【作者】 雷霞；

【导师】 李少谦；

【作者基本信息】 电子科技大学 ， 通信与信息系统， 2005， 博士

【摘要】 多载波通信技术由于具有抗频率选择性衰落和频谱效率高等优点,是一种适于无线环境下高速数据传输的技术;多天线的多入多出系统结构为增大系统容量、提高数据传输速率和传输质量提供了可能,二者均是新一代移动通信中的核心技术。采用多入多出的多载波通信系统结构能够提供更大的覆盖范围、更好的传输质量、更高的数据速率和频谱效率。多载波通信技术所存在的高峰值平均功率比问题始终是其得到广泛应用的主要障碍之一,本文对该问题进行了研究。 本文首先介绍了多载波通信系统的特点和高峰值平均功率比抑制技术的研究现状,总结了需要进一步解决的问题。 本文的第二部分针对多载波通信系统中峰值平均功率比的统计特性进行研究。按Nyquist采样率所得到的离散信号的峰值平均功率比的统计特性已经得到广泛研究,并成为很多峰值平均功率比抑制方案的理论基础。目前对过采样信号的分析还不多见,本文通过对连续信号所构成的随机过程进行分析,得到信号相关性的解析表达式,并推广到任意过采样率的情况。理论分析发现,随着过采样率的增加,采样点之间相关性上升,新增加采样点对信号峰值平均功率比的影响下降,系统峰值平均功率比的变化缓慢并趋于稳定。在过采样率为Nyquist采样率的2倍时,采样点之间可以近似满足相互独立同分布的关系,从而给出此时信号峰值平均功率比概率分布的理论表达式。 本文第三部分针对常见的利用多路备选信号进行峰值平均功率比抑制的方案进行了研究。通过对部分传输序列法的峰值平均功率比抑制性能进行理论分析,发现其取决于由子载波分组方式和相位因子所确定的备选信号之间的相关性,与输入信号无关。理论分析进一步证明了子载波按随机方式进行分组比按相邻或交织方式进行分组能得到更好的系统性能。在子载波按随机方式进行分组时,各路备选信号之间相关函数值的平方和存在确定的下限,其代表了备选信号的相关程度。在分组数确定后,该下限随备选信号数目的增加而上升,此时,系统性能上能得到的改善趋于饱和。本文提出应该根据此相关性下限设计更多还原

【Abstract】 Multicarrier communication technology is usually applied to the high speed data transmission in the telecommunication system. It can resist frequency selective fading and have high frequency efficiency. Meanwhile, multiple-input-multiple-output (MIMO) system architecture makes it possible to increase system capacity and improve data transmission speed and system transmission quality. Consequently, they become key technologies in the new generation telecommunication system. Multicarrier communication system with MIMO technology can provide wider covering area, better transmission quality and achieve higher data transmission speed and frequency efficiency. However, the high peak-to-average power ratio (PAPR) problem of multicarrier communication technology becomes one of the main drawbacks in its realization. This thesis is interested in this problem.First of all, this thesis introduces characteristics of the multicarrier communication system and current researches on reducing PAPR schemes, and summarizes problems needed to be resolved.Secondly, this thesis focuses on the research of the PAPR statistic characteristic of the multicarrier communication system. The PAPR statistic characteristic of the discrete signal according to Nyquist sampling has attracted much attention and become the theoretic foundation of many schemes. However, the analysis to the continuous signal is not enough. Therefore, this thesis analyzes the random process composed of continuous signals, and has got the closed form of the signals’ correlation at any time. Apply the expression to any oversampled situation. We can find that correlation value between sampled points ascends and the influence that the new sampled point acts on PAPR decreases with the increase of the oversampling rate. Moreover, analysis results prove that the independent distribution relationship between sampled points can be satisfied when oversampling rate is twice as high as the Nyquist sample rate. The theoretic probability distribution function of PAPR at this moment can be got.Thirdly, the common scheme utilizing several alternative signals to control PAPR is studied in this thesis. By theoretically analyzing the performance of reducing PAPR with partial transmit sequences (PTS), we finds that it is dependent on the correlation of several alternative signals. And it is decided by subblock partitions and phase factors, while it is unconcerned with the input signal. Furthermore, this thesis proves that the random subblock partition is more favorable than the interleaved and the adjacent subblock partitions. Meanwhile, theoretical results indicate that there is a floor of the quadratic sum of the correlation function among several alternative signals with random subblock partition. When the number of subblocks is decided, the floor ascends with the number of alternative signals, and the system performance improvement tends to be saturated. The thesis proposes to design subblock partitions更多还原