Improved ComNet Based on Expectation Propagation for CP-Free OFDM System

To promote the performance of ComNet and OAMPNET for CP-free OFDM, improved ComNet based on expectation propagation (IComNet-EP) is proposed in this paper. The IComNet-EP receiver includes channel estimation network (CENET), expectation propagation equalization (EPE) block and demodulation module. The channel state information is estimated by a model-driven neural network, CE-NET. Due to inter-symbol interference (ISI), the EPE block removes the ISI by buffering the previous OFDM symbol first and then detects the signal by expectation propagation algorithm. The IComNet-EP has comparative complexity with the OAMP-NET and ComNet but has better robustness for the detection part. The simulation results show that the proposed scheme offers a much lower bit-error rate than competitive algorithms.