Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

Displaying 1-40 of 333 results

  • White Papers // Nov 2012

    Generalized Eigenvector for Decentralized Transmit Beamforming in the MISO Interference Channel

    This paper deals with the problem of sum-rate optimal transmit beam-forming for the multiple-input-single-output interference channel. Under realistic assumptions (i.e. the beam-formers are able to decrease the interference power level below the desired signal; the authors derive a decentralized beam-former that optimizes the sum-rate. This is of importance since it...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Nov 2012

    Encoding and Decoding for Turbo-Like Codes

    Generally, the major part of communication systems use Turbo Codes (TC) and/or Low-Density Parity-Check (LDPC) codes to protect the data to transmit (e.g. 3GPPLTE, IEEE 802.11p, IEEE 802.16, etc). Given that these coding strategies share similarities (e.g. two stage iterative decoding, Log-Likelihood ratio based, etc.) in their respective encoding and...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Oct 2012

    Packet Error Outage for Coded Systems Experiencing Fast Fading and Shadowing

    In this paper, the authors consider the performance of coded wireless communication systems experiencing non-frequency selective fading channels in shadowed environments. The Quality of Service (QoS) in a wireless network is dependent on the Packet Error Outage (PEO). They address the problem of finding a tractable expression for the coded...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Oct 2012

    Optimal Transmission Policy for Cooperative Transmission with Energy Harvesting and Battery Operated Sensor Nodes

    In this paper, the authors consider a scenario where one energy harvesting and one battery operated sensor cooperatively transmit a common message to a distant base station. The goal is to find the jointly optimal transmission (power allocation) policy which maximizes the total throughput for a given dead-line. First, they...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Oct 2012

    Artemisa: New GNSS Receiver Processing Techniques for Positioning and Multipath Mitigation

    Advances in computation and signal processing technologies allow the implementation sophisticated non-linear synchronization techniques that can be integrated in the acquisition and tracking modules, estimating both Line Of Sight Signal (LOSS) and Multi-Path (MP) echoes. Instead of using an ordinary DLL/PLL, advanced DLLs as the Multipath Estimating Delay Lock Loop...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Oct 2012

    An Open Source Galileo E1 Software Receiver

    This paper presents an open source implementation of a GNSS software receiver that targets Galileo E1B and E1C signals. After discussing the signal structure and the general architecture of the proposed software receiver, the authors provide detailed descriptions of the main signal processing algorithms involved in acquisition and tracking of...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Sep 2012

    Assisted GNSS in LTE-Advanced Networks and Its Application to Vector Tracking Loops

    This paper describes the positioning protocols provided by Long Term Evolution (LTE) networks, making special emphasis on existing and forthcoming standards for Assisted Global Navigation Satellite Systems (A-GNSS) data, mainly aimed to shorten the time-to-first-fix of the user receiver. The novelty of this paper consists in proposing the usage of...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Sep 2012

    Cooperative Coverage Extension in Heterogeneous Machine-to-Machine Networks

    The authors study the limits of cooperative coverage extension for multicast transmission in heterogeneous machine to machine networks. Terminals are equipped with both a long range interface, through which they connect to, e.g., a cellular network or satellite system, and a short range interface, which is used to create an...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Sep 2012

    Vulnerability Test Business Opportunity for Smart Grid Communication System Certification

    Smart grid concept provides a solution to the growing recognition that current utility grids need an ICT deployment infrastructure to improve efficiency. Wireless Machine-To-Machine (M2M) networks are a key technology to allow advanced smart gird services. Due to wireless channel nature and high number of threats, security is a top-priority...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Aug 2012

    Green-T: Enabling Techniques for Energy Efficient Mobile Terminals

    Although mobile devices are rapidly developing with new advanced functionalities, the advances in battery capacity are much slower. In the Green-T project, the authors address the energy efficiency problem by utilizing multiple radio interfaces in efficient ways in order to optimize the energy consumption. A first step is to use...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Aug 2012

    On the Feasibility of Satellite M2M Systems

    Machine-To-machine (M2M) communications have a very large potential market growth, particularly in the low-end segment. Current satellite systems are not adequate to serve very large populations of low cost devices, with low bandwidth requirements, and severe cost and energy constraints. A satellite system can bring unique advantages in terms of...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Aug 2012

    Towards the Performance and Energy Efficiency Comparison of Spatial Modulation with Conventional Single-Antenna Transmission Over Generalized Fading Channels

    In this paper, the authors present a performance and energy efficiency comparison of the recently devised single RF Multiple-Input-Multiple-Output (MIMO) concept of Spatial Modulation (SM) with the conventional single-antenna transmission method with receive Maximum Ratio Combining (MRC), which they denote as single-antenna/MRC, for different types of fading channels. In particular,...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Aug 2012

    Traffic and Mobility Management in Networks of Femtocells

    A deployment of femtocells that is harmonic with its environment is a challenging issue. In this respect, interference management has traditionally been in the spotlight. However, architectural improvements for efficient femtocells deployments, despite being equally relevant, have received less attention. This paper presents a system architecture conceived for efficiently deploying...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Aug 2012

    Energy Analysis of Cooperative and Duty-Cycled Systems in Shadowed Environments

    The authors assume a traditional three-node cooperative model where a source directly communicates with a sink unless in outage, in which case it reverts to a relay to facilitate communications. In contrast to prior art, however, they focus on ultra-low power wireless sensor and machine-to-machine networks, such as standardized through...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Aug 2012

