Enhanced channel access control for improving IVC performance in integrated IVC/RVC ITS systems

In ITS communication systems based on ARIB STD-T109 which employs time division channel access integrating Inter Vehicles communication (IVC) and Roadside units to Vehicles communication (RVC) in 700MHz frequency band, the transmission performance for the IVC deteriorates due to its channel access congestions at the head of the IVC periods. To overcome this problem, the channel access control scheme which employs randomly delayed channel access has been proposed to achieve performance improvement by distributing the concentrated channel accesses from vehicles. However, this conventional scheme causes large transmission delay and also its large variance for the IVC packet communications. This paper proposes an enhanced channel access control to suppress the large transmission delay and its large variance. Performance evaluations through computer simulation show the proposed scheme can improve the delay performance while achieving better successful packet reception rate for the IVC in the integrated IVC/RVC ITS communication systems.