Pang, Xiaodan

Integrationen mellem fiberoptiske og trådløse kommunikationssystemer i "last mile" acces-net betragtes på nuværende tidspunkt som en lovende løsning for både leverandører og brugere i forhold til lavere implementeringsomkostninger, kortere opgraderingstider samt højere mobilitet og eksibilitet for adgang til bredbåndsservice. For at realisere den sømløse konvergens mellem to netværkssegmenter, må den lavere kapacitet af trådløse systemer øges for at tilpasses den stigende båndbredde i fiberoptiske systemer. Forskningen, som indgår i denne afhandling, fokuserer på eksperimentelle undersøgelser af hybride trådløse/fiberoptiske forbindelser med rekordhøj kapacitet. De væsentlige bidrag for denne afhandling har udvidet stateof-the-art indenfor især to hovedområder: Højhastighed millimeter-bølge (mm-bølger) kommunikationsforbindelser og radio-over-fiber (RoF) systemer, som anvender trådløs multipel input multipel output (MIMO) multiplexningsteknologi.I forbindelse med højhastigheds- mm-bølge forbindelser fokusere denne afhandling på høj kapacitets fiber-trådløs transmission i både V-båndet (50-75 GHz) og W-båndet (75-110 GHz). Optisk mm-bølge signal generationsteknik med både kohærente og inkohærente optiske kilder er undersøgt og demonstreret. Anvendelsen af avancerede modulationsformater (faseskift keying (PSK), M-kvadratur amplitude modulation (QAM) og ortogonale frekvens division multiplexning (OFDM)) for højhastigheds hybride fiberoptisk/trådløs transmission er eksperimentelt undersøgt. Ydermere undersøges der også i denne afhandling implementeringen af tovejs operationer i optiske hybride fiberoptiske/trådløse systemer.Endvidere foreslår og demonstrerer denne afhandling den sømløse oversættelse af både fiber bølgelængde division multiplexning (WDM) og polarisation multiplexing (PolMux) RoF systemer i trådløse MIMO forbindelser for at øge den spektrale effektivitet og den samlede kapacitet på båndbredde begrænsede fiber-trådløse systemer. To forskellige modulationsformater: MIMO-OFDM og MIMO-kvadratur PSK (QPSK), er eksperimentelt undersøgt baseret på forskellige kanal estimerings teknikker.Som konklusion viser resultaterne i afhandlingen muligheden for at anvende mm-bølge signaler, avancerede modulationsformater og rumlige multiplexning teknologi i næste generations med høj kapacitet hybride fiberoptiske/trådløse acces systemer.Integration between fiber-optic and wireless communications systems in the "last mile" access networks is currently considered as a promising solution for both service providers and users, in terms of minimizing deployment cost, shortening upgrading period and increasing mobility and flexibility of broadband services access. To realize the seamless convergence between the two network segments, the lower capacity of wireless systems need to be increased to match the continuously increasing bandwidth of fiber-optic systems. The research works included in this thesis are devoted to experimental investigations of photonic-wireless links with record high capacities to fulfill the requirements of next generation hybrid optical fiber-wireless access networks. The main contributions of this thesis have expanded the state-of-the-art in two main areas: high speed millimeter-wave (mm-wave) communication links and radio-over-fiber (RoF) systems employing wireless multi-input multi-output (MIMO) multiplexing technologies. Regarding high speed mm-wave links, this thesis focuses on high capacity fiber-wireless transmissions in both the V-band (50-75 GHz) and the Wband (75-110 GHz). Photonic mm-wave signal generation techniques with both coherent and incoherent optical sources are studied and demonstrated. Employments of advanced modulation formats including phase-shift keying (PSK), M-quadrature amplitude modulation (QAM) and orthogonal frequency-division multiplexing (OFDM) for high speed photonic-wireless transmission are experimentally investigated. Furthermore, this thesis also studies the implementation of bidirectional operations in hybrid optical fiber-wireless systems.In addition, this thesis proposes and demonstrates the seamless translation of both fiber wavelength division multiplexing (WDM) and polarization multiplexing (PolMux) RoF systems into wireless MIMO links, to increase the spectral efficiency and overall throughput of bandwidth limited fiberwireless systems. Two different modulation formats: MIMO-OFDM and MIMO-quadrature PSK (QPSK), are experimentally investigated based on different channel estimation techniques.In conclusion, the results presented in the thesis show the feasibility of employing mm-wave signals, advanced modulation formats and spatial multiplexing technologies in next generation high capacity hybrid optical fiber-wireless access systems

Online Research Database In Technology

High-Capacity Hybrid Optical Fiber-Wireless Communications Links in Access Networks

http://orbit.dtu.dk/ws/files/77909679/PhD_Thesis_xiaodan..PDF

High-Capacity Hybrid Optical Fiber-Wireless Communications Links in Access Networks

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Online Research Database In Technology