Method for adjusting transmission timing in multiple access system

A method for adjusting a transmission timing of a terminal station, being performed at a base station in a Time-Division Duplex communication system, the method comprising steps of:

• (a) receiving ranging signals and reference signals transmitted from a terminal station, the reference signals being allocated with different sub-carrier intervals from sub-carrier intervals of the ranging signals, identified by a Time-Division Duplex communication system;
• (b) determining whether a transmission timing at the terminal station is appropriate, based at least in part on the ranging signals transmitted from the terminal station;
• (c) generating an adjusting value of the transmission timing of the terminal station to shift forward the transmission timing, by calculating based at least in part on the reference signals;
• (d) transmitting the adjusting value of the transmission timing to the terminal station;
• and
• (e) repeating the steps (a) to (d) until an adjustment of the transmission timing at the terminal station is appropriate in the step (b).

A method for adjusting transmission timing at a terminal station in a multiple access system, the method comprising steps of:

• (a) receiving a ranging command transmitted from a base station;
• (b) generating a value of a transmission timing for the terminal station, by referring to the ranging command;
• and
• (c) transmitting a ranging signal to the base station, at a timing that is shifted forward corresponding to the value of the transmission timing.

A method for adjusting a transmission timing of a terminal station, being performed between a base station and the terminal station in a multiple access system, the method comprising steps of:

• (a) transmitting, by a terminal station, ranging signals to the base station, the ranging signals being allocated to sub-carriers with an interval in Orthogonal Frequency Division Multiplexing Modulation (OFDM) symbols;
• (b) receiving, by the base station, the ranging signals transmitted from the terminal station;
• (c) determining, by the base station, whether an adjustment of a transmission timing at the terminal station is appropriate, based at least in part on a receiving signal transmitted from the terminal station;
• (d) generating, by the base station, an adjusting value of the transmission timing for the terminal station, by calculating an integral multiple of a timing offset detection capability, the timing offset detection capability being identified by referring to the ranging signal;
• (e) transmitting, by the base station, the adjusting value of the transmission timing to the terminal station;
• (f) receiving, by the terminal station, the adjusting value of the transmission timing;
• (g) transmitting, by the terminal station, another ranging signal to the base station, at a timing that is shifted forward corresponding to the adjusting value of the transmission timing;
• (h) repeating the steps (a) to (g) until an adjustment of the transmission timing at the terminal station is appropriate in the step (c), by adding one to the integral multiple, wherein an initial integral multiple is one in the step (d).

A Time-Division Duplex communication system, the system comprising:

• a base station for (a) receiving a ranging signal transmitted from a terminal station, (b) transmitting a first adjusted value of transmission timing to the terminal station, the first adjusted value of transmission timing is calculated based at least in part on a propagation delay of the ranging signal with an ambiguity, (c) determining whether an adjustment of the transmission timing at the terminal station is appropriate, based on a receiving signal transmitted from the terminal station, under a condition that the adjustment of a transmission timing at the terminal station is formally completed, and (d) transmitting a second adjusted value of transmission timing to the terminal station when the adjustment of the transmission timing is determined to be inappropriate, the second adjusted value of transmission timing is a value of integral multiples of a timing offset detection capability of the ranging signal;
• and
• a terminal station for (a) transmitting the ranging signal to a base station, the ranging signal being allocated to a sub-carrier in an Orthogonal Frequency Division Multiplexing Modulation (OFDM) symbol, (b) receiving the first adjusted value of transmission timing from the base station, (c) transmitting a ranging signal at a first transmission timing based at least in part on the first adjusted value of transmission timing designated by the base station, (d) receiving the second adjusted value of transmission timing from the base station, under a condition that the adjustment of the transmission timing at the terminal station is formally completed, and (e) transmitting a ranging signal at a second transmission timing based at least in part on the second adjusted value of transmission timing designated by the base station.