Patent ID: 7519017

Claim:
An apparatus comprising: at least one AP (Access Point) arranged to set and transmit a bit of a beacon message corresponding to a station for exchanging traffic, to register the station on a PS-polling list upon an acknowledgment of the beacon message being received, a time slot calculator to assign a predetermined time slot to the station, and to transmit the at least one piece of traffic during the time slot, when at least one piece of traffic is to be exchanged for wireless voice communication; and at least one station adapted to be awakened into an active mode to parse the received beacon message, to calculate the assigned time slot when a bit of the station is set, and to awaken into the active mode during the assigned time slot to exchange the at least one piece of traffic, when the beacon message has been received from the AP upon being in a doze mode; wherein the time slot calculator is adapted to determine that the start time of the time slot has varied upon frames not being exchanged for a predetermined number of times between the start time of the time slot assigned by the AP and the end time of the time slot, and to recalculate the start time of the time slot in response to the determination.