Design and Optimization of Linear Phase Sr-Nyq Filter Based on Genetic Algorithm

In band-limited digital communications, SquareRoot Nyquist (SR-NYQ) filters are commonly utilized at both the transmitter and receiver to effectively minimize sampling intersymbol interference (ISI). In this papar, we propose a novel design method for linear-phase SR-NYQ filters based on genetic algorithms (GA). Due to the excellent global optimization capability of GA, the proposed method employs a fitness function integrating the filter ISI, passband ripple and stopband ripple. It enables a closer approximation to the Nyquist (NYQ) condition while providing additional flexibility. Moreover, we test the proposed SR-NYQ filter and the conventional Rcosine filter of Matlab softwere, when they are applied to the Orthogonal Frequency Division Multiplexing (OFDM) modulation. Simulations show significant symbol error rate (SER) reductions for the proposed SR-NYQ filter, due to its better frequency response.