Accurate analytical model of saturated throughput of the IEEE 802.11p EDCA <Abstract> The IEEE 802.11p Enhanced Distributed Channel Access (EDCA) is a standardization for vehicle-to-vehicle and road-to-vehicle communications. The saturated throughputs of the IEEE 802.11p EDCA obtained from previous analytical expressions have differences from simulation results. The purpose of this paper is to explain the reason why the differences appear in the previous analytical model of the EDCA. It is clarified that a special state appears at the first time slot of the Backoff procedure, which cannot be expressed in the previous Markov model. In addition, this paper proposes a modified Markov model, which is suitable to analytical expressions of the IEEE 802.11p EDCA. The proposed model describes the node operations at the first time slot of the Backoff procedure accurately by adding new states to the previous model. The validity of the proposed model is confirmed from the quantitative agreements between analytical predictions and simulation results. |