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Analysis of multiplexed ATM traffics: A large-deviation theoretic approach
Title
Analysis of multiplexed ATM traffics: A large-deviation theoretic approach.
Creator
Palaniappa, Malathi., Florida Atlantic University, Neelakanta, Perambur S., College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
Abstract/Description
ATM multiplexing, (which is essentially a statistical multiplexing process with priority constraints) leads to a departure pattern of cells on the trunk (or bearer) line, characterized by the profiles of incoming traffics at the multiplexer. Such profiles are decided by the bit-rate variations and workload fluctuations of the associated sources, namely voice, data and video of the cells. Bit rate statistics of incoming traffic with priority constraints decide the clustered and/or non...
Show moreATM multiplexing, (which is essentially a statistical multiplexing process with priority constraints) leads to a departure pattern of cells on the trunk (or bearer) line, characterized by the profiles of incoming traffics at the multiplexer. Such profiles are decided by the bit-rate variations and workload fluctuations of the associated sources, namely voice, data and video of the cells. Bit rate statistics of incoming traffic with priority constraints decide the clustered and/or non-clustered epochs of cells on the multiplexed fine. If the incoming traffic is delay-sensitive, it gets the priority in the multiplexing strategy and the associated cells inbiting no clusters; whereas, the non-isochronous traffics (facing low priority flow service) induce stagnation in the queue and pose eventually a clustered structure of cells on the trunk line. Workload fluctuation is largely application-dependent. The corresponding teletraffic statistics would also show deviations in the performance from the mean-field regime. In essence, the cell-stream departing from ATM multiplexer would exhibit statistics of deviations. In the present study, the associated delay parameter is considered and modeled under constant and variable bit rate conditions for fluctuating workloads. Mean-field theory is applied in modeling constant bit rate traffics. For variable and bursty rate transmissions, it is shown that the delay is governed by a non-homogeneous compound Poisson process. Relevant statistical bounds are established via large-deviation theory. Determination of the bounds of ATM cell-delay variations is important in developing call admission control algorithms.
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Date Issued
1999
PURL
http://purl.flvc.org/fcla/dt/15737
Subject Headings
Asynchronous transfer mode, Telecommunication--Traffic, Multiplexing
Format
Document (PDF)
Impact of interference on connectivity and outage performances in wireless communication networks
Title
Impact of interference on connectivity and outage performances in wireless communication networks: interference-based channel models.
Creator
Mukasa, Constantine, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
Abstract/Description
In recent years, a plethora of wireless applications such as Bluetooth and Ultra-wide band (UWB) radio have emerged. This drastic increase has overly congested the spectrum. So, new networks such as cognitive radios that can solve the spectrum congestion have emerged. But in such networks, interference is introduced at the physical layer. We study and develop an interference model capable of capturing the intrinsic characteristics of the coexistence of such wireless applications. We...
Show moreIn recent years, a plethora of wireless applications such as Bluetooth and Ultra-wide band (UWB) radio have emerged. This drastic increase has overly congested the spectrum. So, new networks such as cognitive radios that can solve the spectrum congestion have emerged. But in such networks, interference is introduced at the physical layer. We study and develop an interference model capable of capturing the intrinsic characteristics of the coexistence of such wireless applications. We investigate the effect of interference using device isolation probability or outage probability in presence Rayleigh and Nakagami-m fading at the physical layer and the impact of lognormal shadowing. We assume that the devices are either deterministically placed or randomly distributed according to a Poisson point process. We derive explicit expressions for the isolation probability and outage probability that give insight into how these channel impairments affect communication in these applications. We use computer simulations to validate our analytical results.
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Date Issued
2013
PURL
http://purl.flvc.org/fcla/dt/3362551
Subject Headings
Wireless communication systems, Technological innovations, Wireless communication systems, Mathematical models, Orthogonal frequency division multiplexing
Format
Document (PDF)
Optimal chunk-based resource allocation for OFDMA systems with multiple BER requirements
Title
Optimal chunk-based resource allocation for OFDMA systems with multiple BER requirements.
