Patent ID: 7304978

Claim:
A medium access control method, for use in a communication network system including a control station for controlling access to a network and a plurality of terminal stations for accessing the network under the control of the control station, and for controlling network access by using a time division technique, the method comprising: steps performed by the control station of: generating transmission schedules for a plurality of communications performed in the network, the transmission schedules including information allocating a time zone usable for each of the communications; collecting the transmission schedules and generating one schedule frame based on the collected transmission schedules; transmitting the generated schedule frame to the plurality of terminal stations; and performing a communication in a time zone which is allocated to the control station, and steps performed by each of the terminal stations of: receiving the schedule frame transmitted by the control station; determining, based on the received schedule frame, a terminal station's own time zone in which communication can be performed; and performing the communication in the determined time zone; steps performed by the control station and each of the terminal stations of: monitoring a state of transmission of another station; detecting that communication is not performed by the other station in the time zone allocated by the transmission schedule or that communication has been completed by the other station before an end time allocated by the transmission schedule; and starting the station's own transmission earlier than scheduled by using an unused time zone of the other station based on the detection results in the detecting step.