Patent ID: 6956829

Claim:
A method for measuring a propagation delay value of a frame transmitted by a UE (User Equipment) to a Node B in a TDD (Time Division Duplexing) mobile communication system including a frame divided into two sub-frames, each of the sub-frames having a plurality of time slots and also having a downlink pilot time slot and an uplink pilot time slot, both intervening between a first time slot and a second time slot of the plurality of time slots, the system also including the Node B for transmitting the frame fixed to a time axis, and the UE for transmitting a propagation-delayed frame in response to the frame received from the Node B, the method comprising the steps of: acquiring synchronization with the Node B based on a downlink pilot channel signal transmitted in a period of the downlink pilot time slot, and determining an estimated round trip delay value T 1 by comparing transmission power of a physical common channel signal in the first time slot with reception power of the physical common channel signal; transmitting an uplink pilot channel signal by applying the estimated round trip delay value T 1 to a desired transmission point of the uplink pilot channel signal; receiving a transmission point correcting value T 2 through a forward physical access channel (FPACH) signal transmitted from the Node B in a period of one downlink time slot among the time slots; and transmitting a physical random access channel (PRACH) message with the estimated round trip delay value T 1 at a transmission point determined based on the transmission point correcting value T 2 and the estimated round trip delay value T 1 , so that the PRACH message is received at the Node B at a start point of a period of one uplink time slot among the time slots.