Information on power save

[channareddy]

Can anybody explains how power save works in IEEE 802.11 b standards

[badger11]

I think you are talking about power save polling. PSP allows a client to power down for a fraction of a second which enables the client to save battery life. PSP works differently in a basic service set than ad hoc mode.

PSP in a BSS the client sends a frame to the access point notifying the access point it is going into sleep mode, The access point makes a record and buffers any frames destined for the client in sleep mode. Access points are constantly sending out beacons which contain what is called a traffic indication map (TIM). Since the client is time synched with the access point and the beacons are sent at a regularly scheduled time intervals the client knows when to listen for the beacon. The client will check out the TIM to see if it is listed in the TIM. IF it is in the TIM the client then powers up and sends a frame to the access point indicating it is ready for the data. The access point then sends the data. The process starts over again.

Hope that helps and makes sense to you.

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