Gradient Based Estimation of Equivalent Bandwidth in Satellite Communications with Loss and Delay Constraints

Equivalent bandwidth (EqB) is defined as the minimum service rate to be provided to a traffic buffer to guarantee a certain degree of Quality of Service (QoS) in terms of objective parameters (packet loss, delay, jitter). EqB techniques are usually obtained analytically for homogeneous traffic trunks, with respect to a single QoS constraint. Modern network solutions (e.g., DiffServ edge routers, wireless access points, for example WiMAX or satellite access technologies) often imply the aggregation of service classes with different QoS constraints, thus generating heterogeneous trunks from the point of view of both traffic sources and QoS requirements. This situation leads to the need to develop new equivalent bandwidth techniques so as to match heterogeneity. In this view, the paper firstly introduces the key elements of the access architectures where QoS meets heterogeneity. The Satellite Independent – Service Access Point, currently under study within the European Telecommunications Standardization Institute, is taken as technological reference. Then, a novel EqB algorithm is developed to “optimally” match heterogeneity together with the joint control of loss and delay performance metrics. The proposed methodology is tested through real fading and traffic traces to highlight its effectiveness to support bandwidth dimensioning in heterogeneous conditions.