400 research outputs found
Efficient resource allocation and call admission control in high capacity wireless networks
Resource Allocation (RA) and Call Admission Control (CAC) in wireless networks are processes that control the allocation of the limited radio resources to mobile stations (MS) in order to maximize the utilization efficiency of radio resources and guarantee the Quality of Service (QoS) requirements of mobile users. In this dissertation, several distributed, adaptive and efficient RA/CAC schemes are proposed and analyzed, in order to improve the system utilization while maintaining the required QoS.
Since the most salient feature of the mobile wireless network is that users are moving, a Mobility Based Channel Reservation (MBCR) scheme is proposed which takes the user mobility into consideration. The MBCR scheme is further developed into PMBBR scheme by using the user location information in the reservation making process. Through traffic composition analysis, the commonly used assumption is challenged in this dissertation, and a New Call Bounding (NCB) scheme, which uses the number of channels that are currently occupied by new calls as a decision variable for the CAC, is proposed.
This dissertation also investigates the pricing as another dimension for RA/CAC. It is proven that for a given wireless network there exists a new call arrival rate which can maximize the total utility of users, while maintaining the required QoS. Based on this conclusion, an integrated pricing and CAC scheme is proposed to alleviate the system congestion
Service oriented networking for multimedia applications in broadband wireless networks
Extensive efforts have been focused on deploying broadband wireless networks. Providing mobile users with high speed network connectivity will let them run various multimedia applications on their wireless devices. In order to successfully deploy and operate broadband wireless networks, it is crucial to design efficient methods for supporting various services and applications in broadband wireless networks. Moreover, the existing access-oriented networking solutions are not able to fully address all the issues of supporting various applications with different quality of service requirements. Thus, service-oriented networking has been recently proposed and has gained much attention.
This dissertation discusses the challenges and possible solutions for supporting multimedia applications in broadband wireless networks. The service requirements of different multimedia applications such as video streaming and Voice over IP (VoIP) are studied and some novel service-oriented networking solutions for supporting these applications in broadband wireless networks are proposed. The performance of these solutions is examined in WiMAX networks which are the promising technology for broadband wireless access in the near future. WiMAX networks are based on the IEEE 802.16 standards which have defined different Quality of Service (QoS) classes to support a broad range of applications with varying service requirements to mobile and stationary users.
The growth of multimedia traffic that requires special quality of service from the network will impose new constraints on network designers who should wisely allocate the limited resources to users based on their required quality of service. An efficient resource management and network design depends upon gaining accurate information about the traffic profile of user applications. In this dissertation, the access level traffic profile of VoIP applications are studied first, and then a realistic distribution model for VoIP traffic is proposed. Based on this model, an algorithm to allocate resources for VoIP applications in WiMAX networks is investigated. Later, the challenges and possible solutions for transmitting MPEG video streams in wireless networks are discussed. The MPEG traffic model adopted by the WiMAX Forum is introduced and different application-oriented solutions for enhancing the performance of wireless networks with respect to MPEG video streaming applications are explained. An analytical framework to verify the performance of the proposed solutions is discoursed, and it is shown that the proposed solutions will improve the efficiency of VoIP applications and the quality of streaming applications over wireless networks. Finally, conclusions are drawn and future works are discussed
EVEREST IST - 2002 - 00185 : D23 : final report
Deliverable públic del projecte europeu EVERESTThis deliverable constitutes the final report of the project IST-2002-001858 EVEREST. After its successful completion, the project presents this document that firstly summarizes the context, goal and the approach objective of the project. Then it presents a concise summary of the major goals and results, as well as highlights the most valuable lessons derived form the project work. A list of deliverables and publications is included in the annex.Postprint (published version
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Modelling and Analysis of Resource Management Schemes in Wireless Networks. Analytical Models and Performance Evaluation of Handoff Schemes and Resource Re-Allocation in Homogeneous and Heterogeneous Wireless Cellular Networks.
