一种无线公交车载网络MAC协议的设计及性能分析

为公交车乘客提供高质量的Internet服务,可以让其在乘车过程中享受娱乐甚至工作,进而大大提高乘客的生活质量.基于此,提出一种无线公交车载网络MAC协议——BusMAC,支持公交车乘客的Internet访问.该协议基于改进的公交车载网络结构,可以大大减少由于公交车上多个用户同时发起产生的大量访问冲突.BusMAC协议基于超帧结构,结合动态竞争机制和捎带机制可以大大减少公交车网络的通信瓶颈.通过建立请求竞争访问模型和数据调度访问模型,对BusMAC协议的性能进行了分析.大量仿真实验结果表明,BusMAC与传统结构及协议相比可以获得相当好的性能,且更加适合于公交车通信.真实移动性场景下的实验说明了该协议在实际系统部署中的可行性.

Design and Performance Analysis of A MAC Protocol for Wireless Public Bus Networks

Providing high quality Internet service in public buses allows bus passengers to entertain themselves and even to work remotely during their travel time, thus significantly improving their quality of life. In this paper, a MAC protocol for public bus networks, called BusMAC, is proposed to provide high quality Internet service for bus passengers. The proposed protocol decreases collisions caused by multiple access from multiple passengers based on the improved bus network architecture. The MAC protocol based on super-frame structure decreases greatly the communication bottleneck in the bus network, combined with dynamical contention and piggyback mechanisms. The performance analysis of BusMAC is carried out based on request contention model and data scheduling model. Each model is expressed as a two-layer structure which catches up two access phases in the proposed MAC protocol. Extensive simulations are conducted to evaluate the BusMAC protocol. With simulations, the performance analytical models are verified to be accurate. Also, the results show that BusMAC can achieve much better performance than the traditional ones, and is more adaptive to bus communication. Specially, the deployment feasibility in the realistic system for the protocol can be accounted for through the experiments conducted under realistic mobility trace scenarios.