University of Toronto

Displaying 1-40 of 188 results

  • White Papers // May 2014

    Value Cocreation Modeling: Supporting the Analysis and Design of B2B Service Engagements Through Agent Orientation and Business Intelligence

    Current modeling approaches for designing services do not address the characteristics of collaborative Business-To-Business (B2B) service engagements. Yet, these types of service engagements, for example R&D services and other knowledge-intensive business services, are key components of industrialized economies. The authors identify the requirements of a modeling technique able to support...

    Provided By University of Toronto

  • White Papers // Apr 2014

    SleepScale: Runtime Joint Speed Scaling and Sleep States Management for Power Efficient Data Centers

    Power consumption in data centers has been growing significantly in recent years. To reduce power, servers are being equipped with increasingly sophisticated power management mechanisms. Different mechanisms offer dramatically different trade-offs between power savings and performance penalties. Considering the complexity, variety, and temporally varying nature of the applications hosted in...

    Provided By University of Toronto

  • White Papers // Jun 2012

    Cost Efficient Datacenter Selection for Cloud Services

    Many cloud services nowadays are running on top of geographically distributed infrastructures for better reliability and performance. They need an effective way to direct the user requests to a suitable datacenter, in a cost efficient manner. Previous work focused mostly on the electricity cost of datacenters. The approaches favor datacenters...

    Provided By University of Toronto

  • White Papers // May 2012

    MixApart: Decoupled Analytics for Shared Storage Systems

    Data analytics and enterprise applications have very different storage functionality requirements. For this reason, enterprise deployments of data analytics are on a separate storage silo. This may generate additional costs and inefficiencies in data management, e.g., whenever data needs to be archived, copied, or migrated across silos. The authors introduce...

    Provided By University of Toronto

  • White Papers // May 2012

    Oruta: Privacy-Preserving Public Auditing for Shared Data in the Cloud

    With cloud storage services, it is commonplace for data to be not only stored in the cloud, but also shared across multiple users. However, public auditing for such shared data - while preserving identity privacy - remains to be an open challenge. In this paper, the authors propose the first...

    Provided By University of Toronto

  • White Papers // May 2012

    A General and Practical Datacenter Selection Framework for Cloud Services

    Many cloud services nowadays are running on top of geographically distributed infrastructures for better reliability and performance. They need an effective way to direct the user requests to a suitable datacenter, depending on factors including performance, cost, etc. Previous work focused on efficiency and invariably considered the simple objective of...

    Provided By University of Toronto

  • White Papers // May 2012

    Mining for Data: Assessing the Use of Online Research

    In this paper, the authors provide evidence on the way that people use research resources posted on websites. Although the Internet is now 'The' main point of access to research findings, little is known about how it is used to this end. The paper reported here has gradually developed some...

    Provided By University of Toronto

  • White Papers // Apr 2012

    Postcard: Minimizing Costs on Inter-Datacenter Traffic With Store-and-Forward

    It is typical for cloud providers to operate a number of geographically distributed datacenters, where inter-datacenter traffic constitutes a large portion of a cloud provider's traffic demand over the Internet. Though such inter-datacenter traffic incurs substantial operational costs that are charged by ISPs, it varies significantly across different overlay links,...

    Provided By University of Toronto

  • White Papers // Apr 2012

    Towards Optimal Capacity Segmentation With Hybrid Cloud Pricing

    Cloud resources are usually priced in multiple markets with different service guarantees. For example, Amazon EC2 prices virtual instances under three pricing schemes - the subscription option (a.k.a., Reserved Instances), the pay-as-you-go offer (a.k.a., On-Demand Instances), and an auction-like spot market (a.k.a., Spot Instances) - simultaneously. There arises a new...

    Provided By University of Toronto

  • White Papers // Mar 2012

    Bargaining Towards Maximized Resource Utilization in Video Streaming Datacenters

    Datacenters can be used to host large-scale video streaming services with better operational efficiency, as the multiplexing achieved by virtualization technologies allows different videos to share resources at the same physical server. Live migration of videos from servers that are overloaded to those that are under-utilized may be a solution...

