Adaptive Equalizer Design for Unmanned Aircraft Vehicle Image Transmission over Relay Channels

A novel length adaptive method is proposed for time domain equalizer by taking the channel attenuation ratio between different multipath components into account in UAV‐UAV and UAV‐ground channels. Then, considering received image quality, the minimum bit error ratio (MBER) criterion is exploited to design adaptive equalizers for both amplify‐and‐forward (AF) and decode‐and‐forward (DF) relaying systems by the proposed length adaptive method. Results show that proposed MBER adaptive equalizers outperform the traditional ones in both AF relaying and DF relaying as channel attenuation ratio in UAV‐ground channel increases. Moreover, DF outperforms AF as channel attenuation ratio in UAV‐UAV channel increases. Furthermore, bit error ratio (BER) and peak signal‐to‐noise ratio (PSNR) performances in both AF and DF are evaluated to show the enhancement by the proposed MBER adaptive equalizers.