Research On Impairement Compensation And Networking For Advanced Optical Access Networks

Information technology profoundly changes people's life.We are in an explosive growth of the information society,and the global flow of information increases exponentially.Multimedia content-based IPTV,high definition TV,mobile multimedia,video streaming and other new services are emerging to promote the rapid growth of the people's communication needs,especially the access to the convenient wireless communication.We can clearly see two trends in the field of communications,1)the rapid growth in global IP and data traffic is demanding and will demand a fast development of the optical access network bearer network in the future;2)mobile data traffic has occupied the main part of all traffic,and will further affect future network layouts,especially optical access network layouts.In this paper,based on aforementioned two trends,two core technologies are discussed in depth,namely,orthogonal frequency division multiplexing passive optical network(OFDM-PON)technology and radio-over-fiber technology suitable for mobile data transmission.This thesis focuses on:1)physical impairment compensation with digital signal processing algorithms in the IM-DD(intensity modulation-direct detection)architecture OFDM-PON system;2)physical impairment of OFDM-ROF system and the corresponding compensation methods;3)future applications for low-cost hybrid wired-wireless service networking technology.The main contents of this paper and its novelty are shown as follows:First,we explored the physical impairments of OFDM-PON systems based on IM-DD architecture and the corresponding digital signal processing algorithms to compensate for these raised physical impairments.We introduced the simple IM-DD OFDM-PON architectures and their technical advantages.Further,we established the corresponding theoretical model to analyze the physical impairments of the systems,mainly including the dispersion-induced(selective)frequency fading and subcarrier-to-subcarrier beating interference(SSBI).Based on such model,we first proposed the use of digital signal processing to immune the physical impairments without frequency guard interval.Based on this idea,the system transmission capacity can be doubled.Related results has been published in the top optical communication journal IEEE Photonic Technology Letters which has been cited up to 20 times(web of science).The Australia scholar Prof.Ampalavanapillai Nirmalathas(University of Melbourne)mentioned the paper as a typical form of digital signal processing method.2)we propose three new digital signal processing algorithms to compensate for physical impairments based on the modulation,the channel estimation and the channel coding.Experimental results demonstrate the effectiveness of all the algorithms.Second,we discussed the OFDM-ROF system with its physical impairment and the corresponding signal processing algorithms for the corresponding compensation.We carried out the theoretical analysis and the numerical simulation for the IM-DD OFDM-ROF systems based on external modulators,mainly focusing on the system performance in the presence of dispersion-induced(selective)frequency fading and subcarrier-to-subcarrier beating interference.The theoretical model was first proposed by myself and was then widely cited.Based on this model,we put forward innovative digital signal processing methods which can be used to suppress the corresponding damage and two digital signal processing compensation algorithms based on the modulation and channel coding are proposed.Experimental results demonstrate the effectiveness of these algorithms.As the first author,I have published the relevant research results in Journal of Lightwave Technology(the top journal of optical communication)in terms of invited paper.The paper has been cited for 28 times(web of science).Australia ROF domain expert Prof.Christina Lim consider the results as one of the latest research achievement of OFDM-ROF.Follow-up study in 2012,as the first author,I published the relevent research results in the IEEE Journal of Optical Communication and Networking.Third,we discussed reversely modulated single sideband modulation technique suitable for the wideband wireless signal transmission.Reversely modulated sideband modulation was first proposed by the author,which was not similar to any of the currently proposed single sideband modulation structures.Its structure is simple,and does not require electric mixers,and can provide optical frequency doubling.Then,we built up a theoretical model of this new modulation scheme and quantitatively analyzed it by numerical simulations.Finally,this scheme was experimentally demonstrated in a 60GHz ROF system.The corresponding experimental results published in the IEEE Photonics Technology Letters in 2012 has been cited for 9 times(web of science).In the end of 2013,the detailed theoretical modeling and quantitative analysis of the results have been published in the SCI top journal Journal selected Areas in Communication(JSAC).Finally,we discussed the future applications of low-cost hybrid wired-wireless service networking technology.We first introduced a low-cost 60GHz OFDM-ROF system network,and then proposed a novel solution based on direct modulation lasers.Then,we explored the long-reach 60GHz OFDM-ROF systems suitable for low-density applications,and creatively proposed the digital signal processing to compensate for long distance transmission impairments.To allow the combination of OFDM-PON and OFDM-ROF system in WDM networks,we proposed a novel network architecture.Experimental results verify the feasibility and effectiveness of all the systems.Related series of articles are published respectively in multiple SCI journal.As the first author I published in the IEEE Journal of Optical Communication and Networking Journal a paper entitled "WDM-ROF-PON architecture for flexible wireless and wire-line layout" which has been cited for 29 times.Prof.Nirwan Ansari(IEEE Fellow)summarize this paper as a typical system for future 4G wireless communication technology.The famous expert on microwave photonic Jianping Yao also considered the proposed system as a mainstream solution.The author during the period of the Ph.D,published in the IEEE SCI just top journals JSAC article one and article on IEEE JLT PTL and OFC/ECOC international optical communication meeting the academic papers published over 20 articles.The first author is 13 papers in SCI retrieval of communication.Total citation of my publications are 180 times.The times cited without self-citations are 132 times.The highest citation of a single paper reference is 29 times(web of science).This paper is a comprehensive summary of research during the Ph.D studying period,its advanced optical access network technology basic theory for further research and put forward the corresponding multiple solutions.The results of the study includes both theoretical results provide a platform for follow-up study,including the innovation of the targeted technical research and provide direct support for advanced optical access application.