Place: Conference Room, Level 7 School of Computer Sciences
The concept of Common Radio Resource Management (CRRM) has been proposed by 3GPP in order to efficiently manage the common pool of radio resources that are available for each of the existing radio access technologies in the heterogeneous wireless networks (HWNs). The main challenge of CRRM for HWNs is to search the best connection for the demanded services, enabling calls transference from one interface to another seamlessly and utilizing the availability of all radio resources. Thus, this thesis proposes a joint call admission control (JCAC) and traffic offloading algorithms in the CRRM for an integrated cellular and mobile network. The contributions of this work are threefold. First, a user mobility model in the wireless overlay network is proposed. The equation of dwelling time in the WLAN is derived and the probability of moving out from the coverage area and its sojourn time is calculated. Next, the vertical handoff (VHO) rate equation is produced. The performance is assessed analytically using the theory of continuous time Markov Chain (CTMC). Second, JCAC comprises of initial network selection and VHO is proposed. User mobility, usage duration, service characteristics and system load have been incorporated in the JCAC decision making parameters and evaluated by using three dimension Markov Chains. Third, traffic offloading algorithm is introduced in the proposed CRRM. An analytic hierarchy process (AHP) is applied for weight assignment to the decision making criteria and the cost function is used for the user’s selection in the offloading algorithm. The tradeoff between different system performance metrics are examined between proposed CRRM scheme with and without offloading. Results obtained show that the proposed JCAC scheme reduces the new and VHO calls blocking probabilities, and increases the overall system throughput. Furthermore, the proposed scheme also minimizes the service cost and improves the variance between network utilizations of the entire system. The proposed CRRM with offloading scheme can admit more users into the system and improve the overall throughput and profit of the network operator. Finally, the findings of the proposed CRRM which consist of JCAC and offloading algorithms have shown the impact on different attributes of the system performance, providing insights and design guidelines for future research in this domain.