| 摘要 |
In a wireless network containing battery powered stations, one station is designated as a control point (CP). Each of the remaining stations has two operating modes: an active mode in which it receives and transmits messages, and an inactive or sleep mode which incurs reduced power consumption. The Control Point periodically transmits a beacon signal, and each station switches to its active mode to receive at least some of these beacon signals. A beacon signal may indicate that data is available for transmission to a particular station (from another station), in which case that particular station then broadcasts a message to indicate that it is awake and can receive messages. A beacon signal also indicates whether a broadcast period is in progress, and time to elapse until a next possible broadcast period will commence; if the Control Point has previously received and stored any broadcast messages it will re-broadcast them during the next following broadcast period and the remaining stations will react by remaining in active mode for the duration of that period.
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