Patent ID: 7904070

Claim:
A method for searching and releasing an abnormal subscriber station in a wireless communication system, the method comprising: allocating one group number from among periodic ranging code groups to a subscriber station upon receiving a ranging request of the subscriber station, and transmitting the allocated group number and a corresponding ranging code to the subscriber station; determining a ranging code group that includes the ranging code when a ranging request message including the ranging code is transmitted from the subscriber station; classifying and processing the ranging request message for the ranging code group and searching for an abnormal group that includes the abnormal subscriber station from among the ranging code groups; transmitting a connection maintenance request message only to subscriber stations included in the abnormal group to determine an operation status of each of the subscriber stations included in the abnormal group and searching for the abnormal subscriber station in the abnormal group in accordance with the determined operation statuses; and releasing a connection of the abnormal subscriber station.