中文摘要：

为了更有效地实现IEEE802．16e正交频分多址接人（OFDMA）系统的服务质量（QoS）保证，提出了一种基于功率和信道联合预留的准人控制策略．介绍了一种子信道和功率分配算法，该算法将预留信道以外的可用信道完全分配从而实现发射功率最小化．针对2种切换用户——小区间切换用户和小区内切换用户，分别设计了2种预留方案，并引入2个切换预留因子．为了在呼叫阻塞概率和呼叫损耗概率之间寻求折中，以最小化服务等级（GoS）作为优化选择切换预留因子的目标，并通过动态调整预留因子，用较低的计算复杂度实现对最优解的逼近．仿真结果表明，这种自适应的方式有效地优化了系统的GoS，并且联合预留策略的GoS性能优于功率预留策略．

英文摘要：

A novel admission control scheme based on joint power and channel reservation was proposed for quality of service （QoS） guarantee in IEEE 802.16e orthogonal frequency division multiple access （OFDMA） system. A joint subchannel and power allocation algorithm for WiMAX system was introduced to minimize the overall downlink transmit power by utilizing all available subchannels except the reserved ones. Two reservation schemes for inter-cell handoff calls and intra-cell handoff calls were designed respec- tively. Correspondingly, two reservation factors were introduced. The reservation factors were optimally determined by minimizing the metric of grade of service （GoS） in order to achieve a tradeoff between call blocking rate and call dropping rate. And a suboptimal solution with lower computational complexity was introduced by dynamically adapting the reservation factors. Simulation results show that the adaptive approach can efficiently optimize the GoS performance, and the joint power and channel reservation is better than the power reservation scheme in terms of GoS performance.