Low-complexity group precoding in multi-beam satellite systems

The lattice reduction aided Tomlinson-Harashima precoding (LRA-THP) is computationally intensive. In order to reduce the computational complexity, a low-complexity group precoding algorithm is proposed for multi-beam satellite systems based on an existing group precoding algorithm. Users are split into groups according to the distance between beams in the proposed algorithm. Then, preprocessing matrix is obtained by maximizing the successive signal-to-leakage-plus-noise ratio (SSLNR) to suppress the inter-group interference. The LRA-THP is applied in each group. The characteristic of the multi-beam satellite channel is exploited to reduce the dimension of the preprocessing matrix which results in computational complexity reduction. Simulation results show that the complexity of the proposed algorithm is much less than that of the LRA-THP. Furthermore, the proposed algorithm reduces the complexity over the existing group precoding algorithm by 24% while limiting the performance loss to 0.1 dB. In addition, the proposed algorithm can provide a flexible tradeoff between the performance and complexity. ©, 2015, Harbin Institute of Technology. All right reserved.