Admission control in UMTS in the presence of shared channels

  • Authors:

  • S. -E. Elayoubi;T. Chahed;G. HéButerne

  • Affiliations:

  • GET/Institut National des Telecommunications, 9 rue C. Fourier, Evry, Cedex 91011, France;GET/Institut National des Telecommunications, 9 rue C. Fourier, Evry, Cedex 91011, France;GET/Institut National des Telecommunications, 9 rue C. Fourier, Evry, Cedex 91011, France

  • Venue:
  • Computer Communications
  • Year:
  • 2004

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Abstract

In this article, we focus on Call Admission Control (CAC) in the presence of both real-time and elastic flows in a multicell UMTS environment where elastic flows share a common, shared channel. We first study the capacity of a multicell UMTS system. We determine an upper bound on the other-cell interference and obtain novel expressions for the SIR and powers for both the uplink and the downlink. The former is an asynchronous CDMA system, often using one of three types of receivers: matched filter, minimum mean-square error and decorrelator. In the latter, the SIR depends on the distance between the user and the base station. Based on these expressions, we develop a novel CAC algorithm that takes into account the effects of mobility, coverage as well as the wired capacity in the UMTS Terrestrial Radio Access Network (UTRAN), for the uplink, and the maximal transmission power of the base station, for the downlink. Our algorithm outperforms classical ones as it achieves lower dropping rates. We eventually use this framework to manage priorities between real-time calls, transmitted over dedicated channels, and elastic calls, transmitted over common or shared ones. Real-time calls are given an admission priority if the channel is constrained, while decreasing the ongoing elastic calls share.