The use of vehicle's on-board sensors in increasing the perception of cooperative vehicles is becoming prevailing and essential for the road safety. However trusting only on the on-board sensors could limit the perception of the cooperative vehicles for example an object/vehicle can not be detected if it is impeded by some obstruction. The perception efficiency of vehicles can be increased beyond their field of view (FoV) by exchanging the sensor detected information through V2X communication. The perception of vehicles can be more accurate as much as frequent they share the information. However by transmitting numerous messages could saturate the communication channel and deteriorate the perception improvement specially in the dense circumstances. In this paper we address both these issues and propose two different schemes, (i) an information propagating mechanism to increase the cooperative vehicle's perception above their FoV and (ii) an optimal dynamic cooperative priority based beaconing model to coup with the channel congestion. By using the information propagation mechanism we can increase the perception of cooperative vehicles up to their maximum communication range and on the other end probability based dynamic cooperative priority beaconing scheme selects the most suitable cooperative vehicle to transmit based on its on-board sensor facility. These proposed mechanisms immensely decrease the contention on the channel while extend the perception beyond the FoV. We evaluate both the mechanisms for the performance in terms of vehicles awareness, channel load and communication range through simulations for several vehicle densities. The simulation results show that these proposals provide better performance compare to the classical beaconing schemes.

Intelligent Transportation Systems (ITS) are expected to play a vital role in increasing road safety and road efficiency in the near future. The primary feature of ITS applications is to provide road safety, which is based on IEEE-802.11p technology, by transmitting safety messages to the vehicles in the surrounding. The channel congestion is a significant challenge for the IEEE802.11p, ITS is operating on. Congestion increases the data loss and degrades the ITS performance resulting from compromising passengers safety. In this paper, we analyze the benefits of exploiting vehicle's embedded sensors to enhance car perception and hence improve the efficiency of cooperative communications. To this purpose, we implemented the collaborative environment perception approach for vehicular safety applications proposed by [1] and analyze its performance and behavior in congested urban traffic. In this proposal, so-called ECAM (Extended Cooperative Awareness Message), vehicles use a different type of sensors (cameras, radars, lidars etc.) to collect the status information of the surrounding vehicles in their detection range and share this information through a collaborative beaconing scheme to reduce congestion on the communication channel. This scheme implements a dual step mechanism to function. The first phase implements the collaborative perception mechanism by adding the locally collected information in the safety message and sharing this up to date data to intensify the awareness among the vehicles in its communication surrounding. In the second phase, the recipient vehicles verify the accuracy of the information received from the collective perception enabled vehicles by leveraging the position by adding an error threshold. Performance evaluation conducted through extensive simulations shows the benefits of exploiting increased perception to enhance awareness among cars while reducing the contention on the wireless interface.