An algorithm to eliminate self-interference of bidirectional relaying for satellite communication systems

An algorithm to eliminate self-interference of bidirectional relaying for satellite communication system is proposed to deal with the problem that the spectrum resource strain is increasing and adjacent band interference is hard to remove in satellite communication systems. Both the uplink and downlink transmission in grand stations occupy the common matching band and the relaying satellite plays the role of amplification and forwarding to achieve frequency reuse. Since the self-transmitted signal is known to certain ground terminal, the interference of its emission signal can be reduced by using the relay register to multitap sampling of itself transmitted signal, and calculating a weighted sum of the samples with the weights determined from interference of the multitap samples to received signal. The symbol is recovered from the residual signal by network grille. The algorithm dynamically adjusts the size of grille according the signal modulation and code delay length. The proposed algorithm can effectively reduce the decoding complexity, and shorten the satellite communication link establishment time, while the bit error rate is ensured. Simulation results and comparisons with the full network grille algorithm show that when the modulation is 16APSK the SNR are 27 dB and the bit error ratio is 10^-3 for both methods but the decoding complexity of the proposed method is only 10% of that of the full network grille algorithm.