The Rreasch On Reducing PAPR Of MIMO-OFDM System

As a key technology of B3/4G communication systems, MIMO-OFDM combines with MIMO and OFDM technologys can inerease the system apacity with high speed transmission, and make the system tolerance of noise, interference and fading improved greatly.But high Peak-to-average Power ratio (PAPR) is one of the major drawbaeks of MIMO-OFDM systems. At first, this dissertation discussed the reasons of high PAPR and the characteristic of PAPR in MIMO-OFDM systems, and introduced the methods of reducing PAPR with Selected Mapping (SLM), Partial Transmit Sequences (PTS), and Cross-Antenna Rotation and Inversion (CARI), then presents several methods based on CARI.Subblock Successive Rotation PTS (SSR-PTS) is a method that based on CARI and PTS, which can make use of the freedom of mulitiple antennas and phase; Symbols Random Rotation and Inversio with PN (PN-SRRI) is a method that base on CARI and PN. This dissertation also presents two new method with SSR or PN-SRRI and Tones Reservation (TR) to reduce the Peak-to-Average Power Ratio (PAPR).Simulation results showed the effectiveness of these methods, compared with Successive Suboptimal CARI (SS-CARI), these methods have a similar performance and need less side information (SI).