Constellation shifting based on QAM with gray coding for PAPR reduction of OFDM systems

High PAPR has long been a main drawback of OFDM systems. With the lengthening of OFDM symbol and the increasing popularity of high-order modulation, such as OFDM symbol size of 32768 and 256-QAM in DVB-T2, reducing PAPR is of growing importance. In this paper, a constellation shifting technique based on QAM with gray coding will be introduced to reduce PAPR. This technique keeps the minimum Euclidean distance of the constellation points and gray coding´s benefit, costs no extra bandwidth, and consumes little extra power.