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Non-blocking and distributed routing principles in ATM packet switching networks. / CUHK electronic theses & dissertations collectionJanuary 1997 (has links)
by Philip Pak-tung To. / Thesis (Ph.D.)--Chinese University of Hong Kong, 1997. / Includes bibliographical references (p. 126). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web.
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A high speed fault-tolerant multimedia network and connectionless gateway for ATM networks.January 1997 (has links)
by Patrick Lam Sze Fan. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1997. / Includes bibliographical references (leaves 163-[170]). / Chapter 1 --- Introduction --- p.1 / Chapter 2 --- Fault-tolerant CUM LAUDE NET --- p.7 / Chapter 2.1 --- Overview of CUM LAUDE NET --- p.7 / Chapter 2.2 --- Network architecture of CUM LAUDE NET --- p.8 / Chapter 2.3 --- Design of Router-node --- p.10 / Chapter 2.3.1 --- Architecture of the Router-node --- p.10 / Chapter 2.3.2 --- Buffers Arrangement of the Router-node --- p.12 / Chapter 2.3.3 --- Buffer transmission policies --- p.13 / Chapter 2.4 --- Protocols of CUM LAUDE NET --- p.14 / Chapter 2.5 --- Frame Format of CUM LAUDE NET --- p.15 / Chapter 2.6 --- Fault-tolerant (FT) and Auto-healing (AH) algorithms --- p.16 / Chapter 2.6.1 --- Overview of the algorithms --- p.16 / Chapter 2.6.2 --- Network Failure Scenarios --- p.18 / Chapter 2.6.3 --- Design and Implementation of the Fault Tolerant Algorithm --- p.19 / Chapter 2.6.4 --- Design and Implementation of the Auto Healing Algorithm --- p.26 / Chapter 2.6.5 --- Network Management Signals and Restoration Times --- p.27 / Chapter 2.6.6 --- Comparison of fault-tolerance features of other networks with the CUM LAUDE NET --- p.31 / Chapter 2.7 --- Chapter Summary --- p.31 / Chapter 3 --- Overview of the Asynchronous Transfer Mode (ATM) --- p.33 / Chapter 3.1 --- Introduction --- p.33 / Chapter 3.2 --- ATM Network Interfaces --- p.34 / Chapter 3.3 --- ATM Virtual Connections --- p.35 / Chapter 3.4 --- ATM Cell Format --- p.36 / Chapter 3.5 --- ATM Address Formats --- p.36 / Chapter 3.6 --- ATM Protocol Reference Model --- p.38 / Chapter 3.6.1 --- The ATM Layer --- p.39 / Chapter 3.6.2 --- The ATM Adaptation Layer --- p.39 / Chapter 3.7 --- ATM Signalling --- p.44 / Chapter 3.7.1 --- ATM Signalling Messages and Call Setup Procedures --- p.45 / Chapter 3.8 --- Interim Local Management Interface (ILMI) --- p.47 / Chapter 4 --- Issues of Connectionless Gateway --- p.49 / Chapter 4.1 --- Introduction --- p.49 / Chapter 4.2 --- The Issues --- p.50 / Chapter 4.3 --- ATM Internetworking --- p.51 / Chapter 4.3.1 --- LAN Emulation --- p.52 / Chapter 4.3.2 --- IP over ATM --- p.53 / Chapter 4.3.3 --- Comparing IP over ATM and LAN Emulation --- p.59 / Chapter 4.4 --- Connection Management --- p.61 / Chapter 4.4.1 --- The Indirect Approach --- p.62 / Chapter 4.4.2 --- The Direct Approach --- p.63 / Chapter 4.4.3 --- Comparing the two approaches --- p.64 / Chapter 4.5 --- Protocol Conversion --- p.65 / Chapter 4.5.1 --- Selection of Protocol Converter --- p.68 / Chapter 4.6 --- Packet Forwarding Modes --- p.68 / Chapter 4.7 --- Bandwidth Assignment --- p.70 / Chapter 4.7.1 --- Bandwidth Reservation --- p.71 / Chapter 4.7.2 --- Fast Bandwidth Reservation --- p.72 / Chapter 4.7.3 --- Bandwidth Advertising --- p.72 / Chapter 4.7.4 --- Bandwidth Advertising with Cell Drop Detection --- p.73 / Chapter 4.7.5 --- Bandwidth Allocation on Source Demand --- p.73 / Chapter 4.7.6 --- The Common Problems --- p.74 / Chapter 5 --- Design and Implementation of the Connectionless Gateway --- p.77 / Chapter 5.1 --- Introduction --- p.77 / Chapter 5.1.1 --- Functions Definition of Connectionless Gateway --- p.79 / Chapter 5.2 --- Hardware Architecture of the Connectionless Gateway --- p.79 / Chapter 5.2.1 --- Imposed Limitations --- p.82 / Chapter 5.3 --- Software Architecture of the Connectionless Gateway --- p.83 / Chapter 5.3.1 --- TCP/IP Internals --- p.84 / Chapter 5.3.2 --- ATM on Linux --- p.85 / Chapter 5.4 --- Network Architecture --- p.88 / Chapter 5.4.1 --- IP Addresses Assignment --- p.90 / Chapter 5.5 --- Internal Structure of Connectionless Gateway --- p.90 / Chapter 5.5.1 --- Protocol Stacks of the Gateway --- p.90 / Chapter 5.5.2 --- Gateway Operation by Example --- p.93 / Chapter 5.5.3 --- Routing Table Maintenance --- p.97 / Chapter 5.6 --- Additional Features --- p.105 / Chapter 5.6.1 --- Priority Output Queues System --- p.105 / Chapter 5.6.2 --- Gateway Performance Monitor --- p.112 / Chapter 5.7 --- Setup an Operational ATM LAN --- p.117 / Chapter 5.7.1 --- SVC Connections --- p.117 / Chapter 5.7.2 --- PVC Connections --- p.119 / Chapter 5.8 --- Application of the Connectionless Gateway --- p.120 / Chapter 6 --- Performance Measurement of the Connectionless Gateway --- p.121 / Chapter 6.1 --- Introduction --- p.121 / Chapter 6.2 --- Experimental Setup --- p.121 / Chapter 6.3 --- Measurement Tools of the Experiments --- p.123 / Chapter 6.4 --- Descriptions of the Experiments --- p.124 / Chapter 6.4.1 --- Log Files --- p.125 / Chapter 6.5 --- UDP Control Rate Test --- p.126 / Chapter 6.5.1 --- Results and analysis of the UDP Control Rate Test --- p.127 / Chapter 6.6 --- UDP Maximum Rate Test --- p.138 / Chapter 6.6.1 --- Results and analysis of the UDP Maximum Rate Test --- p.138 / Chapter 6.7 --- TCP Maximum Rate Test --- p.140 / Chapter 6.7.1 --- Results and analysis of the TCP Maximum Rate Test --- p.140 / Chapter 6.8 --- Request/Response Test --- p.144 / Chapter 6.8.1 --- Results and analysis of the Request/Response Test --- p.144 / Chapter 6.9 --- Priority Queue System Verification Test --- p.149 / Chapter 6.9.1 --- Results and analysis of the Priority Queue System Verifi- cation Test --- p.150 / Chapter 6.10 --- Other Observations --- p.153 / Chapter 6.11 --- Solutions to Improve the Performance --- p.154 / Chapter 6.12 --- Future Development --- p.157 / Chapter 7 --- Conclusion --- p.158 / Bibliography --- p.163 / A List of Publications --- p.171
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Hybrid FDMA/CDMA wireless ATM and subband image coding.January 1996 (has links)
by Yeung Chi Kit. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1996. / Includes bibliographical references (leaves 89-91). / Chapter I --- Hybrid FDMA/CDMA Wireless ATM --- p.1 / Chapter 1 --- Introduction --- p.2 / Chapter 1.1 --- Motivation --- p.2 / Chapter 1.2 --- Thesis Organization (PART I) --- p.5 / Chapter 2 --- Fundamentals --- p.6 / Chapter 2.1 --- Spread Spectrum --- p.6 / Chapter 2.1.1 --- Direct Sequence (DS) CDMA --- p.6 / Chapter 2.1.2 --- Frequency Hopping (FH) CDMA --- p.8 / Chapter 2.1.3 --- Time Hopping (TH) CDMA --- p.8 / Chapter 2.1.4 --- MC-CDMA (Multicarrier-CDMA) --- p.9 / Chapter 2.2 --- Asynchronous Transfer Mode (ATM) --- p.10 / Chapter 3 --- System Model --- p.12 / Chapter 4 --- System Capacity --- p.16 / Chapter 4.0.1 --- One Homogeneous User Population --- p.16 / Chapter 4.0.2 --- Two Homogeneous User Populations --- p.18 / Chapter 5 --- Conclusion --- p.24 / Chapter II --- Subband Image Coding --- p.28 / Chapter 6 --- Introduction --- p.29 / Chapter 6.1 --- Motivation --- p.29 / Chapter 6.2 --- Thesis Organization (PART II) --- p.31 / Chapter 7 --- Fundamentals --- p.33 / Chapter 7.1 --- Image Fidelity Criteria --- p.33 / Chapter 7.1.1 --- Numerical (Quantitative) Measures --- p.34 / Chapter 7.1.2 --- Perceptual (Subjective) Measure --- p.34 / Chapter 8 --- Wavelet Transform --- p.36 / Chapter 8.1 --- Wavelet Theory --- p.37 / Chapter 8.2 --- Multiresolution Analysis --- p.39 / Chapter 8.3 --- Quality Criteria for Wavelets --- p.42 / Chapter 8.4 --- Criteria for filters...................