Modified PTS with circular shifting for PAPR reduction in MIMO OFDM systems

Multiple input multiple output (MIMO) orthogonal frequency division multiplexing (OFDM) technology is one of the most attractive candidates for fourth generation (4G) mobile radio communications. It effectively combats the multipath fading channel and improves the bandwidth efficiency. At the same time, it also increases system capacity so as to provide a reliable transmission. However, the main drawback of MIMO OFDM systems is high peak to average power ratio (PAPR), which result in many restrictions for practical applications. In this paper, the low complexity partial transmit sequences (PTS) is adopted to be modified using circular shifting, it exploits the extra degree of freedom provided by MIMO, to improve PAPR reduction in MIMO OFDM systems. Merging the circular shifting with phase rotation in low complexity PTS is also proposed, to provide more PAPR reduction.