Adaptive Modulation and Coding for Reliable Vehicular Real-Time Communication

Abstract:
Cooperative vehicles rely on communication to share information for improved decision-making. Related safety requirements for vehicular applications can therefore result in high reliability constraints for vehicular communication. In order to improve reliability in wireless communications, Adaptive Modulation and Coding (AMC) is usually used. However, since reliability requirements are defined for systems and not for single transmissions, traditional AMC has to be improved to meet application level requirements. This work presents a method for AMC based on stochastic channel models to increase reliability. In contrast to traditional AMC, the method is not based on instantaneous or short term channel quality. Instead, we consider communication availability in the sense of preventing too long deep fades causing an unavailable communication system. Therefore, metrics are implemented to map application layer communication availability to channel properties. According to this prediction method, the Modulation and Coding Scheme (MCS) can be adapted to meet strict real-time communication requirements. Since wireless channel properties may change over time, model parameters have to be continuously estimated. Thus, techniques for parameter estimation are described and evaluated.