Method and apparatus for indicating timing advance in communication system

A method performed by a user equipment (UE) in a communication system, the method comprising:

• receiving, from a base station, configuration information on a non-terrestrial network (NTN) communication;
• identifying a value of a timing advance (TA);
• transmitting an uplink signal by applying the value of the TA;
• identifying that a TA report is triggered based on a threshold value for the TA report configured by the base station;
• and
• transmitting, to the base station, the TA report via a medium access control (MAC) control element (CE),
• wherein the TA report includes the value of the TA that the UE calculates, and the value of the TA included in the TA report is determined with reference to a timing of TA reporting, and
• wherein the value of the TA is associated with a first offset common for plural UEs and a second offset specific for the UE.

A base station in a communication system, the base station comprising:

• a transceiver;
• and
• a controller coupled with the transceiver and configured to:
• transmit, to a user equipment (UE), configuration information on a non-terrestrial network (NTN) communication,
• receive, from the UE, an uplink signal associated with a timing advance (TA), and
• receive, from the UE, a TA report via a medium access control (MAC) control element (CE),
• wherein the TA report is triggered based on a threshold value for the TA report configured by the base station,
• wherein the TA report includes a value of the TA that the UE calculates, and the value of the TA included in the TA report is determined with reference to a timing of TA reporting, and
• wherein the value of the TA is associated with a first offset common for plural UEs and a second offset specific for the UE.

A user equipment (UE) in a communication system, the UE comprising:

• a transceiver;
• and
• a controller coupled with the transceiver and configured to:
• receive, from a base station, configuration information on a non-terrestrial network (NTN) communication,
• identify a value of a timing advance (TA),
• transmit an uplink signal by applying the value of the TA,
• identify that a TA report is triggered based on a threshold value for the TA report configured by the base station, and
• transmit, to the base station, the TA report via a medium access control (MAC) control element (CE),
• wherein the TA report includes the value of the TA that the UE calculates, and the value of the TA included in the TA report is determined with reference to a timing of TA reporting, and
• wherein the value of the TA is associated with a first offset common for plural UEs and a second offset specific for the UE.