Reseach And Implementation Of Out-Of-Band Power Radiation Reduction Technique Of OFDM Signal

With the explosive growth of information, wireless communication plays a more and more important role. However, the spectrum resource is increasingly tense. All of these are due to the current static spectrum access strategy, which leads to an insufficient utilization of the spectrum resources. Thus, a new dynamic spectrum access mechanisms was proposed. Dynamic spectrum access(DSA) technology obtain much more spectrum resources by improving the utilization of allocated spectrum available. OFDM technique is increasingly employed by communication systems because of its high transferring rate and spectrum ultilization.etc. However, high out-of-band power in OFDM limits the application for DSA which leads to the importance of reducing it.Firstly, we introduce the classification of the dynamic spectrum access techniques and OFDM technique. In the meanwhile, large sidelobe and high peak-to-average power ratio which are the reasons leading to high out-of-band are introduced in this thesis. Stimulate the effects of non-linearity based on Rapp model SSPA.Present sidelobe and PAPR reduction algorithms are inappropriate for overlay system due to the inherent dissadvantages. SLM and MCS techniques are proposed to apply for overlay sytem because of distortion-free and low complexity. SLM technique based on conversion matrix(CM-SLM) and its modified scheme(MCM-SLM) have been researched in this thesis due to its low complexity compared to conventional SLM. The MCM-SLM greatyly reduces the complexity comparing with the conventional SLM in the cost of little loss in PAPR reduction.Finally, we model the fixed-point simulation of low complexity SLM algorithm based on improved convension matrix. Meanwhile we investigate the circuit design and build the co-simulation platform on Matlab and Modelsim. Implement and verification are conducted on Stratix IV FPGA which achieves a 250 MHz operating frequency.