´ب --- p.43 / Chapter 8.5 --- Orthogonal Discrete Wavelet Transform --- p.45 / Chapter 8.6 --- Biorthogonal Discrete Wavelet Transform --- p.47 / Chapter 8.7 --- Wavelet Packets Transform --- p.48 / Chapter 8.8 --- Appendix --- p.50 / Chapter 8.8.1 --- QMF & CQF --- p.50 / Chapter 8.8.2 --- Examples of Orthogonal Filters --- p.53 / Chapter 8.8.3 --- Examples of Biorthogonal Filters --- p.53 / Chapter 9 --- Transform Coding and Compression --- p.55 / Chapter 9.1 --- Transformation Techniques --- p.56 / Chapter 9.2 --- Quantization --- p.57 / Chapter 9.2.1 --- Scalar Quantization --- p.57 / Chapter 9.2.2 --- Llyod-Max Quantization --- p.59 / Chapter 9.2.3 --- Vector Quantization --- p.59 / Chapter 9.2.4 --- Successive Approximation Entropy-Coded Quantization --- p.60 / Chapter 9.3 --- Entropy Coding --- p.61 / Chapter 9.3.1 --- Huffman Coding --- p.61 / Chapter 9.3.2 --- Arithmetic Coding --- p.62 / Chapter 9.3.3 --- Dictionary Based Coding --- p.64 / Chapter 9.3.4 --- Run Length Coding --- p.65 / Chapter 9.3.5 --- Example --- p.65 / Chapter 10 --- Embedded Zerotree Algorithm --- p.69 / Chapter 10.1 --- Significance Map Encoding --- p.70 / Chapter 10.2 --- Successive Approximation Entropy Coded Quantization --- p.72 / Chapter 10.3 --- Example --- p.74 / Chapter 10.4 --- Comments on EZW --- p.77 / Chapter 11 --- Residue Coding Using Embedded Zerotree Algorithm --- p.79 / Chapter 11.1 --- Residue Coding --- p.80 / Chapter 11.2 --- Results --- p.81 / Chapter 12 --- Conclusion --- p.86
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A self-routing non-buffering ATM switch.January 1996 (has links)
by Timothy Kai-Cheung Chung. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1996. / Includes bibliographical references. / Chapter 1. --- INTRODUCTION --- p.1 / Chapter 2. --- ASYNCHRONOUS TRANSFER MODE SWITCHING --- p.4 / Chapter 2.1 --- Transfer Modes --- p.4 / Chapter 2.1.1 --- Circuit Switching --- p.4 / Chapter 2.1.2 --- ATM Switching --- p.6 / Chapter 2.1.3 --- Packet Switching --- p.8 / Chapter 2.2 --- Different Types of ATM Switching System --- p.8 / Chapter 2.2.1 --- Central Control Type --- p.9 / Chapter 2.2.2 --- Self-Routing Type --- p.9 / Chapter 2.3 --- Self-Routing Non-Buffering ATM Switching Node --- p.10 / Chapter 3. --- FUNCTIONAL DESCRIPTION OF MODULE ´بA´ة --- p.16 / Chapter 3.1 --- ATM Cell Format --- p.17 / Chapter 3.2 --- Concentrator --- p.17 / Chapter 3.3 --- Routing Cell --- p.19 / Chapter 4. --- PHYSICAL STRUCTURE OF MODULE ´بA´ة --- p.23 / Chapter 4.1 --- Clocking Scheme --- p.23 / Chapter 4.2 --- Concentrator --- p.25 / Chapter 4.2.1 --- 2-by-2 Sorter --- p.25 / Chapter 4.2.2 --- Input Framer --- p.30 / Chapter 4.2.3 --- Data Buffer --- p.38 / Chapter 4.3 --- Routing Cell --- p.38 / Chapter 4.3.1 --- Type I Router --- p.39 / Chapter 4.3.2 --- Type II Router --- p.42 / Chapter 4.4 --- Block By-Passed Function --- p.43 / Chapter 5. --- SIMULATION AND TEST --- p.48 / Chapter 5.1 --- Computer Simulation --- p.48 / Chapter 5.2 --- Actual Chip Testing --- p.53 / Chapter 5.3 --- Measurement Results --- p.55 / Chapter 5.3.1 --- Functionality --- p.55 / Chapter 5.3.2 --- Maximum Clock Frequency --- p.60 / Chapter 5.3.3 --- Power Dissipation --- p.61 / Chapter 6. --- CONCLUSION --- p.63 / Chapter A. --- BRIEF HISTORY OF ATM SWITCH ARCHITECTURE DEVELOPMENT --- p.65 / Chapter B. --- BIBLIOGRAPHY --- p.66 / Chapter C. --- A N-WELL CMOS PROCESS --- p.70 / Chapter D. --- CADENCE DESIGN FLOW --- p.73 / Chapter E. --- YERILOG SIMULATION PROGRAMS --- p.77 / Chapter F. --- SCHEMATIC DIAGRAMS --- p.100
