多波束卫星系统中低复杂度分组预编码算法

Low-complexity group precoding in multi-beam satellite systems

针对格基约减辅助的THP(LRA-THP)算法运算复杂度高问题,在一种分组预编码算法的基础上,提出一种适用于多波束卫星系统的低复杂度分组预编码算法,该算法根据波束间的距离对用户进行分组,通过最大化SSLNR得到预处理矩阵,抑制组间干扰,各组内采用LRA-THP算法,计算预处理矩阵时充分利用多波束卫星信道的特点,降低需要求解的预处理矩阵的维度,从而减小算法的运算复杂度.理论及仿真分析结果显示,该算法的运算量远低于LRA-THP,与原分组预编码算法相比,该算法的复杂度能够降低24%,同时性能损失不超过0.1 d B.另外,该算法中引入一组参数,使其能够灵活地在复杂度与可靠性之间进行折中.

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.