A Hybrid CAC Scheme for Integrated Services in CDMA Wireless Access Networks

Current advances in the area of wireless access networks, and the increasing demand for real time services (e.g. video-on-demand, voice), requires, that the quality of service (QoS) guarantees in wireless networks are met, while ensuring a high level of network utilization. Call admission control (CAC) plays a significant role in providing the desired QoS in code division multiple access (CDMA) integrated wireless access network with heterogeneous services. Several CAC schemes for integrated services in CDMA wireless access network.s are available. Signal to interference ratio (SIR) based call admission and mobility based channel reservation (MBCR) call admission schemes are frequently used CAC schemes. SIR- based CAC always outperforms fixed CAC under hot spot loadings, as it can deal with varying traffic conditions very effectively. This is not the case in FDMA/TDMA cellular systems. But SIR based algorithms do not consider the mobility of users which have a profound effect on QoS. MBCR schemes are flexible to handle the dynamic traffic situations, as these schemes use the traffic information in the current cell and its neighboring cells and hence can adapt to the real-time network conditions. The drawback of this scheme is that it doesn´t consider the effect of interference between cells which is a more realistic factor improving the performance of radio links in wireless access networks. To overcome these problems, this paper proposes a hybrid scheme which allocates channels in an efficient manner by taking into account the interference between cells and the mobility of users. Our simulation results show that this hybrid scheme performs better than the SIR and MBCR schemes.