Improving Performance of Packet Combining Relay for ITS V2V Communication

Packet payload combining relay (PCRL) scheme was proposed to increase efficiency of relaying and achieve higher reliability in vehicle-to-vehicle (V2V) broadcast communication. Effectiveness of the scheme, however, is limited when the number of vehicle stations becomes large. This paper studies airtime occupancy ratio (AOR) of the relaying schemes and its relationship with packet delivery rate, assuming large number of vehicle stations locating around an intersection. A modified PCRL scheme is proposed to reduce the AOR and obtain better packet delivery rate by introducing adaptive modulation and coding at relay station. Simulated results show that the proposed scheme can effectively reduce the AOR that is increased by relaying, and improves performance of the V2V communication at intersection.