    Provided By University of Toronto

  • White Papers // Mar 2012

    Distributional Measures of Semantic Distance: A Survey

    The ability to mimic human notions of semantic distance has widespread applications. Some measures rely only on raw text (distributional measures) and some rely on knowledge sources such as WordNet. Although extensive studies have been performed to compare WordNet-based measures with human judgment, the use of distributional measures as proxies...

    Provided By University of Toronto

  • White Papers // Feb 2012

    Maximizing Revenue With Dynamic Cloud Pricing: The Infinite Horizon Case

    The authors study the infinite horizon dynamic pricing problem for an infrastructure cloud provider in the emerging cloud computing paradigm. The cloud provider, such as Amazon, provides computing capacity in the form of virtual instances and charges customers a time-varying price for the period they use the instances. The provider's...

    Provided By University of Toronto

  • White Papers // Jan 2012

    Quality-Assured Cloud Bandwidth Auto-Scaling for Video-on-Demand Applications

    There has been a recent trend that Video-on-Demand (VoD) providers such as Netflix are leveraging resources from cloud services for multimedia streaming. In this paper, the authors consider the scenario that a VoD provider can make reservations for bandwidth guarantees from cloud service providers to guarantee the streaming performance in...

    Provided By University of Toronto

  • White Papers // Jan 2012

    Jointly Optimal Bit Loading, Channel Pairing and Power Allocation for Multi-Channel Relaying

    The authors aim to enhance the end-to-end rate of a general dual-hop relay network with multiple channels and finite modulation formats, by jointly optimizing channel pairing, power allocation, and integer bit loading. Such an optimization problem has both a discrete feasible region, due to the combinatoric nature of channel pairing,...

    Provided By University of Toronto

  • White Papers // Jan 2012

    A Theory of Cloud Bandwidth Pricing for Video-on-Demand Providers

    Current-generation cloud computing is offered with usage-based pricing, with no bandwidth capacity guarantees, which is however unappealing to bandwidth-intensive applications such as Video-on-Demand (VoD). The authors consider a new type of service where VoD providers, such as Netflix and Hulu, make reservations for bandwidth guarantees from the cloud at negotiable...

    Provided By University of Toronto

  • White Papers // Jan 2012

    Truthful Spectrum Auction Design for Secondary Networks

    Opportunistic wireless channel access by non-licensed users has emerged as a promising solution for addressing the bandwidth scarcity challenge. Auctions represent a natural mechanism for allocating the spectrum, generating an economic incentive for the licensed user to relinquish channels. A severe limitation of existing spectrum auction designs lies in the...

    Provided By University of Toronto

  • White Papers // Jan 2012

    Supporting Efficient Collective Communication in NoCs

    Across many architectures and parallel programming paradigms, collective communication plays a key role in performance and correctness. Hardware support is necessary to prevent important collective communication from becoming a system bottleneck. Support for multicast communication in Networks-on-Chip (NoCs) has achieved substantial throughput improvements and power savings. In this paper, the...

    Provided By University of Toronto

  • White Papers // Jan 2012

    From RTL to Silicon: The Case for Automated Debug

    Computer-aided design tools are continuously improving their scalability and efficiency to mitigate the high cost associated with designing and fabricating modern VLSI systems. A key step in the design process is the root-cause analysis of detected errors. Debugging may take months to close, introduce high cost and uncertainty ultimately jeopardizing...

    Provided By University of Toronto

  • White Papers // Jan 2012

    Automated Data Analysis Techniques for a Modern Silicon Debug Environment

    With the growing size of modern designs and more strict time-to-market constraints, design errors unavoidably escape pre-silicon verification and reside in silicon prototypes. As a result, silicon debug has become a necessary step in the digital integrated circuit design flow. Although embedded hardware blocks, such as scan chains and trace...

    Provided By University of Toronto

  • White Papers // Jan 2012

    MANET Extensions to Ns2

    This is a set of software modules providing additional models for the simulation of multi-hop Mobile Ad hoc NETworks (MANETs) in the ns2 simulator. The authors provide implementations of the CM and Shell mobility models, and the AF and LOS radio propagation models described in. They also provide instrumentation tools...

