KTH - Royal Institute of Technology

Displaying 1-40 of 102 results

  • White Papers // Jan 2014

    Exact Optimized-cost Repair in Multi-hop Distributed Storage Networks

    The problem of exact repair of a failed node in multi-hop networked distributed storage systems is considered. Contrary to the most of the current studies which model the repair process by the direct links from surviving nodes to the new node, the repair is modeled by considering the multi-hop network...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Jan 2013

    Repair for Distributed Storage Systems with Erasure Channels

    The authors study the repair problem of distributed storage systems in erasure networks where the packets transmitted from surviving nodes to the new node might be lost. The fundamental storage-bandwidth tradeoff is calculated by multicasting analysis in erasure networks. The optimal tradeoff bound can be asymptotically achieved when the number...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Nov 2012

    Low Complexity Adaptive Antenna Selection for Cognitive Radio MIMO Broadcast Channels

    A multi-antenna cognitive radio network, with a single pair of primary users and a secondary broadcast channel, is considered. Under perfect Channel State Information (CSI), the rate-optimal strategy for the primary link is waterfilling, resulting in possibly unused dimensions. The secondary base station, supplied with perfect and global CSI, employs...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Oct 2012

    Overload Management in Data Stream Processing Systems With Latency Guarantees

    Stream processing systems are becoming increasingly important to analyze real-time data generated by modern applications such as online social networks. Their main characteristic is to produce a continuous stream of fresh results as new data are being generated at real-time. Resource provisioning of stream processing systems is difficult due to...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Sep 2012

    Integrating Conventional ERP System With Cloud Services: From the Perspective of Cloud Service Type

    Integrating conventional ERP system with cloud services is an emerging topic nowadays as IT technologies are developing very fast. It is proved that cloud computing has many benefits, and cloud services with flexible licensing model and cost saving features bring opportunities to enterprise's IT operations. Conventional ERP system, an important...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Aug 2012

    A Conservation-Law-Based Modular Fluid-Flow Model for Network Congestion Modeling

    A modular fluid-flow model for network congestion analysis and control is proposed. The model is derived from an information conservation law stating that the information is either in transit, lost or received. Mathematical models of network elements such as queues, users, and transmission channels, and network description variables, including sending/...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Mar 2012

    On Rate Allocation for Multiple Plants in a Networked Control System

    The problem of allocating communication resources to multiple plants in a networked control system is investigated. In the presence of a shared communication medium, a total transmission rate constraint is imposed. For the purpose of optimizing the rate allocation to the plants over a finite horizon, two objective functions are...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Feb 2012

    Real-Time Scheduling in LTE for Smart Grids

    The latest wireless network, 3GPP Long Term Evolution (LTE), is considered to be a promising solution for smart grids because it provides both low latency and large bandwidth. However, LTE was not originally intended for smart grids applications, where data generated by the grid have specific delay requirements that are...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Jan 2012

    Approximation for a Sum of On-Off Log-Normal Processes With Wireless Applications

    In this paper, a log-normal approximation is proposed for the sum of log-normal processes weighted by binary processes. The analytical approach moves from the method early proposed by Wilkinson for approximating first order statistics of a sum of log-normal components, and extends to incorporate second order statistics and the presence...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Jan 2012

    State-of-The Art and Future In-Car Navigation Systems - A Survey

    A survey of the information sources and information fusion technologies used in the current in-car navigation systems is presented. The pros and cons of the four commonly used information sources - GNSS/RF-based positioning, vehicle motion sensors, vehicle models and map information - are described. Common filters to combine the information...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Oct 2011

    Aggregate Interference in Secondary Access With Interference Protection

    This paper presents a derivation of the probability distribution function (pdf) of the aggregate interference in a secondary access network where multiple secondary users cause interference to a single primary user. The derivation considers a practical interference protection mechanism that the transmission of each secondary user is regulated by an...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Sep 2011

    A Constrained Optimization Approach to Nonlinear Interference Cancellation

    Non-linear interference cancellation has been successful as a low-complexity iterative detection strategy for multiple-input, multiple-output channels. However, such strategies are generally difficult to analyze. Here, the authors develop a connection to constrained optimization through the use of penalty functions. The resulting framework provides a means of analysis, and includes known...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Sep 2011

