密闭舱体内高可靠性TR无线通信关键技术与方法研究

发布时间：2018-03-11 18:38

本文选题：航天器　切入点：时间反演　出处：《电子科技大学》2017年硕士论文　论文类型：学位论文

【摘要】：近年来,随着人类探索宇宙的步伐,空间技术正在迅速发展,航天舱内信息传输需求也日益增长,传统的通过有线电缆传输信息的方式受到航天舱的体积、重量等条件的限制,逐渐成为航天器发展受限的重要因素之一。因此,实现舱内无线通信非常必要。然而,与传统地面应用环境不同,航天器是封闭舱体,舱内各点之间的无线信道环境异常复杂,电磁波密集多径传输效应显著,引起符号间干扰严重,传统的无线通信方案效果不佳,无线信息传输的可靠性受到严重挑战。时间反演(Time Reversal,TR)技术具备独特的“空-时同步聚焦”、“超分辨率聚焦”等特性。一方面“时间聚焦”特性能显著提高SNR(Signal to Noise Ratio,SNR)、有效抑制信道时延拓展、降低ISI(Inter-Symbol Interference,ISI);另一方面“空间聚焦”特性具有天然的SDMA(Space Division Multiple Access,SDMA)通信能力,能够降低无线通信设备间电磁干扰;而且TR的“超分辨率聚焦”特性使得天线单元间距能够突破分辨率极限λ2/,不仅能缩小无线通信设备体积,而且显著提升通信容量。TR这些特性在航天器内无线通信应用方面,拥有无可比拟的技术优势。基于此,本文针对航天舱内TR无线通信开展研究,主要工作包括:第一章,介绍了航天器内传统的通信体制,对国内外针对航天器内无线通信的研究现状进行了分析,明晰了无线通信技术在航天器内应用的前景及挑战。第二章,介绍了OFDM技术的基本原理,针对多径衰落信道对OFDM信号造成的相位弥散问题,探索利用TR“空-时同步聚焦”特性消除多径信道引起的相位旋转。第三章,研究了TDD-TR系统上行链路信道预探测技术,仿真分析了模拟航天舱内环境中LS-DFT与MMSE信道估计算法的性能。研究表明LS-DFT信道估计算法不仅具有较低的运算复杂度,而且具有优异的估计精度。这为TDD-TR-OFDM无线通信系统航天舱内应用奠定了坚实的基础。第四章,在传统MISO-OFDM系统方案基础上,提出了TDD-TR-MISO-OFDM系统方案,建立了TDD-TR-MISO-OFDM系统数学分析模型,并仿真分析了模拟航天舱内环境中上述系统的通信性能。仿真结果表明,TDD-TR-MISO-OFDM系统通信性能远远优于传统的MISO-OFDM系统。第五章,针对航天舱内WSN(Wireless-Sensor-Network,WSN)节点分布密集,通信性能下降问题,基于TR电磁波自适应聚焦特性,提出了TR-MIMO聚焦无线通信系统方案,并仿真分析了上述系统误码率性能。仿真结果表明,随着SNR提升,系统误码率逐渐逼近于0。上述结论充分验证了TR技术太空舱内无线通信应用的潜在优势。第六章,对本文的相关工作内容进行了总结与展望。
[Abstract]:In recent years, with the pace of human exploration of the universe, space technology is developing rapidly, and the demand for information transmission in the space module is increasing day by day. The traditional way of transmitting information through cable is limited by the space module volume, weight and other conditions. Gradually becoming one of the important factors that limit the development of spacecraft, it is very necessary to realize the wireless communication in the cabin. However, unlike the traditional ground application environment, the spacecraft is a closed cabin, and the wireless channel environment between the various points in the cabin is extremely complex. The electromagnetic wave dense multipath transmission effect is remarkable, causing serious intersymbol interference, and the traditional wireless communication scheme is not effective. The reliability of wireless information transmission is seriously challenged. Time ReversalTRT has unique characteristics such as "space-time synchronous focusing", "super-resolution focusing" and so on. On the one hand, "time focusing" can significantly improve SNR(Signal to Noise Ratio San. Effectively suppress channel delay expansion, On the other hand, the "spatial focusing" feature has the natural communication capability of SDMA(Space Division Multiple access ISI(Inter-Symbol, which can reduce the electromagnetic interference between wireless communication devices. Moreover, the "super-resolution focusing" characteristic of tr enables the antenna unit spacing to break through the resolution limit 位 _ 2 /, which can not only reduce the volume of wireless communication equipment, but also significantly enhance the communication capacity. Based on this, this paper studies tr wireless communication in space module. The main work includes: chapter 1, introduce the traditional communication system in spacecraft. This paper analyzes the present research situation of wireless communication in spacecraft at home and abroad, clarifies the prospect and challenge of wireless communication technology in spacecraft. Chapter two introduces the basic principle of OFDM technology. Aiming at the phase dispersion problem caused by multipath fading channel to OFDM signal, the phase rotation caused by multipath channel is eliminated by using "space-time synchronous focusing" characteristic of tr. In chapter 3, the uplink channel pre-detection technology of TDD-TR system is studied. The performance of LS-DFT and MMSE channel estimation algorithms in simulated cabin environment is analyzed by simulation. The results show that LS-DFT channel estimation algorithm not only has low computational complexity. It lays a solid foundation for the application of TDD-TR-OFDM wireless communication system in space module. Chapter 4th, on the basis of the traditional MISO-OFDM system scheme, puts forward the TDD-TR-MISO-OFDM system scheme, and establishes the mathematical analysis model of TDD-TR-MISO-OFDM system. The simulation results show that the communication performance of TDD-TR-MISO-OFDM system is much better than that of the traditional MISO-OFDM system. Chapter 5th, aiming at the problem of dense distribution of WSNSNWSND-TR-MISO-OFDM system, the communication performance of WSND-TR-MISO-OFDM system is reduced. Based on the adaptive focusing characteristic of tr electromagnetic wave, the scheme of TR-MIMO focused wireless communication system is proposed, and the BER performance of the system is simulated and analyzed. The simulation results show that, with the increase of SNR, The BER of the system is approaching to 0. The above conclusion fully validates the potential advantages of wireless communication applications in tr spacecraft. Chapter 6th summarizes and prospects the related work of this paper.
【学位授予单位】：电子科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN92

【参考文献】