Robust dynamic admission control for unified cell and call QoS in statistical multiplexers

Abstract

The design of connection admission control (CAC) for a simple Markovian model of a multiservice statistical multiplexer is considered. The paper begins by laying the foundation through several fundamental analytic concepts, such as a semi-Markov decision process formulation of the design problem and time scale decomposition, before progressively leading up to real-world requirements, like robustness and simplicity of design. Several numerical illustrations are given. The salient contributions of the paper are as follows. 1) A unified treatment of multiclass cell and call QoS. 2) A CAC design which is robust, fair, and efficient. 3) Simplicity in the CAC design, together with an evaluation of the tradeoff with performance. 4) An analytic technique for computing the feasibility region in the space of call arrival rates where some control exists to satisfy QoS. 5) The discovery of near linearity of the boundary of the feasible region, which is then used to decompose the design problem. 6) A unified treatment of aggressive and conservative forms of CAC, the latter being conventional and the former yielding better call level performance. 7) An effective bandwidth definition based on the aggressive form of CAC, which influences the CAC design. 8) Demonstration of the beneficial impact on performance of cell level control. 9) An asymptotic theory of the joint behavior of cell loss and call blocking. 10) A rigorous development of time scale decomposition. 11) A numerical evaluation of the accuracy of the notion of nearly completely decomposable Markov chains.

Untitled

“…Then the states associated with a class i call arrival are s = (x, e i ), and the states associated with a class i call departure are s = (x, −e i ), 1 ≤ i ≤ I . This reduction, by ignoring the number of calls in the ON state and the events of a call being turned ON or OFF, gives us enough accuracy for the CAC problem, as shown experimentally by Mitra, Reiman, and Wang (1998).…”

“…There is a substantial literature on CAC in one link multiservice networks, e.g. Marbach and Tsitsiklis (1997), Mitra, Reiman, and Wang (1998), and references in Dziong and Mason (1994). The single link case is significant since it is the basic building block for larger networks and, as shown in Section 6 of this paper, combined CAC and routing for a multi-link network system can be decomposed into single link processes.…”

“…Maximizing revenue while meeting QoS constraints suggests a constrained semi-Markov decision process (SMDP) (Mitra, Reiman, & Wang, 1998). The rapid growth in the number of states with problem complexity has led to RL approaches to the problem (Marbach & Tsitsiklis, 1997;Marbach, Mihatsch, & Tsitsiklis, 2000).…”

“…linear programming in Mitra, Reiman, and Wang (1998)), the RL algorithm used in this paper is a stochastic iterative algorithm, it does not require a priori knowledge of the state transition models (i.e., the state transition probabilities) associated with the underlying Markov chain, and thus can be used to solve real network problems with very large state spaces that cannot be handled by model-based algorithms, and can automatically adapt to real traffic conditions. This work builds on earlier work of the authors (Brown, Tong, & Singh, 1999) in that it provides a more general framework for studying the CAC and routing problem, under QoS constraints.…”

A priority based call admission control protocol with call degradation for cellular networks

“…In [12] a call admission protocol is proposed with the objective of guaranteeing the overall loss ratio of the system. Call admission protocols that takes into account the user velocity and the direction of movement in allocating bandwidth not only in the current cells but in the cell the user is moving into are studied in [7]and [8].…”