Blocking Probability Bounds in Multi-service CDMA Networks

Several previous contributions have proposed calculation methods that can be used to determine the steady state (and from it the blocking probabilities) of Code Division Multiple Access (CDMA) systems. This present work extends the classical Kaufman-Roberts formula such that it becomes applicable in CDMA systems in which elastic services with state dependent instantaneous bit rate and average bit rate dependent residency time are supported. Our model captures the effect of soft blocking, that is an arriving session may be blocked in virtually all system states but with a state dependent probability. The core of this method is to approximate the original irreversible Markov chain with a reversible one and to give lower and upper bounds on the so called partially blocking macro states of the state space. We employ this extended formula to establish lower and upper bounds on the steady state and the class-wise blocking probabilities.