Method of configuring an aperiodic sounding reference signal

1. A method of configuring an aperiodic sounding reference signal by a base station in a mobile communication system, the method comprising:

transmitting a first radio resource control layer signaling to indicate configuration of a first part of parameters of the aperiodic sounding reference signal;

transmitting a second radio resource control layer signaling to pre-define sets of parameter value combinations of a second part of the parameter set of the aperiodic sounding reference signal;

transmitting an aperiodic sounding reference signal request field in downlink control information format 4 to select one of the pre-defined sets of parameter value combinations;

wherein the second part of the parameter set comprises at least one and at most three of the following parameters: cyclic shift, the number of antenna ports, carrier aggregation, sounding reference signal bandwidth, frequency-domain position, sounding reference signal hopping switch, sounding reference signal hopping bandwidth, multi-shot sounding reference signal duration, and transmission comb; and

wherein the first part of the parameter set comprises sounding reference signal configuration index and the parameters of the parameter set that are not included in the second part of the parameters.

2. The method of claim 1 , wherein transmitting a first radio resource control layer signaling to indicate configuration of the first part of the parameter set of the aperiodic sounding reference signal, transmitting a second radio resource control layer signaling to pre-define sets of a parameter value combinations of a second part of the parameter set of the aperiodic sounding reference signal and transmitting the aperiodic sounding reference signal request field in downlink control information format 4 to select one of the pre-defined sets of parameter value combinations are performed individually per component carrier.

3. The method of claim 1 , wherein transmitting the first radio resource control layer signaling to indicate configuration of the first part of the parameter set of the aperiodic sounding reference signal, transmitting a second radio resource control layer signaling to pre-define sets of parameter value combinations of the second part of the parameter set of the aperiodic sounding reference signal and transmitting the aperiodic sounding reference signal request field in downlink control information format 4 to select one of the pre-defined sets of parameter value combinations are performed commonly for a plurality of component carriers.

4. The method of claim 1 , wherein the pre-defined sets of parameter value combinations are parameter values of one of:

combination 1 , wherein the second part of the parameters corresponding to combination 1 comprises cyclic shift;

combination 2 , wherein the second part of the parameters corresponding to combination 2 comprises cyclic shift and the number of antenna ports;

combination 3 , wherein the second part of the parameters corresponding to combination 3 comprises cyclic shift and carrier aggregation;

combination 4 , wherein the second part of the parameters corresponding to combination 4 comprises the number of antenna ports and carrier aggregation;

combination 5 , wherein the second part of the parameters corresponding to combination 5 comprises cyclic shift and transmission comb;

combination 6 , wherein the second part of the parameters corresponding to combination 6 comprises cyclic shift and hopping switch;

combination 7 , wherein the second part of the parameters corresponding to combination 7 comprises the number of antenna ports and hopping switch;

combination 8 , wherein the second part of the parameters corresponding to combination 8 comprises carrier aggregation and hopping switch;

combination 9 , wherein the second part of the parameters corresponding to combination 9 comprises cyclic shift and bandwidth.

5. The method of claim 4 , wherein the indicated pre-defined sets of parameter value combinations are combination 1 , and the parameter value combinations of combination 1 indicate the following configurations:

state 1 , wherein the aperiodic sounding reference signal is triggered and the cyclic shift of the aperiodic sounding reference signal is a cyclic shift indicator configured by the radio resource control layer;

state 2 , wherein the aperiodic sounding reference signal is triggered and the cyclic shift of the aperiodic sounding reference signal is a cyclic shift indicator configured by the radio resource control layer and is offset by a first shift offset;

state 3 , wherein the aperiodic sounding reference signal is triggered and the cyclic shift of the aperiodic sounding reference signal is a cyclic shift indicator configured by the radio resource control layer and is offset by a second shift offset.

