Joint Decoding of TCM and Detection of PTS Side Information: a Multiple Trellis Solution

One of the major drawback of orthogonal frequency-division multiplexing (OFDM) systems is the large Peak-to-Average power Ratio (PAR) of the transmit signal. High levels of PAR may be a limiting factor for power line communication (PLC) where regulatory bodies have fixed the maximum amount of transmit power. Partial transmit sequence (PTS) is a well-known solution for PAR reduction, but its effectiveness depends on an accurate, and possibly error-free, exchange of side information (SI) between the transmitter and the receiver. In this article, a new maximum likelihood (ML) algorithm for joint decoding of trellis code modulation (TCM) and detection of PTS is presented. The proposed algorithm exploits the redundancy introduced by the TCM code to estimate the correct PTS, and represents a practical solution to avoid the explicit insertion of SI into the OFDM signal. The proposed algorithm has been assessed by bit-error rate (BER) simulation, showing a good performance over additive white Gaussian noise (AWGN) channels and amplifier nonlinearities.