    Geo-Location Spectrum Opportunities Database in Downlink Radar Bands for OFDM Based Cognitive Radios

    In this paper a model to investigate the spectrum opportunities for cognitive radio networks in three radar frequency bands L, S and C at a specific location is introduced. The authors consider underlay unaware spectrum sharing model. The Secondary System they assume is an OFDM based system. The followed strategy...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Aug 2011

    Encryption for Peer-to-Peer Social Networks

    To address privacy concerns over online social networking services, several distributed alternatives have been proposed. These Peer-To-Peer (P2P) online social networks do not rely on centralized storage of user data. Instead, data can be stored not only on a computer of a profile owner but almost anywhere (friends' computers, random...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Aug 2011

    P2P Social Networks With Broadcast Encryption Protected Privacy

    Existing centralized, provider-dependent networks do not provide users with mechanisms to fully protect their data. The provider has complete control of the service, and users have to rely on security mechanisms provided by the service. There is no guarantee that the trusted provider will enforce the privacy preferences of the...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Aug 2011

    Cloud Computing and the Business Consequences of ERP Use

    A Cloud Computing system is intended to improve and automate the controlling single point operations. By using a single point of control, this goal is accomplished through the elimination of duplicate entry and the contribution of data integrity, detailed drilldown, simple training, manageable support, minimal IT maintenance, easy upgrades and...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Jul 2011

    Error Floor Analysis of LT Codes Over the Additive White Gaussian Noise Channel

    The authors investigate the error floor performance of Luby Transform (LT) codes over the additive white Gaussian noise channel. They first derive a lower bound on the bit error rate for an LT code, which they subsequently use to show that the corresponding error floor is predominantly caused by low-degree...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Jul 2011

    Aggregate Interference From Secondary Users With Heterogeneous Density

    This paper presents an analytical model to approximate the probability distribution function of the aggregate interference that a primary user receives from multiple secondary transmitters. In particular, the authors consider heterogeneity in spatial distribution of secondary users such that there are several sites with densely populated secondary users in the...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Jul 2011

    Efficient Scheduling for Relay-Aided Broadcasting With Random Network Codes

    The authors investigate efficient scheduling algorithms for a relay-aided broadcasting system using random network codes, where their objective is to maximize the transmission efficiency. The broadcast from a Base-Station (BS) is divided into an information phase and a redundancy phase, where the half-duplex relay assists in the redundancy phase. Time-division...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Jun 2011

    Myopic Multi-Hop Transmission Strategies in Layered Wireless Networks

    A layered wireless network is considered, where information is transmitted in a multi-hop MIMO-like fashion from the source node layer through several intermediate layers of nodes before reaching the sink node layer. Analog network coding is investigated as the network transmission strategy, exploiting the inherent superposition features of the wireless...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Jun 2011

    Optimal Power Allocation in Multi-Hop Cognitive Radio Networks

    Optimal power allocation in a multi-hop cognitive radio network is investigated. Information transmitted from the source passes through several wireless relay nodes before reaching the destination. At each hop, the received signal is decoded, re-encoded and retransmitted to the following node. Transmissions at every hop are overheard by nearby nodes...

    Provided By KTH - Royal Institute of Technology

  • White Papers // May 2011

    Compress-and-Forward Relaying Based on Symbol-Wise Joint Source-Channel Coding

    The authors propose a new compress-and-forward implementation for the relay channel based on joint source-channel coding techniques. The relay performs scalar quantization of its observation in combination with a redundant index mapping. The system utilizes the correlation between the quantized signal and the direct-link observation of the transmitted symbols as...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Apr 2011

    How Far from Kronecker can a MIMO Channel be? Does it Matter?

