On-line optimization and control of the buffer sizes in a cellular network communication system

Motivated by the cellular model paradigm, this paper develops a distributed on-line algorithm for determining the values of the control parameters (in this case, the buffer sizes) that optimize some predefined performance metrics of interest (e.g. average queue length, average loss probability). Stochastic Fluid Model (SFM) framework is adopted to model the queuing systems. Using this framework, we derive Infinitesimal Perturbation Analysis (IPA) estimates of the performance metrics of interest with respect to the control parameters. These estimates are shown to be unbiased which means that they can be used in a Stochastic Approximation (SA) based algorithm to drive the system to the optimal solution. Subsequently, these estimators are evaluated based on data observed from the sample path of the “real” system and used in the SA algorithm to dynamically control the buffer sizes in a distributed manner, allowing the network to work continuously at an optimal point. The correctness of the algorithm is verified through simulations using a network model of two tightly coupled nodes. The contribution of this paper is that it derives the fluid-based IPA algorithms for the specific communication network investigated, which can eventually lead to distributed protocols for controlling the buffer size of the nodes of a cellular network to optimize the overall network´s performance.