An analysis of incident information transmission performance using MCS/CDMA scheme

Incident information transmission using an IVC (inter-vehicle communication) system is one of the most important factors in ITS in order to increase safety and efficiency of road traffic. In IVC systems that use a spread spectrum communication (SS) scheme, when communication traffic goes into crowded conditions due to an increase of density of vehicles and IVC traffics, communication resources beyond the capacity of the system are sometimes required and this leads to unstable communication. Under this situation, the incident information that must be transmitted immediately is afraid to be jammed by excessive IVC traffics and relay transmission of the incident information may be intercepted. In this paper, an IVC system based on slotted MCS/CDMA scheme is proposed in order to avoid such a situation. The proposed system prepares an exclusive time slot for incident information in order to prioritize incident information from the general IVC packets that are less important than the incident information packets. As the result, it is considered that the possibility of interception of relay transmission can be decreased. Since the proposed system prepares an exclusive slot of incident information, there is a disadvantage where IVC throughput is reduced by an addition of an exclusive slot. In this paper, the performance of the proposed system is examined by computer simulation and optimization of parameters is discussed.