RANGING METHOD FOR MOBILE COMMUNICATION SYSTEM USING ORTHOGONAL FREQUENCY DIVISION MULTIPLEXING ACCESS, ESPECIALLY CONCERNED WITH GIVING PRIORITY TO ACTIVE SUBSCRIBER TERMINALS TO PERFORM BANDWIDTH REQUEST RANGING

• Main Authors: CHO, MIN HEE, EOM, KWANG SEOP, SUNG, SANG HOON, SONG, BONG GEE
• Format: Patent
• Language: English; Korean
• Published: 07.02.2005
• Edition: 7
• Subjects: ELECTRIC COMMUNICATION TECHNIQUE; ELECTRICITY; MULTIPLEX COMMUNICATION; TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHICCOMMUNICATION

PURPOSE: A ranging method for a mobile communication system using OFDMA is provided to give priority to active subscriber terminals to perform bandwidth request ranging, consequently access delay can be minimized and collisions of ranging code is prevented. CONSTITUTION: A mobile communication system includes ranging slots and ranging codes for ranging for user terminals and a base station. The ranging are divided into a bandwidth request ranging and a periodical ranging. An initial ranging is performed when an initial ranging request is generated under a null state(810) before performing the initial ranging. When the initial ranging is successful, the operation state is shifted to an idle state(820). The operation state is shifted to a connection state(830) when the bandwidth request ranging is generated at the idle state. The operation state is shifted to a busy state(840) when the bandwidth request ranging is successful. A bandwidth request ranging is performed using a scheduled access method when the bandwidth request ranging occurs at the busy state. The operation state is shifted to a hold state(850), when data transmission is terminated at the busy state. The bandwidth request ranging is performed using the scheduled access method when the bandwidth request range is generated at the hold state.