Mixing conversational and interactive traffic in the UMTS radio access network

The definition and assessment of suitable Radio Resource Management (RRM) strategies able to provide QoS in the framework of the UTRA segment of UMTS is a key issue for achieving the expectations created on 3G technology. This paper proposes and evaluates specific algorithms for the different RRM functions involved in the uplink direction in a scenario with a mixture of interactive and conversational services. In particular the effect of prioritization of conversational users in the admission control has been analyzed in terms of admission, dropping probabilities and packet delay. Furthermore, the paper also studies the importance of suitable congestion control mechanisms that cope with load fluctuations in order to guarantee the negotiated QoS to already connected users. These fluctuations are mainly due to the randomness in the traffic generation of interactive users, that can seriously degrade performance of both conversational and even interactive users if no congestion control is carried out.