Flexible aperiodic SRS triggering in a cellular communication system
A cellular base station (BS) which transmits more flexible downlink control information (DCI) to the UE, and a UE capable of receiving and processing a received DCI message. The DCI message may have a DCI format of 0_1 or 0_2 and further may comprise an UL-SCH set to 0, a CSI request field of all 0s and an SRS request field having a nonzero value. The DCI message may indicate to the UE that the UE should: 1) transmit an aperiodic SRS corresponding to SRS request; and 2) that the UE should not transmit on the PUSCH. The DCI may include existing fields that specify either a slot offset or beam information useable when transmitting the aperiodic SRS. The base station may also generate a DCI message with an SRS trigger that is targeted to a plurality of UEs in a group, or a plurality of groups of UEs, for greater efficiency.
1. A method, comprising:
transmitting downlink control information (DCI) to a user equipment (UE) including an indication to the UE to transmit aperiodic sounding reference signaling (SRS) only when the DCI includes at least one first parameter field set to indicate no uplink shared channel (UL-SCH) is requested from the UE, at least one second parameter field set to indicate no channel state information (CSI) is requested from the UE, and at least one third parameter field that requests transmission of aperiodic SRS to a cellular base station, wherein when the UE is communicating with multiple transmission reception points (TRPs), the DCI further includes an indication to the UE to adjust its open loop power control and to perform at least one of a changing of a beam used to transmit the aperiodic SRS or a changing of a spatial relation of the aperiodic SRS; and
receiving an aperiodic SRS transmission from the UE, wherein the aperiodic SRS transmission is received from the UE in response to transmission of the DCI.
2. The method of claim 1 ,
wherein the downlink control information has a DCI format of 0_1 or 0_2.
3. The method of claim 2 ,
wherein the at least one first parameter field comprises a UL-SCH indicator set to 0, wherein the at least one second parameter field comprises a CSI request field set to all 0s,
wherein the at least one third parameter field comprises an SRS request field that has a nonzero value,
wherein the DCI indicates to the UE that the UE should transmit an aperiodic SRS to the cellular base station corresponding to the nonzero value in the SRS request field, and wherein no uplink data is requested to be transmitted on the UL-SCH.
4. The method of claim 1 ,
wherein, when the DCI comprises a CSI request field with value 0, an UL-SCH field with value 0, and an SRS request field of value 0, the DCI is interpreted by the UE as an invalid DCI.
5. The method of claim 1 ,
wherein the DCI includes a field having a value that specifies a slot offset of the aperiodic SRS transmission.
6. The method of claim 5 ,
wherein the DCI includes an SRS resource indicator field that specifies beam information useable by the UE when transmitting the aperiodic SRS transmission to the base station.
7. The method of claim 1 , further comprising:
determining that the UE should transmit aperiodic SRS to the base station; and
transmitting the DCI in response to the determination that the UE should transmit aperiodic SRS to the cellular base station.
8. A processor, comprising:
circuitry configured to:
receive downlink control information (DCI) from a base station;
process the DCI received from the base station as including an indication to transmit aperiodic sounding reference signaling (SRS) only when the DCI includes at least one first parameter field set to indicate no uplink—shared channel (UL-SCH) is requested from a user equipment (UE), at least one second parameter field set to indicate no channel state information (CSI) is requested from the UE, and at least one third parameter field that requests transmission of aperiodic SRS to the base station, wherein when the UE is communicating with multiple transmission reception points (TRPs), the DCI further includes an indication to the UE to adjust its open loop power control and to perform at least one of a changing of a beam used to transmit the aperiodic SRS or a changing of a spatial relation of the aperiodic SRS; and
transmit an aperiodic SRS transmission to the base station in response to receipt of the DCI.
9. The processor of claim 8 ,
wherein the DCI has a DCI format of 0_1 or 0_2.
10. The processor of claim 8 ,
wherein when the DCI includes a UL-SCH indicator set to 0, a CSI request field set to 0 and an SRS request field having a zero value,
the circuitry is configured to interpret the DCI as an invalid DCI.
11. The processor of claim 8 ,
wherein the DCI includes a field having a value that specifies a slot offset of the aperiodic SRS transmission.
12. The processor of claim 8 ,
wherein the DCI includes an SRS resource indicator field that specifies beam information useable by the UE when transmitting the aperiodic SRS transmission to the base station.
13. A method, comprising:
receiving downlink control information (DCI) from a base station;
processing the DCI received from the base station as including an indication to transmit aperiodic sounding reference signaling (SRS) only when the DCI includes at least one first parameter field set to indicate no uplink—shared channel (UL-SCH) is requested from a user equipment (UE), at least one second parameter field set to indicate no channel state information (CSI) is requested from the UE, and at least one third parameter field that requests transmission of aperiodic SRS to the base station, wherein when the UE is communicating with multiple transmission reception points (TRPs), the DCI further includes an indication to the UE to adjust its open loop power control and to perform at least one of a changing of a beam used to transmit the aperiodic SRS or a changing of a spatial relation of the aperiodic SRS; and
transmitting an aperiodic SRS transmission to the base station in response to receipt of the DCI.
14. The method of claim 13 , further comprising:
transmitting the aperiodic SRS transmission to the base station in response to receipt of the DCI,
wherein the UE does not transmit data on the physical uplink shared channel (PUSCH) in response to receipt of the DCI with the UL-SCH set to 0 and the CSI request field set to 0.
15. The method of claim 13 ,
wherein the DCI has a DCI format of 0_1 or 0_2.
16. The method of claim 13 ,
further comprising:
receiving second DCI from the base station, wherein when the DCI includes a UL-SCH indicator set to 0, a CSI request field set to 0 and an SRS request field having a zero value,
the method further comprises interpreting the DCI as an invalid DCI.
17. The method of claim 13 ,
wherein the DCI includes a time domain resource assignment field having a value that specifies a slot offset of the aperiodic SRS transmission.
18. The method of claim 13 ,
wherein the DCI includes an SRS resource indicator field that specifies beam information useable by the UE when transmitting the aperiodic SRS transmission to the base station.
19. The method of claim 13 , wherein the method is performed by a processor.
20. The method of claim 19 , wherein the processor is a baseband processor.