD RS. Also, a semi-persistent CSI-RS or aperiodic CSI-RS may act as a BFD RS. An enhanced update procedure may be used to update the path loss RS dynamically using MAC-CE or DCI. In some cases, the path loss RS parameters updated via MAC-CE or DCI may overwrite the previously RRC configured path loss RS parameters. In another example, if the path loss RS is not configured, then the path loss RS by default may be the spatial relation reference signal of the corresponding uplink beam.
1. A method for wireless communications, comprising:
receiving a radio resource control message comprising a first configuration of a first quasi co-location parameter associated with a control resource set and a reference signal, wherein the first quasi co-location parameter is indicated by a transmission configuration indicator state identifier within the radio resource control message; and
receiving, via one or more of a medium access control (MAC) control element or downlink control information, a second configuration for the reference signal based at least in part on the first quasi co-location parameter associated with the control resource set changing to a second quasi co-location parameter associated with the control resource set and the reference signal and different from the first quasi co-location parameter, wherein the second configuration comprises an update to the first configuration, the second configuration indicating that the second quasi co-location parameter is configured for the reference signal.
2. The method of claim 1 , further comprising:
determining that the reference signal comprises a periodic channel state information reference signal for beam failure detection.
3. The method of claim 1 , further comprising:
determining that the reference signal comprises one or more of a semi-persistent channel state information reference signal or an aperiodic channel state information reference signal for beam failure detection.
4. The method of claim 3 , wherein the first configuration indicates that the reference signal comprises the semi-persistent channel state information reference signal or the aperiodic channel state information reference signal for beam failure detection.
5. The method of claim 1 , wherein the reference signal comprises one or more of a beam failure detection reference signal, a periodic channel state information reference signal, or a time/frequency tracking reference signal.
6. The method of claim 1 , further comprising:
determining that the first quasi co-location parameter associated with the control resource set has changed to the second quasi co-location parameter.
7. The method of claim 1 , further comprising:
identifying the second configuration based at least in part on a format of the downlink control information.
8. The method of claim 1 , further comprising:
monitoring for the reference signal based at least in part on the second quasi co-location parameter.
9. A method for wireless communications, comprising:
transmitting a radio resource control message comprising a first configuration of a first quasi co-location parameter associated with a control resource set and a reference signal, wherein the first quasi co-location parameter is indicated by a transmission configuration indicator state identifier within the radio resource control message;
determining that the first quasi co-location parameter associated with the control resource set has changed to a second quasi co-location parameter associated with the control resource set and the reference signal and different from the first quasi co-location parameter;
identifying a second configuration for the reference signal based at least in part on the first quasi co-location parameter associated with the control resource set changing, wherein the second configuration comprises an update to the first configuration, the second configuration configuring the reference signal with the second quasi co-location parameter; and
transmitting, via one or more of a medium access control (MAC) control element or downlink control information, the second configuration of the reference signal.
10. The method of claim 9 , further comprising:
selecting a periodic channel state information reference signal as the reference signal, wherein the first configuration indicates the periodic channel state information reference signal is for beam failure detection.
11. The method of claim 9 , further comprising:
selecting one or more of a semi-persistent channel state information reference signal or an aperiodic channel state information reference signal as the reference signal, wherein the first configuration indicates that one or more of the semi-persistent channel state information reference signal or the aperiodic channel state information reference signal is for beam failure detection.
12. The method of claim 9 , wherein a format of the downlink control information indicates the reference signal being configured with the second quasi co-location parameter.
13. The method of claim 9 , wherein the reference signal comprises one or more of a beam failure detection reference signal, a periodic channel state information reference signal, or a time/frequency tracking reference signal.
14. The method of claim 9 , further comprising:
transmitting the reference signal in accordance with the second configuration.