车载网VANET是一种应用于智能交通系统的新型无线移动自组织网络(mobile ad hoc network,MANET).随着车辆以及移动ad hoc网络技术的发展,车载网已经成为一个新兴的研究领域.针对VANET中车辆行驶的特征,提出一种拓扑相对稳定的车辆分簇算法.在此算法基础上,根据专用短程通信(dedicated short range communication,DSRC)标准中控制信道(control channel,CCH)和服务信道(service channel,SCH)的分配,考虑车辆间的无线通信干扰和不同应用的QoS需求,提出一种基于分簇的多信道混合型MAC协议,簇内通信采用非竞争的TDMA机制,簇间通信采用基于竞争的CSMA/CA机制,相邻簇采用不同的服务信道.模拟实验表明,提出的MAC协议在同时满足实时应用的延迟需求和非实时应用的吞吐量方面,优于现有协议.
VANET features. On the basis of this algorithm, according to DSRC (dedicated short range communication) allocation of CCH (control channel) and SCH (service channel), considering the wireless communication interference between vehicles and the QoS requirements for different applications, the paper also proposes a cluster-based multi-channel hybrid MAC protocol. The non- competition based TDMA scheme is taken for intra-cluster communications and the competition based CSMA/CA scheme is taken for inter-cluster communications. The different SCHs are allocated for neighbor clusters. Such a concept is attractive as it can be combined with cluster-based routing strategies. So the overhead introduced by the clustering process is beneficial not only on one layer, but for the whole communication process. Simulation experiments show that the protocol is superior to the current MAC protocol in the delay requirement of safety applications and the throughput of non- safety applications.