On capacity of OFDM/TDM using MMSE-FDE in a nonlinear and frequency-selective fading channel

Orthogonal frequency division multiplexing (OFDM) is adopted for several wireless network standards due to its high capacity and robustness against multipath fading. OFDM, however, has a problem with high peak-to-average power ratio (PAPR) that strictly limits its application. Recently, OFDM combined with time division multiplexing (TDM) using minimum mean square error frequency domain equalization (MMSE-FDE) was proposed to improve the transmission performance of conventional OFDM in terms of the bit error rate (BER) while reducing the PAPR. In this paper, we theoretically analyze and discuss the trade-off for OFDM/TDM using MMSE-FDE between the channel capacity and the PAPR in a nonlinear and frequency-selective fading channel. Our results show that OFDM/TDM using MMSE-FDE achieves a larger capacity with a lower PAPR in comparison with the conventional OFDM. It is also shown that the channel capacity of OFDM/TDM using MMSE-FDE is bounded between the conventional OFDM and single-carrier (SC) transmission.