On the computation reduction of the peak-to-average power ratio in multicarrier communications

For any code C defined over an equal energy constellation, it is first show n that at any time instance, the problem of determining codewords of C with high peak-to-average power ratios (PAPR): in a multicarrier communication system is intimately related to::the problem of minimum-distance decoding o f C, Subsequently, a method is proposed for computing the PAPR by minimum-d istance decoding of C at many points of time. Moreover, an upper bound on t he error between this computed value and the true one is derived. Analogous results are established for codes defined over arbitrary signal constellat ions. As an application of this computational method, an approach for reduc ing the PAPR of C proposed-by Jones and Wilkinson is revisited. This approa ch is based on introducing a specific phase shift to each coordinate of ail the codewords where phase shifts are independent of the codewords and know n both to the transmitter and the receiver, We optimize the phase shifts of fline by applying our method for computing the PAPR for the coding scenario proposed by ETSI BRAN Standardization Committee. Reductions of order 4.5 d B can be freely obtained using;the computed phase shifts, Examples are prov ided showing that most of the gain is preserved when the computed optimal p hase shifts are rounded to quantenary phase-shift keying (PSK), 8-PSK, and 16-PSK type phase shifts.