Dimensioning of the downlink in OFDMA cellular networks via an Erlang’s loss model

Conference: European Wireless 2009 - 15th European Wireless Conference
05/17/2009 - 05/20/2009 at Aalborg, Denmark

Proceedings: European Wireless 2009

Pages: 5Language: englishTyp: PDF

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B?aszczyszyn, Bart?omiej (INRIA & Ecole Normale Supérieure and Math. Inst., Univ. of Wroc?aw, 45 rue d’Ulm, 75005 Paris France)
Karray, Mohamed Kadhem (France Télécom Research and Development, 38/40 rue du Général Leclerc, 92794 Issy-Moulineaux, France)

In this paper we propose the following approach to the dimensioning of the radio part of the downlink in OFDMA networks. First, we use information theory to characterize the bitrate in the channel from a base station to its mobile. It depends on the power and bandwidth allocated to this mobile. Then, we describe the resource (power and bandwidth) allocation problem and characterise feasible configurations of bit-rates of all users. As the key element, we propose some particular sufficient condition (in a multi-Erlang form) for a given configuration of bit-rates to be feasible. Finally, we consider an Erlang’s loss model, in which streaming arrivals whose admission would lead to the violation of this sufficient condition are blocked and lost. In this model, the blocking probabilities can be calculated using Kaufman-Roberts algorithm. We propose it to evaluate the minimal density of base stations assuring acceptable blocking probabilities for a streaming traffic of a given load per surface unit. We validate this approach by comparison of the blocking probabilities to these simulated in the similar model in which the admission control is based on the original feasibility property (instead of its sufficient condition). Our sufficient bit-rate feasibility condition can also be used to dimension the network with respect to the elastic traffic.