The doctoral dissertations of the former Helsinki University of Technology (TKK) and Aalto University Schools of Technology (CHEM, ELEC, ENG, SCI) published in electronic format are available in the electronic publications archive of Aalto University - Aaltodoc.

A Study of Teletraffic Problems in Multicast Networks

Jouni Karvo

Dissertation for the degree of Doctor of Science in Technology to be presented with due permission for public examination and debate in Auditorium S4 at Helsinki University of Technology (Espoo, Finland) on the 29th of November, 2002, at 12 o'clock noon.

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This dissertation studies teletraffic engineering of dynamic multicast connections. The traditional models in teletraffic engineering do not handle multicast connections properly, since in a dynamic multicast tree, users may join and leave the connection freely, and thus the multicast tree evolves in time.

A model called multicast loss system is used to calculate blocking probabilities in a single link and in tree-type networks. In a single link case, the problem is a generalised Engset problem, and a method for calculating call blocking probabilities for users is presented. Application of the reduced load approximation for multicast connections is studied. Blocking probabilities in a cellular system are studied by means of simulation.

The analysis is mainly concentrated on tree type networks, where convolution-truncation algorithms and simulation methods for solving the blocking probabilities exactly are derived. Both single layer and hierarchically coded streams are treated. The presented algorithms reduce significantly the computational complexity of the problem, compared to direct calculation from the system state space. An approximative method is given for background traffic.

The simulation method presented is an application of the Inverse Convolution Monte-Carlo method, and it gives a considerable variance reduction, and thus allows simulation with smaller sample sizes than with traditional simulation methods.

Signalling load for dynamic multicast connections in a node depends on the shape of the tree as well as the location of the node in the tree. This dissertation presents a method for calculating the portion of signalling load that is caused by call establishments and tear-downs.

This thesis consists of an overview and of the following 9 publications:

  1. Karvo, J., Virtamo, J., Aalto, S., and Martikainen, O. Blocking of dynamic multicast connections in a single link. In Proc. of International Broadband Communications Conference, Future of Telecommunications (Stuttgart, Germany, Apr. 1998), pp. 473-483. © 1998 Kluwer Academic Publishers. By permission.
  2. Karvo, J., Martikainen, O., Virtamo, J., and Aalto, S. Blocking of dynamic multicast connections. Telecommunication Systems 16, 3,4 (2001), 467-481. © 2001 Kluwer Academic Publishers. By permission.
  3. Karvo, J., and Aalto, S. Average signalling load for multicast group management. In Proc. International Teletraffic Congress ITC-16 (Edinburgh, Great Britain, June 1999), D. Smith and P. Key, Eds., pp. 509-518.
  4. Aalto, S., Karvo, J., and Virtamo, J. Calculating blocking probabilities in multicast loss systems. In Proc. Intl Symposium on Performance Evaluation of Computer and Telecommunication Systems (SPECTS 2002) (San Diego, CA, July 2002), pp. 833-842.
  5. Karvo, J., Aalto, S., and Virtamo, J. Blocking probabilities of two-layer statistically indistinguishable multicast streams. In Proc. International Teletraffic Congress ITC-17 (Salvador da Bahia, Brazil, Sept. 2001), J. M. de Souza, N. L. S. Fonseca, and E. A. de Souza e Silva, Eds., pp. 769-779.
  6. Karvo, J., Aalto, S., and Virtamo, J. Blocking probabilities of multi-layer multicast streams. In 2002 Workshop on High Performance Switching and Routing (HPSR 2002) (Kobe, Japan, May 2002), pp. 268-277. © 2002 IEICE. By permission.
  7. Lassila, P., Karvo, J., and Virtamo, J. Efficient importance sampling for Monte Carlo simulation of multicast networks. In Proc. INFOCOM'01 (Anchorage, Alaska, Apr. 2001), pp. 432-439. © 2001 IEEE. By permission.
  8. Karvo, J. Efficient simulation of blocking probabilities for multilayer multicast streams. In Proc. IFIP Networking 2002 (Pisa, Italy, May 2002), E. Gregori, M. Conti, A. T. Campbell, G. Omidyar, and M. Zukerman, Eds., vol. 2345 of Lecture Notes in Computer Science (LNCS), pp. 1020-1031. © 2002 Springer-Verlag. By permission.
  9. Aaltonen, J., Karvo, J., and Aalto, S. Multicasting vs. unicasting in mobile communication systems. In Proc. Workshop on Wireless Mobile Multimedia, WoWMoM 2002 (Atlanta, GA, Sept. 2002), pp. 104-108.

Errata of publication 1

Keywords: multicast, blocking probability, loss systems, signalling load, Monte-Carlo simulation, convolution

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© 2002 Helsinki University of Technology

Last update 2011-05-26