Transmission scheduling in multi-carrier multi-code spread aloha inter-vehicle communications system

Intelligent Transportation System (ITS) sets its target at a quite high level such as zero fatalities, to which safety driving support with inter-vehicle communications can largely contribute. Because code division multiple access (CDMA) technology provides delay-free channel access, we developed a CDMA-based inter-vehicle communications system, called a multi-carrier multi-code spread ALOHA (MM-SA) system, to meet challenging requirements on supporting safety driving. This paper introduces a transmission scheduling method that is a key function of MM-SA to provide highly reliable communications between vehicles. The performances of MM-SA are evaluated under realistic traffic accident scenarios. Our evaluation results show that MM-SA system is a promising solution to offering safety driving support.