时变OFDM稀疏信道估计中最优导频选择

针对时变OFDM系统中基于压缩感知的频率选择性衰落信道估计,为了提高其估计精度,结合最优导频选择方式,给出一种自适应求最优导频方法。通过闭环反馈信道稀疏度变化的方式,实时的求取最优导频进行信道估计,并与周期性求最优导频方法进行对比分析。仿真结果表明,自适应方法具有更低的信道估计均方误差,与随机方式相比,性能增益平均提高了11 dB,比周期性方法,平均提高了4 dB,且自适应方法误差曲线更平滑。

Choice of optimized pilot for sparse channel estimation in OFDM systems over time-varying channels

In orthogonal frequency division multiplexing (OFDM) systems, the frequency selective channel estimation problem is investigated by using compressed sensing (CS) theory. In order to improve the precision of channel estimation, combining with the way to optimize the pilot placement, a scheme of attaining the optimized pilot adaptively is obtained. Through a way of closed loop feedback the channel sparsity, we calculate the optimal pilot in real time; also we study and compare it with the periodic way. Simulation results show that attaining the optimized pilot adaptively has much lower mean square error of channel estimation, compared with the random way, the performance gain has increased 11 dB in average, even in comparison with the periodic way, it also has enhanced 4 dB in average, and the error curve is much smooth.