Optimal Power Allocation Method and Outage Probability Analysis in AP-Assisted Inter-Vehicular Communications

This paper studies the relay-assisted inter-vehicular communications (IVCs) with double Rayleigh fading vehicleto-vehicle links. The OPA (optimal power allocation) solution is derived through maximizing source-to-destination channel capacity assuming amplify-and-forward relaying. The outage performance is discussed and the lower bound on outage probability at medium to high SNR (signal-to-noise ratio) is presented. Simulation results manifest that the ergodic capacity can be improved by about 2 dB at low SNR through OPA method over EPA (equal power allocation) solution, whereas the outage probability decreases more than 2dB at high SNR compared to EPA. They also show that the lower bound on average outage probability approximates to the exact calculation result at medium to high SNR in the relay-assisted IVC system.