Phase-sequence blind estimation for phase-rotation based PAPR reduction in MIMO coded-OFDM systems

Major drawback in orthogonal frequency division multiplexing (OFDM) systems is that the transmit signal exhibits high peak-to-average power ratio (PAPR). In this paper, a phase sequence blind estimation method is presented for PAPR reduction based on a selected mapping (SLM) or a partial transmit sequence (PTS) in multi-input multi-output (MIMO) coded OFDM systems, where low density parity check (LDPC) code is employed. On the receiver side, the selected phase sequence information is estimated using a maximum likelihood method which selects the most likelihood sequence among all candidate sequences by exploiting soft-output information of the decoder. Computer simulation results show that when the number of candidate sequences in SLM is M = 256, instantaneous power of the transmit signal at the CCDF of 10^-6 can be reduced by about 3.9dB as compared to case without PAPR reduction, while almost the same bit error rate (BER) performance as case of the prefect phase sequence estimation is achieved in attenuated 12-path Rayleigh fading condition.