Creator
He, Tianzhou, Wang, Xin, Florida Atlantic University, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
Abstract/Description
In wireless orthogonal frequency division multiple-access (OFDMA) standards, subcarriers are grouped into chunks and a chunk of subcarriers is made as the minimum allocation unit for subcarrier allocation. We investigate the chunk-based resource allocation for OFDMA downlink, where data streams contain packets with diverse bit-errorrate (BER) requirements. Supposing that adaptive transmissions are based on a number of discrete modulation and coding modes, we derive the optimal resource...
Show moreIn wireless orthogonal frequency division multiple-access (OFDMA) standards, subcarriers are grouped into chunks and a chunk of subcarriers is made as the minimum allocation unit for subcarrier allocation. We investigate the chunk-based resource allocation for OFDMA downlink, where data streams contain packets with diverse bit-errorrate (BER) requirements. Supposing that adaptive transmissions are based on a number of discrete modulation and coding modes, we derive the optimal resource allocation scheme that maximizes the weighted sum of average user rates under the multiple BER and total power constraints. With proper formulation, the relevant optimization problem is cast as an integer linear program (ILP). We can rigorously prove that the zero duality gap holds for the formulated ILP and its dual problem. Furthermore, it is shown that the optimal strategy for this problem can be obtained through Lagrange dual-based gradient iterations with fast convergence and low computational complexity per iteration. Relying on the stochastic optimization tools, we further develop a novel on-line algorithm capable of dynamically learning the underlying channel distribution and asymptotically approaching the optimal strategy without knowledge of intended wireless channels a priori. In addition, we extend the proposed approach to maximizing the a-fair utility functions of average user rates, and show that such a utility maximization can nicely balance the trade-off between the total throughput and fairness among users.
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Date Issued
2014
PURL
http://purl.flvc.org/fau/fd/FA00004291, http://purl.flvc.org/fau/fd/FA00004291
Subject Headings
Adaptive signal processing, Mathematical optimization, Orthogonal frequency division multiplexing, Wireless communication systems
Format
Document (PDF)
Passive Optical Networks with a New Bandwidth Allocation Scheme in Ethernet Passive Optical Networks
Title
Passive Optical Networks with a New Bandwidth Allocation Scheme in Ethernet Passive Optical Networks.
Creator
Krijestorac, Sadeta, Bagby, Jonathan S., Florida Atlantic University, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
Abstract/Description
With the ever increasing demand for bandwidth intensive applications like video-ondemand, interactive television services, high-defmition television (HDTV) and internet telephony, the first mile network, referred to as the last mile network in the earlier stages of its development, has proven to solve the "bottleneck" often experienced between users and the central office. The Ethernet Passive Optical Network (EPON), developed by the IEEE 802.3ah Task Force for Ethernet in the First Mile (EFM...
Show moreWith the ever increasing demand for bandwidth intensive applications like video-ondemand, interactive television services, high-defmition television (HDTV) and internet telephony, the first mile network, referred to as the last mile network in the earlier stages of its development, has proven to solve the "bottleneck" often experienced between users and the central office. The Ethernet Passive Optical Network (EPON), developed by the IEEE 802.3ah Task Force for Ethernet in the First Mile (EFM), resolves this bottleneck by providing the user with a fiber optic link to the central office that has many advantages, such as nearly infinite bandwidth, low cost, easy installation and immunity to electromagnetic interference, and a saving of the need for powered components in the signal path from the user to the switch. EPON s have proven to deliver the essential services of voice, video, and data communications reliably, while at the same time providing expected guarantees of the delivery of those services in terms of defined Quality of Service measures (QOS). A continuous theme throughout EPON research has been the study of efficient Dynamic Bandwidth Allocation (DBA) as a key factor in achieving fairness in distributing bandwidth amongst remote network units. This research investigates another factor and its effect on network performance and service delivery: Cycle Demand Proportionality (CDP). By observing the patterns of demand in the network on an individual network unit basis cycle after cycle, deductions regarding load characteristics of some units over others can be made. Decisions can be make about subsequent grant allocations based on this factor and aim to achieve better results in the process. Simulations of EPONs Lmder varying loads incorporating the usc of CDP in conjunction with currently used DBA schemes are made and results are analyzed. A major contribution of this research is a new bandwidth allocation algorithm that gives improved performance in terms of packet delay versus offered load. Performance metrics are compared against two common bandwidth allocation algorithms: Interleaved Polling with Adaptive Cycle Time (IPACT) and Cyclic Polling (CP). Additional results also include improvements in packet loss and throughput. The data that represents traffic for this network has two properties, self-similarity and long range dependency. Plotting the auto-covariance, auto-correlation, and variance for this traffic, for various aggregation levels demonstrates these properties.
