Method and apparatus for automatic gain control in vehicle-to-everything system

A method by a second terminal in a wireless communication system, the method comprising:

• determining whether to receive a preamble for an automatic gain control (AGC) based on a subcarrier spacing;
• monitoring a slot and at least one symbol in the slot to receive the preamble for the AGC, in case that it is determined to receive the preamble for the AGC;
• and
• receiving, to a first terminal, the preamble for the AGC in the slot and the at least one symbol in the slot,
• wherein the slot and the at least one symbol in the slot to receive the preamble for AGC is determined by the first terminal, in case that it is determined by the first terminal to transmit the preamble for the AGC,
• wherein the slot is a previous slot of a slot to which a signal for the second terminal is transmitted, and the at least one symbol includes a last symbol or a last two symbols of the previous slot, and
• wherein a length of the at least one symbol is determined based on the subcarrier spacing for the slot.

A first terminal in a wireless communication system, the first terminal comprising:

• a transceiver configured to communicate with other network entities;
• and
• a controller configured to:
• determine whether to transmit a preamble for an automatic gain control (AGC) based on a subcarrier spacing,
• determine a slot and at least one symbol in the slot to transmit the preamble for AGC, in case that it is determined to transmit the preamble for the AGC, and
• transmit, to a second terminal, the preamble for the AGC in the determined slot and at least one symbol in the slot,
• wherein the slot is a previous slot of a slot to which a signal for the second terminal is transmitted, and the at least one symbol includes a last symbol or a last two symbols of the previous slot, and
• wherein a length of the at least one symbol is determined based on the subcarrier spacing for the slot.

A second terminal in a wireless communication system, the second terminal comprising:

• a transceiver configured to communicate with other network entities;
• and
• a controller configured to:
• determine whether to receive a preamble for an automatic gain control (AGC) based on a subcarrier spacing,
• monitor a slot and at least one symbol in the slot to receive the preamble for AGC, in case that it is determined to receive the preamble for the AGC, and
• receive, to a first terminal, the preamble for the AGC in the slot and the at least one symbol in the slot,
• wherein the slot and the at least one symbol in the slot to receive the preamble for AGC is determined by the first terminal, in case that it is determined by the first terminal to transmit the preamble for the AGC,
• wherein the slot is a previous slot of a slot to which a signal for the second terminal is transmitted, and the at least one symbol includes a last symbol or a last two symbols of the previous slot, and
• wherein a length of the at least one symbol is determined based on the subcarrier spacing for the slot.