High-rate codes with bounded PMEPR for BPSK and other symmetric constellations

Abstract

In this letter, we consider the problem of constructing high-rate codes with low peak-to-mean-envelope power ratio (PMEPR) for multicarrier signals. Assuming coefficients of the multicarrier signal are chosen from a symmetric q-ary constellation, we construct codes with rate 1-(1/r)log/sub q/2 and PMEPR of less than crlogn for any r and n, where n is the number of subcarriers and c is a constant independent of n and r. The construction is based on dividing n subcarriers into n/r groups of r subcarriers and choosing a sign for each group to minimize the PMEPR. The signs are chosen using a variation of the algorithm proposed by the authors in previous papers. For large n, we can, in fact, construct a code with a rate of 1-O(1/logn) and PMEPR of less than clog/sup 2/n. For binary phase-shift-keying-modulated signals, this partially solves the problem posed by Litsyn and implies a construction of 2/sup n/2/ codewords with PMEPR less than 2clogn.