Outage probability bound analysis in vehicle-assisted inter-vehicular communications

The paper studies two moving vehicles exchanging messages assisted by another vehicle which is used as a relay. All the vehicle-to-vehicle (V2V) links are modeled as flat double-Rayleigh fading. Based on this particular channel model, the OPA (optimal power allocation) solutions are derived through maximizing source-to-destination channel capacity on the assumptions of amplify-and-forward relaying strategy. Then, the outage probability is discussed and the lower bound on it is acquired. Simulation results manifest that the OPA method improves the average throughput of the IVC (inter-vehicular communication) system by about 2 dB at low SNR (signal-to-noise ratio) and has no less than 2 dB gains on outage probability at medium to high SNR over equal power allocation (EPA) scheme. They also show that the lower bound on outage probability approximates to the Monte Carlo numerical calculations at low to medium SNR region and, as the exact outage probability is not easy to obtain, it can be used to estimate the outage performance of the relay-assisted IVC system roughly.