Over recent years, wireless communication systems have been experiencing a dramatic and continuous growth in the number of subscribers, thus placing extra demands on system capacity. At the same time, keeping Quality of Service (QoS) at an acceptable level is a critical concern and a challenge to the wireless network designer. In this sense, performance analysis must be the first step in designing or improving a network. Thus, powerful mathematical tools for analysing most of the performance metrics in the network are required. A good modelling and analysis of the wireless cellular networks will lead to a high level of QoS.
In this thesis, different analytical models of various handoff schemes and resource re-allocation in homogeneous and heterogeneous wireless cellular networks are developed and investigated. The sustained increase in users and the request for advanced services are some of the key motivations for considering the designing of Hierarchical Cellular Networks (HCN). In this type of system, calls can be blocked in a microcell flow over to an overlay macrocell. Microcells in the HCN can be replaced by WLANs as this can provide high bandwidth and its users have limited mobility features. Efficient sharing of resources between wireless cellular networks and WLANs will improve the capacity as well as QoS metrics.
This thesis first presents an analytical model for priority handoff mechanisms, where new calls and handoff calls are captured by two different traffic arrival processes, respectively. Using this analytical model, the optimised number of channels assigned to
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handover calls, with the aim of minimising the drop probability under given network scenarios, has been investigated. Also, an analytical model of a network containing two cells has been developed to measure the different performance parameters for each of the cells in the network, as well as altogether as one network system. Secondly, a new solution is proposed to manage the bandwidth and re-allocate it in a proper way to maintain the QoS for all types of calls. Thirdly, performance models for microcells and macrocells in hierarchical cellular networks have been developed by using a combination of different handoff schemes. Finally, the microcell in HCN is replaced by WLANs and a prioritised vertical handoff scheme in an integrated UMTS/WLAN network has been developed. Simulation experiments have been conducted to validate the accuracy of these analytical models. The models have then been used to investigate the performance of the networks under different scenarios
A high speed fault-tolerant multimedia network and connectionless gateway for ATM networks.
by Patrick Lam Sze Fan.Thesis (M.Phil.)--Chinese University of Hong Kong, 1997.Includes bibliographical references (leaves 163-[170]).Chapter 1 --- Introduction --- p.1Chapter 2 --- Fault-tolerant CUM LAUDE NET --- p.7Chapter 2.1 --- Overview of CUM LAUDE NET --- p.7Chapter 2.2 --- Network architecture of CUM LAUDE NET --- p.8Chapter 2.3 --- Design of Router-node --- p.10Chapter 2.3.1 --- Architecture of the Router-node --- p.10Chapter 2.3.2 --- Buffers Arrangement of the Router-node --- p.12Chapter 2.3.3 --- Buffer transmission policies --- p.13Chapter 2.4 --- Protocols of CUM LAUDE NET --- p.14Chapter 2.5 --- Frame Format of CUM LAUDE NET --- p.15Chapter 2.6 --- Fault-tolerant (FT) and Auto-healing (AH) algorithms --- p.16Chapter 2.6.1 --- Overview of the algorithms --- p.16Chapter 2.6.2 --- Network Failure Scenarios --- p.18Chapter 2.6.3 --- Design and Implementation of the Fault Tolerant Algorithm --- p.19Chapter 2.6.4 --- Design and Implementation of the Auto Healing Algorithm --- p.26Chapter 2.6.5 --- Network Management Signals and Restoration Times --- p.27Chapter 2.6.6 --- Comparison of fault-tolerance features of other networks with the CUM LAUDE NET --- p.31Chapter 2.7 --- Chapter Summary --- p.31Chapter 3 --- Overview of the Asynchronous Transfer Mode (ATM) --- p.33Chapter 3.1 --- Introduction --- p.33Chapter 3.2 --- ATM Network Interfaces --- p.34Chapter 3.3 --- ATM Virtual Connections --- p.35Chapter 3.4 --- ATM Cell Format --- p.36Chapter 3.5 --- ATM Address Formats --- p.36Chapter 3.6 --- ATM Protocol Reference Model --- p.38Chapter 3.6.1 --- The ATM Layer --- p.39Chapter 3.6.2 --- The ATM Adaptation Layer --- p.39Chapter 3.7 --- ATM Signalling --- p.44Chapter 3.7.1 --- ATM Signalling Messages and Call Setup Procedures --- p.45Chapter 3.8 --- Interim Local Management Interface (ILMI) --- p.47Chapter 4 --- Issues of Connectionless Gateway --- p.49Chapter 4.1 --- Introduction --- p.49Chapter 4.2 --- The Issues --- p.50Chapter 4.3 --- ATM Internetworking --- p.51Chapter 4.3.1 --- LAN Emulation --- p.52Chapter 4.3.2 --- IP over ATM --- p.53Chapter 4.3.3 --- Comparing IP over ATM and LAN Emulation --- p.59Chapter 4.4 --- Connection Management --- p.61Chapter 4.4.1 --- The Indirect Approach --- p.62Chapter 4.4.2 --- The Direct Approach --- p.63Chapter 4.4.3 --- Comparing the two approaches --- p.64Chapter 4.5 --- Protocol Conversion --- p.65Chapter 4.5.1 --- Selection of Protocol Converter --- p.68Chapter 4.6 --- Packet Forwarding Modes --- p.68Chapter 4.7 --- Bandwidth Assignment --- p.70Chapter 4.7.1 --- Bandwidth Reservation --- p.71Chapter 4.7.2 --- Fast Bandwidth Reservation --- p.72Chapter 4.7.3 --- Bandwidth Advertising --- p.72Chapter 4.7.4 --- Bandwidth Advertising with Cell Drop Detection --- p.73Chapter 4.7.5 --- Bandwidth Allocation on Source Demand --- p.73Chapter 4.7.6 --- The Common Problems --- p.74Chapter 5 --- Design and Implementation of the Connectionless Gateway --- p.77Chapter 5.1 --- Introduction --- p.77Chapter 5.1.1 --- Functions Definition of Connectionless Gateway --- p.79Chapter 5.2 --- Hardware Architecture of the Connectionless Gateway --- p.79Chapter 5.2.1 --- Imposed Limitations --- p.82Chapter 5.3 --- Software Architecture of the Connectionless Gateway --- p.83Chapter 5.3.1 --- TCP/IP Internals --- p.84Chapter 5.3.2 --- ATM on Linux --- p.85Chapter 5.4 --- Network Architecture --- p.88Chapter 5.4.1 --- IP Addresses Assignment --- p.90Chapter 5.5 --- Internal Structure of Connectionless Gateway --- p.90Chapter 5.5.1 --- Protocol Stacks of the Gateway --- p.90Chapter 5.5.2 --- Gateway Operation by Example --- p.93Chapter 5.5.3 --- Routing Table Maintenance --- p.97Chapter 5.6 --- Additional Features --- p.105Chapter 5.6.1 --- Priority Output Queues System --- p.105Chapter 5.6.2 --- Gateway Performance Monitor --- p.112Chapter 5.7 --- Setup an Operational ATM LAN --- p.117Chapter 5.7.1 --- SVC Connections --- p.117Chapter 5.7.2 --- PVC Connections --- p.119Chapter 5.8 --- Application of the Connectionless Gateway --- p.120Chapter 6 --- Performance Measurement of the Connectionless Gateway --- p.121Chapter 6.1 --- Introduction --- p.121Chapter 6.2 --- Experimental Setup --- p.121Chapter 6.3 --- Measurement Tools of the Experiments --- p.123Chapter 6.4 --- Descriptions of the Experiments --- p.124Chapter 6.4.1 --- Log Files --- p.125Chapter 6.5 --- UDP Control Rate Test --- p.126Chapter 6.5.1 --- Results and analysis of the UDP Control Rate Test --- p.127Chapter 6.6 --- UDP Maximum Rate Test --- p.138Chapter 6.6.1 --- Results and analysis of the UDP Maximum Rate Test --- p.138Chapter 6.7 --- TCP Maximum Rate Test --- p.140Chapter 6.7.1 --- Results and analysis of the TCP Maximum Rate Test --- p.140Chapter 6.8 --- Request/Response Test --- p.144Chapter 6.8.1 --- Results and analysis of the Request/Response Test --- p.144Chapter 6.9 --- Priority Queue System Verification Test --- p.149Chapter 6.9.1 --- Results and analysis of the Priority Queue System Verifi- cation Test --- p.150Chapter 6.10 --- Other Observations --- p.153Chapter 6.11 --- Solutions to Improve the Performance --- p.154Chapter 6.12 --- Future Development --- p.157Chapter 7 --- Conclusion --- p.158Bibliography --- p.163A List of Publications --- p.17
Rule-based expert server system design for multimedia streaming transmission
Ph.DDOCTOR OF PHILOSOPH
Applications of satellite technology to broadband ISDN networks