    Provided By University of Toronto

  • White Papers // Jan 2012

    SFlow: Towards Resource-Efficient and Agile Service Federation in Service Overlay Networks

    Existing research work towards the composition of complex federated services has assumed that service requests and deliveries flow through a particular service path or tree. In this paper, the authors extend such a service model to a directed acyclic graph, allowing services to be delivered via parallel paths and interleaved...

    Provided By University of Toronto

  • White Papers // Jan 2012

    A High-Throughput Overlay Multicast Infrastructure With Network Coding

    Network coding has been recently proposed in information theory as a new dimension of the information multicast problem that helps achieve optimal transmission rate or cost. End hosts in overlay networks are natural candidates to perform network coding, due to its available computational capabilities. In this paper, the authors seek...

    Provided By University of Toronto

  • White Papers // Jan 2012

    Linear Processing for the Downlink in Multiuser MIMO Systems With Multiple Data Streams

    In this paper, the authors solve the problem of linear precoding for the downlink in multiuser Multiple-Input Multiple-Output (MIMO) systems. The transmitter and the receivers may be equipped with multiple antennas and each user may receive multiple data streams. Their objective is to jointly optimize the power allocation and transmit-receive...

    Provided By University of Toronto

  • White Papers // Jan 2012

    ToX - The Toronto XML Engine

    The authors present ToX - the Toronto XML Engine - a repository for XML data and metadata, which supports real and virtual XML documents. Real documents are stored as files or mapped into relational or object databases, depending on their structuredness; indices are defined according to the storage method used....

    Provided By University of Toronto

  • White Papers // Dec 2011

    Distributed Optimal TXOP Control for Throughput Requirements in IEEE 802.11e Wireless LAN

    This paper designs a distributed Transmission OPportunity (TXOP) adaptation algorithm for IEEE802.11e Enhanced Distributed Channel Access (EDCA). Each node measures its throughput in a window and compares it with a target value. If the measured throughput is higher than the target value, the node reduces its TXOP, otherwise if the...

    Provided By University of Toronto

  • White Papers // Dec 2011

    Non-Solution Implications Using Reverse Domination in a Modern SAT-Based Debugging Environment

    With the growing complexity of VLSI designs, functional debugging has become a bottleneck in modern CAD flows. To alleviate this cost, various SAT-based techniques have been developed to automate bug localization in the RTL. In this paper, dominance relationships between circuit blocks have been recently shown to reduce the number...

    Provided By University of Toronto

  • White Papers // Dec 2011

    Leveraging Reconfigurability to Raise Productivity in FPGA Functional Debug

    The authors propose new hardware and software techniques for FPGA functional debug that leverage the inherent re-configurability of the FPGA fabric to reduce functional debugging time. The functionality of an FPGA circuit is represented by a programming bit-stream that specifies the configuration of the FPGA's internal logic and routing. The...

    Provided By University of Toronto

  • White Papers // Nov 2011

    On Error Tolerance and Engineering Change With Partially Programmable Circuits

    The growing size, density and complexity of modern VLSI chips are contributing to an increase in hardware faults and design errors in the silicon, decreasing manufacturing yield and increasing the design cycle. The use of Partially Programmable Circuits (PPCs) has been recently proposed for yield enhancement with very small overhead....

    Provided By University of Toronto

  • White Papers // Nov 2011

    Joint Power Control and Beamforming Codebook Design for MISO Channels under the Outage Criterion

    This paper investigates the joint design of power control and beamforming codebooks for limited-feedback Multiple-Input Single-Output (MISO) wireless systems. The problem is formulated as the minimization of the outage probability subject to the transmit power constraint and cardinality constraints on the beamforming and power codebooks. The authors show that the...

    Provided By University of Toronto

  • White Papers // Nov 2011

    Efficient Debugging of Multiple Design Errors

    After functional verification detects a failure, design debugging aims to find all locations in the design that could be responsible for the observed error. The task of debugging becomes more difficult in modern designs because of the presence of multiple design errors. Multiple design errors exponentially increase the solution space...

