Research And Simulation On Peak-to-Average Power Ratio Reduction Algorithm In OFDM System

Orthogonal frequency division multiplexing (OFDM) systems provide highspectral efficiency, robustness to multi-path fading channels and simpleaccommodation to multiple users. It is also straightforward to combine multipleinput multiple output (MIMO) technology to improve spectral efficiency. Thus,OFDM has been adopted in numerous applications.The major drawback of OFDM systems, and also the topic of this paper, isits high peak-to-average power ratio (PAPR). When the transmitted data withlarge peaks are passing through nonlinear devices or channels, the signal maysuffer from significant spectral spreading, in-band distortion and out-of bandradiation. Another shortcoming is the additional nonlinear distortion whichcreates inter-carrier interference (ICI). Thus, reducing PAPR of OFDM signalsremains a challenge for OFDM applications.In this paper, we conducted research on PAPR reduction algorithms. Firstly,we introduced the features of OFDM systems, the cause of PAPR problems anddivided the existing algorithms into three types: clipping, coding andprobabilistic methods. Then, we put forward two new algorithms to reducePAPR. The first one based on traditional tone reservation algorithm, newalgorithm one use a new iterative way to reduce PAPR of OFDM symbols. Thenew algorithm one broad the application occasion and lower the computationalcomplexity. This algorithm is especially suit for the occasion when thereceiver’s computational ability is weak. The new algorithm two combines theclipping algorithm and tone reservation algorithm. This algorithm usescompressive sensing algorithm to recover the orignal signal and has lowcomputational complexity. The new algorithm two is especailly suit for theoccasion when the transmitter’s computational ability is weak. Lastly,simulational and mathmatical analysis show that our proposed algorithm isreliable with low computational complexity. Since OFDM system has a bright future, a low computational complexity,easy to applicate and stable PAPR reduction algorithm could be a greatpromotion to the development of wireless communication and4G. The twoalgorithm proposed in this paper have flexible application occasion, easy to use,reliable and low computational complexity, they are good alterative oftraditional algorithm.