Call Admission Control (CAC) and Dynamic Channel Assignments (DCA) are important decision-making problems in mobile cellular communication systems. Current research in mobile communication considers them as two independent problems, although the former greatly depends on the resulting free channels obtained as the outcome of the latter. This book provides a solution to the CAC problem, considering DCA as an integral part of decision-making for call admission. Further, current technical resources ignore movement issues of mobile stations and fluctuation in network load (incoming calls) in the control strategy used for call admission. In addition, the present techniques on call admission offers solution globally for the entire network, instead of considering the cells independently. CAC here has been formulated by two alternative approaches. The first approach aimed at handling the uncertainty in the CAC problem by employing fuzzy comparators. The second approach is concerned with formulation of CAC as an optimization problem to minimize call drop, satisfying a set of constraints on feasibility and availability of channels, hotness of cells, and velocity and angular displacement of mobile stations. Evolutionary techniques, including Genetic Algorithm and Biogeography Based Optimization, have been employed to solve the optimization problems. The proposed approaches outperform traditional methods with respect to grade and quality of services.

Call Admission Control in Cellular Networks.

Joint Call Admission Control in Integrated Wireless LAN and 3G Cellular Networks.

Discusses Call Admission Control (CAC) is a standard operating procedure responsible for accepting or rejecting calls based on the availability of network resources. It is also used to guarantee good Quality of Service (QoS) to ongoing users. However, there are a number of imprecisions to consider during the admission and handoff processes. These uncertainties arise from the mobility of subscribers and the time-varying nature of key admission factors such as latency and packet loss.These parameters are often imprecisely measured, which has a negative impact on the estimation of a channel spectral efficiency. In mobile networking, greater emphasis is towards delivering good QoS to real-time (RT) applications. It has become increasingly necessary to develop a model capable of handling uncertainties associated with the network in order to improve the quality of decisions relating to CAC. Type-1 and Type-2 Fuzzy Logic Controllers (FLCs) were deployed to allow the CAC to make better decisions in the presence of numerous uncertainties. The model successfully proposed associated meanings and degrees of certainty to the measured values of loss and latency by means of fuzzy sets and Membership Functions (MFs). The results obtained show that the fuzzy-based CAC performs better by reducing the call blocking and call dropping probabilities which are some of the key measurement parameters of QoS in wireless networking.

This dissertation investigates the optimal call admission control (CAC) policies for Non Priority Scheme (NPS) and Reserved Channel Scheme (RCS) in wireless cellular networks for the following cases: 1. Homogenous traffic in a cell; 2. Multimedia traffic in a cell; 3. Homogenous traffic in a network; 4. Multimedia traffic in a network. Both new call and handoff call arrival processes are assumed to be Poisson processes, and the call holding times are exponentially distributed with different rate for new calls and handoff calls. Admitting each call would bring a reward to the network provider but holding each call in the system would also incur some cost to the provider. This dissertation focuses on the optimization problem of when to admit or reject a call in order to achieve the maximum reward. By establishing an infinite horizon discounted Semi Markov Decision Process (SMDP) model, this research verifies that the optimal policies of all the four cases mentioned above are state-related control policies for NPS as well as RCS. More over, this research also finds that optimal control policy for Case (1) above is still state-related control policy even if the combined arrival process for new and handoff calls are described by General Distribution. The numerical results presented in this dissertation in both tables and diagrams for all of the above cases are consistent with the theoretical results derived.

Our research aims to solve the problems of Call Admission Control (CAC), and resource reservation (RR) in next-generation cellular networks and in the fourth generation (4G) wireless heterogeneous networks.