基于梯度追踪的压缩感知超宽带通信信道估计

摘要

针对现有压缩感知超宽带信道估计方法运算复杂度较高的问题,提出了基于梯度追踪算法的压缩感知超宽带信道估计方法.将超宽带信道估计转化为压缩感知的重构问题,并使用梯度追踪算法进行重构得到信道估计值,最终实现信息解调.梯度追踪算法通过每步计算目标函数的负梯度方向和搜索步长,使目标函数沿负梯度方向以此步长搜索得到每步重构值的最优解,从而避免了正交匹配追踪算法中高维度最小二乘运算以及基追踪算法中求解凸优化问题所导致的运算复杂度高的缺点.仿真结果表明该方法相对于正交匹配追踪算法和基追踪算法能够降低运算复杂度,提高运算速度,同时依然能够保证估计效果.%An ultra wide-band (UWB) channel estimation method based on gradient pursuit (GP) algorithm is proposed.UWB is a newly developed high-speed wireless communication technology.It is difficult to sample it directly as its wider band width.However,compressed sensing(CS) provides a novel way with lower sampling speed.Considering the high complexity of current CS-UWB channel estimation method,UWB channel estimation is transformed as a CS reconstruction problem.Then GP algorithm is used to obtain the estimated channel value and decode the UWB signal.GP algorithm computes the negative gradient direction and the searching step size of objective function at each iteration,then objective function is searched at the negative gradient direction and step size to find optimum.The method avoids to compute the high dimensional least square problem in orthogonal matching pursuit(OMP) algorithm and the convex optimization problem in basis pursuit(BP) algorithm with complicated computation.The simulation results show that the method can reduce the computational complexity,increase the computational speed compared with OMP and BP algorithms,and remain the excellent estimation performance.