Tandem links with burst errors are analyzed using alternative renewal processes in continuous time. As in the well-known Gilbert model it is assumed that individual links can be either in the good state in which the bit error rate is low, or in the bad (bursty) state in which the bit error rate is momentarily high. For end-to-end digital connection utilizing M links in tandem, three performance measures are derived: average bit error rate, the percentage of available time and the percentage of error-free seconds. These measures are currently being proposed by CCITT for developing performance specifications of ISDN connections.>

The authors describe an approach to combatting impulse noise (IN) on digital subscriber loops using short-constraint length convolutional codes and Viterbi decoding operating in hard-decision-and-erasure mode. Attention is restricted to time-compression-multiplexing transmission schemes using bipolar, or alternate-mark inversion (AMI), line coding, and a rather idealized IN model, although the approach and general conclusions are more broadly applicable. They discuss the tradeoffs in choosing the channel encoding rate to yield an optimum compromise between error-control protection and the combined effects of intersymbol interference and crosstalk. Numerical results are demonstrated for selected typical line configurations.>

We describe a methodology for the characterization of the 2-wire twisted-pair subscriber loop plant for high-speed digital communications typical of evolving integrated service digital networks (ISDN's). Through use of this analytical/numerical approach it is possible to predict the resulting error probability performance as a function of signal-to-noise ratio for a given set of input parameters representing a particular subscriber loop and its noise environment, including such effects as intersymbol interference, crosstalk and impulse noise. The results are useful in penetration assessment studies of the loop plant population at a fixed grade of service measured objectively in terms of operating bit error probability. This approach is in contrast to simulation-based methodologies leading to subjective performance assessment criteria, such as eye opening measurements. In the present paper we describe the modeling assumptions together with the analytical/numerical techniques underlying this approach. Attention is restricted to time-compression multiplexing (TCM) schemes with bipolar line coding, although the approach is much more general. Numerical results are illustrated through sample graphical output of an extensive computer program implementing this approach. Finally, we illustrate the application of this approach to objective penetration assessment of the GTE subscriber loop plant utilizing data collected as part of an extensive recent survey.