瑞利衰落信道下改进的AMC/SR-ARQ跨层设计方案  

A modified cross-layer scheme with AMC/SR-ARQ over Rayleigh fading channels

作　　者：郝丹丹[1] 肖峻峰[1] 邹仕洪[1] 程时端[1] 

机构地区：[1]北京邮电大学网络与交换技术国家重点实验室,北京100876

出　　处：《高技术通讯》2007年第7期686-692,共7页Chinese High Technology Letters

基　　金：973计划（2003CB314806）和国家自然科学基金（60603060,60502037,90604019）资助项目.

摘　　要：针对瑞利衰落信道提出了一种改进的自适应调制编码（AMC）与选择性自动重传请求（SR-ARQ）相结合的无线网络跨层设计方案.通过在计算不同调制方式对应的信噪比区间门限值时使用信道状态信息的二阶统计特性来计算误比特率（BER）,使得选取的调制方式因考虑了无线信道的时变特性而更为合理,从而保证了为用户提供有服务质量（QoS）保证的服务.同时,对系统信道状态和系统吞吐进行了建模,并提出了N-成功/N＋1-失败系统吞吐模型.在系统模型的基础上,对比分析了改进的方案和现有方案的性能指标.仿真实验证明,改进的AMC/SR-ARQ方案可以真正确保网络的平均误包率约束条件并提高平均频谱效率.A modified cross-layer scheme combined with adaptive modulation and ceding （AMC） and selective repeat-automatic repeat request （SR-ARQ） was proposed for wireless networks over Rayleigh channels. When computing the thresholds of signal-to-noise-rate （SNR） levels corresponding to each modulation mode, the more suitable modulation mode was selected by estimating bit error rate （BER） based on the second-order statistics method. The selected modulation mode was more suitable for providing QoS guaranteed services because of considering the time-varying characters of the channels. Moreover, a Markov model and the N-succeed/N ＋ 1-failure model were modeled for channels and system throughput respectively. The performance of the proposed scheme has been compared with one of the existing scheme by simulations in three performance metrics. And the simulation results demonstrate that the modified scheme does guarantee the average packet error rate （PER） as well as improve the average spectral efficiency.

关 键 词：AMC SR-ARQ 跨层 无线网络 

分 类 号：TN911.22[电子电信—通信与信息系统]