Collision Warning System in Dynamic Cooperative Environment with Alamouti STBC Algorithm

Emergency Medical Services (EMS) accident notification time is often delayed in areas with sparse cellular coverage and non-periodic communication access points. It is possible to mitigate such coverage gaps using cooperative communication which, by its distributed nature, does not rely on fixed base stations in remote areas. In the event of a collision EMS notification can be relayed through surrounding cellular equipped vehicles. This paper proposes a cooperative environment using Amplify and Forward (AF) protocol to communicate with the nearest accessible base station to transmit a collision message or even video for the first responders. The intent of the paper is to analyze the performance of different modulation techniques in this dynamic surrounding using Alamouti Space-Time Block coding (STBC) scheme for achieving spatial diversity. Use of multiple relay antennas is used to improve the diversity. Data is encoded using a space-time block code, and then split into n streams which are simultaneously transmitted using n transmit antennas. The paper examines if the cooperative relaying technique outweighs the advantages of a fixed relay system due to the dynamic nature of the highway.