Performance Evaluation of DS/SS Inter Vehicle Communication System

Application of CSMA/CA (Carrier Sense Multiple Access/Collision Avoidance) scheme is widely studied for IVC (Inter Vehicle Communication in ITS (Intelligent Transport Systems). By using CSMA, it is possible to share single frequency band by multiple users by changing the packet transmission timing. CSMA is applied to many systems such as wireless LAN, IVC and so on because of its simple implementation. However CSMA scheme has a problem called "hidden terminal problem" which degrades the communication performance. In this paper, CDMA (Code Division Multiple Access) scheme using DS/SS (Direct Sequence/Spread Spectrum) is applied to IVC in order to improve "hidden terminal problem". DS/SS CDMA scheme makes it possible to demodulate packets even under the hidden terminal situations with its multiple access performance. In this paper, the performance of DS/SS CDMA IVC system is evaluated. As the result, it was confirmed that IVC performance was well improved and the collisions caused by hidden terminals condition could be reduced.