认知无线电中多址接入的随机延时边界分析

摘要

In Cognitive Radio (CR) systems, Secondary Users (SUs) access to the channels of Primary Users (PUs) by using opportunistic scheduling and multiple access scheme. To analyze the delay performance, the stochastic network calculus is deployed. A stochastic service model is constructed for the two main access schemes, i.e. Contention-Free (CF) access and Contention-Based (CB) access, as well as opportunistic scheduling. And then, a stochastic service curve is derived for the service model, after which, the delay bound is obtained for the SUs. A comparison is made for the computational results of different network configurations, which demonstrates the correctness of the delay bound. And this frame work gives light to the improvement of multiple access scheme for the SUs.%认知无线电(CR)系统中，次用户通过机会调度和多址方式接入主用户信道进行传输。为分析延时性能，该文采用随机网络演算方法，将非竞争接入(CF)和竞争接入(CB)两种主要的多址接入方式，以及机会调度建模为次用户得到的随机服务。然后推导出相应的随机服务曲线，及次用户的延时边界。通过分析比较不同网络参数下的数值计算结果，证明了延时边界的正确性，并为次用户多址接入方式的改进提供了重要的参考。