    Provided By University of Toronto

  • White Papers // Oct 2011

    Propelling SAT-Based Debugging Using Reverse Domination

    With the growing complexity of VLSI designs, functional debugging has become a bottleneck in modern CAD flows. To alleviate this cost, various SAT-based techniques have been developed to automate bug localization in the RTL. In this paper, dominance relationships between circuit blocks have been recently shown to reduce the number...

    Provided By University of Toronto

  • White Papers // Sep 2011

    Modeling on Quicksand

    Researchers studying the inter-domain routing system, its properties and new protocols, face many challenges in performing realistic evaluations and simulations. Modeling decisions with respect to AS-level topology, routing policies and traffic matrices are complicated by a dearth of ground truth for each of these components. Moreover, scalability is-sues arise when...

    Provided By University of Toronto

  • White Papers // Jul 2011

    Collaborative Caching for Video Streaming Among Selfish Wireless Service Providers

    Video streaming is now at the fingertips of mobile users with recent advances in wireless communications and mobile networking. Caching has been widely deployed by Wireless Service Providers (WSPs) to facilitate video content dissemination. Yet, capacity provisioning of cache servers is challenging given dynamic user demands and limited wireless bandwidth...

    Provided By University of Toronto

  • White Papers // Jul 2011

    YMMV: Multiple Session Multicast With MIMO

    Multicast is an important application in cellular networks. The 4G technologies, including WiMAX and LTE, invariably adopt Multiple-Input-Multiple-Output (MIMO) to facilitate spatial multiplexing and fundamentally increase channel capacity. However, state-of-the-art multicast protocols are designed to perform in single-hop mode with a single session, leading to under-utilization of the scarce spectrum...

    Provided By University of Toronto

  • White Papers // Jul 2011

    Completion Delay Reduction in Lossy Feedback Scenarios for Instantly Decodable Network Coding

    In this paper, the authors study the effect of packet feedback loss events on the broadcast completion delay performance of instantly decodable network coding. These feedback loss events result in a continuous lack of knowledge about the reception status at different subsets of receivers. This lack of knowledge creates a...

    Provided By University of Toronto

  • White Papers // Jul 2011

    Jointly Optimal Channel Pairing and Power Allocation for Multi-Channel Multi-Hop Relaying

    The authors study the problem of channel pairing and power allocation in a multi-channel multi-hop relay network to enhance the end-to-end data rate. Both Amplify-and-Forward (AF) and Decode-and-Forward (DF) relaying strategies are considered. Given fixed power allocation to the channels, they show that channel pairing over multiple hops can be...

    Provided By University of Toronto

  • White Papers // Jun 2011

    Latch-Based Performance Optimization for FPGAs

    The authors explore using pulsed latches for timing optimization - a first in the FPGA community. Pulsed latches are transparent latches driven by a clock with a non-standard (non-50%) duty cycle. They exploit existing functionality within commercial FPGA chips to implement latch-based optimizations that do not have the power or...

    Provided By University of Toronto

  • White Papers // Jun 2011

    Usury, Calvinism, And Credit In Protestant England: From The Sixteenth Century To The Industrial Revolution

    This paper analyzes the impact of Protestantism on interest rates in England from the 16th century to the Industrial Revolution. One of many myths about the usury doctrine - the prohibition against demanding anything above the principal in a loan (mutuum) - is that it ceased to be observed in...

    Provided By University of Toronto

  • White Papers // Jun 2011

    Low-Cost Hardware Profiling of Run-Time and Energy in FPGA Embedded Processors

    Field-Programmable Gate Arrays (FPGAs) are a widely used technology in the design of embedded systems due to their improving speed, density and power, steadily decreasing cost, and their programmability which reduces a product's time-to-market. The advent of FPGA soft processors permits the creation of hybrid systems within a single FPGA...

    Provided By University of Toronto

  • White Papers // Jun 2011

    Reducing FPGA Router Run-Time Through Algorithm and Architecture

    The authors propose a new FPGA routing approach that, when combined with a low-cost architecture change, results in a 34% reduction in router run-time, at the cost of a 3% area overhead, with no increase in critical path delay. Their approach begins with traditional Path-Finder-style routing, which they run on...

