Fairness-optimal initial shaping rate for HSDPA transport network congestion control

In the HSDPA (high-speed downlink packet access) Iub transport network (TN) which connects the radio network controller with base stations (node Bs), congestion control is needed. Because of the TN¿s often narrow resources, fairness of resource sharing is an important issue. Basic Additive Increase multiplicative decrease (AIMD) congestion control guarantees convergence to fairness in the long run; all flows converge to an equal share of resources in steady state, where no flows join or leave. However, incoming flows decrease the level of fairness, that is why transient fairness should be taken into account as well. This paper proposes a method which provides fairness-optimal initial rate for incoming HSDPA flows. The proposed method improves average fairness. The method can be applied in a rate based congestion control where flows share the same bottleneck. The paper also gives a general solution for fairness-optimal initial rate in case of second-order fairness measures.