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Study On Key Technologies And Optimization Design Of OFDM-PON Downlink

Posted on:2013-11-25Degree:MasterType:Thesis
Country:ChinaCandidate:J H LuFull Text:PDF
GTID:2248330371466386Subject:Communication and Information System
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Fueled by an exponentially growing demand for broadband services and the advent of 40 Gb/s Ethernet technologies, the R&D focus for passive optical networks (PON) has shifted toward next-generation access systems that are capable of providing a "future-proof" broadband solution. Moreover, it is also critical that these optical access systems be highly flexible and cost-efficient to readily accommodate emerging services and applications. Unlike long-haul networks, practical access networks (<20 km) generally focus on low hardware, low operational complexity and easily reconfiguration.Optical orthogonal frequency-division multiplexing (OFDM), is natural compatible with advanced modulation formats, resilient to both chromatic and polarization-mode dispersion, spectral efficient, and fit for signal processing (DSP)-based implementation. As such, O-OFDM has been viewed as a emerged as an attractive candidate for future optical transmission systems.Recent researches have proposed the effective application of orthogonal frequency division multiple access (OFDMA) technologies in PON system, which could simply support heterogeneous applications and dynamic bandwidth allocation with small granularity.To meet further increase spectral efficiency at ultrahigh speeds, using the two polarization modes, which supported in the SSMF, each to be carried a high-speed OFDM signal present an attractive avenue to enables high-speed transmission systems with lower speed electronics.In this manuscript, we propose a low complexity OFDMA-PON architecture using POLMUX based on direct detection (DD) and optical single sideband (OSSB) modulation. In the OSSB signal generation, we utilize Hermitian symmetry mapping, Hilbert transformations and the optimized dual-drive MZ modulators to reduce the hardware requirement at the optical line terminal (OLT). Then, two OSSB-OFDM signals are modulated onto two frequency-orthogonal optical carriers to reduce the cross-polarization interference. At the optical network unit (ONU), we introduce a corresponding MIMO channel estimation to recover the POLMUX-OFDM signals with direct detection. This architecture could simplify hardware facilities while increasing spectral efficiency to achieve 40 Gb/s data transmission. Moreover, we discuss the system factors that would affect the performance of the proposed OFDMA-PON architecture based on the simulation results.
Keywords/Search Tags:direct detection, orthogonal frequency-division multiple access, polarization multiplexing, passive optical networks
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