| Mobility of mobile station, which is generally energized by battery, implies that energy-saving becomes a wireless network issue so that lifetime of mobile station can be extended before recharging. Therefore, energy-saving strategy is recently specified in the MAC protocol. To support battery powered mobile broadband wireless access devices efficiently, IEEE 802.16e defines a sleep mode operation for conserving the energy of mobile terminals. Nevertheless, if the MS works in high load, frequent startups will cost so much energy that such an energy-saving mechanism is not energy efficient. And excessive listen window will still consumption energy so large limited energy that cannot meet the requirement of practical services when the mobile station works in light traffic load. In addition, with the rapid development of radio resource management, more and more attentions are paid on reduce receive and transmit data power consumption, one of the essential problems is to allocate radio resources efficiently so that the overall performance of networks can be improved while meet the quality of services requirements. The objective of this dissertation is to enhance the energy efficiency and to bind the delay in the required range over 802.16e sleep mode operation. We conduct our energy-saving strategy into three topics, i.e., the sleep mode start-up time, the dynamic parameter setting and the bandwidth allocating properly and efficiently. The main contributions of this work are as follows:1. To solve the problem of energy consumption inefficient due to frequently sleep-awake transitions when mobile stations'traffic load is high, we propose a heuristic algorithm to improve the energy efficiency of battery powered IEEE 802.16e devices according to real time traffic load of the network. By analyzing the sleep mode operation presented idle state with a precise Markov chain model, we explore the relationship among traffic load, energy consumption and idle check time. Based on the analytical results, we propose a dynamic algorithm to tune the idle check time according to the statistical measurement of traffic load.2. Energy-saving efficiency is very important in IEEE 802.16 sleep mode operation. To solve the problem of excessive listening interval in sleep mode of IEEE 802.16e, which is generally reduces the efficiency of be used air interface and waste a lot of limited energy resources of a mobile station, a dynamic algorithm based on cross-layer design is proposed to set the parameters of sleep mode operation with real-time sleep cycle from MAC layer and the information of physical layer. Then, the Base Station adjusts the parameters from the flow intervals information of its physical layer. A Markov chain model was presented to analyze the energy efficiency and mean sojourn time of packets in the base station. It is proved that the proposed algorithm can achieve marked gain in power consumption compared to the traditional sleep mechanism with a Markov chain model.3. For lack of bandwidth allocation algorithm in IEEE 802.16e standard, a research strategy is presented, which is to transform equivalent assignable bandwidth into equivalent assignable time. We emphasize on building the utility-based resource management model. Then, a bandwidth allocation algorithm based on the priority weighting, which is decided by network function of mobile station, residual capacity of battery, traffic characteristics and signal to interference ratio of subcarrier, is proposed to significantly decrease computational complexity. The proposed algorithm may optimize resource allocation according to traffic characteristics by allocation rate, power efficiency and the inclination parameters of the utility function which can be flexibly shifted to meet different traffic characteristics demand.
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