Information Multihop Forward Strategy Design And Implementation Based On WAVE Protocol Stack

With the increase of vehicles, more and more cities are faced with the problem of traffic congestion, ITS(Intelligent Transportation System) gradually shows its promising market. WAVE(Wireless Access in Vehicular Environment) is one of the hot technology of ITS, dominated by the US Department of Transportation, and developed by IEEE. It is a suitable vehicle mobile ad-hoc network communication technology between vehicles. WAVE protocol stack is composed of IEEE 802.11 p and IEEE 1609 protocol suite, and follows the OSI(Open System Interconnection) hierarchical model design.WAVE protocol stack provides IPv6 protocol and WSMP(WAVE Short Message Protocol) protocol to support data transmission on data plane. WSMP protocol is a point to point communication protocol, and do not provide multi-hop functionality. The IP parameters of IPv6 are configured by the system administrator, or information obtained from the WSA(WAVE Service Advertisement), and do not provide multi-hop functionality. Meanwhile WAVE stack provides multi-channel operation at the bottom layer, the bottom layer channel switch will affect the upper application forwarding information. WAVE protocol stack provides a standardized set of services and interfaces enables communication between the vehicles, and communication between the vehicle and infrastructure. They only support a hop within communication range, therefore the communication range of WAVE devices is limited.Based on the overall framework of the WAVE protocol stack, against the characteristics of the WAVE protocol stack of multiple channels of information transmission, this paper proposes forwarding information on the next service channel SCH(Service Channel), provides a new way to solve the problem of multi channel information forwarding. At the same time, according to different application requirements, this paper proposes the mandatory and optional forwarding mode, to meet the different application requirements of information forwarding.Subsequently, based on information forwarding in a multi-channel, against unicast multi-hop and broadcast multi-hop messages, this paper takes different processing strategies. For the broadcast multi-hop messages forwarding, through the node selectively forwarding its never forwarded message, avoids heavy network load and simple flooding message repeated forwarding problem. For the unicast multi-hop messages forwarding, this parper proposed GPSR-A routing strategy which based on geographic location. This routing strategy based on GPSR route, introducing the speed and direction information, assist greedy routing; adding angles and distances constitute GPSR-AD algorithm, handle greedy forwarding failures; introducing lifetime in the neighbor node list, perfect neighbor node list update.Finally, this paper based on the OMNeT ++ simulation platform, used Veins for simulation framework, build road model by SUMO, simulate the information forwarding under multi-channel and two routing policies. Experimental results show that the information forwarded under the multi-channel strategy is effective, and GPSR-A location-based routing strategie will have better packet delivery ratio and smaller delay.