Improving Emergency Messages Transmission Delay in Road Monitoring based WSNs

The main wireless technology used for events sensing and data collection is wireless sensor devices. These sensors are mounted on vehicles or in the roadside to send data collected periodically or upon incident detection. In this latter case, ensuring low transmission delay from the detector sensor to WSNs gateway is a real challenge. Indeed, faster notification of the Traffic Management System (TMS) leads to more efficient reaction to the emergency situation. Thus, cars collision and human lives loss as well as road traffic jam will be mitigated. In this paper, we investigate the Medium Access Control (MAC) layer in WSNs to improve the real time data collection scheme. To this end, we propose an enhanced backoff selection scheme for IEEE 802.15.4 protocol to ensure fast transmission of the detected events on the road towards the TMS. The main feature of our scheme is its ability to assign a shorter waiting time for messages carrying critical information without changing the basic principle of the backoff mechanism. The obtained simulation results under various scenarios have proven the effectiveness of our scheme in terms of transmission delay reduction.