空分多址技术在跳频通信系统中的应用研究

【作者】 陈晓旭；

【导师】 龚耀寰；

【作者基本信息】 电子科技大学 ， 信号与信息处理， 2003， 硕士

【摘要】 20世纪90年代以来，空域阵列信号处理被引入到移动通信领域，相应产生了空分多址(SDMA，Space Division Multiple Access)技术。引入空分多址技术后，现有的通信系统的容量可以得到很大的提高；同时，空分多址技术的引入，也为通信系统提供了空域抗干扰的能力，这样可以提高现有的通信系统的抗干扰能力。空分多址技术在未来的民用或军用移动通信系统中具有很大的应用潜力。跳频通信是扩频通信的一种方式。跳频是通过伪随机码(PN码)来控制频率合成器，使得携带信息的发射信号的载波频率发生跳变，扩展发射信号的频谱，提高抗干扰能力。跳频通信在战术无线电通信中得到了广泛的应用。本文对空分多址技术在跳频通信系统中的应用进行研究。要实现空分多址，就要有阵列信号处理技术下的波束形成。从波束形成是否与输入数据相关的角度来分，波束形成可分为数据独立波束形成、最佳波束形成和自适应波束形成。对于跳频通信系统，可以在解跳后的中频端来进行波束形成。为了采用数字信号处理的技术，可以先从中频信号中提取出基带信号，再通过基带处理来实现波束形成。对于采用天线阵列来实现空分多址的跳频系统，射频频率的跳变会影响空分多址波束形成。为了降低跳频对空分多址波束形成的影响，对于数据独立波束形成可以采用相位预补偿的方法；对于自适应波束形成，可以采用增加存储单元以对各跳频频点上自适应算法权值分别进行保存或恢复的方法。本文最后给出了一个空分多址技术在跳频通信系统中应用的仿真平台，并进行了有关的仿真。结果表明，将空分多址技术应用到跳频通信系统中，能更加有效地提高系统的抗干扰能力。更多还原

【Abstract】 Since 90’s in the 20th century, array signal processing has been introduced to mobile communications, which brought SDMA(Space Division Multiple Access) technique. With the SDMA technique, the capacity of present communication system can be greatly improved, and the anti-interference capability of present communication system can be also improved since SDMA makes it possible to antagonize spacial interference. The SDMA technique has great potential to be applied in the future civilian or military mobile communication system.Frequency-hopping communication is a kind of spectrum spread communication. In frequency-hopping, a Pseudo Noise (PN) code is used to control frequency synthesizer, which makes the carrier frequency of transmitted signal hop in certain way and spreads the spectrum of transmitted signal in order to improve the anti-interference capability. Frequency-hopping communication has been widely used in tactical wireless communications.This paper researches SDMA application in frequency-hopping communication system.It needs beam-forming which is supported by array signal processing to realize SDMA. In point of data dependency, beam-forming can be classified to data independent beam-forming, optimal beam-forming and adaptive beam-forming. For frequency-hopping communication system, beam-forming can be performed after the dehopping. In order to adopt digital signal processing, base-band signal is first picked up from the dehopped signal with intermediate frequency, then used to beam-forming which is implemented in base-band.For frequency-hopping communication system with SDMA beam-forming, frequency-hopping will affect beam-forming. To decrease the effect on SDMA beam-forming by frequency-hopping, phase pre-complementation can be employed for data independent beam-forming, and memories can be added to save or restore adaptive beam-forming weights respectively on each hopped frequency for adaptive beam-forming.A simulation platform for SDMA technique application in frequency-hopping communication system is proposed in this paper, and some related simulations have been carried out in the platform. Simulation results indicate that the capability of anti-interference of system can be improved more efficiently when SDMA technique is applied in frequency-hopping communication system.更多还原