【作者】 谷志刚；

【导师】 李万臣；

【作者基本信息】 哈尔滨工程大学 ， 信号与信息处理， 2007， 硕士

【摘要】 由于对频率选择性衰落的强抵抗能力以及高频谱利用率等原因，正交频分复用技术在宽带通信系统中得到越来越广泛的应用。正交频分复用系统的一个主要缺点是高峰均功率比。系统输出符号功率的过大变化范围，要求系统中的功率放大器、数／模转换器和模／数转换器等部件有足够大的动态范围，这将导致这些部件的低效率；一旦这些部件的动态范围不能达到要求，会引起削波失真，系统通信质量下降。因此，在实际的系统中，峰均功率比的抑制是必不可少的任务。本论文在对正交频分复用进行广泛和深入调研的基础上，提出了开展正交频分复用峰均功率比抑制技术研究的可行性和必要性。根据IEEE 802.11a无线局域网标准，完成基于Matlab的发射机物理层仿真系统以及系统整体性能分析等功能。提出一种峰均功率比抑制的相位扰动方法。子载波调制矢量包括信息元分量和抑制元分量。信息元相位扰动操作根据具体情况实施，抑制元相位扰动采取向量空间扫描的方式完成。提出一种峰均功率比抑制的差分回归法，在对信息伪随机化的基础上，在频域对符号相位差分编码，在时域对采样值回归处理。本论文的研究达到了预期目标，实现了无线局域网系统的低峰均功率比设计。更多还原

【Abstract】 Orthogonal Frequency Division Multiplexing (OFDM) receives more and more deployment in many wireless multi-carrier communication systems due to a variety of attractive performances such as its robustness to the frequency-selective channel and high spectrum efficiency.A main drawback of OFDM is high Peak to Average Power Ratio (PAPR/PAR). An excessive fluctuation of the symbol power demands adequate dynamic scope of such components as high power amplifier, AID converter and D/A converter, which leads to low efficiency of these parts. Once such a demand cannot be met, clipping distortion would be introduced and system performance degrades. In practical systems, the suppression of PAR is indispensable.The thesis shows the feasibility and necessity of research on PAPR suppression of OFDM on the basis of a thorough survey of OFDM technology. Based on the specification of IEEE 802.11a WLAN standard, a simulation system for physical layer is completed with Matlab 6.5, which includes such functions as transmitter and system performance evaluation. A scheme named Phase Scrambling is proposed for the suppression of PAPR. The modulating vectors for the subcarriers consist of the information-bearing components and the reduction components. The scrambling of the information components is optional and the scrambling of the reduction components is achieved by vector space scanning. A Differential Recursive scheme for PAPR suppression is put forward. The pseudo-randomized modulating vector to the subcarrier series is differentially phase-encoded between successive components in frequency domain, while recursion manipulates several samples in time domain.Research in the thesis gains the expected ends with ease of hardware implementation, realizing the design of wireless OFDM communication systems with low PAPR.更多还原