An analysis of performance degradation caused by hidden terminal and its improvement in Inter-Vehicle communication

The CSMA scheme that is widely adopted as a media access control in Inter-vehicle communication systems has a hidden terminal problem. And this influence has not yet been analyzed in detail and it is necessary to know the actual influence in order to take appropriate steps against this problem. In this paper, the number of packet collisions that are caused by hidden terminals is analyzed and packet loss rate is shown quantitatively. And it is shown how this problem is improved by using spread spectrum (SS) communication scheme by computer simulation. As a result, it is confirmed that the number of packet collisions that are caused by hidden terminals occurs more than that are caused by carrier sense failures. Moreover, it is also confirmed that packet loss rate can be reduced to up to one-third of the conventional CSMA scheme by using the proposed SS scheme.