Patent ID: 7965731

Claim:
A communication apparatus, comprising: a controller which executes a plurality of instructions to: (a) provide data communication using a bandwidth reservation type transmission area via a power line to which an alternating-current voltage is supplied, the bandwidth reservation type transmission area including a plurality of unit groups, wherein a designated number of the unit groups each includes a plurality of different time-divided units and each of the different time-divided units includes a plurality of different time-divided time slots; and (b) for at least one of the different time-divided units: (i) determine whether a first one of the plurality of time-divided time slots of said at least one time-divided unit is vacant; (ii) if the determination is that the first time slot is vacant, secure the vacant first time slot, wherein: (A) a first communication system transmits a first beacon signal to the secured vacant first time slot; and (B) a second communication system transmits a second beacon signal to the secured vacant first time slot; and (iii) if the determination is that the first time slot is not vacant, secure a second, different one of the plurality of time-divided time slots of said at least one time-divided unit, wherein: (A) the first communication system transmits a third beacon signal to the secured second, different time slot; (B) the second communication system transmits a fourth beacon signal to the secured, different time slot; (C) the secured second, different time slot is shared by: (x) the first communication system used by the communication apparatus; and (y) the second communication system; and (D) the second communication system uses the same communication procedure as the first communication system.