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

A method for triggering, by a base station, a sounding reference signal (SRS) transmission, comprising:

• 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;
• granting the first SRS subframe to a second terminal;
• and
• triggering the SRS transmission in the first SRS subframe for the second terminal.

A method for transmitting, by a terminal, a sounding reference signal (SRS), comprising:

• receiving timing advance (TA) information for an SRS transmission from a base station, through at least one of a radio resource control (RRC) message and a downlink control information (DCI) message;
• and
• transmitting an SRS at timing based on the TA information by using at least one of an SRS subframe configured for the SRS transmission and an extended uplink pilot time slot (UpPTS),
• wherein the extended UpPTS is spaced by a predetermined interval from a downlink partial subframe having a downlink pilot time slot (DwPTS) length.