    A common assumption in the design and analysis of many MIMO transmission schemes is the so-called Kronecker model. This model is often a crucial step to obtain mathematically tractable solutions, but has also been criticized for being unrealistic. In this paper, the authors present a numerical approach to determine a...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Apr 2011

    Aeronautical Communication Systems as Potential Primary Users in Secondary Spectrum Access

    Secondary spectrum access emerges as a means to increase spectrum utilization significantly in a near future. However, the technical availability and the economic value of the secondary access have not been fully investigated. Particularly, the impact of the secondary access on the real-life primary systems remains mostly unaddressed. Among the...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Mar 2011

    Converging an Overlay Network to a Gradient Topology

    In this paper, the authors investigate the topology convergence problem for the gossip-based Gradient overlay network. In an overlay network where each node has a local utility value, a Gradient overlay network is characterized by the properties that each node has a set of neighbors with the same utility value...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Mar 2011

    On Designing Optimal Servomechanism Controller With Limited Model Information

    The family of limited model information designs, which construct controllers by accessing the plant's model in a constrained manner, is introduced in this paper. The closed-loop constant-disturbance rejection performance of the best Proportional-Integral (PI) controller that they can produce is investigated. For a class of linear discrete-time time-invariant plants, it...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Mar 2011

    On the Requirements of Secondary Access to 960-1215 MHz Aeronautical Spectrum

    In this paper, the authors investigate the spectrum sharing requirements of secondary access to 960-1215 MHz band which is primarily allocated to aeronautical usage. Primary system of interest is Distance Measuring Equipments (DME) aiding navigation of airplanes. They consider a scenario where indoor femtocells share the spectrum as secondary users....

    Provided By KTH - Royal Institute of Technology

  • White Papers // Feb 2011

    A Mobile World of Security - The Model

    The authors propose a novel approach to establish cryptographic keys among mobile users and a networking infrastructure. Their approach comes at a low cost and can either be used as an alternative to existing solutions or can be employed in a complementary way. Their basic observation is that users are...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Feb 2011

    Opportunistic Secondary Spectrum Access -Opportunities and Limitations

    Dynamic spectrum sharing technique ("Cognitive Radio") where secondary users opportunistically utilize temporarily or locally unused spectrum has emerged as a prime candidate technology to relieve the perceived spectrum shortage. Making a realistic assessment of the amount of spectrum available for secondary services is the objective of the EU FP7 QUASAR...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Feb 2011

    Relay-Aided Broadcasting With Instantaneously Decodable Binary Network Codes

    The authors consider a base-station broadcasting a set of order-insensitive packets to a user population over packet-erasure channels. To improve efficiency they propose a relay-aided transmission scheme using instantaneously-decodable binary network coding. Their proposed scheme ensures that a coded packet can be immediately decoded at the user side without delay....

    Provided By KTH - Royal Institute of Technology

  • White Papers // Feb 2011

    Sphere Decoding Complexity Exponent for Decoding Full Rate Codes Over the Quasi-Static MIMO Channel

    In the setting of quasi-static Multiple-Input Multiple-Output (MIMO) channels, the authors consider the high Signal-to-Noise Ratio (SNR) asymptotic complexity required by the Sphere Decoding (SD) algorithm for decoding a large class of full rate linear space-time codes. With SD complexity having random fluctuations induced by the random channel, noise and...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Jan 2011

    Wireless Networked Control System Co-Design

    A framework for the joint design of wireless network and controllers is proposed. Multiple control systems are considered where the sensor measurements are transmitted to the controller over the IEEE 802.15.4 protocol. The essential issues of wireless Networked Control Systems (NCSs) are investigated to provide an abstraction of the wireless...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Jan 2011

    Impact of Aggregate Interference on Meteorological Radar From Secondary Users

    In this paper, the authors investigate the impact of aggregate interference in a secondary spectrum access system. Particularly, meteorological radar operating in 5.6 GHz band is considered to be a primary user. Secondary users are WLAN devices spreading in a large area which induce aggregate interference to the radar. They...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Jan 2011

    Sphere Decoding Complexity Exponent for Full Rate Codes Over the Quasi-Static MIMO Channel

    In the setting of quasi-static Multiple-Input Multiple-Output (MIMO) channels, the authors consider the high Signal-to-Noise Ratio (SNR) asymptotic complexity required by the Sphere Decoding (SD) algorithm for decoding a large class of full rate linear space-time codes. With SD complexity being a function of the code and having random fluctuations...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Jan 2011