    Provided By University of Toronto

  • White Papers // Jun 2002

    Profitability, Growth and Efficiency in the US Life Insurance Industry

    This study explores the relationship between operational efficiency and profitability and growth in the life Insurance industry, and provides a framework for linking operating performance and financial success. Earnings and growth have particular importance to life insurance companies; earnings and capital determine the viability of the insurer, while growth is...

    Provided By University of Toronto

  • White Papers // Jan 2005

    Teams Vs. Individual Accountability: Solving Multi-Task Problems Through Job Design

    Many organizations are structured so that workers are jointly accountable for performance; even though alternative organizational structures are available that would align incentive compensation more closely with each worker's tasks. One develops a multi-task agency model that demonstrates that such organizations may be optimal when multi-task problems are severe and/or...

    Provided By University of Toronto

  • White Papers // Jun 2009

    Face Recognition With Biometric Encryption for Privacy-Enhancing Self-Exclusion

    Face recognition has been employed in various security-related applications such as surveillance, mugshot identification, e-passport, and access control. Despite its recent advancements, privacy concern is one of several issues preventing its wider deployment. In this paper, the authors address the privacy concern for a self-exclusion scenario of face recognition, through...

    Provided By University of Toronto

  • White Papers // Jun 2011

    Linking Semistructured Data on the Web

    Many Web data sources and APIs make their data available in XML, JSON, or a domain-specific semi-structured format, with the goal of making the data easily accessible and usable by Web application developers. Although such data formats are more machine-processable than pure text documents, managing and analyzing such data in...

    Provided By University of Toronto

  • White Papers // Sep 2010

    Revisiting Defenses Against Large-Scale Online Password Guessing Attacks

    Brute force and dictionary attacks on password-only remote login services are now widespread and ever increasing. Enabling convenient login for legitimate users while preventing such attacks is a difficult problem. Automated Turing Tests (ATTs) continue to be an effective, easy-to-deploy approach to identify auto-mated malicious login attempts with reasonable cost...

    Provided By University of Toronto

  • White Papers // Aug 2009

    Indeterminacy Of Competitive Equilibrium With Risk Of Default

    The authors prove indeterminacy of competitive equilibrium in sequential economies, where limited commitment requires the endogenous determination of solvency constraints preventing debt repudiation (Alvarez and Jermann). In particular, they show that, for any arbitrary value of social welfare in between autarchy and (constrained) optimality, there exists an equilibrium at which...

    Provided By University of Toronto

  • White Papers // Nov 2009

    Delay Bounds for Networks With Heavy-Tailed and Self-Similar Traffic

    The authors provide upper bounds on the end-to-end backlog and delay in a network with heavy-tailed and self-similar traffic. The analysis follows a network calculus approach where traffic is characterized by envelope functions and service is described by service curves. A key contribution of this paper is the derivation of...

    Provided By University of Toronto

  • White Papers // Jan 2010

    Understanding Latent Sector Errors and How to Protect Against Them

    Latent Sector Errors (LSEs) refer to the situation where particular sectors on a drive become inaccessible. LSEs are a critical factor in data reliability, since a single LSE can lead to data loss when encountered during RAID reconstruction after a disk failure. LSEs happen at a significant rate in the...

    Provided By University of Toronto

  • White Papers // May 2011

    Learning Better Image Representations Using 'Flobject Analysis'

    Unsupervised learning can be used to extract image representations that are useful for various and diverse vision tasks. After noticing that most biological vision systems for interpreting static images are trained using disparity information, the authors developed an analogous framework for unsupervised learning. The output of their method is a...

    Provided By University of Toronto

  • White Papers // Apr 2011

    On Deep Generative Models With Applications to Recognition

    The most popular way to use probabilistic models in vision is first to extract some descriptors of small image patches or object parts using well-engineered features, and then to use statistical learning tools to model the dependencies among these features and eventual labels. Learning probabilistic models directly on the raw...

