基于滤波器组的多载波系统的整体性能完全由一个原型滤波器决定,例如频率选择特性、符号间干扰和信道间干扰.为构建近似完全重构的多载波系统,提出了一种迭代算法来设计原型滤波器.该算法将设计问题归结为一个无约束的优化问题,其目标函数为符号间干扰、信道间干扰以及原型滤波器阻带能量的加权和.通过推导目标函数的梯度向量和海森矩阵,采用修正牛顿算法来迭代优化原型滤波器,每次迭代更新中,原型滤波器都是通过闭合公式求解,因此算法的计算复杂度很低.仿真实验表明,与已有的设计算法相比,所提出的算法提高了系统的整体性能.%Filter bank based multicarrier(FBMC) modulation system is characterized by a single prototype filter which determines the overall performance,including the frequency selectivity,intersymbol interference(ISI),and interchannel interference(ICI).An efficient design algorithm is proposed to design the prototype filter for nearly perfect reconstruction (NPR) FBMC system.The design problem is formulated into an unconstrained optimization problem that minimizes the weighted sum of the ISI/ICI,and stopband energy.By deriving the gradient vector and Hessian matrix of the objective function of the problem,the modified Newton's method is employed to iteratively optimize the prototype filter,which is updated with closed-form formula at each iteration,implying low computational complexity.Numerical examples and comparison with existing methods are included to demonstrate the improved performance of the proposed algorithm.
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