Evaluation of Joint Sleep and Idle Mode in IEEE 802.16e WIMAX
Broadband access networks provide high rate network connection to stationary users. The IEEE 802.16e is defined as a standardized technology that specifies wireless air interface between the fixed or mobile stations. Power saving has been an important challenge issue in mobile broadband wireless access networks because all mobile stations are operating with limited lifetime of batteries. Although the IEEE 802.16e standard adopts the sleep mode operation for power saving with three parameters including the idle threshold, the initial sleep window and the final sleep window. The standard does not define any mechanism to setup these parameters. However, these parameters impose significant effect on average delay and average power consumption. To improve energy efficiency, this paper proposed a battery lifetime aware mechanism to adaptively adjust sleep mode of mobile stations and extend their battery lifetime. Our proposed mechanism was examined with computer simulation. The simulation results demonstrate that the proposed mechanism outperforms the IEEE 802.16e standard in terms of average alive time of mobile stations.