A study on mobility load balancing methods in IVC and RVC cooperative systems

Association of Radio Industries and Businesses (ARIB) has standardized ARIB STD-T109 for IVC (Inter Vehicle Communications) and RVC (Road to Vehicle Communications) as applications of Intelligent Transport Systems in 700 MHz band. In ARIB STD-T109, IVC and RVC share one channel by employing time division duplex. It is possible to avoid frame collisions between IVC and RVC by this scheme. Moreover, in IVC period, it adopts CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance) for the communication among the vehicles. However, this system suffers from a disadvantage of the increase in the frame collision probability because many vehicles may simultaneously start the IVC transmission procedure at the beginning of IVC period. In this paper, we propose a new mobility load balancing method in order to reduce the collision probability at the beginning of IVC period. Our proposed method randomly distributes the start time of the transmission in IVC period. By computer simulations, we evaluate the proposed method in comparison with the conventional one.