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Efficient Buffer Allocation Scheme for Bursty Traffic in ATM Networks using Fast Reservation ProtocolDeshpande, Nikhil Mukund 15 March 1996 (has links)
One of the major problems in the realization of ATM is traffic management, in particular, the resource allocation for an efficient network. Many approaches to the bandwidth management problems [2] and buffer management problems have been proposed. Boyer [IO] suggested a "Fast Bandwidth Reservation" protocol, while Turner [2] applied the same technique to the buffer allocation for the bursty traffic. In this thesis, we extend Turner's scheme in order to make it more efficient with respect to buffer allocation. We define a new parameter "Reduction Factor'', which has the potential of saving a significant amount of buffer space in a commonly shared pool of buffers. It is observed that the amount of savings depends upon the cell loss probability (CLP) bound on the network, Source Activity Probability (SAP) and number of connections supported by the network (N) at particular instant. The performance of the scheme is evaluated under various QoS requirements. It is seen that this scheme leads to approximately 38% of savings in the buffer space under certain circumstances. For supporting multimedia services, we also employ the scheme of partitioning the total buffer space. The results show that it leads to 10 % less savings as compared to single buffer scheme under certain conditions. As usage policing is very critical in this scheme, we outline a suitable mechanism and hardware implementation for Usage Parameter Control. The algorithm for acceptance of virtual circuit in the network is also described.
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Fuzzy logic control techniques and structures for Asynchronous Transfer Mode (ATM) based multimedia networksSekercioglu, Ahmet, ahmet@hyperion.ctie.monash.edu.au January 1999 (has links)
The research presented in this thesis aims to demonstrate that fuzzy logic is a useful tool for developing mechanisms for controlling traffc flow in ATM based multimedia networks to maintain quality of service (QoS) requirements and maximize resource utilization. The study first proposes a hierarchical, multilevel control
structure for ATM networks to exploit the reported strengths of fuzzy logic at various
control levels. Then, an extensive development and evaluation is presented for a subset of the proposed control architecture at the congestion control level.
An ATM based multimedia network must have quite sophisticated traffc control capabilities to effectively handle the requirements of a dynamically varying mixture of voice, video and data services while meeting the required levels of performance.
Feedback control techniques have an essential role for the effective and efficient management of the resources of ATM networks. However, development of conventional feedback control techniques relies on the availability of analytical system models. The characteristics of ATM networks and the complexity of service
requirements cause the analytical modeling to be very difficult, if not impossible.
The lack of realistic dynamic explicit models leads to substantial problems in developing
control solutions for B-ISDN networks. This limits the ability of conventional techniques to directly address the control objectives for ATM networks. In the literature, several connection admission and congestion control methods for B-ISDN networks have been reported, and these have achieved mixed success. Usually they either assume heavily simplified models, or they are too complicated to implement, mainly derived using probabilistic (steady-state) models.
Fuzzy logic controllers, on the other hand, have been applied successfully to the task of controlling systems for which analytical models are not easily obtainable.
