A Prototype Filter Design Method for Filter Bank Multi-Carrier Spread Spectrum System in High Frequency Communication

To enhance the anti-jamming capability of Filter Bank Multi-Carrier Spread Spectrum (FBMC-SS) system in HF communications, this paper proposes an optimized design method for prototype filters based on Artificial Fish Swarm Algorithm (AFSA). Since inter-carrier interference (ICI) and inter-symbol interference (ISI) cannot be simultaneously eliminated during the filter optimization process, a balance between the two must be made. Therefore, our filter design primarily focuses on minimizing ICI while partially mitigating ISI. The method establishes a mathematical model based on optimization design specifications of prototype filters. Then it formulates a multivariable joint minimization problem, and employs AFSA for optimized solutions. Comparative evaluations with filter optimization, such as window functions and raised-cosine filtering, were conducted to assess the performance, including spectral characteristics and bit error rate (BER). Simulation results demonstrate that the proposed filter exhibits good performance in stopband attenuation, transition band width and time-domain tail decay rate, in addition to the effective integration with FBMC-SS systems and achieves lower BER in simulated HF channels. In addition, the weighting coefficients integrated into the optimization criterion in this paper can be adaptively adjusted based on channel conditions. This approach offers valuable guidelines for designing prototype filters with enhanced flexibility to meet diverse communication requirements.