OFDM系统中峰均功率比研究

【作者】 孙向峰；

【导师】 陈如山；

【作者基本信息】 南京理工大学 ， 电磁场与微波技术， 2004， 硕士

【摘要】 正交频分复用(OFDM)是一种新颖的高比特率无线通信技术，通过把整个频带分成许多相互正交的子窄带信道，有效地把多径产生的影响降到最低。 但是，OFDM系统却存在着潜在的高峰均功率比(PAPR)，在遇到射频功率放大器等非线性器件时，会发生严重的非线性畸变。限幅方法是一种高效的降低PAPR的技术，但同时会降低系统误码率(BER)性能。本文在对传统的限幅方法和部分传输序列(PTS)方法深入研究的基础上，提出一种结合限幅和PTS的新方法。这种方法在限幅之前先对信号进行PTS操作，明显的改善了系统的BER性能。在应用PTS方法的过程中，为了在较低的计算复杂度的条件下得到好的PAPR性能，本文提出了自适应的双层相位序列(ADLPS)方法和自适应的结合遗传算法的PTS(APTS_GA)方法。仿真数据显示，两种新方法都能在较低的计算复杂度下改善系统的PAPR性能。更多还原

【Abstract】 Orthogonal frequency division multiplexing (OFDM) is an attractive technique for high-bit-rate transmission in a radio environment. By dividing the total bandwidth into many orthogonal narrow subchannels, the effects of multipath delay spread can be minimized.Unfortunately, a central disadvantage of OFDM is potentially high peak-to-average power ratio (PAPR) values, which can result in significant distortion when transmitted through a nonlinear device, such as a transmitter power amplifier. Clipping could be an effective technique for PAPR reduction, but it degrades the bit-error-rate (BER) performance. In this thesis we analyze the conventional Clipping and Partial Transmit Sequences (PTS) methods, then propose a hybrid algorithm to get a better performance of BER by using the PTS method before Clipping. Next, in order to provide good performance of PAPR with lower complexity by PTS method, two new techniques are proposed: Adaptive Dual Layered Phase Sequencing (ADLPS) and Adaptive PTS with Genetic Algorithm (APTS_GA) methods. Based on simulation results, both of the methods can improve the performance with lower complexity.更多还原