OFDM系统中降低峰均功率比技术的研究

发布时间：2018-01-21 00:13

本文关键词： 正交频分复用峰均功率比部分传输序列法输入序列定标法　出处：《天津大学》2009年硕士论文　论文类型：学位论文

【摘要】： 正交频分复用(OFDM)是一种特殊的多载波传输技术。它的基本思想是将所要传输的高速数据流通过串/并转换,变成多路并行的若干个子数据流,每个子数据流具有比发送端原始数据流低得多的传输速率,然后用这些子数据流去并行调制若干个相互正交的载波,最后再合并成一个OFDM符号进行传输。 OFDM技术的优点在于它可以提供更高的频谱效率、更强的抗符号间干扰能力和更好的抗多径衰落能力。但是,OFDM技术也有一些缺点,例如对频偏的敏感性、较高的峰均功率比等,这些问题限制了OFDM技术的发展和应用。本文论述了移动通信的发展概况,OFDM系统的基本原理、发展概况、主要技术及优缺点,重点论述了OFDM系统中降低PAPR的方法。目前,国内外降低PAPR技术的方法主要包括信号畸变类方法、编码类方法和概率类方法。其中:信号畸变类方法直接在OFDM信号幅度峰值或其附近进行非线性操作来降低信号的PAPR值;编码类方法是通过限制可用于传输的信号码集来降低PAPR,其核心思想是运用一种特殊的前向纠错编码技术来剔除高PAPR的OFDM信号;概率类方法着眼于降低OFDM信号峰值出现的概率。针对PTS全搜索算法计算复杂度过大,而传统的PTS迭代算法性能较差的缺点,本文提出了一种PTS改进算法,仿真结果表明,该算法很好地折衷了OFDM系统的PAPR性能和计算的复杂度。针对传统的输入序列定标全搜索算法计算复杂度过大的缺点,本文提出了一种简化算法,该算法是通过施加终止门限并进行迭代计算实现的,仿真结果验证了该算法的有效性。
[Abstract]:Orthogonal Frequency Division Multiplexing (OFDM) is a special multicarrier transmission technology. The basic idea of OFDM is to transform the high speed data stream to several sub-data streams in parallel. Each sub-data stream has a transmission rate much lower than the original data stream at the sender, and these sub-data streams are then used to modulate a number of mutually orthogonal carriers in parallel. Finally, it is merged into a OFDM symbol for transmission. The advantage of OFDM technology is that it can provide higher spectral efficiency, stronger anti-intersymbol interference ability and better anti-multipath fading ability, but OFDM technology also has some disadvantages. For example, the sensitivity to frequency offset and the high peak-to-average power ratio limit the development and application of OFDM technology. This paper discusses the basic principle, development, main technology, advantages and disadvantages of the mobile communication system, especially the methods to reduce the PAPR in the OFDM system. The methods of reducing PAPR technology at home and abroad mainly include signal distortion class method. Coding method and probabilistic method, in which the signal distortion class method directly performs nonlinear operation at or near the peak amplitude of the OFDM signal to reduce the PAPR value of the signal; The coding method is to reduce the PAPR by limiting the number set which can be transmitted. Its core idea is to use a special forward error correction coding technology to eliminate the high PAPR OFDM signal. Probabilistic methods aim at reducing the probability of peak OFDM signal. Because the computational complexity of PTS full search algorithm is too large, but the performance of traditional PTS iterative algorithm is poor, an improved PTS algorithm is proposed in this paper, and the simulation results show that. This algorithm tradeoffs the PAPR performance and computational complexity of OFDM system. Aiming at the disadvantage of the traditional full-search algorithm of input sequence calibration, a simplified algorithm is proposed in this paper, which is realized by applying the termination threshold and iterating calculation. Simulation results verify the effectiveness of the algorithm.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2009
【分类号】：TN919.3

【引证文献】