6. The method of claim 4 , wherein the pre-defined sets of parameter value combinations are combination 2 , and the parameter value combinations of combination 2 indicate the following configurations:

state 1 , wherein the aperiodic sounding reference signal is triggered from only one antenna port and the cyclic shift of the aperiodic sounding reference signal is a cyclic shift indicator configured by the radio resource control layer;

state 2 , wherein the aperiodic sounding reference signal is triggered from only one antenna port and the cyclic shift of the aperiodic sounding reference signal is a cyclic shift indicator configured by the radio resource control layer and is offset by a shift offset;

state 3 , wherein the aperiodic sounding reference signal is triggered from all or half of the antenna ports and the cyclic shift of the aperiodic sounding reference signal is a cyclic shift indicator configured by the radio resource control layer;

or state 3 ′, wherein the aperiodic sounding reference signal is triggered from all or half of the antenna ports and the cyclic shift of the aperiodic sounding reference signal is a cyclic shift indicator configured by the radio resource control layer and is offset by a shift offset.

7. The method of claim 4 , wherein the pre-defined sets of parameter value combinations are combination 3 , and the parameter value combinations of combination 3 indicate the following configurations:

state 1 , wherein the aperiodic sounding reference signal is triggered on one uplink component carrier and the cyclic shift of the aperiodic sounding reference signal is a cyclic shift indicator configured by the radio resource control layer;

state 2 , wherein the aperiodic sounding reference signal is triggered on one uplink component carrier and the cyclic shift of the aperiodic sounding reference signal is a cyclic shift indicator configured by the radio resource control layer and is offset by a shift offset;

state 3 , wherein the aperiodic sounding reference signal is triggered on all activated uplink component carriers or a subset thereof and the cyclic shift of the aperiodic sounding reference signal is a cyclic shift indicator configured by the radio resource control layer;

or state 3 ′, wherein the aperiodic sounding reference signal is triggered on all activated uplink component carriers or a subset thereof and the cyclic shift of the aperiodic sounding reference signal is a cyclic shift indicator configured by the radio resource control layer and is offset by a shift offset.

8. The method of claim 4 , wherein the pre-defined sets of parameter value combinations are combination 4 , and the parameter value combinations of combination 4 indicate the following configurations:

state 1 , wherein the aperiodic sounding reference signal is triggered from one antenna port and on one uplink component carrier and the cyclic shift of the aperiodic sounding reference signal is a cyclic shift indicator configured by the radio resource control layer;

state 2 , wherein the aperiodic sounding reference signal is triggered from all or half of the antenna ports and on one uplink component carrier and the cyclic shift of the aperiodic sounding reference signal is a cyclic shift indicator configured by the radio resource control layer;

state 3 , wherein the aperiodic sounding reference signal is triggered from one antenna port and on at least two uplink component carriers and the cyclic shift of the aperiodic sounding reference signal is a cyclic shift indicator configured by the radio resource control layer;

or state 3 ′, wherein the aperiodic sounding reference signal is triggered from all or half of the antenna ports and on at least two uplink component carriers and the cyclic shift of the aperiodic sounding reference signal is a cyclic shift indicator configured by the radio resource control layer.

9. The method of claim 4 , wherein the pre-defined sets of parameter value combinations are combination 5 , and the parameter value combinations of combination 5 indicate the following configurations:

state 1 , wherein the aperiodic sounding reference signal is triggered, the cyclic shift of the aperiodic sounding reference signal is a cyclic shift indicator configured by the radio resource control layer, and the transmission comb of the aperiodic sounding reference signal is a transmission comb configured by the radio resource control layer;

state 2 , wherein the aperiodic sounding reference signal is triggered, the cyclic shift of the aperiodic sounding reference signal is a cyclic shift indicator configured by the radio resource control layer and is offset by a cyclic shift offset, and the transmission comb of the aperiodic sounding reference signal is a transmission comb configured by the radio resource control layer;

state 3 , wherein the aperiodic sounding reference signal is triggered, the cyclic shift of the aperiodic sounding reference signal is a cyclic shift indicator configured by the radio resource control layer, and the transmission comb of the aperiodic sounding reference signal is a transmission comb different from that configured by the radio resource control layer;

or state 3 ′, wherein the aperiodic sounding reference signal is triggered, the cyclic shift of the aperiodic sounding reference signal is a cyclic shift indicator configured by the radio resource control layer and is offset by a cyclic shift offset, and the transmission comb of the aperiodic sounding reference signal is a transmission comb different from that configured by the radio resource control layer.