    Provided By University of Toronto

  • White Papers // Jan 2011

    Finding A Path Among The Concrete: Work-Life Narratives Of Urban Aboriginal Young Adults

    Aboriginal peoples are the fastest growing population in Canada (Statistics Canada, 2008). Over half of the Aboriginal population is under the age of 24 and, according to Human Resources and Skills Development Canada (2008), Aboriginal young adults are two to three times more likely to be unemployed than their non-Aboriginal...

    Provided By University of Toronto

  • White Papers // Jun 2011

    Usury, Calvinism, And Credit In Protestant England: From The Sixteenth Century To The Industrial Revolution

    This paper analyzes the impact of Protestantism on interest rates in England from the 16th century to the Industrial Revolution. One of many myths about the usury doctrine - the prohibition against demanding anything above the principal in a loan (mutuum) - is that it ceased to be observed in...

    Provided By University of Toronto

  • White Papers // Feb 2010

    Portfolio Choice, Attention Allocation, And Price Comovement

    This paper models the attention allocation of portfolio investors. Investors choose the composition of their information subject to an information flow constraint. Given their expected investment strategy in the next period, which is to hold a diversified portfolio, in equilibrium investors choose to observe one linear combination of asset payoffs...

    Provided By University of Toronto

  • White Papers // Jan 2010

    Communication, Timing, And Common Learning

    The authors study the effect of stochastically delayed communication on common knowledge acquisition (common learning). If messages do not report dispatch times, communication prevents common learning under general conditions even if common knowledge is acquired without communication. If messages report dispatch times, communication can destroy common learning under more restrictive...

    Provided By University of Toronto

  • White Papers // Sep 2010

    Inequality And Growth In A Knowledge Economy

    The authors develop a two sector growth model to understand the relation between inequality and growth. Agents, who are endowed with different levels of knowledge, select either into a retail or a manufacturing sector. Agents in the manufacturing sector match to carry out production. A by-product of production is creation...

    Provided By University of Toronto

  • White Papers // Aug 2010

    Awareness Requirements for Adaptive Systems

    Recently, there has been a growing interest in self-adaptive systems. Roadmap papers in this area point to feedback loops as a promising way of operationalizing adaptivity in such systems. In this paper, the authors present a new type of requirement - called Awareness Requirement - that can refer to other...

    Provided By University of Toronto

  • White Papers // Jan 2011

    Trading Frenzies And Their Impact On Real Investment

    The authors study a model where a capital provider learns from the price of a firm's security in deciding how much capital to provide for new investment. This feedback effect from the financial market to the investment decision gives rise to trading frenzies, where speculators all wish to trade like...

    Provided By University of Toronto

  • White Papers // Apr 2011

    Asset Returns And Volatility Clustering In Financial Time Series

    An analysis of the stylized facts in financial time series is carried out. The authors find that, instead of the heavy tails in asset return distributions, the slow decay behaviour in autocorrelation functions of absolute returns is actually directly related to the degree of clustering of large fluctuations within the...

    Provided By University of Toronto

  • White Papers // May 2009

    Computer Meteorology: Monitoring Compute Clouds

    Cloud computing environments allow customers to execute arbitrary code on hardware owned by a cloud provider. While cloud providers use virtualization to ensure isolation between customers, they face additional security challenges. Malicious customers may leverage the provider's hardware to launch attacks, either from VMs they own or by compromising VMs...

    Provided By University of Toronto

  • White Papers // May 2009

    Blackboards, PowerPoint, and Tablet PCs in the Classroom

    Research into eye movements of subjects who are reading provides a window into the reader's cognitive processes. This paper uses some conclusions of that research to guide a discussion of the delivery of visual information in the classroom. The paper will briefly review some of the highlights of the research...

    Provided By University of Toronto

  • White Papers // Dec 2009

    Haste: Practical Online Network Coding in a Multicast Switch

    The use of network coding has been shown to improve throughput in input-queued multicast switches, but not without costs of computational complexity and delays. This paper investigates the design of efficient online network coding algorithms in a switch with multicast traffic. The paper presents Haste, an online opportunistic coding algorithm...

