Near-optimality of distributed load-adaptive Dynamic Channel Allocation strategies for cellular mobile networks

Abstract

In this paper we focus on the so-called load-adaptive Dynamic Channel Allocation (DCA) strategies for cellular mobile networks. Such strategies envisage the dynamic assignment of radio resources with the constraint that the outage probability (i.e. the probability that the carrier-to-interference power ratio be less than a given threshold) be less than a specified value, even in the worst foreseen propagation scenario. We identify a set of constraints to be satisfied in order that a DCA strategy belongs to the load-adaptive class. This provides a tight lower bound on traffic blocking and dropping performance such that: (i) it implies a dramatically lower computational effort than the known optimum strategy (based on the Maximum Packing algorithm); (ii) it is much tighter than the bound provided by the simple Erlang-B formula. A performance evaluation is carried out to compare the call blocking and dropping probabilities resulting from the tight bound above with those relevant to the Fixed Channel Allocation and to some recently proposed DCA strategies, including the Geometric DCA. The simulations exploit a mobility model that provides different degrees of offered traffic peakedness. It emerges that the Geometric DCA yields a practical way to attain near optimal performance in the load-adaptive class, leading a viable pathway to enhance the capacity of nowadays 2nd generation cellular networks in the short-medium term.