A Modified PTS Combined with Interleaving and Pulse Shaping Method Based on PAPR Reduction for STBC MIMO-OFDM System

Multiple input multiple output orthogonal frequency division multiplexing (MIMO-OFDM) system have been proposed in the recent past for providing high data-rate services over wireless channels. When combined with space time coding it provides the advantages of space-time coding and OFDM, resulting in a spectrally efficient wideband communication system. However, MIMO-OFDM system suffer with the problem of inherent high peak-to-average power ratio (PAPR) due to the intersymbol interference between the subcarriers. To overcome this problem, the partial transmit sequence (PTS) based on PAPR reduction by optimally combining signal subblocks and the phase rotation factors is considered. As the number of subblocks and rotation factors increases, PAPR reduction improves. The number of calculation increases as the number of subblocks increases, such that complexity increases exponentially and the process delay occur simultaneously. In this paper, PAPR reduction schemes based on a modified PTS combined with interleaving and pulse shaping method for STBC MIMO-OFDM system has been presented. The paper analyses the influence of the number of the detected peaks on PAPR reduction performance and on complexity, and then obtain the optimal parameter to achieve better PAPR reduction performance and lower complexity. Simulation results show that the proposed modified PTS with interleaving and the pulse shaping method can obviously improve PAPR performance in the MIMO-OFDM system. Key-Words: MIMO-OFDM, PAPR, STBC, Partial Transmit Sequences, Interleaved Subblock Partition Scheme, Raised-Cosine pulse shape