Transmission of sounding reference signals from a user equipment in response to multiple requests

1. A method for a User Equipment (UE) to transmit a Sounding Reference Signal (SRS), the method comprising the steps of:

receiving a first Downlink Control Information (DCI) format with an aperiodic SRS request field indicating aperiodic SRS transmission with first values for aperiodic SRS transmission parameters;

receiving a second DCI format with an aperiodic SRS request field indicating aperiodic SRS transmission with second values for the aperiodic SRS transmission parameters;

comparing the first values for the aperiodic SRS transmission parameters with the second values for the aperiodic SRS transmission parameters; and

transmitting an aperiodic SRS when the first values are identical to the second values; and

suspending transmission of the aperiodic SRS when the first values are not identical to the second values.

2. The method of claim 1 , wherein the aperiodic SRS request field in the first DCI format is represented by a first number of bits and indicates the aperiodic SRS transmission parameters from a first set of aperiodic SRS transmission parameters, and wherein the aperiodic SRS request field in the second DCI format is represented by a second number of bits and indicates the aperiodic SRS transmission parameters from a second set of aperiodic SRS transmission parameters.

3. The method of claim 1 , wherein the first DCI format and the second DCI format are received in different transmission time intervals.

4. The method of claim 1 , wherein the aperiodic SRS transmission parameters are configured to the UE from a network through higher layer signaling and comprise at least one of a transmission comb, a cyclic shift, a starting position in an operating bandwidth, a transmission bandwidth, a transmission instance, and a number of UE transmitter antenna ports.

5. A method for a User Equipment (UE) to transmit a Sounding Reference Signal (SRS), the method comprising the steps of:

receiving a first number of Downlink Control Information (DCI) formats and a second number of DCI formats, wherein each of the first number of DCI formats conveys an aperiodic SRS request field indicating aperiodic SRS transmission and values for aperiodic SRS transmission parameters, and wherein each of the second number of DCI formats conveys an aperiodic SRS request field indicating no aperiodic SRS transmission;

comparing the values for the aperiodic SRS transmission parameters indicated by the aperiodic SRS request fields of each of the first number of DCI formats;

disregarding the aperiodic SRS request field in each of the second number of DCI formats;

transmitting an aperiodic SRS, when all of the values for the aperiodic SRS transmission parameters indicated by the aperiodic SRS request fields of each of the first number of DCI formats are identical; and

suspending transmission of the aperiodic SRS, when all of the values for the aperiodic SRS transmission parameters indicated by the aperiodic SRS request fields of each of the first number of DCI formats are not identical.

6. The method of claim 5 , wherein the aperiodic SRS request field in a first DCI format from the first number of DCI formats or from the second number of DCI formats is represented by a first number of bits and indicates the aperiodic SRS transmission parameters from a first set of aperiodic SRS transmission parameters, and wherein the aperiodic SRS request field in a second DCI format from the first number of DCI formats or from the second number of DCI formats is represented by a second number of bits and indicates the aperiodic SRS transmission parameters from a second set of aperiodic SRS transmission parameters.

7. The method of claim 5 , wherein a first DCI format and a second DCI format from the first number of DCI formats or from the second number of DCI formats are received in different transmission time intervals.

8. The method of claim 5 , wherein the aperiodic SRS transmission parameters are configured to the UE from a network through higher layer signaling and comprise at least one of a transmission comb, a cyclic shift, a starting position in an operating bandwidth, a transmission bandwidth, a transmission instance, and a number of UE transmitter antenna ports.

9. A User Equipment (UE) apparatus for transmitting a Sounding Reference Signal (SRS), the UE apparatus comprising:

a receiver for receiving a first Downlink Control Information (DCI) format with an aperiodic SRS request field indicating aperiodic SRS transmission with first values for aperiodic SRS transmission parameters, and a second DCI format with an aperiodic SRS request field indicating aperiodic SRS transmission with second values for the aperiodic SRS transmission parameters;

a comparator for comparing the first values for the aperiodic SRS transmission parameters with the second values for the aperiodic SRS transmission parameters; and

a transmitter for transmitting an aperiodic SRS when the first values are identical to the second values and for suspending transmission of the aperiodic SRS when the first values are not identical to the second values.

10. The UE apparatus of claim 9 , wherein the aperiodic SRS request field in the first DCI format is represented by a first number of bits and indicates the aperiodic SRS transmission parameters from a first set of aperiodic SRS transmission parameters, and wherein the aperiodic SRS request field in the second DCI format is represented by a second number of bits and indicates the aperiodic SRS transmission parameters from a second set of aperiodic SRS transmission parameters.

11. The UE apparatus of claim 9 , wherein the first DCI format and the second DCI format are received in different transmission time intervals.

12. The UE apparatus of claim 9 , wherein the aperiodic SRS transmission parameters are configured to the UE apparatus from a network through higher layer signaling and comprise at least one of a transmission comb, a cyclic shift, a starting position in an operating bandwidth, a transmission bandwidth, a transmission instance, and a number of UE transmitter antenna ports.

13. A User Equipment (UE) apparatus for transmitting a Sounding Reference Signal (SRS), the UE apparatus comprising:

a receiver for receiving a first number of Downlink Control Information (DCI) formats and a second number of DCI formats, wherein each of the first number of DCI formats conveys an aperiodic SRS request field indicating aperiodic SRS transmission and values for aperiodic SRS transmission parameters, and wherein each of the second number of DCI formats conveys an aperiodic SRS request field indicating no aperiodic SRS transmission;

a comparator for comparing the values for the aperiodic SRS transmission parameters indicated by the aperiodic SRS request fields of each of the first number of DCI formats, and disregarding the aperiodic SRS request field in each of the second number of DCI formats; and

a transmitter for transmitting an aperiodic SRS when all of the values for the aperiodic SRS transmission parameters indicated by the aperiodic SRS request fields of each of the first number of DCI formats are identical, and suspending transmission of the aperiodic SRS when all of the values for the aperiodic SRS transmission parameters indicated by the aperiodic SRS request fields of each of the first number of DCI formats are not identical.

14. The apparatus of claim 13 , wherein the aperiodic SRS request field in a first DCI format from the first number of DCI formats or from the second number of DCI formats is represented by a first number of bits and indicates the aperiodic SRS transmission parameters from a first set of aperiodic SRS transmission parameters, and wherein the aperiodic SRS request field in a second DCI format from the first number of DCI formats or from the second number of DCI formats is represented by a second number of bits and indicates the aperiodic SRS transmission parameters from a second set of aperiodic SRS transmission parameters.

15. The apparatus of claim 13 , wherein a first DCI format and a second DCI format from the first number of DCI formats or the second number of DCI formats are received in different transmission time intervals.

16. The apparatus of claim 13 , wherein the aperiodic SRS transmission parameters are configured to the UE from a network through higher layer signaling and comprise at least one of a transmission comb, a cyclic shift, a starting position in an operating bandwidth, a transmission bandwidth, a transmission instance, and a number of UE transmitter antenna ports.