    Power and Rate Control Outage Based in CDMA Wireless Networks Under MAI and Heterogeneous Traffic Sources

    The authors characterize the maximum throughput achievable for the up-link of a power-controlled WCDMA wireless system with variable spreading factor. Their system model includes multi access interference caused by users with heterogeneous data sources, and quality of service expressed in terms of outage probability. Inner loop and outer loop power...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Dec 2010

    Advances in Wireless Network Coding for IMT-Advanced & Beyond

    In a classical network, data streams originating from a source and intended to a desired destination are routed through intermediate nodes before reaching their final destination. By contrast, Network Coding (NC) manipulates at an intermediate node those data streams by combining the data from the streams before forwarding it to...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Nov 2010

    On the Use of Compressive Sampling for Wide-Band Spectrum Sensing

    In a scenario where a cognitive radio unit wishes to transmit, it needs to know over which frequency bands it can operate. It can obtain this knowledge by estimating the power spectral density from a Nyquist-rate sampled signal. For wide-band signals sampling at the Nyquist rate is a major challenge...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Oct 2010

    SIP-Based Context Distribution: Does Aggregation Pay Off?

    Context-aware applications need quickly access to current context information, in order to adapt their behavior before this context changes. To achieve this, the context distribution mechanism has to timely discover context sources that can provide a particular context type, then acquire and distribute context information from these sources to the...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Sep 2010

    Run-Time Partitioning of Hybrid Distributed Shared Memory on Multi-Core Network-on-Chips

    On multi-core Network-on-Chips (NoCs), memories are preferably distributed and supporting Distributed Shared Memory (DSM) is essential for the sake of reusing huge amount of legacy code and easy programming. However, the DSM organization imports the inherent overhead of translating virtual memory addresses into physical memory addresses, resulting in negative performance....

    Provided By KTH - Royal Institute of Technology

  • White Papers // Sep 2010

    CSI Acquisition Concepts for Advanced Antenna Schemes in the WINNER+ Project

    This paper summarizes four novel advanced antenna concepts explored in the framework of the WINNER+ project. The concepts are related to multiuser MIMO communication in cellular networks, focusing on the acquisition and application of Channel State Information (CSI) at the transmitter in Time-Division-Duplex (TDD) mode. The concepts include new ideas...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Dec 2008

    Optimal Stopping for Event-Triggered Sensing and Actuation

    Novel event-triggered sensing and actuation strategies are presented for networked control systems with limited communication resources. Two architectures are considered: one with the controller co-located with the sensor and one with the control co-located with the actuator. A stochastic control problem with an optimal stopping rule is shown to capture...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Sep 2008

    Subgradient Methods and Consensus Algorithms for Solving Convex Optimization Problems

    In this paper, the authors propose a subgradient method for solving coupled optimization problems in a distributed way given restrictions on the communication topology. The iterative procedure maintains local variables at each node and relies on local subgradient updates in combination with a consensus process. The local subgradient steps are...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Jul 2008

    The Break-Even Cost of Bit-Rate Fairness in Cellular-Relaying Networks

    In order to maximize the profit, an operator must choose the network architecture, deployment solution, and radio resource allocation depending on which fairness should the network enforce. The use of fixed relays has been proposed in the literature as cost-efficient way to enhance cellular networks. In this paper, the authors...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Jan 2010

    Advances in Device-to-Device Communications and Network Coding for IMT-Advanced

    In this paper, the authors introduce two innovative concepts which have not been present in cellular systems for IMT-Advanced so far: Device-To-Device (D2D) communication and network coding. Both of them are promising techniques to increase the efficiency of cellular communication systems, especially from a network point of view. They study...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Aug 2011

    Cloud Computing and the Business Consequences of ERP Use

    A Cloud Computing system is intended to improve and automate the controlling single point operations. By using a single point of control, this goal is accomplished through the elimination of duplicate entry and the contribution of data integrity, detailed drilldown, simple training, manageable support, minimal IT maintenance, easy upgrades and...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Jun 2006

