Configuration of sounding reference signal resources in an uplink transmission time interval

1. A method for wireless communication by a user equipment (UE), comprising:

receiving control signaling indicating a sounding reference signal (SRS) configuration in a transmission time interval (TTI), wherein the indicated configuration includes both a first symbol period that occurs no later than a symbol period for a demodulation reference signal (DMRS) of a physical uplink channel in the TTI and a second symbol period that occurs later than the physical uplink channel in the TTI; and

transmitting a first SRS in the first symbol period and a second SRS in the second symbol period based at least in part on the received control signaling.

2. The method of claim 1 , further comprising:

processing the control signaling to determine that the indicated configuration includes the first symbol period that occurs no later than the symbol period for the DMRS of the physical uplink channel in the TTI.

3. The method of claim 1 , further comprising:

processing the control signaling to determine that the indicated location includes the first symbol period that occurs no later than the symbol period for the DMRS of the physical uplink channel in the TTI, and the second symbol period that occurs later than the physical uplink channel in the TTI.

4. The method of claim 1 , wherein the physical uplink channel is a physical uplink control channel (PUCCH) or a physical uplink shared channel (PUSCH).

5. The method of claim 1 , further comprising:

processing the control signaling to determine that the indicated configuration includes the second symbol period that occurs later than the physical uplink channel in the TTI.

6. The method of claim 1 , wherein the control signaling comprises a bit sequence indicating the indicated configuration from a plurality of different semi-statically configured configurations.

7. The method of claim 1 , further comprising:

processing the control signaling to identify a grant of resources in a physical uplink channel in a second TTI that occurs after the TTI;

determining a location for a periodic SRS resource in the second TTI, wherein the determined location for the periodic SRS resource occurs later than the physical uplink channel in the second TTI; and

transmitting a second SRS in the determined location of the second TTI.

8. The method of claim 1 , further comprising:

receiving second control signaling indicating a second location for a second SRS resource within a second TTI; and

processing the second control signaling to identify a grant of resources in a physical uplink channel in the second TTI and to determine that the indicated second location includes one or more adjacent symbols that occur no later than a symbol period for a second DMRS of the physical uplink channel in the second TTI.

9. The method of claim 1 , wherein receiving the control signaling comprises:

receiving the control signaling in a control channel region of the TTI or in a control channel region of a second TTI that occurs prior to the TTI.

10. A method for wireless communication by a user equipment (UE), comprising:

receiving control signaling indicating a first symbol location for a first sounding reference signal (SRS) in a transmission time interval (TTI) and a second symbol location for a second SRS within the TTI;

determining, based on the control signaling, that the first symbol location and the second symbol location are adjacent symbol locations in time; and

transmitting the first SRS in the first symbol location and the second SRS in the second symbol location based on the control signaling and the determination.

11. The method of claim 10 , further comprising:

performing a frequency hop between the first symbol location and the second symbol location.

12. A method for wireless communication by a user equipment (UE), comprising:

receiving control signaling indicating a symbol location for a sounding reference signal (SRS) and a symbol location for a demodulation reference signal (DMRS) in a transmission time interval (TTI);

determining that the symbol locations for the SRS and DMRS are the same symbol location;

adjusting a ratio of transmission power of pilot resource elements to transmission power of data resource elements within a bandwidth associated with the TTI based at least in part on determining that the UE is configured to simultaneously transmit the SRS and the DMRS in the symbol location; and

generating a frequency division multiplexed signal by frequency division multiplexing the SRS and the DMRS; and

transmitting the frequency division multiplexed signal in the symbol location based on the adjusted ratio.

13. A method for wireless communication at a base station, comprising:

transmitting control signaling indicating a sounding reference signal (SRS) configuration in a transmission time interval (TTI), wherein the indicated configuration includes a first symbol period that occurs no later than a symbol period for a demodulation reference signal (DMRS) of a physical uplink channel in the TTI and a second symbol period that occurs later than the physical uplink channel in the TTI; and

receiving a first SRS in the first symbol period and a second SRS in the second symbol period based at least in part on the transmitted control signaling.

14. The method of claim 13 , wherein the control signaling comprises a bit sequence indicating the indicated configuration from a set of different semi-statically configured configurations.

15. The method of claim 13 , wherein transmitting the control signaling comprises:

transmitting the control signaling in a control channel region of the TTI or in a control channel region of a second TTI that occurs prior to the TTI.

16. The method of claim 13 , further comprising receiving the DMRS, wherein receiving the SRS and the DMRS comprises:

receiving a frequency division multiplexed signal at the first symbol period in the TTI; and

frequency de-multiplexing the frequency division multiplexed signal to obtain the first SRS and the DMRS.

17. The method of claim 16 , further comprising:

demodulating the physical uplink channel in the TTI based at least in part on the DMRS.

18. An apparatus for wireless communication, comprising:

a processor;

memory in electronic communication with the processor; and

instructions stored in the memory and operable, when executed by the processor, to cause the apparatus to:

receive control signaling indicating a sounding reference signal (SRS) configuration in a transmission time interval (TTI), wherein the indicated configuration includes both a first symbol period that occurs no later than a symbol period for a demodulation reference signal (DMRS) of a physical uplink channel in the TTI and a second symbol period that occurs later than the physical uplink channel in the TTI; and

transmit an SRS in the first symbol period and the second symbol period based at least in part on the received control signaling.

19. The apparatus of claim 18 , wherein the control signaling comprises a bit sequence indicating the indicated configuration from a plurality of different semi-statically configured configurations.