Patent ID: 8379557

Claim:
A method for controlling sleep mode of a mobile station, the method comprising: determining N of the N-ary exponential sleep mode to decide a length of a sleep duration including a sleep interval, wherein N is equal to or greater than 2; measuring the amount of downlink traffic addressed to the mobile station at the beginning of a listening interval right after the sleep interval; when there exist downlink traffic but m times, wherein m is greater than zero, additional consecutive sleep duration is not expired, confirming whether the measured amount of the downlink traffic satisfies a mode transition condition; conducting a sleep interval of a next sleep duration of which the length is determined by multiplying the length of a current sleep duration by the N unless the measured amount of the downlink traffic satisfies the mode transition condition; and transmitting the downlink traffic to the mobile station when the m times the additional consecutive sleep duration is expired or when the measured amount of the downlink traffic satisfies the mode transition condition even when the m times the additional consecutive sleep duration is not expired.