Browsing by Author "Kundaeli, Herald N."

Now showing 1 - 12 of 12
  • Thumbnail Image
    Item
    The Analysis of a Transmission System Employing SONET-Like Frames
    (Elsevier, 1998) Kundaeli, Herald N.
    Frame synchronization systems that employ multiple-code markers have been shown to give better synchronization performance than systems that employ single-code markers. It has been shown, however, that only a few of the codewords in the marker need to be used in order to attain optimum synchronization performance. Among the multiple-code marker systems which have gained wide usage recently is the SONET scheme for information transmissions at high data rates. In this report, a model for the analysis of the synchronization performance of systems which employ SONET-like frames is developed. The model is then applied to the SONET scheme to study how its performance varies with the choice of the parameters in its frame structure.
  • Thumbnail Image
    Item
  • Thumbnail Image
    Item
    The Analysis of an Optical Fibre Communication System Using Laser Rate Equations.
    (2001) Kundaeli, Herald N.
    Fibre dispersion has been the main limitation to high-speed data transmissions employing optical fibres. Various techniques and methods for combating this limitation have therefore been proposed. Such techniques include electrical and optical dispersion compensation, optical and electrical pulse shaping, and modifications of the fibre dispersion profiles. Some of these techniques and methods have resulted into very effective but expensive systems, and it has been difficult to adopt them. Others have resulted into inexpensive systems with moderate performance, and some of these have been adopted. In the present paper, the effect of electrical pulse shaping on dispersion-induced pulse distortion is investigated by computer simulation techniques. The results show that the detrimental effects of the dispersion can be greatly reduced without incurring very high costs. Moreover, this method is applicable to systems employing standard optical fibres, the major component in the already installed systems.
  • Thumbnail Image
    Item
    Comparison of Some CCITT and Computed Design Parameters.
    (Elsevier, 1998) Kundaeli, Herald N.
    Among the widely used frame synchronization algorithms in digital communication systems are the CCITT recommendations. Although these are used as standards, they become subject to modifications as developments in communication technology continue to produce new algorithms with better performance characteristics. This paper presents a set of new design parameters which show improved performance over some CCITT recommended ones.
  • Thumbnail Image
    Item
    Design Parameters for a Bit-Synchronized Transmission System
    (Taylor & Francis, 1993) Kundaeli, Herald N.
    The transmission reliability of transmission systems that employ synchronization codes For frame synchronization has been analysed in a previous report (Kundaeli 1991) in which it was shown that the introduction of verify states in the synchronization recovery and loss paths of the receiver resulted in increased reliability. Here we extend that analysis to provide a general method for determining the receiver design and performance parameters. We first derive the synchronization efficiency as a new performance parameter, then the applicable number of verify states for a receiver for practical ranges of both the channel error-rate and frame length.
  • Thumbnail Image
    Item
    Design Parameters for a Code-Synchronized Transmission System
    (Taylor & Francis, 1995) Kundaeli, Herald N.
    The reliability of a communication system depends on the design of its receiver, because it is the receiver which has to retrieve the information from the channel with high accuracy even if that information has been corrupted by noise. The design parameters chosen for the receiver are more critical than the other design parameters of the communication system. The design parameters of a code-synchronized communication system are determined. In addition, the role of the synchronization efficiency in determining the design parameters of the receiver is demonstrated.
  • Thumbnail Image
    Item
    The Distortion of Square-Shaped Pulses by Dispersive Optical Fibres
    (Taylor & Francis, 1998) Kundaeli, Herald N.
    There have been numerous reports on the distortions suffered by gaussian-shaped pulses transmitted through dispersive optical fibres. Such distortions are in the form of pulse broadening due to second-order fibre dispersion and the breakdown of the transmitted pulses into multiple pulses due to third-order dispersion. In this paper, the distortions suffered by square-shaped pulses transmitted through dispersive optical fibres are investigated. It is shown that square-shaped pulses suffer the same kinds of distortions as gaussian-shaped pulses.
  • Thumbnail Image
    Item
    The Effect of Synchronization Codes on System Design Parameters
    (Taylor & Francis, 1996) Kundaeli, Herald N.
    The analysis of frame synchronized systems based on synchronization codes with fixed combinations of bits has been analysed in previous reports. In those reports, the design parameters of the system were also derived. In this report, expressions that allow the synchronization codes to assume any bit combination are developed. The performance of the receiver with the type of synchronization code is then investigated and optimum sync codes derived. New design parameters for the system based on the obtained codes are also derived.
  • Thumbnail Image
    Item
  • Thumbnail Image
    Item
    Throughput Analysis of Arq Schemes Using State Transition Diagrams
    (2010) Kundaeli, Herald N.
    Automatic-Repeat-Request (ARQ) schemes have been widely used and various methods and representations have been used in their analysis. In this paper, the schemes are represented by ztransform based transition diagrams to yield easily retractable expressions. The approach has enabled the analysis of the Selective Repeat-Stutter 2 (SR-ST2) scheme having variable selective repeat mode retransmissions and the Selective Repeat-Stutter-Go Back N (SR-ST-GBN) scheme having variable stutter mode retransmissions. Using the SR-ST-GBN scheme, it is also shown that it is possible to choose the design parameters of ARQ-based communication systems in order to achieve maximum throughput.
  • Thumbnail Image
    Item
    The Z-Transform Applied to a birth-death Process Having Varying birth and death rates
    (2010) Kundaeli, Herald N.
    The analysis of a birth-death process using the z-transform was recently reported for processes hav-ing fixed transition probabilities between states. The current report extends that analysis to proc-esses having transition probabilities that can differ from state to state. It is then shown that the model can be used to study practical queuing and birth-death systems where the arrival, birth, ser-vice and death rates may differ from state to state.
  • Thumbnail Image
    Item
    The Z-Transform Applied to Birth-Death Markov Processes
    (2008) Kundaeli, Herald N.
    Birth-death Markov models have been widely used in the study of natural and physical processes. The analysis of such processes, however, is mostly performed using time series analysis. In this report, a finite state birth‑death Markov process is analyzed using the z‑transform approach. The performance metrics of the system and their variation with the system parameters are then derived and presented.