恒包络调制关键技术研究

发布时间：2018-01-16 10:00

本文关键词：恒包络调制关键技术研究　出处：《西安电子科技大学》2014年硕士论文　论文类型：学位论文

【摘要】：对于功率和带宽双重受限的无线信道,如深空通信、卫星通信、移动通信及超短波电台通信等信道,如何更高效的利用有限的频率和功率是众多无线通信系统所追求的首要目标。为了提高无线通信系统的有效性和可靠性,不仅需要采用高效的调制方案,还要考虑如何在低信噪比/大频偏环境下实现有效的载波同步。恒包络调制所产生的信号具有功率有效性高的特点,根据恒包络调制信号的相位是否连续,将恒包络调制分为连续相位调制和非连续相位调制,由于连续相位调制(CPM)具有较高的功率利用率,更适合在无线通信信道中传输,因此本文针对CPM信号进行了深入的研究。在CPM信号中,成形偏移四相相移键控(SOQPSK)信号在功率利用率,频带利用率等方面具有更加优秀的性能,因此本文首先介绍了CPM的基本概念,接着研究了SOQPSK信号的调制技术,之后针对递归/非递归SOQPSK-MIL、递归/非递归SOQPSK-TG的简化解调算法进行了研究与仿真,不仅对递归SOQPSK-TG信号的两状态判决反馈解调算法进行了深入的研究,还针对非递归SOQPSK-TG信号提出了两状态解调算法。然后针对无线信道的极低信噪比、大多普勒频偏的环境,提出了一种适用于CPM的时频联合的载波同步方法,能够达到理想的载波同步性能,该算法所用导频开销小、复杂度低,非常适合应用在无线通信系统中。最后,以TI公司的DSP芯片TMS320C5510为目标器件,对CPM的准相干解调算法进行了硬件实现,并测试了准相干解调算法的性能。
[Abstract]:For wireless channels with dual power and bandwidth constraints, such as deep space communications, satellite communications, mobile communications and ultrashort radio communications, etc. How to make more efficient use of limited frequency and power is the primary goal pursued by many wireless communication systems. In order to improve the effectiveness and reliability of wireless communication systems, it is not only necessary to adopt efficient modulation schemes. We also consider how to realize effective carrier synchronization in low SNR / large frequency offset environment. The signal generated by constant envelope modulation has the characteristics of high power efficiency, according to whether the phase of the constant envelope modulation signal is continuous. The constant envelope modulation is divided into continuous phase modulation and discontinuous phase modulation. Because CPM (continuous phase modulation) has high power efficiency, it is more suitable for transmission in wireless communication channel. In the CPM signal, the shaping shift four-phase shift keying (SOQPSK) signal is used in power utilization. Frequency band efficiency has better performance, so this paper first introduces the basic concept of CPM, and then studies the modulation technology of SOQPSK signal. Then, the simplified demodulation algorithm of recursive / non-recursive SOQPSK-MIL, recursive / non-recursive SOQPSK-TG is studied and simulated. Not only the two-state decision feedback demodulation algorithm of recursive SOQPSK-TG signal is studied deeply. A two-state demodulation algorithm is also proposed for non-recursive SOQPSK-TG signals. Then, for the very low signal-to-noise ratio (SNR) of wireless channel and the large Doppler frequency offset environment. A carrier synchronization method suitable for CPM is proposed, which can achieve ideal carrier synchronization performance. The proposed algorithm has low pilot overhead and low complexity. It is very suitable for wireless communication system. Finally, the quasi-coherent demodulation algorithm of CPM is implemented by hardware with TMS320C5510 chip of TI Company as the target device. The performance of the quasi-coherent demodulation algorithm is tested.
【学位授予单位】：西安电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN911.3

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