Single channel occupied voice and multi-channel occupied HSCSD over GSM

  • Authors:

  • Jahangir H. Sarker;Seppo J. Halme

  • Affiliations:

  • Communications Laboratory, Helsinki University of Technology, PO Box 2300, FIN-02015 HUT, Finland;Communications Laboratory, Helsinki University of Technology, PO Box 2300, FIN-02015 HUT, Finland

  • Venue:
  • Computer Communications
  • Year:
  • 2002

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Abstract

Random access and traffic channel parts are utilized, respectively, for call establishment and information transmission in the uplink direction, comprising mobile to base station of the Global System for Mobile Communication (GSM) networks. Voice (V) and High Speed Circuit Switched Data (HSCSD) calls use two parallel random access parts and a common traffic channel part where a V call occupies a single traffic channel and a HSCSD call occupies a multiple number of traffic channels. A call is either rejected or blocked if it is unsuccessful either in the random access part or in the traffic channel part. The optimum number of random access slots is directly proportional to the average access arrival rate. According to the specification, four types of retransmission cut-off policies can be executed in the random access part wherein only one type can provide almost zero call rejection probability, pertaining to a limited amount of traffic arrival rate per random access slot. A complete analysis for the traffic channel utilization and call blocking probability for V and HSCSD calls with an exact number of random access slots in collaboration with four different types of retransmission cut-off schemes is introduced. The overall call success probability is devised resorting to call rejection and call blocking probabilities. Results demonstrate that the overall call success probability can be independent of random access part up to a certain call arrival rate if a special type of retransmission cut-off is utilized.