Composite QAM sequences with low PMEPR for application to multi-carrier transmission system

We propose a construction scheme of composite QAM sequence by weighted sum of the QPSK sequences that have relatively low peak-to-mean envelope power ratio (PMEPR). We derive a general expression of the upper bound on PMEPR for such composite QAM sequences. For the proposed QAM sequence construction, which we call ´linear-sum mapping´, we investigate the information transfer capability. Although it is inferior to Gray mapping, by utilizing the decisions of the previously decoded codeword and employing successive decoding, we can obtain almost the same performance as that of Gray mapping.