Method and apparatus for transmitting sounding reference signal in wireless communication system of unlicensed band and method and apparatus for triggering sounding reference signal transmission
Disclosed herein is a method for transmitting, by a terminal, a sounding reference signal (SRS). The terminal receives a grant for uplink multiple subframes from a base station. The terminal determines a first subframe for an SRS transmission of the terminal among the uplink multiple subframes on the basis of SRS transmission position information received from the base station. Further, the terminal transmits the SRS in the first subframe.
1. An apparatus for transmitting a sounding reference signal (SRS) through an unlicensed band, the apparatus comprising:
a processor; a memory; and a communication device,
wherein the processor executes a program stored in the memory to perform:
receiving a downlink control information (DCI) for triggering an SRS transmission through uplink multiple subframes from a base station;
determining an SRS subframe for the SRS transmission among the uplink multiple subframes on the basis of SRS transmission position information of 2 bits included in the DCI received from the base station; and
transmitting the SRS in the SRS subframe,
wherein the SRS transmission position information of 2 bits indicates that the SRS is not transmitted, or the SRS is configured in a first subframe of the uplink multiple subframes, or the SRS is configured in a second subframe of the uplink multiple subframes, or the SRS is configured in a last subframe of the uplink multiple subframes.
2. The apparatus of claim 1 , wherein:
the determining comprises:
receiving the SRS transmission position information of 2 bits from the base station when a first value is 4 and a second value is 4, wherein the first value is the maximum number of subframes included in the uplink multiple subframes and a second value is the maximum number of subframes configurable for the SRS transmission among the uplink multiple subframes.
3. The apparatus of claim 1 , wherein:
the determining comprises:
determining a time domain symbol for the SRS transmission among time domain symbols in the SRS subframe on the basis of SRS symbol position information, and
the SRS symbol position information is included in a UE-specific SRS configuration parameter signaled by a higher layer.
4. The apparatus of claim 1 , wherein:
the determining comprises:
determining a first time domain symbol for the SRS transmission of the terminal among time domain symbols in the SRS subframe on the basis of SRS symbol position information, and the SRS symbol position information is included in the DCI for triggering of the SRS transmission.
5. A apparatus for triggering, by a base station, a sounding reference signal (SRS) transmission in an unlicensed band, the apparatus comprising:
a processor; a memory; and a communication device,
wherein the processor executes a program stored in the memory to perform:
granting, to a first terminal, first uplink multiple subframes including a plurality of SRS subframes in which the SRS transmission is possible;
triggering the SRS transmission in a first SRS subframe among the plurality of SRS subframes for the first terminal through first downlink control information (DCI) for granting the first uplink multiple subframes;
granting the first SRS subframe to a second terminal; and
triggering the SRS transmission in the first SRS subframe for the second terminal through second DCI for granting the second uplink multiple subframes,
wherein the granting the first SRS subframe to a second terminal comprises:
granting, to the second terminal, the second uplink multiple subframes which is different from the first uplink multiple subframes and comprises the first SRS subframe.
6. The apparatus of claim 5 , wherein:
the triggering of the SRS transmission for the first terminal comprises:
triggering the SRS transmission in the first SRS subframe and the remaining SRS subframes among the plurality of SRS subframes for the first terminal, through an SRS request field included in the first DCI.
7. The apparatus of claim 5 , wherein:
the triggering of the SRS transmission for the first terminal comprises:
triggering the SRS transmission in the headmost first SRS subframe among the plurality of SRS subframes for the first terminal, through an SRS request field included in the first DCI, and
the SRS transmission in the remaining SRS subframes other than the first SRS subframe among the plurality of SRS subframes is not triggered.
8. The apparatus of claim 7 , wherein:
a physical uplink shared channel (PUSCH) is configured in a last time domain symbol of the remaining SRS subframes.
9. The apparatus of claim 5 , wherein:
the triggering of the SRS transmission for the first terminal comprises:
triggering the SRS transmission in the first SRS subframe that is the last subframe among the plurality of SRS subframes for the first terminal, through an SRS request field included in the first DCI, and
the SRS transmission in the remaining SRS subframes other than the first SRS subframe among the plurality of SRS subframes is not triggered.
10. The apparatus of claim 5 , wherein:
the triggering of the SRS transmission for the first terminal comprises:
triggering the SRS transmission in the first SRS subframe for the first terminal, through an SRS request field included in the first DCI, and
the triggering of the SRS transmission for the second terminal comprises:
triggering the SRS transmission in the first SRS subframe for the second terminal, through an SRS request field included in the second DCI.
11. The apparatus of claim 10 , wherein:
the SRS is not transmitted in the remaining subframes other than the first SRS subframe among the first uplink multiple subframes, and
the SRS is not transmitted in the remaining subframes other than the first SRS subframe among the second uplink multiple subframes.