Channel-Sounding Method Using a Plurality of Antennas, and Apparatus for Same

1. A method of transmitting sounding reference signals in a wireless communication system, the method comprising: generating, by a user equipment (UE), sounding reference sequences for multiple antenna ports of the UE, wherein each sounding reference sequence is defined using a base sequence number and a cyclic shift value; mapping, by the UE, each sounding reference sequence to resource elements of a corresponding antenna port of the multiple antenna ports on a single carrier frequency division multiple access (SC-FDMA) symbol of a subframe; and transmitting, by the UE, the sounding reference sequences for the multiple antenna ports within the SC-FDMA symbol of the subframe, wherein sounding reference sequences for a first group of antenna ports among the multiple antenna ports are mapped to a first set of every two resource elements in the SC-FDMA symbol of the subframe, wherein sounding reference sequences for a second group of antenna ports among the multiple antenna ports are mapped to a second set of every two resource elements in the SC-FDMA symbol of the subframe, the second set being different from the first set, wherein the cyclic shift value is defined for each antenna port within N cyclic shift values based on a signaled value and an offset corresponding to each antenna port of the multiple antenna ports, and wherein N is a predetermined positive integer equal to or greater than 2.

2. The method of claim 1 , wherein the SC-FDMA symbol is a last SC-FDMA symbol of the subframe.

3. A method of processing sounding reference signals in a wireless communication system, the method comprising: receiving, by a base station (BS), sounding reference sequences for multiple antenna ports of a user equipment (UE) on resource elements of a single carrier frequency division multiple access (SC-FDMA) symbol of a subframe, wherein each sounding reference sequence is defined using a base sequence number and a cyclic shift value; and de-mapping, by the BS, each sounding reference sequence from the resource elements of a corresponding antenna port of the multiple antenna ports on the SC-FDMA symbol of the subframe, wherein sounding reference sequences for a first group of antenna ports among the multiple antenna ports are de-mapped from a first set of every two resource elements in the SCFDMA symbol of the subframe, wherein sounding reference sequences for a second group of antenna ports among the multiple antenna ports are de-mapped from a second set of every two resource elements in the SC-FDMA symbol of the subframe, the second set being different from the first set, wherein the cyclic shift value is defined for each antenna port within N cyclic shift values based on a signaled value and an offset corresponding to each antenna port of the multiple antenna ports, and wherein N is a predetermined positive integer equal to or greater than 2.

4. The method of claim 3 , wherein the SC-FDMA symbol is a last SC-FDMA symbol of the subframe.

5. The method of claim 3 , further comprising: estimating an uplink channel state using the de-mapped sounding reference sequences.

6. A user equipment (UE) for use in a wireless communication system, the UE comprising: a radio frequency (RF) unit configured to transmit signals; and a processor, configured to: generate sounding reference sequences for multiple antenna ports of the UE, wherein each sounding reference sequence is defined using a base sequence number and a cyclic shift value; map each sounding reference sequence to resource elements of a corresponding antenna port of the multiple antenna ports on a single carrier frequency division multiple access (SC-FDMA) symbol of a subframe; and transmit the sounding reference sequences for the multiple antenna ports within the SC-FDMA symbol of the subframe, wherein sounding reference sequences for a first group of antenna ports among the multiple antenna ports are mapped to a first set of every two resource elements in the SC-FDMA symbol of the subframe, wherein sounding reference sequences for a second group of antenna ports among the multiple antenna ports are mapped to a second set of every two resource elements in the SC-FDMA symbol of the subframe, the second set being different from the first set, wherein the cyclic shift value is defined for each antenna port within N cyclic shift values based on a signaled value and an offset corresponding to each antenna port of the multiple antenna ports, and wherein N is a predetermined positive integer equal to or greater than 2.

7. The UE of claim 6 , wherein the SC-FDMA symbol is a last SC-FDMA symbol of the subframe.

8. A base station (BS) for use in a wireless communication system, the BS comprising: a radio frequency (RF) unit configured to transmit signals; and a processor configured to: receive sounding reference sequences for multiple antenna ports of a user equipment (UE) on resource elements of a single carrier frequency division multiple access (SC-FDMA) symbol of a subframe, wherein each sounding reference sequence is defined using a base sequence number and a cyclic shift value; and de-map each sounding reference sequence from the resource elements of a corresponding antenna port of the multiple antenna ports on the SC-FDMA symbol of the subframe, wherein sounding reference sequences for a first group of antenna ports among the multiple antenna ports are de-mapped from a first set of every two resource elements in the SCFDMA symbol of the subframe, wherein sounding reference sequences for a second group of antenna ports among the multiple antenna ports are de-mapped from a second set of every two resource elements in the SC-FDMA symbol of the subframe, the second set being different from the first set, wherein the cyclic shift value is defined for each antenna port within N cyclic shift values based on a signaled value and an offset corresponding to each antenna port of the multiple antenna ports, and wherein N is a predetermined positive integer equal to or greater than 2.

9. The BS of claim 8 , wherein the SC-FDMA symbol is a last SC-FDMA symbol of the subframe.

10. The BS of claim 8 , wherein the processor is further configured to estimate an uplink channel state using the de-mapped sounding-reference sequences.