| 摘要 |
PURPOSE:To cope with the increase of an earth station, and also to execute efficiently a channel access by dividing a communication area into plural small zones of at least >=2, assigning one control channel to each small zone, respectively, and making each earth station execute a random access on the control channel. CONSTITUTION:A control signal is accumulated temporarily in a control signal accumulating device 5 because its transmission rate is high, and a collision detecting device 6 fetches a control signal at every zone from the accumulating device 5, and detects whether a collision of an access caused by a disorder of a flag exists or not. In case when the collision of an access does not exist, the control signal is transferred to a central control device 7 through a system data bus 12, and if there is no error, a dead data channel is caught from a data channel busy idle table in a memory 8, a data channel number and an office number brough to an access are sent out to a transmitting device 4, and informed by a down-channel. In case the collision is detected, and access NG signal is sent out, a fact that a packet has collided is informed, then a data channel is reserved. |
