Real-time car-to-car communication protocol for intersecting roads

Space-division multiple access (SDMA) protocols provide a bounded delay communication medium that is collision free. In these protocols, there is one-to-one mapping between a specific location on the road to a bandwidth division (i.e. a specific timeslot). An implicit assumption is that there is no interference among vehicles traveling on different roads that could be within the sensing range of each other. Although this assumption is generally valid for highway scenarios, it does not always hold for urban road scenarios such as intersecting roads. Message losses due to packet collisions can take place near intersections when vehicles from different approaching roads attempt to transmit at the same time. Hence, in this paper, we address the extension of SDMA protocols for intersecting roads. We present and compare two algorithms for this problem based on a set of evaluation criteria for real-time car-to-car communication systems.