A Tail-Biting Turbo Coded OFDM System for PAPR and BER Reduction

In a turbo coded orthogonal frequency-division multiplexing (TCOFDM) system, low peak-to-average power ratio (PAPR) can be achieved by selective-mapping (SLM). In this paper, we propose to generate multiple candidates used in SLM by employing the tail-biting bits in a tail-biting turbo code. In our method, no explicit side information is needed and no error propagation is observed. Low PAPR can also be achieved by distortion-based techniques such as deliberate clipping. Although SLM is originally proposed for PAPR reduction, we also apply a concept similar to SLM to clipping-based TCOFDM systems for improved bit error rate (BER). With these proposed techniques, a tail-biting TCOFDM system can achieve both low PAPR and low BER.