Sounding reference signal transmission in low latency wireless transmissions
Methods, systems, and devices for wireless communication are described that support sounding reference signal (SRS) transmission in low latency wireless transmissions. A set of shortened transmission time intervals (sTTIs) for uplink transmissions of a first wireless service may be identified; the set of sTTIs located within subframe time boundaries of a subframe of a second wireless service with a longer TTI than the sTTIs. Two or more sTTIs within the set of sTTIs may be used for SRS transmissions within the subframe time boundaries.
1. A method for wireless communication, comprising:
receiving a configuration that indicates a set of short transmission time intervals (sTTIs) that are for uplink transmissions, wherein the set comprises a first subset of sTTIs being within a first slot, the first subset of sTTIs each spanning two orthogonal frequency division multiplexing (OFDM) symbols, and wherein the first subset of sTTIs comprises at least two consecutive OFDM symbols for transmission of sounding reference signal (SRS) transmissions; and
transmitting one or more SRS transmissions in at least the at least two consecutive OFDM symbols.
2. The method of claim 1 , wherein the at least two consecutive OFDM symbols are configured across one sTTI of the first subset of sTTIs.
3. The method of claim 1 , wherein the at least two consecutive OFDM symbols are configured across two sTTIs of the first subset of sTTIs.
4. The method of claim 3 , wherein the remaining OFDM symbols of the two sTTIs not configured for SRS transmission are configured for a null pattern, a demodulation reference signal (DMRS) transmission, a data transmission, or a combination thereof.
5. The method of claim 1 , wherein the set comprises a second subset of sTTIs that each span three OFDM symbols.
6. The method of claim 5 , wherein a final sTTI within each of the first slot and a second slot within a subframe time boundary is a three-symbol sTTI of the second subset.
7. The method of claim 6 , further comprising:
selecting an SRS symbol location within the first slot to be either an initial symbol or a last symbol of a respective three-symbol sTTI; and
selecting an SRS symbol location within the second slot to be a last symbol of a respective three-symbol sTTI.
8. An apparatus for wireless communication, in a system comprising:
one or more processors;
memory in electronic communication with the one or more processors; and
instructions stored in the memory and operable, when executed by the one or more processors to cause the apparatus to:
receive a configuration that indicates a set of short transmission time intervals (sTTIs) that are for uplink transmissions, wherein the set comprises a first subset of sTTIs being within a first slot, the first subset of sTTIs each spanning two orthogonal frequency division multiplexing (OFDM) symbols, and wherein the first subset of sTTIs comprises at least two consecutive OFDM symbols for transmission of sounding reference signal (SRS) transmissions; and
transmit one or more SRS transmissions in at least the at least two consecutive OFDM symbols.
9. The apparatus of claim 8 , wherein the at least two consecutive OFDM symbols are configured across one sTTI of the first subset of sTTIs.
10. The apparatus of claim 8 , wherein the at least two consecutive OFDM symbols are configured across two sTTIs of the first subset of sTTIs.
11. The apparatus of claim 10 , wherein the remaining OFDM symbols of the two sTTIs not configured for SRS transmission are configured for a null pattern, a demodulation reference signal (DMRS) transmission, a data transmission, or a combination thereof.
12. The apparatus of claim 8 , wherein the set comprises a second subset of sTTIs that each span three OFDM symbols.
13. The apparatus of claim 12 , wherein a final sTTI within each of the first slot and a second slot within a subframe time boundary is a three-symbol sTTI of the second subset.
14. The apparatus of claim 13 , wherein the instructions are operable to cause the apparatus to:
select an SRS symbol location within the first slot to be either an initial symbol or a last symbol of a respective three-symbol sTTI; and
select an SRS symbol location within the second slot to be a last symbol of a respective three-symbol sTTI.
15. An apparatus for wireless communication, in a system comprising:
one or more processors;
memory in electronic communication with the one or more processors; and
instructions stored in the memory and operable, when executed by the one or more processors, to cause the apparatus to:
receive a configuration that indicates a set of short transmission time intervals (sTTIs) that are for uplink transmissions, wherein the set comprises a first subset of one or more sTTIs being within a first slot, the first subset of sTTIs each spanning two orthogonal frequency division multiplexing (OFDM) symbols, and wherein the first subset of one or more sTTIs comprises at least two consecutive OFDM symbols for transmission of sounding reference signal (SRS) transmissions; and
transmit one or more SRS transmissions in at least the at least two consecutive OFDM symbols.
16. An apparatus for wireless communication, in a system comprising:
one or more processors;
memory in electronic communication with the one or more processors; and
instructions stored in the memory and operable, when executed by the one or more processors, to cause the apparatus to:
receive a configuration that indicates a set of short transmission time intervals (sTTIs) that are for uplink transmissions, wherein the set comprises a first subset of at least one sTTI being within a first slot, the first subset of sTTIs spanning two orthogonal frequency division multiplexing (OFDM) symbols, and wherein the first subset of at least one sTTI comprises at least two consecutive OFDM symbols for transmission of sounding reference signal (SRS) transmission; and
transmit one or more SRS transmissions in at least the at least two consecutive OFDM symbols.
17. A method for wireless communication, comprising:
identifying two or more short transmission time intervals (sTTIs) within a set of sTTIs that is for uplink transmissions, the set of sTTIs being within a slot, the two or more sTTIs spanning two or three orthogonal frequency division multiplexing (OFDM) symbols, the two or more sTTIs being for transmission of sounding reference signal (SRS) transmissions, at least one of the two or more sTTIs comprising an initial OFDM symbol configured for an SRS transmission; and
transmitting one or more SRS transmissions in at least one of the two or more sTTIs.
18. An apparatus for wireless communication, in a system comprising:
one or more processors;
memory in electronic communication with the one or more processors; and
instructions stored in the memory and operable, when executed by the one or more processors, to cause the apparatus to:
identify two or more short transmission time intervals (sTTIs) within a set of sTTIs that is for uplink transmissions, the set of sTTIs being within a slot, the two or more sTTIs spanning two or three orthogonal frequency division multiplexing (OFDM) symbols, the two or more sTTIs being for transmission of sounding reference signal (SRS) transmissions, at least one of the two or more sTTIs comprising an initial OFDM symbol configured for an SRS transmission; and
transmit one or more SRS transmissions in at least one of the two or more sTTIs.