Reducing the peak-to-average power ratio of orthogonal frequency division multiplexing signal through bit or symbol interleaving

An interleaver-based technique for improving the peak-to-average power ratio (PAP) of an orthogonal frequency division multiplexing signal is presented. For this technique, K - 1 random interleavers are used to produce (K - 1) permuted sequences from the same information sequence. The PAPs of the permuted sequences and the original information sequence are then computed using K oversampled fast Fourier transforms (OFFTs). The sequence with the lowest PAP is chosen for transmission. Results show that for 256 subcarriers and quadrature phase shift keying data symbols, even with K identical with 2, the 0.1% PAP is reduced by 1.3dB and with K identical with 4, it is reduced by 2dB. The 0.1% PAP can be reduced by 3dB and the 0.01% PAP by 4dB at a cost of 16 OFFTs and a data rate loss of < 0.8% with K identical with 16.