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.