    Strategic Business and IT Alignment: A Prioritized Theory Diagram

    Many academic and practitioners' studies have shown that misalignment or lack of alignment between Information Technology (IT) and business strategies is one of the main reasons why enterprises fail to exploit the full potential of their IT investments. Furthermore, organizations that have accomplished a high degree of alignment are often...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Apr 2009

    Modelling Business Transactions from the Value and Collaboration Perspective

    Business collaborations between actors encompass different business objectives, such as making product awareness, buying or selling specific products or goods, providing post-sale services, and so forth. Thereby, a clear identification of required business transactions is vital for modeling complex business collaboration, as well as for their further implementation with IT...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Sep 2012

    Integrating Conventional ERP System With Cloud Services: From the Perspective of Cloud Service Type

    Integrating conventional ERP system with cloud services is an emerging topic nowadays as IT technologies are developing very fast. It is proved that cloud computing has many benefits, and cloud services with flexible licensing model and cost saving features bring opportunities to enterprise's IT operations. Conventional ERP system, an important...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Oct 2012

    Overload Management in Data Stream Processing Systems With Latency Guarantees

    Stream processing systems are becoming increasingly important to analyze real-time data generated by modern applications such as online social networks. Their main characteristic is to produce a continuous stream of fresh results as new data are being generated at real-time. Resource provisioning of stream processing systems is difficult due to...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Jan 2014

    Exact Optimized-cost Repair in Multi-hop Distributed Storage Networks

    The problem of exact repair of a failed node in multi-hop networked distributed storage systems is considered. Contrary to the most of the current studies which model the repair process by the direct links from surviving nodes to the new node, the repair is modeled by considering the multi-hop network...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Jan 2013

    Repair for Distributed Storage Systems with Erasure Channels

    The authors study the repair problem of distributed storage systems in erasure networks where the packets transmitted from surviving nodes to the new node might be lost. The fundamental storage-bandwidth tradeoff is calculated by multicasting analysis in erasure networks. The optimal tradeoff bound can be asymptotically achieved when the number...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Oct 2004

    Human Capital Development and Competence Structures in Changing Media Production Environments

    This doctoral paper discusses the competence structures and the development of human capital in the graphic arts and media sector. The study has focused on exploring the new media landscape and in particular the structural changes that influence the sector, the print-versus electronic-media debate and the future of print media....

    Provided By KTH - Royal Institute of Technology

  • White Papers // Jan 2009

    MagicNET: The Human Immune System and Network Security System

    Most of the current security systems do not provide adequate level of protection against ever-increasing threats. The main reason for their failure is the use of point solutions to protect hosts and reactive approach against intrusions. The paper studied human immune system, which survives under dynamic changing conditions and provides...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Jun 2009

    Scheduling Packets for Event-Triggered Control

    There is a tight interaction between the control architecture and the communication protocols in networked control systems. Periodic time-triggered control loops are natural to use together with a TDMA scheduled communication medium, while a periodic event-triggered control loops are suitable for contention-based medium access. Only recently has a thorough study...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Oct 2009

    A Cross-Layer Protocol for Wireless Sensor Networks in Control and Automation

    Control applications over Wireless Sensor Networks (WSNs) require timely, reliable, and energy efficient communications. Cross layer interaction is an essential design paradigm to exploit the complex interaction among the layers of the protocol stack and reach a maximum efficiency. Such a design approach is challenging because reliability and latency of...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Aug 2009

    MAC Protocol Engine for Sensor Networks

    This paper presents a novel approach for Medium Access Control (MAC) protocol design based on protocol engine. Current way of designing MAC protocols for a specific application is based on two steps: First the application specifications (such as network topology and packet generation rate), the requirements for energy consumption, delay...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Sep 2009

    Live Migration of Virtual Machines: Sustaining Active TCP-Sessions

    Virtualization and the technology associated with it, has attracted quite a lot of attention during the past years. As of 2009, it is estimated that the market for virtualized X86 server solutions will be worth in the vicinity of $1.8 Billion. So far, the main advantages presented by virtual solution...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Mar 2010

    An Approach to Network Security Assessment Based on Probalistic Relational Models

