Patent ID: 8867421

Claim:
A method of operating a wireless station, said method comprising: powering-down a portion of said wireless station, wherein said portion comprises a radio circuit and a processor; setting a timer to a first value computed based on an error between a low-frequency clock and a high-frequency clock; and powering up said portion upon expiry of said timer, wherein said timer is operated using a high-frequency clock in awake intervals when said portion is powered up, but is operated using a low-frequency clock when said portion is powered down, said method further comprising receiving a beacon from an access point (AP), wherein powering up based on said error ensures that said beacon is received when said radio circuit is powered up, wherein said processor is also powered down along with said radio circuit, said method further comprising: identifying, using said processor when powered up, a future time instance at which said beacon is expected to be received; initializing said timer to a second value upon powering down of both of said processor and said radio circuit, wherein said second value corresponds to an ideal duration at which a beacon transmission is expected to start; powering up only said processor, at a first time instance, when said timer initialized to said second value expires; using said processor, upon being powered up at said first time instance, determining whether said future time instance has already occurred or not; if said future time instance has already occurred: computing again a next future time instance at which said beacon is expected to be received; maintaining said radio circuit in said powered down mode until said next future time instance and powering up said radio circuit immediately thereafter; and continuing operation of said processor using said high frequency clock until said next future time instance; if said future time instance has not already occurred: computing a difference value corresponding to a duration from a present time instance to said future time instance, wherein said duration is proportionate to said error between said low-frequency clock and said high frequency clock, wherein said difference value is used as said first value in said setting of said timer.