【作者】 王铁滨；

【导师】 王克奇；

【作者基本信息】 东北林业大学 ， 机械设计及理论， 2013， 博士

【摘要】 正交频分复用OFDM以其高频谱效率、传输速率和对抗多径衰落的能力,成为适合林业无线通信的传输技术之一。但OFDM发射信号具有较高的包络动态范围和峰均比,从而影响了发射端的功率效率和能量效率。本研究从林业通信的需求出发,研究了非失真的正交频分复用系统的峰均比抑制技术,这些技术可以看作是计算复杂度和峰均比抑制能力之间的优化设计。第一章介绍了基于OFDM的林业通信背景,对现有的OFDM通信中所使用的峰均比抑制算法进行了概括。第二章通过理论分析和仿真验证,介绍了OFDM的基本框架和数学建模,揭示了其对抗多径衰落的原理,并对OFDM所具有的高峰均比问题进行了分析和建模,为后续章节的优化技术提供了理论依据。第三章对部分传输序列PTS和选择映射SLM这两类主要的非失真峰均比抑制技术分别进行了研究。对于选择映射法,分析和仿真了其传输结构和峰均比抑制性能。对于部分传输序列法,先对其峰均比抑制能力在不同子载波数的环境下进行了仿真,再通过复杂度分析为系统实现提供了理论依据,最后研究了基于门限判决的自适应部分传输序列法以降低原有系统的计算复杂度。第四章研究了具有连续相位因子的高效部分传输序列算法。在对传统算法进行了分析和仿真的基础上,一方面,通过理论分析和系统设计,提出了一种新型连续相位因子PTS算法,该算法可以在不增加计算复杂度的前提下,提升峰均比抑制能力；另一方面,针对连续相位因子PTS系统所固有的前馈频谱效率不高的问题,提出了利用离散量化的方式以实现高效的前馈传输；此外,针对相位因子离散量化所引起的传输性能下降,提出了一种基于判决反馈的相位因子恢复方式以提升其传输性能。第五章研究了基于傅立叶扩展的OFDM峰均比抑制算法。先对于传统的无线通信多址通信中的峰均比抑制技术,进行了峰均比抑制的验证；再将傅立叶扩展的技术应用到全部带宽占用的高速宽带通信中,通过计算机仿真验证了其性能；最后,针对传统技术峰均比抑制能力偏低的问题,提出了一种出结合相位因子旋转来优化其峰均比抑制能力的新技术。第六章中研究了MC-CDM系统的峰均比抑制问题。基于多载波码分复用的MC-CDM技术,可以综合码分复用和正交频分复用的优势,是一类在林业通信中有前途的传输技术。第一,通过对于不同的正交码所具有的峰均比特性进行了分析和比较,为系统设计的正交码选型提供了理论依据；第二,考虑了部分传输序列与MC-CDM的联合优化,并提出了一种新的峰均比抑制技术,仿真表明该技术能够比单纯的联合技术获得更好的峰均比抑制性能；第三,研究了基于选择映射的MC-CDM系统中的码字、相位因子序列联合设计方法,通过计算机仿真,证明了二者联合优化在性能方面的改善。第七章进行了总结和对未来研究的展望。更多还原

【Abstract】 Orthogonal frequency division multiplexing OFDM with its high spectral efficiency, transmission rate and combat multi-path fading ability, become one of the appropriate transmission technology for forestry wireless communication. But the OFDM signal has a high envelopment dynamic range and PAPR, which affect the power efficiency and the energy efficiency of the transmitter. According to the demand of forestry communication, we study on the PAPR reduction techniques of the orthogonal frequency division multiplexing system without distortion. These techniques can be considered as optimization design of the computational complexity and the PAPR suppression.In the first chapter, we have introduced the background of the Forestry Communication based on OFDM. We also give a summary of PAPR reduction algorithms used in OFDM communication.In the second chapter, through the theory analysis and simulation verification, we introduce the basic framework and mathematical modeling of OFDM, reveal the principle of multipath-fading, and also give analysis and do modeling of the high PAPR problem in OFDM system, which provides a theoretical basis for the following chapters.In the third chapter, we have studied the two kinds of technology which are the Partial transmit sequence and the selected mapping method. For the selected mapping method, we have done analysis and simulation of the transmission structure and PAPR reduction performance. For the partial transmit sequence, we firstly do simulation of the PAPR reduction capability under different number of subcarriers environment. Secondly, we analyze it complexity which provide a theoretical basis for system implementation. Finally, we discuss the adaptive partial transmit sequence algorithm based on threshold decision in order to reduce the computational complexity.In the fourth chapter, we study the efficient partial transmit sequence algorithm with continuous phase factor. Based on the analysis and simulation of the traditional algorithm, we propose two new algorithms. On one hand, through theoretical analysis and system design, we presents a new type of continuous phase factor of the PTS algorithm, the algorithm can enhance the PAPR reduction capability without any increase of the computational complexity. On the other hand, because the feed forward spectral efficiency natural continuous phase factor PTS system is not high, we propose use Discrete-quantitative way to realize high efficiency feed forward transmission. Furthermore, to solve the transmission performance decline problem caused by discrete phase factor quantization, this paper proposes a phase factor recovery method based on decision-directed to improve its transmission performance.In the fifth chapter, we study the PAPR suppression algorithm based on Flourier extended OFDM system. First of all, we do PAPR reduction verification of the traditional PAPR reduction technique for the wireless multiple-access communication; secondly, we apply the Flourier extended technology to the all-bandwidth occupied high-speed broadband communication. Its performance is also verified by the computer simulation; finally, we propose new technology of phase factor rotation method to optimize the PAPR suppression ability.In the sixth chapter of this paper, we study the PAPR suppression of the MC-CDM system. Firstly, we analyzed and compared the PAPR characteristic of different orthogonal codes, to provide theoretical basis for the orthogonal code selection; secondly, we consider the joint optimization of partial transmit sequences and MC-CDM, and proposes a novel PAPR reduction technique, simulation results show that the technology can get better PAPR reduction performance than use the combined technology only; thirdly, this paper studies codes and phase factor sequence joint design based on selected mapping in the MC-CDM system. The computer simulation proved that the joint design is optimal in terms of performance improvement.Finally, the seventh chapter summarizes the full thesis and gives prospects for future research.更多还原