跨层自适应无线资源分配方案

提出了一种新的跨层自适应资源分配方案,该方案不仅考虑了业务数据到达的随机特性、数据缓存队列状态、业务时延等MAC层的QoS要求,还考虑了无线信道的时变特性和功率限制,并通过自适应技术实现了系统性能的优化.仿真结果显示,该方案提高了系统频谱效率、功率效率和系统容量,可以满足多用户实时业务的QoS要求,是一种适用于时变选择性衰落信道的资源分配方案.

Cross-layer adaptive wireless resource allocation scheme

A new cross-layer adaptive resource allocation scheme for real-time services under a time-varying fading wireless communication system was proposed,in considevation of not only the random service arrival,limited buffers and QoS requirements at MAC layer,but also the wireless channel characteristics,and end-to-end system performance was improved the thanks to adaptive process.The algorithm(CLARA) was composed of two parts:adaptive scheduling and adaptive subcarrier-power allocation.The adaptive scheduling controlled the order in which packets from different users were served according to traffic QoS requirements,such as packet delay,buffer status as well as CSI.The second part dynamically allocated subcarriers and the corresponding transmission power to users according to scheduling results,traffic QoS requirements,such as BER and the BS power constraint.Thus,the system performance could be improved by sufficient exploiting of time diversity,frequency diversity and multiuser diversity.Simulation results show that the CLARA algorithm has about 7dB gain when the throughput,which was defined as successfully received packets in a frame,began to stablize compared to fixed subcarrier-power allocation.The performance of normalized packet delay,which was defined as the ratio of total packets delayed in simulation with the total simulation times,was also significantly improved by the algorithm.