无线Mesh网络的跨层设计理论与关键技术

由于无线M esh网络(WMN)在拓扑、传输和业务上的特性,传统的用于有线网络的分层协议设计方法已不能保证其服务质量(QoS).探索基于物理层、MAC层、路由等协议层的WMN跨层设计方法的目标是在无线资源利用率和多媒体业务的QoS需求两方面达到较好的折衷.WMN各个协议层在设计过程中的有关协议和算法要求附加统一的跨层管理器,监测各层的分组传输性能或需求,动态控制或调节相关算法.通过实现较高协议层的多媒体业务QoS需求与较低协议层的网络状态信息在各协议层之间的共享,可以达到对协议层控制算法的优化.在合理地选择跨层设计目标的基础上,多个协议层需要联合设计与优化.从物理层、MAC层、路由协议层和TCP层等层面介绍了WMN跨层设计的一般原则和方法.归纳了目前WMN跨层设计中亟待深入研究的一些理论和关键技术,包括自适应速率与节能机制、基于QoS需求的跨层MAC协议设计和路由协议设计等.

Theory and Key Technologies of Cross-Layer Design in Wireless Mesh Networks

Due to the characteristics of wireless mesh network(WMN) in terms of topology,transmission link and traffic,the conventional layered protocol design methods for wired networks can not guarantee the QoS performance for WMN.To reach a tradeoff between the efficiency of radio resources and QoS requirements to multimedia traffic,it is required to explore the new design method for WMN based on physical layer,MAC layer,routing layer,etc.A unified cross-layer manager for all the layers is a necessity to monitor the transmission performances or requirements,thereby to control or adjust the relevant algorithms dynamically.The protocol and algorithm in respective layers are optimized by sharing the information on the QoS requirements to higher layers and the network states in lower layers,and multiple protocols in relevant layers are co-designed and co-optimized after the targets to be cross-layer designed are reasonably chosen.The general principles and methods of cross-layer design from physical,MAC and routing layers to TCP layer were presented respectively,and the theory and key technologies to be deeply researched were outlined,including the design of adaptive rate control and energy-saving mechanism,QoS-based MAC protocol and routing protocol.