Methods for PAPR and Spectral Improvement of Correlatively Coded OFDM Systems

• Main Authors: Chen-wei Shih, 施辰緯
• Other Authors: Miin-Jong Hao
• Format: Others
• Language: en_US
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/93882275297279287301

碩士 === 國立高雄第一科技大學 === 電腦與通訊工程研究所 === 101 === A class of correlative codes is proposed to significantly improve the spectral performance of the rectangularly pulsed orthogonal frequency-division multiplexing (OFDM) signal. High PAPR is one of the most serious drawbacks of OFDM. However, correlatively coded OFDM has much larger PAPR than general OFDM. In this thesis, proposed two method to reduce the PAPR in correlatively coded OFDM signals. The first method, it use singular value decomposition (SVD) precoding matrix of correlative codes OFDM, and then recombine a new precoding matrix, thus at the same time to improve the spectral performance and reduce PAPR value. The second method, it use the low autocorrelation characteristics of CAZAC sequence, expands the correlatively coded OFDM signal constellation points, and decreases relevance between the frequency symbols, in order to reduce PAPR value of the correlative codes OFDM signal. Simulation results show that, the first method, at the same time improve the spectral performance and reduction PAPR value 3dB. The second method, PAPR value is even better than the general OFDM, and it not cause decrease spectral performance.