Two satellite architectures for delivering broadband integrated services digital network (B-ISDN) service are evaluated. The first is assumed integral to an existing terrestrial network, and provides complementary services such as interconnects to remote nodes as well as high-rate multicast and broadcast service. The interconnects are at a 155 Mbs rate and are shown as being met with a nonregenerative multibeam satellite having 10-1.5 degree spots. The second satellite architecture focuses on providing private B-ISDN networks as well as acting as a gateway to the public network. This is conceived as being provided by a regenerative multibeam satellite with on-board ATM (asynchronous transfer mode) processing payload. With up to 800 Mbs offered, higher satellite EIRP is required. This is accomplished with 12-0.4 degree hopping beams, covering a total of 110 dwell positions. It is estimated the space segment capital cost for architecture one would be about 250M. The net user cost is given for a variety of scenarios, but the cost for 155 Mbs services is shown to be about $15-22/minute for 25 percent system utilization
Impact of Mobility and Wireless Channel on the Performance of Wireless Networks
This thesis studies the impact of mobility and wireless channel characteristics, i. e. , variability and high bit-error-rate, on the performance of integrated voice and data wireless systems from network, transport protocol and application perspectives. From the network perspective, we study the impact of user mobility on radio resource allocation. The goal is to design resource allocation mechanisms that provide seamless mobility for voice calls while being fair to data calls. In particular, we develop a distributed admission control for a general integrated voice and data wireless system. We model the number of active calls in a cell of the network as a Gaussian process with time-dependent mean and variance. The Gaussian model is updated periodically using the information obtained from neighboring cells about their load conditions. We show that the proposed scheme guarantees a prespecified dropping probability for voice calls while being fair to data calls. Furthermore, the scheme is stable, insensitive to user mobility process and robust to load variations. From the transport protocol perspective, we study the impact of wireless channel variations and rate scheduling on the performance of elastic data traffic carried by TCP. We explore cross-layer optimization of the rate adaptation feature of cellular networks to optimize TCP throughput. We propose a TCP-aware scheduler that switches between two rates as a function of TCP sending rate. We develop a fluid model of the steady-state TCP behavior for such a system and derive analytical expressions for TCP throughput that explicitly account for rate variability as well as the dependency between the scheduler and TCP. The model is used to choose RF layer parameters that, in conjunction with the TCP-aware scheduler, improve long-term TCP throughput in wireless networks. A distinctive feature of our model is its ability to capture variability of round-trip-time, channel rate and packet error probability inherent to wireless communications. From the application perspective, we study the performance of wireless messaging systems. Two popular wireless applications, the short messaging service and multimedia messaging service are considered. We develop a mathematical model to evaluate the performance of these systems taking into consideration the fact that each message tolerates only a limited amount of waiting time in the system. Using the model, closed-form expressions for critical performance parameters such as message loss, message delay and expiry probability are derived. Furthermore, a simple algorithm is presented to find the optimal temporary storage size that minimizes message delay for a given set of system parameters
Telecommunications Networks
This book guides readers through the basics of rapidly emerging networks to more advanced concepts and future expectations of Telecommunications Networks. It identifies and examines the most pressing research issues in Telecommunications and it contains chapters written by leading researchers, academics and industry professionals. Telecommunications Networks - Current Status and Future Trends covers surveys of recent publications that investigate key areas of interest such as: IMS, eTOM, 3G/4G, optimization problems, modeling, simulation, quality of service, etc. This book, that is suitable for both PhD and master students, is organized into six sections: New Generation Networks, Quality of Services, Sensor Networks, Telecommunications, Traffic Engineering and Routing
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