A Comparative Study of Prioritized Handoff Schemes with Guard Channels in Wireless Cellular Networks

Mobility management has always been the main challenge in most mobile systems. It involves the management of network radio channel resource capacity for the purpose of achieving optimum quality of service (QoS) standard. In this era of wireless Personal Communication Networks such as Global System for Mobile Communication (GSM), Wireless Asynchronous Transfer Mode (WATM), Universal Mobile Telecommunication System (UMTS), there is a continuous increase in demand for network capacity. In order to accommodate the increased demand for network capacity (radio resource) over the wireless medium, cell sizes are reduced. As a result of such reduction in cell sizes, handoffs occur more frequently, and thereby result in increased volume of handoff related signaling. Therefore, a handoff scheme that can handle the increased signaling load while sustaining the standard QoS parameters is required.This work presents a comparative analysis of four popular developed handoff schemes. New call blocking probability, forced termination probability and throughput are the QoS parameters employed in comparing the four schemes. The four schemes are:RCS-GC,MRCS-GC, NCBS-GC, and APS-GC. NCBS-GChas the leased new call blocking probability while APS-GC has the worst. In terms of forced termination probability, MRCS-GC has the best result, whileRCS-GChas the worst scheme.MRCS-GC delivers the highest number of packets per second while APS-GC delivers the least. These performance metrics are computed by using the analytical expressions developed for these metrics in the considered models in a Microsoft Excel spreadsheet environment.http://dx.doi.org/10.4314/njt.v34i3.2

Dynamic Channel Allocation in Mobile Multimedia Networks Using Error Back Propagation and Hopfield Neural Network (EBP-HOP)

AbstractIn mobile multimedia communication systems, the limited bandwidth is an issue of serious concern. However for the better utilization of available resources in a network, channel allocation scheme plays a very important role to manage the available resources in each cell. Hence this issue should be managed to reduce the call blocking or dropping probabilities. This paper gives the new dynamic channel allocation scheme which is based on handoff calls and traffic mobility using hopfield neural network. It will improve the capacity of existing system. Hopfield method develops the new energy function that allocates channel not only for new call but also for handoff calls on the basis of traffic mobility information. Moreover, we have also examined the performance of traffic mobility with the help of error back propagation neural network model to enhance the overall Quality of Services (QoS) in terms of continuous service availability and intercell handoff calls. Our scheme decreases the call handoff dropping and blocking probability up to a better extent as compared to the other existing systems of static and dynamic channel allocation schemes

Admission Control for Multiuser Communication Systems

During the last few years, broadband wireless communication has experienced very rapid growth in telecommunications industry. Hence, the performance analysis of such systems is one of the most important topics. However, accurate systems’ analysis requires first good modeling of the network traffic. Moreover, broadband wireless communication should achieve certain performance in order to satisfy the customers as well as the operators. Therefore, some call admission control techniques should be integrated with wireless networks in order to deny new users/services if accepting them will lead to degrade the network performance to less than the allowed threshold. This thesis mainly discusses the above two issues which can be summarized as follows. First issue is the traffic modeling of wireless communication. The performance analysis is discussed in terms of the quality of services (QoS) and also the grade of services (GoS). Different scenarios have been studies such as enhancing the GoS of handover users. The second issue is the admission control algorithms. Admission Control is part of radio resource management. The performance of admission control is affected by channel characteristics such as fading and interference. Hence, some wireless channel characteristics are introduced briefly. Seven different channel allocation schemes have been discussed and analyzed. Moreover, different admission control algorithms are analyzed such as power-based and multi-classes fuzzy-logic based. Some simulations analyses are given as well to show the system performance of different algorithms and scenarios.fi=Opinnäytetyö kokotekstinä PDF-muodossa.|en=Thesis fulltext in PDF format.|sv=Lärdomsprov tillgängligt som fulltext i PDF-format

Application of genetic algorithm to wireless communications

Wireless communication is one of the most active areas of technology development of our time. Like all engineering endeavours, the subject of the wireless communication also brings with it a whole host of complex design issues, concerning network design, signal detection, interference cancellation, and resource allocation, to name a few. Many of these problems have little knowledge of the solution space or have very large search space, which are known as non-deterministic polynomial (NP) -hard or - complete and therefore intractable to solution using analytical approaches. Consequently, varied heuristic methods attempts have been made to solve them ranging from simple deterministic algorithms to complicated random-search methods. Genetic alcyorithm (GA) is an adaptive heuristic search algorithm premised on the evolutionary ideas of evolution and natural selection, which has been successfully applied to a variety of complicated problems arising from physics, engineering, biology, economy or sociology. Due to its outstanding search strength and high designable components, GA has attracted great interests even in the wireless domain. This dissertation is devoted to the application of GA to solve various difficult problems spotlighted from the wireless systems. These problems have been mathematically formulated in the constrained optimisation context, and the main work has been focused on developing the problem-specific GA approaches, which incorporate many modifications to the traditional GA in order to obtain enhanced performance. Comparative results lead to the conclusion that the proposed GA approaches are generally able to obtain the optimal or near-optimal solutions to the considered optimisation problems provided that the appropriate representation, suitable fitness function, and problem-specific operators are utilised. As a whole, the present work is largely original and should be of great interest to the design of practical GA approaches to solve realistic problems in the wireless communications systems.EThOS - Electronic Theses Online ServiceBritish Council (ORS) : Newcastle UniversityGBUnited Kingdo

An Alternative Approach to the Determination of Optimum Reservations for Handover in GSM Networks

This work presents an alternative approach to the computation of the optimum reservations to be made in a GSM network for handover call requests. Prioritizing handover calls in a cellular network such as the GSM is necessary so as to guarantee seamless connection. Successful handover enhances the quality of service (QoS) of a network as the later is directly dependent on call continuity. In a previous analysis, the expression for the optimum reservations to be made was determined using the Gaussian Elimination method which had limitations because the power series used only considered the second order. Also, the set of equations to be solved was reduced to three thereby giving a result that does not quite represent the general system. In this work, the logarithmic approach is adopted which captures the total system capacity under test. A more reliable function for the determination of optimum reservations required in a system is thus derived. This new approach is also compared with that obtained using the Gaussian Elimination method

Resource allocation in cellular CDMA systems with cross- layer Optimization

Ph.DDOCTOR OF PHILOSOPH