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Effects of bridged taps on the channel capacity of very high-bit-rate digital subscriber lines Wang, Amanda
Abstract
The Digital Subscriber Line (DSL) technologies have been developed to meet the growing demand for high speed data transmissions to home. These technologies offer data rates that are of several order of magnitudes compared to today's analog modems operating over the same existing copper twisted pairs. Very-high-bit-rate DSL (VDSL) is the latest member of the DSL family. To date, most of the analysis on channel performance for VDSL systems are based on the model of transmission lines without considering the adverse effects caused by the presence of bridged taps. In practical situations; however, multiple bridged taps can introduce severe propagation loss. This is especially pronounced in VDSL systems because the operating frequency range is higher and the bridged taps are shorter as compared to other DSL systems. Motivated by the above, the objective of this thesis is to study the effects of bridged taps on the channel capacity of VDSL services over the Unshielded Twisted Pair (UTP) under various noise impairment conditions. First, we develop channel models of VDSL loops with the presence of bridged taps. Then, we employ these models to obtain the mathematical expressions for the channel capacity by taking the additive white Gaussian noise (AWGN) and the far-end crosstalk (FEXT) noise into account: Using the proposed analytical models, we have discovered that the channel capacity is only affected by the lengths of the bridged taps but not their physical locations for homogeneous loops in AWGN environment. On the other hand, in a FEXT dominated environment, we have proved that the channel capacity increases when the bridging locations are moved away from the transmitter. In addition, we have determined that FEXT is the dominant impairment for short VDSL loops, while AWGN is the dominating impairment for long loops.
Item Metadata
Title |
Effects of bridged taps on the channel capacity of very high-bit-rate digital subscriber lines
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Creator | |
Publisher |
University of British Columbia
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Date Issued |
1999
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Description |
The Digital Subscriber Line (DSL) technologies have been developed to meet the growing
demand for high speed data transmissions to home. These technologies offer data rates that are of
several order of magnitudes compared to today's analog modems operating over the same existing
copper twisted pairs. Very-high-bit-rate DSL (VDSL) is the latest member of the DSL family. To
date, most of the analysis on channel performance for VDSL systems are based on the model of
transmission lines without considering the adverse effects caused by the presence of bridged taps.
In practical situations; however, multiple bridged taps can introduce severe propagation loss. This
is especially pronounced in VDSL systems because the operating frequency range is higher and
the bridged taps are shorter as compared to other DSL systems.
Motivated by the above, the objective of this thesis is to study the effects of bridged taps
on the channel capacity of VDSL services over the Unshielded Twisted Pair (UTP) under various
noise impairment conditions. First, we develop channel models of VDSL loops with the presence
of bridged taps. Then, we employ these models to obtain the mathematical expressions for the
channel capacity by taking the additive white Gaussian noise (AWGN) and the far-end crosstalk
(FEXT) noise into account: Using the proposed analytical models, we have discovered that the
channel capacity is only affected by the lengths of the bridged taps but not their physical locations
for homogeneous loops in AWGN environment. On the other hand, in a FEXT dominated
environment, we have proved that the channel capacity increases when the bridging locations are
moved away from the transmitter. In addition, we have determined that FEXT is the dominant
impairment for short VDSL loops, while AWGN is the dominating impairment for long loops.
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Extent |
5070621 bytes
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Genre | |
Type | |
File Format |
application/pdf
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Language |
eng
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Date Available |
2009-06-16
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Provider |
Vancouver : University of British Columbia Library
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Rights |
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
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DOI |
10.14288/1.0064808
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URI | |
Degree | |
Program | |
Affiliation | |
Degree Grantor |
University of British Columbia
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Graduation Date |
1999-11
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Campus | |
Scholarly Level |
Graduate
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Aggregated Source Repository |
DSpace
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Item Media
Item Citations and Data
Rights
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.