本文選題：航天器　切入點(diǎn)：時(shí)間反演　出處：《電子科技大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：近年來,隨著人類探索宇宙的步伐,空間技術(shù)正在迅速發(fā)展,航天艙內(nèi)信息傳輸需求也日益增長(zhǎng),傳統(tǒng)的通過有線電纜傳輸信息的方式受到航天艙的體積、重量等條件的限制,逐漸成為航天器發(fā)展受限的重要因素之一。因此,實(shí)現(xiàn)艙內(nèi)無線通信非常必要。然而,與傳統(tǒng)地面應(yīng)用環(huán)境不同,航天器是封閉艙體,艙內(nèi)各點(diǎn)之間的無線信道環(huán)境異常復(fù)雜,電磁波密集多徑傳輸效應(yīng)顯著,引起符號(hào)間干擾嚴(yán)重,傳統(tǒng)的無線通信方案效果不佳,無線信息傳輸?shù)目煽啃允艿絿?yán)重挑戰(zhàn)。時(shí)間反演(Time Reversal,TR)技術(shù)具備獨(dú)特的“空-時(shí)同步聚焦”、“超分辨率聚焦”等特性。一方面“時(shí)間聚焦”特性能顯著提高SNR(Signal to Noise Ratio,SNR)、有效抑制信道時(shí)延拓展、降低ISI(Inter-Symbol Interference,ISI);另一方面“空間聚焦”特性具有天然的SDMA(Space Division Multiple Access,SDMA)通信能力,能夠降低無線通信設(shè)備間電磁干擾;而且TR的“超分辨率聚焦”特性使得天線單元間距能夠突破分辨率極限λ2/,不僅能縮小無線通信設(shè)備體積,而且顯著提升通信容量。TR這些特性在航天器內(nèi)無線通信應(yīng)用方面,擁有無可比擬的技術(shù)優(yōu)勢(shì)。基于此,本文針對(duì)航天艙內(nèi)TR無線通信開展研究,主要工作包括:第一章,介紹了航天器內(nèi)傳統(tǒng)的通信體制,對(duì)國(guó)內(nèi)外針對(duì)航天器內(nèi)無線通信的研究現(xiàn)狀進(jìn)行了分析,明晰了無線通信技術(shù)在航天器內(nèi)應(yīng)用的前景及挑戰(zhàn)。第二章,介紹了OFDM技術(shù)的基本原理,針對(duì)多徑衰落信道對(duì)OFDM信號(hào)造成的相位彌散問題,探索利用TR“空-時(shí)同步聚焦”特性消除多徑信道引起的相位旋轉(zhuǎn)。第三章,研究了TDD-TR系統(tǒng)上行鏈路信道預(yù)探測(cè)技術(shù),仿真分析了模擬航天艙內(nèi)環(huán)境中LS-DFT與MMSE信道估計(jì)算法的性能。研究表明LS-DFT信道估計(jì)算法不僅具有較低的運(yùn)算復(fù)雜度,而且具有優(yōu)異的估計(jì)精度。這為TDD-TR-OFDM無線通信系統(tǒng)航天艙內(nèi)應(yīng)用奠定了堅(jiān)實(shí)的基礎(chǔ)。第四章,在傳統(tǒng)MISO-OFDM系統(tǒng)方案基礎(chǔ)上,提出了TDD-TR-MISO-OFDM系統(tǒng)方案,建立了TDD-TR-MISO-OFDM系統(tǒng)數(shù)學(xué)分析模型,并仿真分析了模擬航天艙內(nèi)環(huán)境中上述系統(tǒng)的通信性能。仿真結(jié)果表明,TDD-TR-MISO-OFDM系統(tǒng)通信性能遠(yuǎn)遠(yuǎn)優(yōu)于傳統(tǒng)的MISO-OFDM系統(tǒng)。第五章,針對(duì)航天艙內(nèi)WSN(Wireless-Sensor-Network,WSN)節(jié)點(diǎn)分布密集,通信性能下降問題,基于TR電磁波自適應(yīng)聚焦特性,提出了TR-MIMO聚焦無線通信系統(tǒng)方案,并仿真分析了上述系統(tǒng)誤碼率性能。仿真結(jié)果表明,隨著SNR提升,系統(tǒng)誤碼率逐漸逼近于0。上述結(jié)論充分驗(yàn)證了TR技術(shù)太空艙內(nèi)無線通信應(yīng)用的潛在優(yōu)勢(shì)。第六章,對(duì)本文的相關(guān)工作內(nèi)容進(jìn)行了總結(jié)與展望。
[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.
【學(xué)位授予單位】：電子科技大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TN92

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