Co-channel interference cancellation based on BSS for multi-satellite MIMO communication systems with FFR

Multiple-input multiple-output (MIMO) technology can boost the capacity of conventional satellite communications, and full frequency reuse (FFR) can further improve the capacity by making full use of frequency resources. However, FFR will cause severe co-channel interference and lead to a degradation of channel capacity. Blind source separation (BSS) algorithm can be used to eliminate co-channel interference and does not require prior information, which avoids the extra occupation of channel frequency resources. While the multi-satellite MIMO communication system have delay mixing characteristic, the separation performance will be degraded if the delay is ignored. In this paper, DMBSS algorithm for delay mixing is proposed. Firstly, the DMBSS algorithm utilizes Taylor expansion to achieve dimension expansion of observed signals and so as to transform the delay mixing into instantaneous mixing with extended dimension. Secondly, complex non-orthogonal joint diagonalization algorithm is used to solve the separation matrix equation of extended observation signals and extended source signals and thus to eliminate the co-channel interference. Simulation results show that for multi-satellite MIMO communication scenarios with FFR, the proposed algorithm can effectively improve the performance of co-channel interference cancellation and reduce the value of BER. Furthermore, the influence of order of Taylor expansion on the separation performance is also analyzed and simulated in this paper to show the cost performance of the proposed algorithm.