Precoding reference signals for uplink transmission with downlink interference information
Certain aspects of the present disclosure relate to methods and apparatus relating to precoding reference signals for uplink transmissions with downlink interference information. In certain aspects, a method, performed by a user equipment (UE) comprises receiving, from a base station, one or more signals for use in estimating channel quality for a downlink between the base station and the UE. The method also includes determining a first frequency resource and a second frequency resource from a frequency band allocated for transmitting a reference signal (RS). The method further includes computing a first downlink channel quality estimate for the first frequency resource using the one or more signals, transmitting a first RS precoded using the first downlink channel quality estimate, computing a second downlink channel quality estimate for the second frequency resource using the one or more signals and transmitting a second RS precoded using the second downlink channel quality estimate.
1. A method of wireless communications for use by a user equipment (UE), comprising:
receiving, from a base station, one or more signals for use in estimating channel quality for a downlink between the base station and the UE;
determining a first frequency resource and a second frequency resource from a frequency band allocated for transmitting a reference signal (RS);
computing a first downlink channel quality estimate for the first frequency resource using the one or more signals;
transmitting a first RS precoded with the first downlink channel quality estimate, wherein the first RS comprises the first downlink channel quality estimate;
computing a second downlink channel quality estimate for the second frequency resource using the one or more signals; and
transmitting a second RS precoded with the second downlink channel quality estimate, wherein the second RS comprises the second downlink channel quality estimate.
2. The method of claim 1 , wherein the second frequency resource is determined after the transmitting of the first RS.
3. The method of claim 1 , wherein the first downlink channel quality estimate comprises a first interference covariance matrix (R nn ) and the second downlink channel quality estimate comprises a second R nn , and wherein the first RS comprises a first sounding reference signal (SRS) and the second RS comprises a second SRS.
4. The method of claim 1 , wherein the determining is based on a message received from the base station for triggering the UE to perform a RS transmission.
5. The method of claim 4 , wherein the message comprises downlink control information for sounding reference signal (SRS) scheduling.
6. The method of claim 4 , wherein the message identifies one of a plurality of configurations, each configuration corresponding to a different set of frequency resources.
7. The method of claim 1 , wherein the determining is based on a range of the frequency band allocated for transmitting the RS.
8. The method of claim 1 , wherein the frequency band allocated for transmitting the RS comprises resource blocks (RBs).
9. The method of claim 1 , wherein the determining is based on capabilities of the UE.
10. The method of claim 1 , wherein the determining is based on time available between events of receiving a message indicating transmission of RS, receiving the one or more signals for use in estimating the channel quality, and transmitting the first RS.
11. The method of claim 1 , wherein the first RS is transmitted in the first frequency resource and the second RS is transmitted in the second frequency resource.
12. The method of claim 1 , wherein the first RS is transmitted at a first time period, and wherein the second RS is transmitted at a second time period.
13. An apparatus, comprising:
a non-transitory memory comprising executable instructions; and
a processor in data communication with the memory and configured to execute the instructions to cause the apparatus to:
receive, from a base station, one or more signals for use in estimating channel quality for a downlink between the base station and the apparatus;
determine a first frequency resource and a second frequency resource from a frequency band allocated for transmitting a reference signal (RS);
compute a first downlink channel quality estimate for the first frequency resource using the one or more signals;
transmit a first RS precoded with the first downlink channel quality estimate, wherein the first RS comprises the first downlink channel quality estimate;
compute a second downlink channel quality estimate for the second frequency resource using the one or more signals; and
transmit a second RS precoded with the second downlink channel quality estimate, wherein the second RS comprises the second downlink channel quality estimate.
14. The method of claim 13 , wherein the second frequency resource is determined after the transmitting of the first RS.
15. The method of claim 13 , wherein the first downlink channel quality estimate comprises a first interference covariance matrix (R nn ) and the second downlink channel quality estimate comprises a second R nn , and wherein the first RS comprises a first sounding reference signal (SRS) and the second RS comprises a second SRS.
16. The method of claim 13 , wherein the first frequency resource and the second frequency resource are determined based on a message received from the base station for triggering the apparatus to perform a RS transmission.
17. The method of claim 16 , wherein the message comprises downlink control information for sounding reference signal (SRS) scheduling.
18. The method of claim 16 , wherein the message identifies one of a plurality of configurations, each configuration corresponding to a different set of frequency resources.
19. The method of claim 13 , wherein the first frequency resource and the second frequency resource are determined based on a range of the frequency band allocated for transmitting the RS.
20. The method of claim 13 , wherein the frequency band allocated for transmitting the RS comprises resource blocks (RBs).
21. The method of claim 13 , wherein the first frequency resource and the second frequency resource are determined based on capabilities of the apparatus.
22. The method of claim 13 , wherein the first frequency resource and the second frequency resource are determined based on time available between events of receiving a message indicating transmission of RS, receiving the one or more signals for use in estimating the channel quality, and transmitting the first RS.
23. The method of claim 13 , wherein the first RS is transmitted in the first frequency resource and the second RS is transmitted in the second frequency resource.
24. The method of claim 13 , wherein the first RS is transmitted at a first time period, and wherein the second RS is transmitted at a second time period.
25. An apparatus for wireless communications, comprising:
means for receiving, from a base station, one or more signals for use in estimating channel quality for a downlink between the base station and the apparatus;
means for determining a first frequency resource and a second frequency resource from a frequency band allocated for transmitting a reference signal (RS);
means for computing a first downlink channel quality estimate for the first frequency resource using the one or more signals;
means for transmitting a first RS precoded with the first downlink channel quality estimate, wherein the first RS comprises carries the first downlink channel quality estimate;
means for computing a second downlink channel quality estimate for the second frequency resource using the one or more signals; and
means for transmitting a second RS precoded with the second downlink channel quality estimate, wherein the second RS comprises carries the second downlink channel quality estimate.
26. The apparatus of claim 25 , wherein the determining is based on a message received from the base station for triggering the apparatus to perform a RS transmission.
27. The apparatus of claim 25 , wherein the second frequency resource is determined after the transmitting of the first RS.
28. A non-transitory computer readable medium storing instructions to be executed in an apparatus, wherein the instructions when executed in the apparatus perform a method comprising:
receiving, from a base station, one or more signals for use in estimating channel quality for a downlink between the base station and the apparatus;
determining a first frequency resource and a second frequency resource from a frequency band allocated for transmitting a reference signal (RS);
computing a first downlink channel quality estimate for the first frequency resource using the one or more signals;
transmitting a first RS precoded with the first downlink channel quality estimate, wherein the first RS comprises carries the first downlink channel quality estimate;
computing a second downlink channel quality estimate for the second frequency resource using the one or more signals; and
transmitting a second RS precoded with the second downlink channel quality estimate, wherein the second RS comprises carries the second downlink channel quality estimate.
29. The non-transitory computer readable medium of claim 28 , wherein the determining is based on a message received from the base station for triggering the apparatus to perform a RS transmission.
30. The non-transitory computer readable medium of claim 28 , wherein the second frequency resource is determined after the transmitting of the first RS.