COMMUNICATION SYSTEM, COMMUNICATION METHOD, AND CHILD STATION OF COMMUNICATION SYSTEM

摘要

A child station (3) of a communication system performs communication while synchronizing the reference time of a parent station (2) with the local time (RT) of the child station (3). When the child station (3) is switched from a normal mode to a power saving mode in accordance with a mode change instruction from the parent station (2), correction is performed for one or both of a stop period in which the apparatus of the child station (3) is stopped and a non-stop period in the power saving mode using an error (Δt) generated during the time between the reference time of the parent station (2) and the local time (RT) of the child station (3). This makes it possible to synchronize the parent station (2) with the child station (3) and reliably and efficiently transfer a control frame (CF) from the parent station (2) to the child station (3).

主权项

1. A communication system including a parent station and one or a plurality of child stations,
said parent station comprising: a parent station communication unit that has a reference time and communicates with said plurality of child stations; one or a plurality of parent station power control units each of which determines whether said child station should be in a power saving mode in which an apparatus is periodically partially or wholly stopped or in a normal mode in which the apparatus is operated without being partially or wholly stopped, and instructs said child station to change a mode; and one or a plurality of parent station period measurement units each of which measures a stop period in which the apparatus of the child station is partially or wholly stopped and a non-stop period in which the apparatus of the child station is not stopped in the power saving mode, and said child station comprising: a child station communication unit that performs communication while synchronizing the reference time of said parent station with a local time of said child station; a child station power control unit that changes the mode between the power saving mode and the normal mode of the child station in accordance with the mode change instruction from said parent station; and a child station period measurement unit that measures the stop period and the non-stop period of said child station, wherein said child station period measurement unit performs correction for one or both of the stop period and the non-stop period in the power saving mode using an error obtained by calculating a difference that is generated during the power saving mode between the reference time of said parent station and the local time of the child station.