    To assist rational decision making regarding network security improvements, decision makers need to be able to assess weaknesses in existing or potential new systems. This paper presents a model based assessment framework for analyzing the network security provided by different architectural scenarios. The framework uses a probabilistic relational model to...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Mar 2011

    Converging an Overlay Network to a Gradient Topology

    In this paper, the authors investigate the topology convergence problem for the gossip-based Gradient overlay network. In an overlay network where each node has a local utility value, a Gradient overlay network is characterized by the properties that each node has a set of neighbors with the same utility value...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Jul 2009

    LQG and Medium Access Control

    The communication channel is a shared resource in networked control systems, and channel access at every instant cannot be guaranteed. In this paper, the authors propose a novel architecture for control over wireless networks with integrated Medium Access Control (MAC).They evaluate the impact of constrained channel access on the cost...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Sep 2011

    A Constrained Optimization Approach to Nonlinear Interference Cancellation

    Non-linear interference cancellation has been successful as a low-complexity iterative detection strategy for multiple-input, multiple-output channels. However, such strategies are generally difficult to analyze. Here, the authors develop a connection to constrained optimization through the use of penalty functions. The resulting framework provides a means of analysis, and includes known...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Feb 2012

    Real-Time Scheduling in LTE for Smart Grids

    The latest wireless network, 3GPP Long Term Evolution (LTE), is considered to be a promising solution for smart grids because it provides both low latency and large bandwidth. However, LTE was not originally intended for smart grids applications, where data generated by the grid have specific delay requirements that are...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Aug 2012

    A Conservation-Law-Based Modular Fluid-Flow Model for Network Congestion Modeling

    A modular fluid-flow model for network congestion analysis and control is proposed. The model is derived from an information conservation law stating that the information is either in transit, lost or received. Mathematical models of network elements such as queues, users, and transmission channels, and network description variables, including sending/...

    Provided By KTH - Royal Institute of Technology

  • White Papers // May 2011

    Compress-and-Forward Relaying Based on Symbol-Wise Joint Source-Channel Coding

    The authors propose a new compress-and-forward implementation for the relay channel based on joint source-channel coding techniques. The relay performs scalar quantization of its observation in combination with a redundant index mapping. The system utilizes the correlation between the quantized signal and the direct-link observation of the transmitted symbols as...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Sep 2010

    Distributed Multichannel Random Access Networks With Selfish Users

    Dynamic Spectrum Access (DSA) schemes allow the users to share spectrum resources by taking advantage of the variations in spectrum demand over time and space. Carrying out dynamic spectrum allocation centrally, however, can be a complex task. For this reason, distributed schemes in which users can access the available channels...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Sep 2010

    Experimental Verification of Indoor TV White Space Opportunity Prediction Model

    Recent work has demonstrated that the underutilized spectrum in the Digital Television Bands, commonly referred to as TV White Space (TVWS), is a prime candidate for Opportunistic Spectrum Access (OSA). However, a systematic assessment of the availability of this spectrum for secondary transmission was, until very recently, lacking. In a...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Nov 2010

    On the Use of Compressive Sampling for Wide-Band Spectrum Sensing

    In a scenario where a cognitive radio unit wishes to transmit, it needs to know over which frequency bands it can operate. It can obtain this knowledge by estimating the power spectral density from a Nyquist-rate sampled signal. For wide-band signals sampling at the Nyquist rate is a major challenge...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Feb 2009

    Automated Multidimensional Characterization of Power Amplifier for Design and Production

    Designing, optimizing and producing modern Power Amplifiers (PA) requires new and fast RF (Radio Frequency) measurement techniques capable of characterizing its real behavior. PAs are a truly multidimensional device where many desired performance parameters are contradictory to each other. This is especially true for the generation of modern communication PAs...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Jul 2008

    Estimation of the Rician K-factor in Reverberation Chambers for Improved Repeatability in Terminal Antenna Measurements

    An estimator of the RicianK-factor for reverberation chamber is derived in this paper using maximum likelihood estimation approach. This is done by reviewing the existing statistical model of the fields in the reverberation chamber. The functionality of the derived K-factor estimator is tested with the measurement data for the well...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Mar 2009

