Ranging method for mobile communication system based on orthogonal frequency division multiple access scheme

A method for classifying a ranging procedure between a transmission side and reception sides into an initial ranging process, a bandwidth request ranging process, and a periodic ranging process, and varying a number of RCs(Ranging Codes) for use in each ranging process in a cell of which a total number of RCs to be used for the ranging processes is predetermined., the method comprising the steps of:

• determining at the transmission side a number of initial RCs for the initial ranging process, a number of bandwidth request RCs for the bandwidth request ranging process, and the number of periodic RCs for the periodic ranging process, and determining a backoff value of the periodic RCs according to the number of the periodic RCs;
• sending the initial RCs, the bandwidth request RCs, the periodic RCs, and the backoff value of the periodic RCs to the reception sides;
• and
• after receiving the initial RCs, the bandwidth request RCs, the periodic RCs, and the backoff value of the periodic RCs, allowing the reception sides to select a RC corresponding to their current target ranging process, and executing a ranging process corresponding to the selected RC.

A method for classifying a ranging procedure between a transmission side and reception sides into an initial ranging process, a bandwidth request ranging process, and a periodic ranging process, and varying a number of RCs(Ranging Codes) for use in each ranging process in a cell of which a total number of RCs to be used for the ranging processes is predetermined, the method comprising the steps of:

• detecting a congestion level of a current cell, and if the detected congestion level of the cell is over a prescribed congestion level, controlling the number of the initial RCs for the initial ranging process to be less than one of a number of bandwidth request RCs for the bandwidth request ranging process and a number of periodic RCs for the periodic ranging process, and varying a backoff value of the periodic RCs;
• sending the initial RCs, the bandwidth request RCs, and the periodic RCs, and the backoff value of the periodic RCs to the reception sides;
• and
• after receiving the initial RCs, the bandwidth request RCs, the periodic RCs, and the backoff value of the periodic RCs, allowing the reception sides to select a RC corresponding to their current target ranging process, and executing a ranging process corresponding to the selected RC.