BASE STATION AND TAG CHANGE METHOD IN MOBILE COMMUNICATION SYSTEM

摘要

PROBLEM TO BE SOLVED: To change a timing advance group (TAG) in a situation suitable for changing the TAG of user equipment (UE).SOLUTION: A base station in a mobile communication system in which carrier aggregation (CA) is performed includes: a transmission section for transmitting a timing advance (TA) value for adjusting transmission timing of an uplink signal in user equipment (UE) to the UE; a receiving section for receiving the uplink signal transmitted by the UE according to the TA value; and a TAG determination section for determining the TAG including a group of CCs in which the TA value is shared for each user equipment. The TAG determination section determines whether or not a first and a second CCs are to be included in the same TAG, as to whether or not a timing difference between a first receiving timing at which the uplink signal of the first CC is received from the UE and a second receiving timing at which the uplink signal of the second CC is received from the UE is a predetermined value or larger.