Fuzzy logic control is a knowledge-based control strategy that can be utilized when an explicit model of a system is not available or, the model itself, if available, is highly complex and nonlinear. In this case, the problem of control system design is based on qualitative and/or empirically acquired knowledge regarding the operation of the system. Representation of qualitative or empirically acquired knowledge in a fuzzy logic controller is achieved by linguistic expressions in the form of fuzzy relational equations. By using fuzzy relational equations, classifications related to system parameters can be derived without explicit description.
The thesis presents a new predictive congestion control scheme, Fuzzy Explicit Rate Marking (FERM), which aims to avoid congestion, and by doing so minimize the cell losses, attain high server utilization, and maintain the fair use of links.
The performance of the FERM scheme is extremely competitive with that of control schemes developed using traditional methods over a considerable period of time.
The results of the study demonstrate that fuzzy logic control is a highly effective design tool for this type of problems, relative to the traditional methods. When controlled systems are highly nonlinear and complex, it keeps the human insight alive and accessible at the lower levels of the control hierarchy, and so higher levels
can be built on this understanding.
Additionally, the FERM scheme has been extended
to adaptively tune (A-FERM) so that continuous automatic tuning of the parameters can be achieved, and thus be more adaptive to system changes leading to better utilization of network bandwidth. This achieves a level of robustness that is not exhibited by other congestion control schemes reported in the literature.
In this work, the focus is on ATM networks rather than IP based networks. For historical reasons, and due to fundamental philosophical differences in the (earlier) approach to congestion control, the research for control of TCP/IP and ATM based networks proceeded separately. However, some convergence between them has recently become evident. In the TCP/IP literature proposals have appeared on active queue management in routers, and Explicit Congestion Notication (ECN) for IP. It is reasonably expected that, the algorithms developed in this study will be applicable to IP based multimedia networks as well.
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Resource management in broadband multimedia networksJiyapanichkul, Prasit, jiyapanichkul@yahoo.com January 1999 (has links)
This research deals with optimal resource management in an overloaded broadband
multimedia network. Optimisation is with respect to user satisfaction, where user
satisfaction reflects both the quality of service experienced by connected users and the
dissatisfaction of users blocked from access to the network.
The research focuses on Asynchronous Transfer Mode (ATM) networks and the Internet, because these are the dominant emerging broadband networks which present some fundamental unsolved problems, related to the sharing of resources between mixed traffic types. ATM networks use conservative admission control, which protects
network resources and ensures a high level of service for those admitted to the network, but results in low network efficiency because of low utilisation of resources due to blocking of many potential users. The Internet does not use admission control, with the result that performance degrades progressively as load increases. This causes frustration among users, and lowers the network efficiency due to high levels of congestion.
We propose an optimisation model for each network (ATM networks and the Internet)which is intended to represent the distribution and consumption of key network resources by different traffic types. The model is aimed at maximising performance such that users admitted to the network are offered no less than some minimum acceptable level of quality of service (QoS). The solution is a set of traffic flow rates on each path which results in maximising an objective function value (revenue based on network operator interest or throughput based on customer interest) for a given network
configuration with given user demand. As an example using the ATM network model, we illustrate the application of the model to an ATM network carrying both connection oriented and connectionless traffic. We explore the optimal response to a link failure which in turn causes node overload. As an example using the Internet model, we consider an overloaded network with link bottlenecks and an overloaded Web server, and explore the effect of transferring some server capacity to a mirror site and a proxy server.
For real-time traffic control, the optimisation model is used to assign quotas for bandwidth or connections to selected paths. A control algorithm is implemented to provide maximum performance by admitting requests within the quotas which are obtained from the optimisation model. In an ATM network simulation, the algorithm is used to manage the virtual path (VP) pool in a network which suffers a link failure. A comparison is made between fixed virtual path management (FVPM) and dynamic
virtual path management (DVPM), comparing the revenue achieved by each. This illustrates how DVPM adapts the VP pool in a robust fashion to achieve maximum revenue in the face of a link failure. However, the transient response suggests that benefit could be obtained using non-steady-state solutions. The model is extended by taking network state and traffic parameters into account to control changes in the VP pool to recognise limits to the rate at which traffic can be moved (through the natural
birth-death processes). This scheme is called state dependent virtual path management (SDVPM). Performance evaluation of the new model shows that SDVPM achieves higher revenue than DVPM when the network suffers a link failure that requires a major change to the VP pool. In an Internet simulation, two algorithms are compared for control of access to a proxy server and a set of primary servers. An algorithm based on
optimal flow solutions provides substantially better network performance than a localised heuristic algorithm. In each simulation case (ATM and Internet examples), the performance using a control system based on the steady state optimum flow model is close to the ideal optimal result.
