Randomized algorithms
Multi-Carrier Digital Communications: Theory and Applications of Ofdm
Multi-Carrier Digital Communications: Theory and Applications of Ofdm
OFDM for Wireless Multimedia Communications
OFDM for Wireless Multimedia Communications
IEEE Transactions on Signal Processing
On the existence and construction of good codes with low peak-to-average power ratios
IEEE Transactions on Information Theory
On multicarrier signals where the PMEPR of a random codeword is asymptotically logn
IEEE Transactions on Information Theory
Discrete and continuous maxima in multicarrier communication
IEEE Transactions on Information Theory
Generalized bounds on the crest-factor distribution of OFDM signals with applications to code design
IEEE Transactions on Information Theory
Novel low-complexity SLM schemes for PAPR reduction in OFDM systems
IEEE Transactions on Signal Processing
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It has recently been shown that significant reduction in the peak to mean envelope power (PMEPR) can be obtained by altering the sign of each subcarrier in a multicarrier system with n subcarriers. However, finding the best sign not only requires a search over 2n possible signs but also may lead to a substantial rate loss for small size constellations. In this paper, we first propose a greedy algorithm to choose the signs based on p-norm minimization and prove that the resulting PMEPR is guaranteed to be less than c log n where c is a constant independent of n for any n. This approach has lower complexity in each iteration compared to the derandomization approach of [1] while achieving similar PMEPR reduction. We further improve the performance of the proposed algorithm by enlarging the search space using pruning. Simulation results show that PMEPR of a multicarrier signal with 128 subcarriers can be reduced to within 1.6 dB of the PMEPR of a single carrier system. In the second part of the paper, we address the rate loss by proposing a block coding scheme in which only one sign vector is chosen for K different modulating vectors. The sign vector can be computed using the greedy algorithm in n iterations. We show that the multi-symbol encoding approach can reduce the rate loss by a factor of K while achieving the PMEPR of c log Kn, i.e., only logarithmic growth in K. Simulation results show that the rate loss can be made smaller than %10 at the cost of only 1db increase in the resulting PMEPR for a system with 128 subcarriers.