ATM over an asymmetric digital subscriber line

Abstract

This thesis investigates Asymmetric Digital Subscriber Line (ADSL) access networks and considers Asynchronous Transfer Mode (ATM) transport in the ADSL network. To analyse the ADSL access network, a simulation was developed using C++ and MATLAB. The thesis outlines the background and implementation of ADSL in the opening sections and then moves on to details about developing a simulation of the network. The development of the simulation model outlining the development of noise sources in the network is described and modules for the network implementation are discussed. The local loop and the effects of different impairments such as bridge taps, line length, and wire gauge are also considered. The impairments in the copper loop are investigated to highlight the effect they have on the frequency response of the line. The line length and gauge increase the attenuation while bride taps introduce a non-linear phase response. The latter non-linear phase shift is very hard to compensate for. The loop characteristics are incorporated into the simulation, so as to represent different loop structures which exist in the network The overall affect of the noise sources and loop characteristics, can then be added to the simulation.