Hybrid CAC for MBMS-Enabled 3G UMTS Networks

In this paper, a novel hybrid connection admission control (CAC) scheme combining downlink transmission power and aggregate throughput in the case of dedicated and shared connection setup respectively, is presented ("DPTCAC: downlink power/throughput based CAC algorithm"). The algorithm has special applicability in the case of wireless networks with particular emphasis on 3G UMTS networks (H. Kaaramen et al., 2001) enhanced with new multicasting technologies namely in this case "multimedia broadcast-multicast service (MBMS)". The motivation for introducing this hybrid CAC approach is twofold: the need to use a representative resource metric on which to base CAC decisions and the necessity to take advantage of the particularities of the resource allocation procedure in true multicast environments with connection sharing. We first present the algorithm which is based on previously conducted work in E.S. Elayoubi and T. Chahed (2004, 2005) augment this presentation with description of the hybrid nature of our proposal. We then compare via simulations the performance of the proposed algorithm against a reference "throughput based CAC algorithm (TCAC)" (H. Holma and A. Toskala, 2001). Simulation results show a beneficial effect of DPTCAC\´s applicability on cell capacity without observable degradation of offered QoS