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为提高认知环境中次用户的吞吐量性能,提出了一种基于QoS的MAC协议. 认知节点将信道状态映射为向量,收端与发端通过“与”操作得到最终的信道映射,并获得备选信道集合. 上层应用程序传来的数据根据QoS要求被划分为2个优先级,每种级别的数据对应不同的竞争窗口,从而保证了实时数据具有较高的优先级. 使用二维离散时间马尔科夫链分析了系统的性能并推导出系统吞吐量的数学表达式. 仿真结果证实,与IEEE 802.11 DCF相比,所提协议有助于提高系统吞吐量.
In order to improve the throughput performance of sub-users in cognitive environment, a QoS-based MAC protocol is proposed, in which cognitive nodes map channel states into vectors, and final and final channel mappings are achieved between the receiving and the sending end through "and And obtain an alternative channel set.The data from the upper application is divided into two priorities according to the QoS requirements, each level of data corresponds to a different contention window, thus ensuring the real-time data has a higher priority.Using two Dimensional discrete-time Markov chain analyzes the performance of the system and deduces mathematical expressions of the system throughput.The simulation results show that the proposed protocol can improve system throughput compared with IEEE 802.11 DCF.