A low-complexity SLM based PAPR reduction scheme for SFBC MIMO-OFDM systems

A number of peak-to-average power ratio (PAPR) reduction techniques have been proposed for multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) systems; however, most of them involve very high computational complexity and are not applicable to MIMO-OFDM systems with space frequency block coding (SFBC). In this paper, we propose a low-complexity PAPR reduction scheme for SFBC MIMO-OFDM systems, where the input sequence is multiplied by a set of phase rotation vectors respectively and then each resulting sequence is decomposed into several sub-sequences based on the linear property of SFBC. After computing the inverse fast Fourier transform (IFFT) to convert each frequency-domain sub-sequence into a time-domain signal, we perform equivalent SFBC encoding operations in the time domain for generating candidate signal sets, where the one with the lowest maximum PAPR is selected for transmission. With the proposed scheme, we can generate a large number of candidate signal sets by computing only a few IFFTs. As compared to previous related schemes, the proposed one achieves similar PAPR reduction performance with much lower computational complexity.