Performance modelling of a queue management scheme with rate control for HSDPA

High Speed Downlink Packet Access (HSDPA) is being increasingly deployed to enhance UMTS Radio Access Networks. Scheduling of Node B (base station) buffered user data for transmission over a shared radio channel is a key HSDPA functionality which enables queue management techniques to be utilized to improve QoS provisioning for mixed ‘multimedia’services. Thus, we have previously proposed and studied a Time-Space Priority (TSP) buffer management scheme for ‘multimedia’QoS control in HSDPA Node B. In this paper the scheme is extended to incorporate a threshold-based rate control mechanism which provides flow control between the RNC and Node B entities over the Iub interface to improve the QoS performance of non-real-time (NRT) streams in the multimedia flow. Mathematical and simulation models are developed for comparative analysis with the previously studied TSP scheme lacking rate control. The results demonstrate the performance improvement achievable with the joint implementation of TSP queue management scheme and Iub flow control mechanism(s)