PAR reduction in OFDM systems based on clipped power re-allocation

Abstract

One of the major drawbacks in Orthogonal Frequency Division Multiplexing (OFDM) is its high Peak-to-Average Power Ratio (PAR). Clipping and filtering is the simplest and most effective method to reduce PAR for OFDM. But clipping and filtering gives rise to serious distortion which seriously degrades the bit error rate (BER) performance. Mitigating the disadvantages while inheriting the advantages of clipping and filtering, a new scheme called clipping and clipped power re-allocation with filtering is proposed for PAR reduction in this paper. The proposed scheme re-allocates the clipped power to other low-power time-domain symbols in the same OFDM block to reduce the distortion. Simulation results show that the BER performance of the proposed scheme is much better than conventional clipping and filtering technique and the PAR performance is slightly better than clipping and filtering. Besides, the proposed scheme is compatible with existing OFDM standards since no changes are required in the receiver structure.