10. The method of claim 4 , wherein the pre-defined sets of parameter value combinations are combination 6 , and the parameter value of combinations of combination 6 indicate the following configurations:

state 1 , wherein the aperiodic sounding reference signal is triggered, the cyclic shift of the aperiodic sounding reference signal is a cyclic shift indicator configured by the radio resource control layer, and hopping is not adopted for the aperiodic sounding reference signal;

state 2 , wherein the aperiodic sounding reference signal is triggered, the cyclic shift of the aperiodic sounding reference signal is a cyclic shift indicator configured by the radio resource control layer and is offset by a cyclic shift offset, and hopping is not adopted for the aperiodic sounding reference signal;

state 3 , wherein the aperiodic sounding reference signal is triggered, the cyclic shift of the aperiodic sounding reference signal is a cyclic shift indicator configured by the radio resource control layer, and hopping is adopted for the aperiodic sounding reference signal;

or state 3 ′, wherein the aperiodic sounding reference signal is triggered, the cyclic shift of the aperiodic sounding reference signal is a cyclic shift indicator configured by the radio resource control layer and is offset by a cyclic shift offset, and hopping is adopted for the aperiodic sounding reference signal.

11. The method of claim 4 , wherein the pre-defined sets of parameter value combinations are combination 7 , and the parameter value combinations of combination 7 indicate the following configurations:

state 1 , wherein the aperiodic sounding reference signal is triggered, the number of antenna ports of the aperiodic sounding reference signal is the number of antenna ports configured by the radio resource control layer, and hopping is not adopted for the aperiodic sounding reference signal;

or state 2 , wherein the aperiodic sounding reference signal is triggered, the number of antenna ports of the aperiodic sounding reference signal is the number of antenna ports configured by the radio resource control layer, and hopping is adopted for the aperiodic sounding reference signal.

12. The method of claim 4 , wherein the pre-defined sets of parameter value combinations are combination 8 , and the parameter value combinations of combination 8 indicate the following configurations:

state 1 , wherein the aperiodic sounding reference signal is triggered, the carrier aggregation of the aperiodic sounding reference signal is carrier aggregation configured by the radio resource control layer, and hopping is not adopted for the aperiodic sounding reference signal;

or state 2 , wherein the aperiodic sounding reference signal is triggered, the carrier aggregation of the aperiodic sounding reference signal is carrier aggregation configured by the radio resource control layer, and hopping is adopted for the aperiodic sounding reference signal.

13. The method of claim 4 , wherein the pre-defined sets of parameter value combinations are combination 9 , and the parameter value combinations of combination 9 indicate the following configurations:

state 1 , wherein the aperiodic sounding reference signal is triggered, the cyclic shift of the aperiodic sounding reference signal is a cyclic shift indicator configured by the radio resource control layer, and the aperiodic sounding reference signal is a wide-band reference signal;

state 2 , wherein the aperiodic sounding reference signal is triggered, the cyclic shift of the aperiodic sounding reference signal is a cyclic shift indicator configured by the radio resource control layer, and the aperiodic sounding reference signal is a narrow-band reference signal;

state 3 , wherein the aperiodic sounding reference signal is triggered, the cyclic shift of the aperiodic sounding reference signal is a cyclic shift indicator configured by the radio resource control layer, is offset by a cyclic shift offset, and the aperiodic sounding reference signal is a narrow-band reference signal.