Enhancing the DSRC reliability to allow the coexistence of VANET´s applications

The Dedicated Short Range Communication (DSRC) technology has been adopted by the IEEE community to enable safety and non-safety application for Vehicular Ad hoc Networks (VANETs). To better serve these two classes of applications, the DSRC standard divides the bandwidth into seven channels. One channel, called control channel (CCH) to serve safety applications and the other six channels, called service channels (SCHs) to serve non-safety applications. The DSRC standard specifies a channel switching scheme to allow vehicles to alternate between these two classes of application. The standard also recommends that vehicles should visit the CCH every 100ms, called Synchronization Interval (SI), to send and receive their status messages. It is highly desirable that these status messages be delivered to the neighbouring vehicles reliably and within an acceptable delay bound. It is obvious that increasing the time share of the CCH from the SI will increase the reliability of safety applications. In this paper, we will optimize the control channel access such that safety applications have a high successful transmission rate within their share of the SI interval. Moreover, a new algorithm, called Optimal Channel Access (OCA), will be introduced to enhance the performance of the DSRC while keeping the CCH I as small as possible. Hence non-safety applications will have a fair share of the DSRC bandwidth.