6 research outputs found
Iterative receiver based on SAGE algorithm for crosstalk cancellation in upstream vectored VDSL
We propose the use of an iterative receiver based on the Space Alternating Generalized Expectation maximization (SAGE) algorithm for crosstalk cancellation in upstream vectored VDSL. In the absence of alien crosstalk, we show that when initialized with the frequency-domain equalizer (FEQ) output, the far-end crosstalk (FEXT) can be cancelled with no more real-time complexity than the existing linear receivers. In addition, the suggested approach does not require offline computation of the channel inverse and thus reduces the receiver complexity. In the presence of alien crosstalk, there is a significant gap between the rate performance of the linear receivers as compared with the single-user bound (SUB). The proposed receiver is shown to successfully bridge this gap while requiring only a little extracomplexity. Computer simulations are presented to validate the analysis and confirm the performance of the proposed receiver
Mitigation of impulsive noise for SISO and MIMO G.fast system
To address the demand for high bandwidth data transmission over telephone transmission lines, International Telecommunication Union (ITU)
has recently completed the fourth generation broadband (4GBB) copper
access network technology, known as G.fast.
Throughout this thesis, extensively investigates the wired broadband
G.fast coding system and the novel impulsive noise reduction technique
has been proposed to improve the performance of wired communications
network in three different scenarios: single-line Discrete Multiple Tone
(DMT)- G.fast system; a multiple input multiple-output (MIMO) DMTG.fast system, and MIMO G.fast system with different crosstalk cancellation methods. For each of these scenarios, however, Impulsive Noise
(IN) is considered as the main limiting factor of performance system.
In order to improve the performance of such systems, which use higher
order QAM constellation such as G.fast system, this thesis examines the
performance of DMT G.fast system over copper channel for six different
higher signal constellations of M = 32, 128, 512, 2048, 8192 and 32768 in
presence of IN modelled as the Middleton Class A (MCA) noise source.
In contrast to existing work, this thesis presents and derives a novel
equation of Optimal Threshold (OT) to improve the IN frequency domain mitigation methods applied to the G.fast standard over copper
channel with higher QAM signal constellations. The second scenario,
Multi-Line Copper Wire (MLCW) G.fast is adopted utilizing the proposed MLCW Chen model and is compared to a single line G-fast system
by a comparative analysis in terms of Bit-Error-Rate(BER) performance
of implementation of MLCW-DMT G.fast system. The third scenario,
linear and non-linear crosstalk crosstalk interference cancellation methods are applied to MLCW G.fas and compared by a comparative analysis
in terms of BER performance and the complexity of implementation.University of
Technology for choosing me for their PhD scholarship and The Higher
Committee For Education Development in Iraq(HCED
Stationary Interference Cancellation in Upstream Coordinated DSL Using a Turbo-MMSE Receiver
International audienceWe investigate the scenario of an upstream coordinated DSL transmission in presence of spatial-correlated noise. Joint signal processing helps mitigate this noise and reduce internal interference effects between coordinated users. We propose to couple noise whitening with a mean-squared error iterative receiver in order to approach the matched filter bound of the DSL coordinated system. The convergence of the iterative scheme in this scenario is predicted using EXIT charts under realistic transmission conditions