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Date Issued
2008
PURL
http://purl.flvc.org/fau/fd/FA00012571
Subject Headings
Ethernet (Local area network system), Optical communications, Computer network protocols, Wavelength divisional multiplexing
Format
Document (PDF)
Stochastic optimization of energy for multi-user wireless networks over fading channels
Title
Stochastic optimization of energy for multi-user wireless networks over fading channels.
Creator
Wang, Di, College of Engineering and Computer Science, Department of Computer and Electrical Engineering and Computer Science
Abstract/Description
Wireless devices in wireless networks are powered typically by small batteries that are not replaceable nor recharged in a convenient way. To prolong the operating lifetime of networks, energy efficiency is indicated as a critical issue and energy-efficient resource allocation designs have been extensively developed. We investigated energy-efficient schemes that prolong network operating lifetime in wireless sensor networks and in wireless relay networks. In Chapter 2, the energy-efficient...
Show moreWireless devices in wireless networks are powered typically by small batteries that are not replaceable nor recharged in a convenient way. To prolong the operating lifetime of networks, energy efficiency is indicated as a critical issue and energy-efficient resource allocation designs have been extensively developed. We investigated energy-efficient schemes that prolong network operating lifetime in wireless sensor networks and in wireless relay networks. In Chapter 2, the energy-efficient resource allocation that minimizes a general cost function of average user powers for small- or medium-scale wireless sensor networks, where the simple time-division multiple-access (TDMA) is adopted as the multiple access scheme. A class of Ç-fair cost-functions is derived to balance the tradeoff between efficiency and fairness in energy-efficient designs. Based on such cost functions, optimal channel-adaptive resource allocation schemes are developed for both single-hop and multi-hop TDMA sensor networks. In Chapter 3, optimal power control methods to balance the tradeoff between energy efficiency and fairness for wireless cooperative networks are developed. It is important to maximize power efficiency by minimizing power consumption for a given quality of service, such as the data rate; it is also equally important to evenly or fairly distribute power consumption to all nodes to maximize the network life. The optimal power control policy proposed is derived in a quasi-closed form by solving a convex optimization problem with a properly chosen cost-function. To further optimize a wireless relay network performance, an orthogonal frequency division multiplexing (OFDM) based multi-user wireless relay network is considered in Chapter 4., In the OFDM approach, each subcarrier is dynamically assigned to a source- destination link, and several relays assist communication between pairs of source-destination over their assigned subcarriers. Using a class of Ç-fair cost-functions to balance the tradeoff between energy efficiency and fairness, jointly with optimal subcarrier and power allocation schemes at the relays. Relevant algorithms are derived in quasi-closed form. Lastly, the proposed energy-efficient schemes are summarized and future work is discussed in Chapter 5.
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Date Issued
2011
PURL
http://purl.flvc.org/FAU/3322519
Subject Headings
Stochastic processes, Data processing, Wireless communication systems, Mathematical models, Computer network protocols, Signal processing, Digital techniques, Code division multiple access, Waveless division multiplexing, Orthogonalization methods
Format
Document (PDF)