Bidirectional Block Decision Feedback Equalization for the Hybrid Carrier System

In this letter, a novel bidirectional block decision feedback equalization (BI-BDFE) algorithm is proposed for hybrid carrier (HC) systems based on the weighted-type fractional Fourier transform (WFRFT). This innovative algorithm employs a bidirectional BDFE structure in the WFRFT domain, which not only highlights the inherent advantage of HC architecture in combating doubly selective fading but also effectively mitigates the error propagation issue inherent in conventional unidirectional BDFE. Numerical results demonstrate that under doubly selective channels, the proposed BI-BDFE achieves significantly superior bit error rate (BER) performance compared to existing nonlinear equalization schemes.