The Research On Reducing PAPR Of MIMO-OFDM System

Orthogonal Frequency Division Multiplexing (OFDM) is a kind of multi-carrier transmission technologies, orthographical sub-carriers that have strong merit of anti multi-path interference had enhanced the frequency spectrum utilization factor efficiently. On the premise of no paying extra resources, Multiple-input multiple-output (MIMO) had obtained the diversity gain or the capacity gain fully using the receive both sides' multi-antenna technology. The system of MIMO-OFDM that combined above two technical not only enhance the transmission rate and capacity of the wireless communication system but also effectively combat noise and fading. It was considered the most effective method of raising the frequency spectrum efficiency and lifting system volume at present, so MIMO-OFDM has became the alternative plan have the prospect extremely in the 4G mobile communication system.MIMO-OFDM based on OFDM also had the problem of high Peak-to-Average Power Ratio (PAPR) which became the main obstruct applying and developing of MIMO-OFDM systems. This dissertation first elaborated the reasons, harm and the distribution characteristic of high PAPR in MIMO-OFDM systems, and introduced some classical algorithms of suppressing high PAPR included Selected Mapping (SLM), Partial Transmit Sequences (PTS) and Cross-Antenna Rotation and Inversion (CARI), then advanced simulation research and the summary analysis. On that basis the new algorithm that suppressed high PAPR was put forward, the simulation and the analysis was carried on too.The new algorithm in this article was a method based on CARI. First according to the overlapping of CARI and PTS, Subblock Successive Inversion (SSI-PTS) was proposed. Simulation results showed that SSI-PTS can suppress high PAPR under the condition of same side information.At last, the algorithm combining SSI and Circle clipping Filter was taken out, also based on SS-CARI. It can eliminate the high PAPR effectively. Simulation results showed that the scenario introduced curbs the PAPR effectively and had less side information.