A Modified DFTs-OFDM with DC Subcarrier Shift for Low PAPR and DC Offset Error Robustness

OFDM (Orthogonal Frequency Division Multiplexing) has been widely accepted in various wireless systems such as cellular systems and wireless LAN because of its robustness to frequency selective fading. However it has a drawback of large PAPR (Peak to Average Power Ratio) since it is a multi-carrier transmission scheme. In order to apply DFTs-OFDM (DFT spreading OFDM) for low PAPR, DC offset error robustness is also required to avoid BER performance degradation due to DC offset error for cost-effective wireless terminal implementation. This paper proposes a modified DFTs-OFDM with DC subcarrier shift to cope with low PAPR and DC offset error robustness. Computer simulation results confirm that BER performance is not degraded by DC offset error and low PAPR is maintained. It is also demonstrated that application of the proposed DFTs-OFDM to wireless LANs can reduce HPA output back-off while keeping adjacent channel leakage power (ACLP).