Research On Reducing PAPR Technology For MIMO-OFDM System

Multiple-Input Multiple-Output (MIMO) technology uses multiple antennas in the receiver and transmitter to realize multiple input and multiple output. It can highly enhance the channel capacity without increasing spectral resources and the transmit power of antennas. Meanwhile, it can provide space diversity gain and coding gain. Orthogonal Frequency Division Multiplexing (OFDM) is one of multi-carrier transmission technologies, whose sub-carriers are orthogonal, can make use of frequency spectrum resources efficiently. Taking full advantage of time, frequency and space diversity, the combination of MIMO and OFDM can increase the tolerance of wireless communication systems to noise, interference and multipath. MIMO-OFDM has become a promising candidate for high performance 4G broadBand wireless communications because of its potential for achieving higher data rate and providing more reliable reception performance.As the OFDM system, one of the main drawbacks of MIMO-OFDM systems is the high peak-to-average-power ratio (PAPR),which makes the distortion occur duing to the nonlinearity of the high power amplifier. It will result in deteriorating the performance of the system. So this dissertation focuses on reducing the PAPR algorithms design for MIMO-OFDM systems, and the main work of this article are:Firstly, we seriously analysis some typical algorithms for reducing PAPR of OFDM system:such as selective mapping(SLM), partial transmit sequence (PTS), clipping algorithms and so on. Meanwhile, we also deeply study several new algorithms using in the MIMO-OFDM system. Such as Cross-antenna Rotation and Inversion (CARI), concurrent partial transmit sequence (CPTS), concurrent selective mapping and so on.Secondly, after analyzing the characteristics of concurrent selective mapping and clipping algorithms, proposes a new method that is CSLM-Clipping combine algorithm. The combine method drops PAPR of MIMO-OFDM effectively, reduces the amount of side information which need to be sent, saves spectrum resources.Thirdly, on the basis of combine algorithm, in order to reduce the impact of clipping noise, proposes an improved method of combine algorithm, which is CSLM-Circle Clipping Filter combine algorithm. The improved algorithm drops PAPR of MIMO-OFDM effectively, and reduces the effect of clipping noise.Fourthly, in order to reduce the complexity of the combine algorithm, proposes a Simplified combine algorithm. This algorithm drops PAPR of MIMO-OFDM effectively, reduces the amount of side information and the complexity of the combine algorithm.