    Provided By University of Toronto

  • White Papers // Jan 2010

    Learning Mixture Models With the Latent Maximum Entropy Principle

    The paper presents a new approach to estimating mixture models based on a new inference principle the author has proposed: the Latent Maximum Entropy principle (LME). LME is different both from Jaynes' maximum entropy principle and from standard maximum likelihood estimation. The paper demonstrates the LME principle by deriving new...

    Provided By University of Toronto

  • White Papers // Jul 2011

    Jointly Optimal Channel Pairing and Power Allocation for Multi-Channel Multi-Hop Relaying

    The authors study the problem of channel pairing and power allocation in a multi-channel multi-hop relay network to enhance the end-to-end data rate. Both Amplify-and-Forward (AF) and Decode-and-Forward (DF) relaying strategies are considered. Given fixed power allocation to the channels, they show that channel pairing over multiple hops can be...

    Provided By University of Toronto

  • White Papers // Nov 2010

    Optimal Channel Pairing and Power Allocation for Multi-Channel Multi-Hop Relay Networks

    The authors study the problem of channel pairing and power allocation in a multi-channel, multi-hop relay network to enhance the end-to-end data rate. OFDM-based relays are used as an illustrative example, and the amplify-and-forward and decode-and-forward relaying strategies are considered. Given fixed power allocation to the OFDM subcarriers, they observe...

    Provided By University of Toronto

  • White Papers // Jan 2011

    Optimal Channel Assignment and Power Allocation for Dual-Hop Multi-Channel Multi-User Relaying

    The authors consider the problem of jointly optimizing channel pairing, channel-user assignment, and power allocation in a single-relay multiple-access system. The optimization objective is to maximize the weighted sum-rate under total and individual power constraints on the transmitters. By observing the special structure of a three-dimensional assignment problem derived from...

    Provided By University of Toronto

  • White Papers // Mar 2010

    Optimal Control of Constrained Cognitive Radio Networks With Dynamic Population Size

    In this paper, the authors consider the problem of optimal control for throughput utility maximization in cognitive radio networks with dynamic user arrivals and departures. The cognitive radio network considered in this paper consists of a number of heterogeneous sub-networks. These sub-networks may be power-constrained and are required to operate...

    Provided By University of Toronto

  • White Papers // Feb 2010

    Universal Relaying for the Interference Channel

    This paper considers a Gaussian relay-interference channel and introduces a generalized hash-and-forward relay strategy, where the relay sends out a bin index of its quantized observation, and the receivers first decode the relay quantization codeword to a list, then use the list to help decode the respective messages from the...

    Provided By University of Toronto

  • White Papers // Aug 2009

    Joint Power Control and Beamforming Codebook Design for MISO Channels With Limited Feedback

    This paper investigates the joint design and optimization of the power control and beamforming codebooks for the single-user Multiple-Input Single-Output (MISO) wireless systems with a rate-limited feedback link. The problem is cast in the form of minimizing the outage probability subject to the transmit power constraint and cardinality constraints on...

    Provided By University of Toronto

  • White Papers // May 2009

    Bandwidth and Routing Optimization in Wireless Cellular Networks With Relays

    This paper aims to quantify the performance improvement due to the use of fixed relays in the uplink of a wireless cellular network. Consider an Orthogonal Frequency Division Multiplex (OFDM) based cellular network in which each cell consists of a base station, multiple mobile users, and a number of relays....

    Provided By University of Toronto

  • White Papers // Jan 2011

    Bit Allocation Laws for Multi-Antenna Channel Quantization: Multi-User Case

    This paper addresses the optimal design of limited-feedback multi-user spatial multiplexing systems. A base station with M antennas is considered serving M single-antenna users, which share a common feedback link with a total rate of B bits per fading block. The optimization problem is cast in form of minimizing the...

    Provided By University of Toronto

  • White Papers // May 2011

    Non-Coherent Capacity of Secret-Key Agreement With Public Discussion

    The authors study the non-coherent capacity of secret-key agreement with public discussion over i.i.d. Rayleigh Fading wireless channels, where neither the sender nor the receivers have access to instantaneous Channel State Information (CSI). They present two results. At high Signal-to-Noise Ratio (SNR), the secret-key capacity is bounded in SNR, regardless...

