Locating the Optimal Sleep Window for Enhancing the Energy Efficiency of VoIP in WiMAX Systems: A Modified Analysis Model and Performance Evaluation

In this paper, we examine the energy-performance tradeoff for the sleep window adjustment in duplex VoIP transmissions. Specifically, we modified the traditional analysis model by giving a new mathematical model to analyze the performance of the sleep scheme, with the natural talking speed, sleep window size, energy expenditure taken into consideration. Guided by this model, we locate the optimal window adjustment parameters for the sleep scheme. Extensive simulation results have validated the analytical model, and indicated that, compared with the traditional scheme, the optimized scheme can achieve as much as 90% reduction in energy dissipation during silence period and prolong battery lifetime for about 20-30%, thus striking a balance between energy conservation and QoS provision.