Patent ID: 8014369
Filing Date: 2011-09-06
Classification: H04W

Abstract:
1. An adaptive power management method for use in a first station and a second station in an ad hoc wireless local area network, in which the second station enters an NBI (Normal Beacon Interval) every certain number of BIs (Beacon Intervals) for power saving and data reception, where the certain number of consecutive BIs is called an LI (Listen Interval), comprising: determining the length of LI (in units of BI) which is one or a prime number that is larger than two, wherein the BIs in the LI are denoted as 0th, 1st, 2nd, . . . , and (n−1)th BIs, respectively, where n is the value of LI, and setting the 0th BI in the LI as the NBI, wherein the NBI comprises an AW (ATIM Window) comprising a BW (Beacon Window), where a station transmits its beacon frame within the BW, transmits and receives ATIM frames within the AW, returns an ATIM ACK (acknowledgement) to a specific station transmitting the ATIM frame and remains awake after the AW ends to wait for the reception of data frames when receiving an ATIM frame within the AW, and returns a data ACK if a data frame is received; determining the number of BBIs (Beacon-Window-Only Beacon Intervals) and determining the positions of the NBI and BBIs in the LI to form a cyclic difference set, in which each of the BBIs comprises a BW (Beacon Window), and the second station broadcasts a beacon frame within the BW of every BBI, and enters a doze state in the BBI after the end of the BW, the beacon frame comprises a station identification and an RBI (Remaining number of BIs) representing the remaining number of BIs between the BBI and the NBI, wherein the beacon frame is transmitted in the BBI; and the first station receiving the beacon frame from the second station in the ad hoc wireless local area network, recording the RBI corresponding to the second station, predicting the NBI of the second station according to the RBI, and transmitting a data frame to the second station at the NBI of the second station in the ad hoc wireless local area network.