    Provided By University of Toronto

  • White Papers // Dec 2010

    Diversity Embedded Streaming Erasure Codes (DE-SCo): Constructions and Optimality

    Streaming erasure codes encode a source stream to guarantee that each source symbol is recovered within a fixed delay at the receiver over a burst-erasure channel. This paper introduces diversity embedded streaming erasure codes (DE-SCo), which provide a flexible tradeoff between the channel quality and receiver delay. When the channel...

    Provided By University of Toronto

  • White Papers // Feb 2011

    Multicell Coordination Via Joint Scheduling, Beamforming and Power Spectrum Adaptation

    The mitigation of intercell interference is a central issue for future generation wireless cellular networks where frequencies are reused aggressively and where hierarchical cellular structures may heavily overlap. The paper examines the benefit of coordinating transmission strategies and resource allocation schemes across multiple cells for interference mitigation. For a multicell...

    Provided By University of Toronto

  • White Papers // Jun 2010

    Interference Mitigation With Joint Beamforming and Common Message Decoding in Multicell Systems

    Conventional multicell wireless systems operate with out-of-cell interference treated as noise - interference detection is infeasible as intercell interference is typically weak. This paper considers the benefit of designing decodable interference signals by allowing common-private message splitting at the transmitter and common message decoding by users in adjacent cells. In...

    Provided By University of Toronto

  • White Papers // Feb 2010

    Structure of Channel Quantization Codebook for Multiuser Spatial Multiplexing Systems

    This paper studies the structure of the channel quantization codebook for multiuser MISO systems with limited channel state information at the base-station. The problem is cast in the form of minimizing the sum power subject to the worst-case SINR constraints over spherical channel uncertainty regions. This paper adopts a zero-forcing...

    Provided By University of Toronto

  • White Papers // Feb 2010

    High Resolution Quantization Codebook Design for Multiple-Antenna Fading Channels

    The use of multiple antennas at the Base-Station (BS) can considerably improve the performance of the wireless communication links. The realization of these improvements however typically requires Channel State Information (CSI) at the BS. In practical limited-feedback systems, the remote terminals need to quantize the channel state and send the...

    Provided By University of Toronto

  • White Papers // Feb 2010

    Joint Scheduling and Dynamic Power Spectrum Optimization for Wireless Multicell Networks

    This paper proposes a joint proportionally fair scheduling and dynamic power spectrum adaptation algorithm for wireless multicell networks. The proposed system allows multiple base-stations in a multicell network to be coordinated by exchanging interference pricing messages among each other. The messages summarize the effect of intercell interference, and they are...

    Provided By University of Toronto

  • White Papers // Sep 2009

    A Hybrid Game Approach for Joint User Selection and Power Allocation Over Unlicensed Spectrum Bands

    This paper studies the sharing of unlicensed spectrum bands between network operators by formulating it as a hybrid noncooperative game. A multi-user multi-channel downlink transmission is considered where the communication links are modeled as Gaussian parallel interference channels. Each transmitter, controlled by a competing operator, selects one user per channel...

    Provided By University of Toronto

  • White Papers // Jun 2010

    Partial Zero-Forcing Precoding for the Interference Channel With Partially Cooperating Transmitters

    A communication model is considered in which the classic two-user Gaussian interference channel is augmented by noiseless rate-limited digital conferencing links between the transmitters. The authors propose a partial zero-forcing pre-coding strategy based on a shared-private rate splitting scheme at the transmitter, in which each transmitter communicates part of its...

    Provided By University of Toronto

  • White Papers // Mar 2010

    On the Symmetric Capacity of the K-User Symmetric Cyclic Gaussian Interference Channel

    The capacity region of Gaussian interference channel in the weak interference regime is an open problem. Recently, Etkin, Tse and Wang derived an outer bound for the two-user Gaussian interference channel and proved that a simple Han-Kobayashi signaling scheme can achieve within one bit of the capacity region for all...

    Provided By University of Toronto