STDMA for Vehicle-to-Vehicle Communication in A Highway Scenario

Vehicle-to-vehicle communication within the intelligent transportation systems has been a hot topic recent years. In this paper the medium access control (MAC) method self-organizing time division multiple access (STDMA) has been simulated in a highway scenario with periodic broadcast packets. Rapidly changing road conditions requires a real-time deadline, so timely and predictable access is especially important to the channel. However, the traditional medium access method used in 802.11p makes a node drop over 80% of its heartbeat messages and as a result, 802.11p using carrier sense multiple access with collision avoidance (CSMA/CA) does not support real-time communications. With STDMA, nodes always get predictable channel access regardless of the number of competing nodes and the maximum delay can be expected. In this paper, we build a simulation platform where the topology dynamically changes and all the nodes need to communicate during the whole simulation in a highway scenario. Then we elaborate with different parameter settings and the results illustrate the relationship between the ratio of reuse and other parameters. Finally we come to a conclusion that with system load increasing, it is helpful to change sensing range and other configuration to reduce the probability of reusing slots by about 10% in order to improve the system performance.