Congestion Control Framework for Real-Time Services in OFDMA-based Systems

Abstract

In [1] the authors proposed a Quality of Service (QoS)-driven adaptive Congestion Control (CC) framework that can provide QoS guarantees for the Voice over IP (VoIP) service in mixed traffic scenarios in a single carrier system. The original framework is composed of three Radio Resource Management (RRM) algorithms: Admission Control (AC), Packet Scheduling (PSC) and Load Control (LC). In this work we generalize that framework to systems that employ a multicarrier access scheme such as Orthogonal Frequency Division Multiple Access (OFDMA). In OFDMA-based systems, there is flexibility to exploit the frequency dimension to achieve even better performance gains. In this work, we propose significant changes especially in the PSC functionality where radio resource allocation is performed. Using simulations, we evaluate the generalized CC framework in an OFDMA-based system with a traffic mix composed of sessions from a Real Time (RT) and a Non-Real Time (NRT) service. The results show that the generalized CC framework not only protects the QoS of sessions from the RT service but also imposes only a small performance degradation to the NRT service.