| 摘要 |
PROBLEM TO BE SOLVED: To achieve reduction in power consumption of each radio node, efficient access control and the like, in an electronic tag system or sensor network system for which power saving at radio nodes is important. SOLUTION: A fixed period starting from a beacon transmitted from a gateway (GW) 100 is specified separately from an active period during which each radio node (P2P tag) transmits/receives a frame, and a sleep period during which a frame transmitting/receiving operation is halted. Further, the active period is divided by a plurality of fixed-length timeslots, such a period is divided and set such that each class of GW, fixed node (P2P-S tag) and mobile node (P2P-M tag) can perform frame transmission, respectively. Each P2P tag randomly selects a timeslot from the period for its own class and after waiting just for a random waiting time in the selected timeslot, a frame is transmitted which includes information specifying its own ID and the selected timeslot or the waiting time. COPYRIGHT: (C)2011,JPO&INPIT
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