A Comprehensive Performance Comparison of OFDM/TDM Using MMSE-FDE and Conventional OFDM

Orthogonal frequency division multiplexing (OFDM) is currently under intense research for broadband wireless transmission due to its robustness against multipath fading. However, OFDM signals have a problem with high peak-to-average power ratio (PAPR) and thus, a power amplifier must be carefully manufactured to have a linear input-output characteristic or to have a large input power backoff. Recently, OFDM combined with time division multiplexing (OFDM/TDM) using minimum mean square error frequency domain equalization (MMSE-FDE) was proposed to improve the bit error rate (BER) performance of conventional OFDM while reducing the PAPR. In this paper, by extensive computer simulation, we present a comprehensive performance comparison between OFDM/TDM using MMSE-FDE and conventional OFDM over a frequency-selective fading channel. We discuss about the trade-off among the transmit peak-power efficiency, the spectrum splatter and the BER performance. Our results show that OFDM/TDM using MMSE-FDE achieves almost the same coded BER performance with a several decibels better peak-power efficiency than conventional OFDM, which is significant reduction of amplifier transmit-power backoff, but with a slight decrease in spectrum efficiency.