Author Type

Graduate Student

Date of Award

2000

Document Type

Thesis

Publication Status

Version of Record

Submission Date

October 2026

Thesis/Dissertation Advisor [Chair]

Neelakanta, Perambur S.

Abstract

The research proposed and elaborated in this dissertation is concerned with the development of new and smart techniques for subchannel allocation in the asymmetric digital subscriber lines (ADSLs). The ADSL refers to a class of access technology adopted currently in modern telecommunications to make use of the available channel capacity on the twisted copper-wires, which exist in the "last-mile" between the central office and subscribers. This available spectrum on the voice grade copper-lines is judiciously used to transport broadband data over the last mile regime. For this purpose, the channel capacity on the access lines is segmented in subchannels and the traffic to be transported is placed on the subchannels matching the bit-rates of the traffic to the subchannel capacity (as dictated by Hartley-Shannon law). The available subchannels for downstream and upstreams are of different extents (640 kbps for upstream and 9 Mbps for downstream); and, hence are qualified as asymmetric transports. Relevant to the subchannel allocation as above, the specific research, carried out can be enumerated as follows: (1) Development of a subchannel allocation metric (SAM) on the basis of information-theoretic considerations and duly accounting for noise/interference effects on the access lines and BER-based information-impairments on the trunks (feeding the access lines); (2) Use of SAM as an algorithmic support to train an artificial neural network (ANN), which is facilitated at the ADSL modem performing subchannel allocation. A new version of ANN training (and subchannel allocation prediction) strategies is developed by implementing the ANN operation in the entropy-plane. This technique allows a fast convergence of the ANN compatible for telecommunication transports. The incorporation of ANN in the modem renders the subchannel allocation smart; (3) Fuzzy considerations are also included in the ANN indicated above and operation of ADSL modem is then tuned to function as an intelligent neuro inference engine in its efforts towards subchannel allocation; (4) ATM support on ADSL lines is investigated and a scheme for allocating the permanent and switched virtual circuits (supporting ATM specified traffic) on the subchannels of access lines is developed. Relevant call-blocking probabilities are assessed; (5) Lastly, the EMI/RFI, and crosstalks on access lines are studied in the framework of practical considerations and mitigatory efforts are suggested thereof. Simulated results using data commensurate with practical aspects of ADSL transport are furnished and discussed. Background literature is comprehensively presented chapterwise and scope for future work is identified via open questions in the concluding chapter.

Extent

229 p.

Comments

College of Engineering and Computer Science|FAU Electronic Theses and Dissertations Collection|Thesis (Ph.D.)--Florida Atlantic University, 2000.|College of Engineering and Computer Science

Identifier

FADT12652

Format

pdf

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