Fifth generation wireless communications are expected to serve future wireless needs such as machine-to-machine communications, tactile internet, be highly reliable, have low latency and perform satisfactorily in high speed communication links. Generalized Frequency Division Multiplexing (GFDM) is one of the promising and leading candidates proposed for the 5G physical layer waveform, to fulfill the above applications. Due to the non-orthogonal pulse shaping of individual subcarriers, GFDM suffers from self interference and also increased peak amplitude. The benefit of prolate windows can be exploited to convert a non-orthogonal GFDM system to an improved orthogonal Multi-taper GFDM (MGFDM) one. Similarly to other multicarrier (MC) techniques, MGFDM also suffers from high peak-to-average-power ratio (PAPR). In this article, we first explore some of the standard PAPR reduction approaches such as, Selective Mapping (SLM), Partial Transmit Sequence (PTS) and Zadoff-Chu Transform (ZCT) and a comparative performance is carried out in terms of the cumulative distribution function (CCDF). In addition, we propose in this article a novel hybrid Walsh-Hadamard precoding with both SLM and PTS PAPR reduction techniques to further reduce the PAPR level at the transmitter side. The Walsh-Hadamard kernel which is a square wave with values {+/- 1} helps to reduce the PAPR without introducing distortion, compared to clipping based methods. Using these proposed schemes the results show a superior PAPR reduction improvement when compared to the conventional SLM and PTS techniques. Mathematical equations of the proposed systems were derived and the corresponding complexity analysis was carried out. (C) 2018 Elsevier B.V. All rights reserved.
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