Method and apparatus for triggering and transmitting uplink sounding reference signal

1. A method of dynamically triggering an aperiodic uplink sounding reference signal SRS for a carrier aggregation system, wherein an uplink schedule in the system comprises an SRS request field, the method comprising:

pre-assigning mapping relationships between different values of the SRS request field in the uplink schedule and joint coding of a carrier aggregation parameter and at least one user-specific SRS parameters, the carrier aggregation parameter indicating one or more carrier component;

determining the carrier aggregation parameter and the at least one user-specific SRS parameter;

assigning values to the SRS request field in the uplink schedule based on the pre-assigned mapping relationships, the determined carrier aggregation parameter, and the at least one user-specific SRS parameter; and

transmitting the uplink grant.

2. The method according to claim 1 , wherein the at least one user-specific SRS parameter is one or two of the following parameters:

SRS time interval, SRS transmission comb offset amount, SRS frequency domain hopping switch, cyclic shift index offset amount.

3. The method according to claim 1 , wherein the at least one user-specific SRS parameter is SRS time interval, the SRS request field is of 2 bits, and the four different values of the SRS request field are mapped as follows, respectively:

no SRS triggering;

triggering one-shot SRS on one UL CC;

triggering multi-shot SRS on one UL CC;

triggering one-shot SRS or multi-shot SRS on all or a subset of configured multiple UL CCs.

4. The method according to claim 1 , wherein the at least one user-specific SRS parameter is SRS transmission comb offset, the SRS request field is of 2 bits, and the four different values of the SRS request field are mapped as follows, respectively:

no SRS triggering;

triggering transmission of aperiodic SRS with one comb offset amount on one UL CC;

triggering transmission of aperiodic SRS with another comb offset that is different from the one comb offset on one UL CC;

triggering transmission of aperiodic SRS with the one comb offset or the another comb offset on all or a subset of configured multiple UL CCs.

5. The method according to claim 1 , wherein the at least one user-specific SRS parameter is SRS frequency domain hopping switch, the SRS request field is of 2 bits, and the four different values of the SRS request field are mapped as follows, respectively:

no SRS triggering;

triggering aperiodic SRS with frequency domain hopping on one UL CC;

triggering aperiodic SRS without frequency domain hopping on one UL CC;

triggering aperiodic SRS with/without frequency domain hopping on all or a subset of configured multiple UL CCs.

6. The method according to claim 1 , wherein the at least one user-specific SRS parameter is SRS cyclic shift index CS offset amount, the SRS request field is of 2 bits, and the four different values of the SRS request field are mapped as follows, respectively:

no SRS triggering;

triggering aperiodic SRS with CS per RRC-configured CS index on one UL CC;

triggering aperiodic SRS with CS being offset by one CS offset amount per the RRC-configured CS index on one UL CC;

triggering aperiodic SRS with CS per RRC-configured CS index on all or a subset of configured multiple UL CCs or triggering aperiodic SRS with CS being offset by one CS offset amount per the RRC-configured CS index on all or a subset of configured multiple UL CCs.

7. The method according to claim 1 , wherein the at least one user-specific SRS parameter is SRS time interval and SRS transmission comb offset amount, the SRS request field is of 3 bits, and the eight different values of the SRS request field are mapped as follows, respectively:

no SRS triggering;

triggering transmission of one-shot SRS with one comb offset amount on one UL CC;

triggering transmission of one-shot SRS with another comb offset amount that is different from the one comb offset amount on one UL CC;

triggering transmission of multi-shot SRS with one comb offset amount on one UL CC;

triggering transmission of multi-shot SRS with another comb offset amount on one UL CC;

triggering one-shot SRS on all or a subset of configured multiple UL CCs, wherein the comb offset amounts corresponding to respective UL CCs conform to the same amount configured by RRC signaling;

triggering one-shot SRS on all or a subset of configured multiple UL CCs, wherein the comb offset amounts corresponding to respective UL CCs conform to different amounts configured by RRC signaling, respectively;

triggering multi-shot SRS on all or a subset of configured multiple UL CCs, wherein the comb offset amounts corresponding to respective UL CCs conform to the same amount/different amounts configured by RRC signaling.

8. The method according to claim 1 , wherein the at least one user-specific SRS parameter is SRS cyclic shift index CS offset amount, the SRS request field is of 3 bits, and the eight different values of the SRS request field are mapped as follows, respectively:

no SRS triggering;

triggering aperiodic SRS with CS being offset 0 per the RRC-configured CS index on one UL CC;

triggering aperiodic SRS with CS being offset+2 per the RRC-configured CS index on one UL CC;

triggering aperiodic SRS with CS being offset+4 per the RRC-configured CS index on one UL CC;

triggering aperiodic SRS with CS being offset+6 per the RRC-configured CS index on one UL CC;

triggering aperiodic SRS with CS being offset 0 per the RRC-configured CS index on all or a subset of configured multiple UL CCs;

triggering aperiodic SRS with CS being offset 2 per the RRC-configured CS index on all or a subset of configured multiple UL CCs;

triggering aperiodic SRS with CS being offset 4 per the RRC-configured CS index on all or a subset of configured multiple UL CCs.

