Selective DF Relaying for Mobile Satellite Broadcasting

This paper addresses mobile terminal (MT) relaying in order to improve the performance of mobile satellite broadcasting. It considers selective decode-and-forward (SDF) relaying with BICM-OFDM air interface. The BER upper bound was derived for the threshold-based SDF relaying in Rician fading channels. The suboptimal SNR threshold was then obtained by minimising this analytical upper bound. This scheme is compared in simulation with a conventional CRC and set threshold schemes. It is shown that the proposed suboptimal-SNR threshold scheme gives up to 1 dB performance gain compared to the conventional CRC-based scheme in the moderate E-b/N-o range (i.e., 2 dB < E-b/N-o < 8 dB). The proposed scheme also significantly outperforms the set threshold schemes (0 dB and 10 dB thresholds). The proposed and CRC-based schemes both offer around 2 dB performance improvement in comparison to the single link for a typical E-b/N-o of 10 dB.