On the impact of prioritised radio resource control on TCP connections in a downlink UMTS channel

Prioritisation based on traffic class is widely used within radio resource control strategies to provide quality of service (QoS) assurances in 3G wireless systems. Under high load conditions, traffic prioritisation can lead to situations where, momentarily, most of the radio resources are assigned to delay-constrained connections (e.g. conversational users) and, consequently, the available bandwidth for less priority users (e.g. interactive traffic) is significantly reduced. In This work we analyse the impact of this bandwidth oscillation phenomenon on TCP connections over a downlink UMTS channel. Experimental results have been obtained using legacy TCP connections over a real-time UMTS testbed.