9. A method of transmitting an aperiodic uplink sounding reference signal SRS for a carrier aggregation system, wherein an uplink schedule in the system comprises an SRS request field, the method comprising:

pre-assigning mapping relationships between different values of the SRS request field in the uplink schedule and joint coding of a carrier aggregation parameter and at least one user-specific SRS parameter, the carrier aggregation parameter indicating one or more carrier component;

receiving the uplink schedule;

de-mapping the SRS request field in the received uplink schedule based on the pre-assigned mapping relationships so as to determine the carrier aggregation parameter used in transmitting the SRS and the at least one user-specific SRS parameter.

10. An apparatus for dynamically triggering an aperiodic uplink sounding reference signal SRS for a carrier aggregation system, wherein an uplink schedule in the system comprises an SRS request field, the apparatus comprising:

one or more processors configured to:

pre-assign mapping relationships between different values of the SRS request field in the uplink grant and joint coding of a carrier aggregation parameter and at least one user-specific SRS parameter, the carrier aggregation parameter indicating one or more carrier component;

determine the carrier aggregation parameter and the at least one user-specific SRS parameters;

assign a value to the SRS request field in the uplink grant based on the pre-assigned mapping relationships, the determined carrier aggregation parameter, and the at least one user-specific SRS parameter, the carrier aggregation parameter indicating one or more carrier components; and

a first transmitter configured to transmit the uplink schedule.

11. An apparatus for transmitting an aperiodic uplink sounding reference signal SRS for a carrier aggregation system, wherein an uplink schedule in the system comprises an SRS request field, the apparatus comprising:

one or more processors configured to pre-assign mapping relationships between different values of the SRS request field in the uplink schedule and joint coding of a carrier aggregation parameter and at least one user-specific SRS parameter, the carrier aggregation parameter indicating one or more carrier component;

a receiver configured to receive the uplink schedule;

wherein the one or more processors is further configured to de-map the SRS request field in the received uplink schedule based on the pre-assigned mapping relationships so as to determine the carrier aggregation parameter used in transmitting the SRS and the at least one user-specific SRS parameter.

12. A method of dynamically triggering an aperiodic uplink sounding reference signal SRS for a carrier aggregation system, wherein an uplink schedule in the system comprises a 1-bit SRS request field and a carrier indicator CIF field, the method comprising:

pre-assigning mapping relationships between different values of the SRS request field and of the CIF field in the uplink schedule and a carrier aggregation parameter, the carrier aggregation parameter indicating one or more carrier components;

determining the carrier aggregation parameter;

assigning a value to the SRS request field in the uplink schedule based on the pre-assigned mapping relationships and the determined carrier aggregation parameter;

transmitting the uplink schedule.

13. A method of transmitting an aperiodic uplink sounding reference signal SRS for a carrier aggregation system, wherein an uplink schedule in the system comprises a 1-bit SRS request field and a CIF field, the method comprising:

pre-assigning mapping relationships between different values of the SRS request field and of the CIF field in the uplink schedule and a carrier aggregation parameter, the carrier aggregation parameter indicating one or more carrier components;

receiving the uplink schedule;

de-mapping the received uplink schedule based on the pre-assigned mapping relationships so as to determine the carrier aggregation parameter used in transmitting SRS.

14. An apparatus for dynamically triggering an aperiodic uplink sounding reference signal SRS for a carrier aggregation system, wherein an uplink schedule in the system comprises a 1-bit SRS request field and a CIF field, the apparatus comprising:

one or more processors configured to:

pre-assign mapping relationships between different values of the SRS request field and of the CIF field in the uplink schedule and a carrier aggregation parameter, the carrier aggregation parameter indicating one or more carrier components;

determine the carrier aggregation parameter;

assign a value to the SRS request field in the uplink schedule based on the pre-assigned mapping relationships and the determined carrier aggregation parameter; and

a transmitter configured to transmit the uplink schedule.

15. An apparatus for transmitting an aperiodic uplink sounding reference signal SRS for a carrier aggregation system, wherein an uplink schedule in the system comprises a 1-bit SRS request field and a CIF field, the apparatus comprising:

one or more processors configured to pre-assign mapping relationships between different values of the SRS request field and of the CIF field in the uplink schedule and a carrier aggregation parameter, the carrier aggregation parameter indicating one or more carrier components;

a receiver configured to receive the uplink schedule;

wherein the one or more processors is further configured to de-map the received uplink schedule based on the pre-assigned mapping relationships so as to determine the carrier aggregation parameter used in transmitting SRS.