基于中繼協(xié)作的FSO通信系統(tǒng)模型性能分析
發(fā)布時(shí)間：2018-08-26 10:59
【摘要】：自由空間光(Free Space Optical,簡稱FSO)通信是一種新型的無線通信技術(shù),因其具有保密性好、頻譜自由、通信容量大和安裝便捷等優(yōu)點(diǎn)被研究人員廣泛關(guān)注。在解決“最后一公里”問題和應(yīng)急通信方面很有發(fā)展前景。然而,自由空間光通信是以光為載波,在開放的自由空間中傳輸信號(hào)的,所以很容易受到天氣等因素的影響,其中大氣湍流是影響無線光通信系統(tǒng)性能的關(guān)鍵因素之一。由大氣湍流引起的光強(qiáng)閃爍、相位偏移等效應(yīng)會(huì)嚴(yán)重影響自由空間光鏈路的傳輸性能。因此,深入研究大氣湍流對(duì)光通信系統(tǒng)的影響機(jī)理和抑制方法很有必要。另外,由光的傳播特性可知,單鏈路的自由空間光通信系統(tǒng)不適宜長距離通信,為了增大通信系統(tǒng)的通信距離和覆蓋范圍,論文從中繼協(xié)作的角度出發(fā),基于指數(shù)韋伯(Exponentiated Weibull,簡稱EW)的FSO鏈路衰落模型,研究了混合RF/FSO中繼系統(tǒng)和全光中繼FSO/FSO系統(tǒng)在不同的大氣湍流情況和不同的接收機(jī)尺寸下的中斷性能,具體內(nèi)容如下:(1)為了解決Log-normal和Gamma-Gamma信道衰落模型的單一適用性,基于Rayleigh-EW信道衰落模型提出中繼協(xié)作RF/FSO通信系統(tǒng)。通過對(duì)指數(shù)韋伯分布型FSO鏈路中斷概率的數(shù)值模擬,重點(diǎn)分析了該混合RF/FSO通信系統(tǒng)在不同大氣湍流強(qiáng)度下的影響。同時(shí),也推導(dǎo)了系統(tǒng)在高信噪比下的中斷概率的漸進(jìn)表達(dá)式,并對(duì)系統(tǒng)的分集度進(jìn)行了分析。(2)為了增大光通信系統(tǒng)的通信距離和覆蓋范圍,提出了一種對(duì)稱式的中繼協(xié)作FSO/FSO自由空間光通信系統(tǒng),系統(tǒng)采用增益可變的全光中繼,并使用副載波調(diào)制,重點(diǎn)研究了指數(shù)韋伯大氣湍流信道下自由空間光通信的中斷性能。具體地,首先,基于指數(shù)衰落分布推導(dǎo)出了端對(duì)端信噪比的累積分布函數(shù),然后得出系統(tǒng)的中斷概率表達(dá)式,進(jìn)而分析了高信噪比下中斷概率的漸進(jìn)性能和分集度。最后,通過仿真對(duì)比分析了RF/FSO通信系統(tǒng)和FSO/FSO中繼系統(tǒng)的中斷概率。
[Abstract]:Free space optical (Free Space Optical, (FSO) communication is a new type of wireless communication technology, which is widely concerned by researchers because of its advantages of good confidentiality, free spectrum, large communication capacity and convenient installation. In solving the "last kilometer" problem and emergency communication is very promising. However, optical communication in free space is transmitted in open free space with light as carrier, so it is easy to be affected by weather and other factors, among which atmospheric turbulence is one of the key factors that affect the performance of wireless optical communication system. The effects of intensity scintillation and phase shift caused by atmospheric turbulence will seriously affect the transmission performance of free space optical links. Therefore, it is necessary to study the influence mechanism and suppression method of atmospheric turbulence on optical communication system. In addition, according to the characteristics of optical propagation, the single link free space optical communication system is not suitable for long distance communication. In order to increase the communication distance and coverage of the communication system, this paper starts from the angle of relay cooperation. Based on the FSO link fading model of exponential Webb (Exponentiated Weibull, (EW), the interrupt performance of hybrid RF/FSO relay system and all-optical relay FSO/FSO system under different atmospheric turbulence conditions and different receiver sizes is studied. The main contents are as follows: (1) in order to solve the single applicability of Log-normal and Gamma-Gamma channel fading model, a relaying cooperative RF/FSO communication system based on Rayleigh-EW channel fading model is proposed. Based on the numerical simulation of the outage probability of exponential Weber distributed FSO link, the influence of the mixed RF/FSO communication system on different atmospheric turbulence intensity is analyzed. At the same time, the asymptotic expression of the outage probability in high SNR is derived, and the diversity of the system is analyzed. (2) in order to increase the communication distance and coverage of the optical communication system, A symmetric relaying cooperative FSO/FSO free space optical communication system is proposed. The system adopts all-optical relay with variable gain and uses subcarrier modulation. The interruption performance of free space optical communication in exponential Webb atmospheric turbulence channel is studied emphatically. Specifically, the cumulative distribution function of end-to-end signal-to-noise ratio is derived based on exponential fading distribution, and then the expression of system interrupt probability is derived, and then the asymptotic performance and diversity of interruption probability under high SNR are analyzed. Finally, the outage probability of RF/FSO communication system and FSO/FSO relay system is analyzed by simulation.
