Cooperative Magnetic Induction Communications: Performance Analysis and Power-Location Optimization

Magnetic induction (MI) has been proven to be an efficient wireless communication technique in extreme en-vironments. In this paper, we investigate the cooperative MI (CMI) communications that use the decode-and-forward (DF) relay (CMI-DF) with the maximal ratio combiner to enhance the output signal-to-noise (SNR). Specifically, by taking into account the angular misalignment in dynamic MI channels, we first derive the closed-form expression for the probability density function (PDF) of the output SNR. Then, the average bit-error-rate (BER) for the CMI-DF communications is rigorously analyzed according to the derived PDF. Furthermore, the optimal power allocation and relay location strategies are proposed to minimize the average BER. Theoretical analyses and simulation results show that the CMI-DF with power-location optimization achieves significant increases in the reliability for MI-based communications in extreme environments.