Cooperative relay system (CRS) is an efficient wireless communication approach, with the advantage of creating diversity. In order to minimize the average symbol error rate (ASER) of a CRS with amplify-and-forward relaying protocol (AF-CRS) in the Nakagami-m fading channel, the optimum relay location and allocating optimal power is determined. To achieve this goal, the ASER for the AF-CRS in the Nakagami-m channel for different modulations is calculated. Then, three scenarios are considered. First, an algorithm, based on fixed point theory to determine the optimal location of the AF relay with a given power allocation for the source and relay, is proposed. Second, the problem of optimizing power allocation for different relay locations is solved. Finally, an algorithm for joint optimization of the power-location that leads to more efficient system operation, is proposed. In this paper, it is shown that the optimum power allocation and relay location is independent of the parameter m of the Nakagami channel. Also, the effect of the path-loss exponent (PLE) on the optimal relay location in the CRS, which shows that the relay should be located closer to the source in dense channels (like near-Earth environments relative to free-space), is investigated. Finally, Simulations and numerical results, which confirm the theoretical achievements, are presented.
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