Research and Improvement of Sleep Mode in IEEE 802.16e

The IEEE 802.16e provides wide wireless access for mobile stations.It proposes an energy saving mechanism that named sleep mode for conserving the power of the mobile stations(MS).When the mobile station is in the sleep interval,the base station will buffer or drop the traffic send to this mobile station,and indicate the mobile station in the listening interval by broadcast message.When mobile station enters the listening interval,it checks if there is traffic indication message from base station.If so,mobile station will turn into awaken mode to receive traffic.Otherwise,it continue next sleep interval.When in low traffic scenario,the exponential increase algorithm of sleep mode brings on long response time.This paper presents linear increase algorithm to solve this problem.Average response time and average energy consumption are two performance measurements.After theoretical analyses and simulation experiments,the authors compare the two algorithms and conclude that the latter one has better performance.And then the authors analyze the above two performance measurements over each parameter of sleep mode and give the experimental results.The conclusion will be helpful to select the value of parameters.