基于改进PLS和PLS_ZP算法的卫星移动通信信道估计

针对传统最小平方(least square,LS)算法和基于离散傅里叶变换(discrete Fourier transform,DFT)的信道估计算法不能有效提高宽带卫星移动信道的传输性能这一问题,提出改进的基于功率判决的LS估计算法(简称PLS)和PLS补零插值算法(简称PLS_ZP).PLS算法在基于DFT估计算法的基础上,利用宽带卫星移动信道的衰落特性,通过对有效抽头数的限制设定功率阈值,抑制有效抽头外的噪声;PLS_ZP算法利用时域补零等效频域内插的原理对原频域插值算法进行改进,充分利用所有已估计导频信息.理论分析和仿真结果表明,与传统信道估计算法相比,PLS和PLS_ZP算法的信道估计均方误差(mean square error,MSE)和误比特率(bit error rate,BER)均有一定程度的提升,且算法复杂度较低,易于硬件实现.

Channel Estimation Based on Improved PLS and PLS_ZP Algorithm for Mobile Satellite Communication System

In order to improve the transmission performance of traditional Least Square(LS) and discrete Fourier transform(DFT) algorithm for broadband mobile satellite channel, an improved power judgement-based LS algorithm named PLS and a PLS with zero padding interpolation algorithm named PLS_ZP were proposed. Based on DFT estimation algorithm, PLS algorithm utilized the fading characteristics of broadband mobile satellite channel, got the power threshold by limiting the number of the effective taps and removed the noise outside the taps. PLS_ZP algorithm improved the original interpolation algorithm in frequency domain by means of the principle that zero padding of the time domain is equivalent to interpolation of the frequency domain, then all the estimated pilot frequency information. Theoretical and experiment results showed that channel estimation mean square error(MSE) and bit error rate(BER) of the proposed algorithm were better than traditional algorithms, and the algorithm complexity was lower for hardware implementation.