    Experiences on Mobile-ATM Deployment in a Developing Country

    Mobile-Commerce is the latest concept of enabling the financial transactions on mobile phones and hand-held devices. With the rapid development of the society, the M-Commerce applications play a vital role. Mobile-ATM is one such application, enabling the banking services on mobile phones. Even though users have a poor computer literacy,...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Aug 2011

    P2P Social Networks With Broadcast Encryption Protected Privacy

    Existing centralized, provider-dependent networks do not provide users with mechanisms to fully protect their data. The provider has complete control of the service, and users have to rely on security mechanisms provided by the service. There is no guarantee that the trusted provider will enforce the privacy preferences of the...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Aug 2011

    Encryption for Peer-to-Peer Social Networks

    To address privacy concerns over online social networking services, several distributed alternatives have been proposed. These Peer-To-Peer (P2P) online social networks do not rely on centralized storage of user data. Instead, data can be stored not only on a computer of a profile owner but almost anywhere (friends' computers, random...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Jan 2011

    Sphere Decoding Complexity Exponent for Full Rate Codes Over the Quasi-Static MIMO Channel

    In the setting of quasi-static Multiple-Input Multiple-Output (MIMO) channels, the authors consider the high Signal-to-Noise Ratio (SNR) asymptotic complexity required by the Sphere Decoding (SD) algorithm for decoding a large class of full rate linear space-time codes. With SD complexity being a function of the code and having random fluctuations...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Jan 2012

    Approximation for a Sum of On-Off Log-Normal Processes With Wireless Applications

    In this paper, a log-normal approximation is proposed for the sum of log-normal processes weighted by binary processes. The analytical approach moves from the method early proposed by Wilkinson for approximating first order statistics of a sum of log-normal components, and extends to incorporate second order statistics and the presence...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Mar 2012

    On Rate Allocation for Multiple Plants in a Networked Control System

    The problem of allocating communication resources to multiple plants in a networked control system is investigated. In the presence of a shared communication medium, a total transmission rate constraint is imposed. For the purpose of optimizing the rate allocation to the plants over a finite horizon, two objective functions are...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Jan 2011

    Power and Rate Control Outage Based in CDMA Wireless Networks Under MAI and Heterogeneous Traffic Sources

    The authors characterize the maximum throughput achievable for the up-link of a power-controlled WCDMA wireless system with variable spreading factor. Their system model includes multi access interference caused by users with heterogeneous data sources, and quality of service expressed in terms of outage probability. Inner loop and outer loop power...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Jan 2012

    State-of-The Art and Future In-Car Navigation Systems - A Survey

    A survey of the information sources and information fusion technologies used in the current in-car navigation systems is presented. The pros and cons of the four commonly used information sources - GNSS/RF-based positioning, vehicle motion sensors, vehicle models and map information - are described. Common filters to combine the information...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Jul 2010

    Optimality of LDGM-LDPC Compound Codes for Lossy Compression of Binary Erasure Source

    The authors consider the Binary Erasure Source (BES) introduced by Martinian and Yedidia. Based on the technique introduced by Martinian and Wainwright, they upper bound the rate-distortion performance of the check regular Poisson LDGM ensemble and the compound LDGM-LDPC ensemble for the BES. They also show that there exist compound...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Jul 2010

    LT Coded MSK Over AWGN Channels

    The authors investigate the design of Luby Transform (LT) codes with Minimum-Shift-Keying (MSK) modulation over Additive White Gaussian Noise (AWGN) channels. Both systematic and nonsystematic LT codes are considered from the perspectives of decoding threshold and bit error rate. Using systematic LT codes, coding complexity can be reduced by eliminating...

    Provided By KTH - Royal Institute of Technology

  • White Papers // Jul 2010

    Relay-Aided Multi-Cell Broadcasting With Random Network Coding

    The authors investigate a relay-aided multi-cell broadcasting system using random network codes, where the focus is on devising efficient scheduling algorithms between relay and base stations. Two scheduling algorithms are proposed based on different feedback strategies; namely, a one-step scheduling algorithm with instantaneous feedback for each redundancy packet; and a...

    Provided By KTH - Royal Institute of Technology