面向实时业务的认知无线网络MAC层频谱接入方案

摘要

These protocols have not satisfied the emergent needs of the increasing real-time businesses and high-level service quality. In order to satisfy the requirement for real-time transmission of high broadband service in cognitive radio networks, a low-delay spectrum access scheme of MAC layer, LD-SAS, was proposed. In spectrum sensing phase, the transmission delay can be minimized by choosing the optimum available channel number of sensing channels. In channel access contention phase, the effect of channel conflict problem and deaf terminal problem in multichannel coordination can be reduced by designing channel access frame. The theoretical and experimental results were presented to demonstrate the effectiveness of our proposed protocol. Compared with the traditional MAC protocols for cognitive networks, LD-SAS has shorter delay time and slightly better throughput performance when the probability of channel being idle is bigger.%为满足认知无线网络中宽带业务实时传输的需求，提出低延迟的MAC层频谱接入方案，包括频谱感知调度与信道接入竞争两部分。在频谱感知阶段，认知用户选取最佳可用信道数实现感知与传输的延迟最小化；在信道接入竞争阶段，协议考虑频谱资源动态变化的特点，通过设计数据帧格式以及邻居节点协同侦听机制，减小信道冲突与“聋终端”的影响。理论与实验结果表明，与传统的认知无线网络MAC层协议相比，提出的接入方案数据传输延迟更短，同时在授权信道空闲率较大时吞吐量性能略优。