Ofdm System To Reduce The Papr Technology

Orthogonal frequency division multiplexing (OFDM) is a special multicarrier transmission technology. It can strongly combat multi-path delay and transmit high-rate data with high bandwidth efficiency. However, many key problems of an OFDM system have not been solved yet, such as sensitivity of frequency offset and high peak-to-average power ratio (PAPR), which limit OFDM's wide applications. This thesis mainly focuses on the techniques of PAPR reduction, and obtains some results by MATLAB simulations. And then under the Code Composer Studio Integrated Development Environment (CCS IDE), it performs hardware simulations of baseband OFDM signal's power spectrum with Digital Signal Processor (DSP).Firstly, the principle of DFT-based OFDM system, its key techniques, advantages and disadvantages of OFDM technology are analyzed in this thesis. Secondly, the definition and distribution of PAPR are introduced, and various techniques on reducing the PAPR are summarized. Thirdly, signal scrambling techniques are analyzed, including Selective Mapping (SLM) and Partial Transmit Sequences (PTS). For SLM using Newman phase sequences, the PAPR curve with simulation is not patch on the theoretical curve, and further improvement is needed in actual application for this scheme. Here a specific scheme is proposed to reduce the PAPR by using the standardarrays of [16,11] extended hamming code. With Monte Carlo simulation, the effect onPAPR reduction of this scheme is testified. Fourthly, a coding scheme based on Golay Complementary Sequences and Reed-Muller codes is proposed to reduce the PAPR. This scheme can control the PAPR of OFDM signal, and have forward error correction capability. In the last part, CCS simulation of OFDM system baseband modulation is performed with TI's TMS320C5402 Digtal Signal Processor. And then a hardware platform of data realtime processing is designed for transmitting data to DSP target system with realtime data exchange (RTDX) technique.