Application of DFT Spreading to OFDM Based WLAN for Energy Efficiency Improvement

Masahiro Umehira, Takuya Nishizawa, Shigeki Takeda
This paper describes an application of Discrete Fourier Transform (DFT) spreading to Orthogonal Frequency Division Multiplexing (OFDM) based wireless LAN (WLAN) to reduce Peak to Average Power Ratio (PAPR) for energy efficiency improvement and to maintain robustness to DC offset error for cost-effective hardware implementation. We call our proposed scheme null DC sub-carrier DFT spreading OFDM, where the DC sub-carrier is made null by splitting the spectrum in the frequency domain after DFT
more » ... omain after DFT spreading of the modulated signals. The computer simulation results confirm that BER performance is not degraded due to DC offset error at the transmitter and/or the receiver like OFDM with null DC sub-carrier and its PAPR is lower than OFDM, and is almost the same as the conventional DFT spreading OFDM.