Bandwidth efficient transceiver design for differentially encoded OFDM system

摘要

In this paper, we present a bandwidth efficient non-coherent transceiver design for single input single output orthogonal frequency division multiplexing (SISO-OFDM) modulation with differential encoding. Under fast channel fading or in low signal-to-noise ratio (SNR) regime, pilot assisted channel estimation is not feasible. In such channel conditions, conventional non-coherent detection methods are not reliable resulting in poor throughput. We propose a frequency-spread time-encoded (FSTE) method for OFDM modulation, which exploits multipath diversity and achieves target energy-per-bit to noise spectral density in low SNR regime by spreading differentially encoded information symbols along OFDM sub-carriers. We investigate the impact of spreading on bit-error rate (BER) and throughput under relative mobility and multipath fading scenarios. In order to maximize the throughput of the proposed method, we also optimize spreading factor and modulation order. The simulation results demonstrate significant BER and throughput performance gain as compared to prevailing differential encoding methods.