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傳統區域網路升級至ATM網路的模式探討沈捷明 Unknown Date (has links)
全球化競爭的趨勢使得溝通與協調必須跨越時間與地域,影響到市場、服務.客戶需求以及競爭力的改變。為了因應顧客、競爭與改變所帶來的挑戰,先進的資訊網路成為金業面對全球化競爭不可或缺的策略性武器。
在眾多網路技術中,非同步傳輸模式(Asynchronous Transfer Mode, ATM)結合了線路交換與分封交換的優點,能夠提供適當的服務品質保證,已被國際電信組織(ITU,前身為CCITT)列為寬頻整合式服務數位網路之傳輸標準。企業在嚐試採用非同步傳輸模式時,需要考量如何將此技術與現有區域網路連結,以保障舊有的設備投資,並且讓使用者能順利渡過適應期。
目前對於有關區域網路升級模式架構探討的研究不多,從企業的角度來思考網路升級模式的研究更少,缺乏完整的理論架構,因此希望透過探索性的個案研究彙整出一個較為完整、合理的網路升級模式供企業界參考。至於公司或機構的個案選擇,為了讓此網路升級模式能夠包容較多不同類型企業,基本上以選擇網路應用在該產業具代表性的公司或機構為原則。
本研究從網路應用需求、網路技術、網路服務品質與成本評估,以及ATM技術與發展現況等層面來探討採用ATM的時機與考量,並探討ATM與傳統網路的連接方式,並提出一個區域網路升級模式,供企業網路建置升級時依循。
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A direct microwave M-QAM adaptive transmitter for fixed wireless ATM networksMohammadi, Abbas 01 January 1999 (has links)
Wireless ATM plays a key role in the realization of broadband wireless networks. The transmission of various classes of traffic and the provision of bandwidth on demand over a wireless channel poses a number of new technical challenges. This thesis addresses the design of a low cost adaptive transmitter for fixed wireless ATM/B-ISDN systems with emphasis on optimum use of wireless network resources. A new architecture for a direct microwave wireless ATM transmitter is proposed. The transmitter capacity adaptation is implemented by using an admission control metric and an M-QAM modulator. The two main components of the transmitter are: an M-QAM control unit and a direct microwave QAM modulator unit. The M-QAM control unit is used to select an optimum modulation level for the QAM modulator. The modulation level is adjusted based on the bandwidth demand, QoS requirements, and outage conditions of the wireless ATM link. The direct microwave QAM modulator unit transforms the broadband traffic to a modulated microwave signal that is suitable for transmission over a wireless network. The required bandwidth of the broadband traffic is estimated using an effective bandwidth metric. An analytical relation, called the capacity reduction factor, is derived to represent the performance degradation due to the wireless channel and channel fading in a B-ISDN network. Using the effective bandwidth metric and the capacity reduction factor, a QoS metric for the wireless broadband network is introduced. This metric is termed as, modified effective bandwidth. This metric is used to adapt the M-QAM modulator. Another significant contribution of this research work is a new architecture for the direct QAM modulator. This is based on use of PIN diode reflection attenuators. The PIN diodes operate in forward bias condition thereby overcoming the speed limitation problem due to charge storage. Using residue theory, analytical results to model the large signal forward bias operation of PIN diodes are presented. This theory also examines the transition time of a PIN diode with bias changes from a reverse bias to a forward bias. The direct microwave QAM modulator implementation using MIC and silicon MMIC technologies is examined. While a realization using MIC is simple and straightforward, a silicon MMIC realization offers a very cost effective solution. A system study was conducted to examine the operation of the adaptive direct microwave M-QAM modulator in the wireless channel with ATM traffic. The operation has been examined for different wireless channels and for various classes of traffic. The call acceptance and outage performance are compared with those for a fixed QAM modulator. The results show that the proposed system can be used for implementation of cost effective adaptive transmitters for broadband wireless applications.
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Network simulator design with extended object model and generalized stochastic petri-net /Soltani-Moghaddam, Alireza, January 2000 (has links)
Thesis (Ph. D.)--University of Missouri-Columbia, 2000. / Typescript. Vita. Includes bibliographical references (leaves 200-206). Also available on the Internet.
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