Adaptive PTS approach for reduction of peak-to-averagepower ratio of OFDM signal

Abstract

An adaptive partial transmit sequence (PTS) technique is presented for the reduction of the peak-to-average power ratio (PAP) of an orthogonal frequency division multiplexing (OFDM) signal. The main problem for PTS is how to minimise the number of iterations necessary for locating the optimal weighting factors (which increases exponentially with the number of sub-blocks). In the proposed adaptive PTS approach, the iterations are stopped once the PAP drops below a preset threshold. For an OFDM system with 256 subcarriers and QPSK data symbols, adaptive PTS reduces the 0.1% PAP by 4 dB, while PTS (non-adaptive) reduces it by 4.1 dB. The complexity of adaptive PTS is just 2% of that of PTS.