Supporting scheduling of sounding reference signals
A user equipment (UE) receives scheduling information for Sounding Reference Signal (SRS) for positioning that includes multiple reserved occasions to transmit the SRS. The multiple reserved occasions may be used on all or on only a subset of configured SRS resources. The UE transmits the positioning SRS on a reserved occasion that is first available for transmission, e.g., without collision or other restrictions of transmission of the SRS. The UE does not transmit the positioning SRS on any earlier reserved occasions that is not available or any subsequent reserved occasions. The base station may attempt to decode the SRS on each reserved occasion until the positioning SRS is transmitted. The base station may reassign unused reserved occasions to other UEs or to other channels. The base station may report positioning measurements with associated time stamps for the reserved occasion on which the positioning SRS was received.
1. A method for supporting scheduling of Sounding Reference Signals (SRS) for a user equipment (UE) performed by the UE in a wireless network, comprising:
receiving from a serving base station an SRS schedule for transmitting a positioning SRS, the SRS schedule comprising multiple reserved occasions for transmitting the positioning SRS; and
transmitting the positioning SRS on a reserved occasion that is first available for transmission of the positioning SRS, wherein the positioning SRS is not transmitted on any earlier reserved occasion that is not available for transmission of the positioning SRS and is not transmitted on any subsequent reserved occasions, and wherein an earlier reserved occasion is not available for transmission of the positioning SRS due to one or more of a collision with a higher priority uplink (UL) transmission, collision with a higher priority non-positioning SRS, collision with an uplink transmission on another carrier, maximum permissible exposure constraints, and channel access failure.
2. The method of claim 1 , further comprising receiving a downlink (DL) Positioning Reference Signal (PRS) schedule, wherein the SRS schedule is in relation to the DL PRS schedule.
3. The method of claim 1 , wherein reserved occasions in the multiple reserved occasions are scheduled with a known time offset relative to a preceding reserved occasion.
4. The method of claim 1 , wherein the SRS schedule is for a plurality of SRS resources and SRS resources in a subset of the plurality of SRS resources are configured with multiple reserved occasions for transmitting the positioning SRS.
5. The method of claim 4 , wherein SRS resources in a remaining subset of the plurality of SRS resources are configured with one SRS occasion and the positioning SRS is not transmitted when there is a collision.
6. The method of claim 4 , further comprising receiving a selection of the subset of the plurality of SRS resources from the serving base station in a message that is separate from the SRS schedule.
7. A user equipment (UE) configured to support scheduling of Sounding Reference Signals (SRS) in a wireless network, comprising:
a wireless transceiver configured to wirelessly communicate with a serving base station in the wireless network;
at least one memory;
at least one processor coupled to the wireless transceiver and the at least one memory, wherein the at least one processor is configured to:
receive from the serving base station an SRS schedule for transmitting a positioning SRS, the SRS schedule comprising multiple reserved occasions for transmitting the positioning SRS; and
transmit the positioning SRS on a reserved occasion that is first available for transmission of the positioning SRS, wherein the positioning SRS is not transmitted on any earlier reserved occasion that is not available for transmission of the positioning SRS and is not transmitted on any subsequent reserved occasions, and wherein an earlier reserved occasion is not available for transmission of the positioning SRS due to one or more of a collision with a higher priority uplink (UL) transmission, collision with a higher priority non-positioning SRS, collision with an uplink transmission on another carrier, maximum permissible exposure constraints, and channel access failure.
8. The UE of claim 7 , wherein the at least one processor is further configured to receive a downlink (DL) Positioning Reference Signal (PRS) schedule, wherein the SRS schedule is in relation to the DL PRS schedule.
9. The UE of claim 7 , wherein reserved occasions in the multiple reserved occasions are scheduled with a known time offset relative to a preceding reserved occasion.
10. The UE of claim 7 , wherein the SRS schedule is for a plurality of SRS resources and SRS resources in a subset of the plurality of SRS resources are configured with multiple reserved occasions for transmitting the positioning SRS.
11. The UE of claim 10 , wherein SRS resources in a remaining subset of the plurality of SRS resources are configured with one SRS occasion and the positioning SRS is not transmitted when there is a collision.
12. The UE of claim 10 , wherein the at least one processor is further configured to receive a selection of the subset of the plurality of SRS resources from the serving base station in a message that is separate from the SRS schedule.
13. A user equipment (UE) configured to support scheduling of Sounding Reference Signals (SRS) in a wireless network, comprising:
means for receiving from a serving base station an SRS schedule for transmitting a positioning SRS, the SRS schedule comprising multiple reserved occasions for transmitting the positioning SRS; and
means for transmitting the positioning SRS on a reserved occasion that is first available for transmission of the positioning SRS, wherein the positioning SRS is not transmitted on any earlier reserved occasion that is not available for transmission of the positioning SRS and is not transmitted on any subsequent reserved occasions, and wherein an earlier reserved occasion is not available for transmission of the positioning SRS due to one or more of a collision with a higher priority uplink (UL) transmission, collision with a higher priority non-positioning SRS, collision with an uplink transmission on another carrier, maximum permissible exposure constraints, and channel access failure.
14. The UE of claim 13 , further comprising means for receiving a downlink (DL) Positioning Reference Signal (PRS) schedule, wherein the SRS schedule is in relation to the DL PRS schedule.
15. The UE of claim 13 , wherein reserved occasions in the multiple reserved occasions are scheduled with a known time offset relative to a preceding reserved occasion.
16. The UE of claim 13 , wherein the SRS schedule is for a plurality of SRS resources and SRS resources in a subset of the plurality of SRS resources are configured with multiple reserved occasions for transmitting the positioning SRS.
17. The UE of claim 16 , wherein SRS resources in a remaining subset of the plurality of SRS resources are configured with one SRS occasion and the positioning SRS is not transmitted when there is a collision.