【學(xué)位授予單位】：廣東工業(yè)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TN929.1
本文編號(hào)：2204666
[Abstract]:Free space optical (Free Space Optical, (FSO) communication is a new type of wireless communication technology, which is widely concerned by researchers because of its advantages of good confidentiality, free spectrum, large communication capacity and convenient installation. In solving the "last kilometer" problem and emergency communication is very promising. However, optical communication in free space is transmitted in open free space with light as carrier, so it is easy to be affected by weather and other factors, among which atmospheric turbulence is one of the key factors that affect the performance of wireless optical communication system. The effects of intensity scintillation and phase shift caused by atmospheric turbulence will seriously affect the transmission performance of free space optical links. Therefore, it is necessary to study the influence mechanism and suppression method of atmospheric turbulence on optical communication system. In addition, according to the characteristics of optical propagation, the single link free space optical communication system is not suitable for long distance communication. In order to increase the communication distance and coverage of the communication system, this paper starts from the angle of relay cooperation. Based on the FSO link fading model of exponential Webb (Exponentiated Weibull, (EW), the interrupt performance of hybrid RF/FSO relay system and all-optical relay FSO/FSO system under different atmospheric turbulence conditions and different receiver sizes is studied. The main contents are as follows: (1) in order to solve the single applicability of Log-normal and Gamma-Gamma channel fading model, a relaying cooperative RF/FSO communication system based on Rayleigh-EW channel fading model is proposed. Based on the numerical simulation of the outage probability of exponential Weber distributed FSO link, the influence of the mixed RF/FSO communication system on different atmospheric turbulence intensity is analyzed. At the same time, the asymptotic expression of the outage probability in high SNR is derived, and the diversity of the system is analyzed. (2) in order to increase the communication distance and coverage of the optical communication system, A symmetric relaying cooperative FSO/FSO free space optical communication system is proposed. The system adopts all-optical relay with variable gain and uses subcarrier modulation. The interruption performance of free space optical communication in exponential Webb atmospheric turbulence channel is studied emphatically. Specifically, the cumulative distribution function of end-to-end signal-to-noise ratio is derived based on exponential fading distribution, and then the expression of system interrupt probability is derived, and then the asymptotic performance and diversity of interruption probability under high SNR are analyzed. Finally, the outage probability of RF/FSO communication system and FSO/FSO relay system is analyzed by simulation.
【學(xué)位授予單位】：廣東工業(yè)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TN929.1
【參考文獻(xiàn)】
相關(guān)期刊論文 前2條
1 韓立強(qiáng);游雅暉;聶向榮;何家歡;;大氣湍流及瞄準(zhǔn)誤差聯(lián)合效應(yīng)下全光中繼自由空間光通信的性能[J];光電子·激光;2016年05期
2 張逸新,宋正方,龔知本;激光大氣閃爍概率分布[J];科學(xué)通報(bào);1988年10期
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