A novel trellis-based PAPR reduction technique for OFDM signals

We propose a new peak-to-average power ratio (PAPR) reduction technique for orthogonal frequency-division multiplexing (OFDM) signals based on the trellis structure. The major drawback of the previously proposed trellis shaping (TS) is that since the constellation controlling and information bit sequences are mixed in a single codeword, its soft-in soft-out (SISO) decoder requires an additional complex process for extracting the soft-outputs from the mixed codeword. On the other hand, our new technique is able to select a controlling sequence separately from information sequences, resulting in a simpler decoder with even a better soft decoding performance. Moreover, we develop an appropriate constellation labeling for our proposed method to enhance its PAPR reduction capability. It is shown that the proposed technique can achieve better bit-error ratio (BER) performance than the conventional TS in the scenario of the soft decoding with a slight loss of PAPR reduction capability.