    Experimental Demonstration of a Cost-Effective Bit Rate Variable Intensity Modulation and Direct Detection Optical OFDM with Reduced Guard Band

    Optical Orthogonal Frequency Division Multiplexing (O-OFDM) is increasingly emerging as enabling technology for future optical networks. Due to its robustness against transmission impairments and its unique flexibility and scalability to high-speed transmission, the range of applications is really huge, spanning different network segments, from long-haul to optical access, and different...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Aug 2012

    Experimental Demonstration of an OpenFlow/PCE Integrated Control Plane for IP Over Translucent WSON with the Assistance of a Per-Request-Based Dynamic Topology Server

    OpenFlow, which allows operators to control the network using software running on a network operating system (e.g. NOX2) within an external controller, has recently been proposed and experimentally validated as a promising Unified Control Plane (UCP) technique for future IP/DWDM multi-layer optical networks, since it provides maximum flexibility for the...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Jul 2012

    Energy Efficiency Analysis of a Cooperative Scheme for Wireless Local Area Networks

    The Persistent Relay Carrier Sensing Multiple Access (PRCSMA) protocol has been proposed in the literature as a Medium Access Control (MAC) protocol suitable for Cooperative Automatic Retransmission reQuest (C-ARQ) schemes. The improvement in throughput achieved with PRCSMA is already known. In this paper, the authors analyze the energy efficiency of...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Jul 2012

    ANGEL: Analog Network-Coded Game Theoretic Energy Efficient Layout for Data Dissemination

    In this paper, the authors present an analog-network-coding-aided layout for data dissemination. They propose a game theoretic Medium Access Control (MAC) protocol that exploits the recent developments in network coding domain to enhance the system performance. In particular, random linear network coding is used to eliminate the need of exchanging...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Jul 2012

    N-Player Medium Access Game for Wireless Data Dissemination

    In this paper, the authors propose a game theoretic medium access strategy for data dissemination in wireless networks. In data dissemination scenarios, where the global target is the spreading of a particular content in a network, the main goal of the wireless nodes is twofold: to guarantee a low completion...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Jul 2012

    Characterization and Design of Coherent Optical OFDM Transmission Systems Based on Hartley Transform

    Orthogonal Frequency Division Multiplexing (OFDM) has emerged in the optical communications field because of its promising capabilities for transmission link reconfiguration and its unique flexibility. Since the OFDM-based transceivers have a strong Digital Signal Processing (DSP), they can be easily reconfigured (even defined by software) and their implementation becomes straightforward...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Jul 2012

    Elastic Transponders for Optical Direct Detection OFDM Systems Based on the FHT

    The rapid growing of IP traffic and the new emerging applications and services such as cloud computing and high quality IP services (VoIP, IPTV, etc.) require a high capacity optical backbone network. Operator's main purpose is to find different ways to provide all these services in a cost-effective manner. Conventional...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Jul 2012

    Energy Analysis of Distributed Neighbour Discovery Algorithms Based on Frame Slotted-ALOHA for Cooperative Networks

    The design of communications protocols that exploit the availability of both cellular and short-range radio access interfaces in a same terminal can be exploited to improve the energy efficiency of wireless communications networks. Devices equipped with a cellular radio interface can act as dynamic gateways to provide energy-constrained devices in...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Jul 2012

    GNSS Array-Based Acquisition: Theory and Implementation

    Global Navigation Satellite Systems (GNSS) is the general concept used to identify those systems that allow user positioning and timing based on a constellation of satellites. Specific GNSSs are the well-known American GPS, the Russian GLONASS or the forthcoming European Galileo. All those systems rely on the same principle: the...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Jul 2012

    Capacity of a Class of Relay Channels with State

    The class of orthogonal relay channels with state in which the source and the relay are connected through a channel that depends on a state sequence is considered. It is assumed that the state sequence is fully known at the destination while it is not known at the source or...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Jul 2012

    On the Resource Abstraction, Partitioning and Composition for Virtual GMPLS-Controlled Multi-Layer Optical Networks

    In the last years, virtualization of optical networks is receiving a lot of attention by network infrastructure providers in order to support dynamic provisioning of dedicated networks over the same network infrastructure. Optical network virtualization technologies allow the partitioning/aggregation of the network infrastructure (i.e., physical optical nodes and links) into...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Jul 2012

    Practical Issues in Multi-User Physical Layer Network Coding

    The throughput of multiple access systems is limited by the collisions that take place when more than one node accesses the channel in the same time slot. This limitation is particularly problematic in satellite networks with random access, where the long Round-Trip Time (RTT) greatly limits feedback from the receiver,...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Jul 2012

    Decentralized Phase Synchronization Scheme for Distributed Beamforming in WSN With Quantized Phase Feedback

    In this paper, the authors propose a phase synchronization scheme for distributed beam-forming in wireless sensor networks. The scheme is decentralized, meaning that the Base Station (BS) is not required to coordinate the allocation of sensors to the corresponding training timeslots. The BS is only asked to perform an estimation...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Jul 2012

    On the Ineffectiveness of Today's Privacy Regulations for Secure Smart City Networks

    Urban growth and migration are putting significant stress on city infrastructure as demand outpaces supply for water, energy, transportation, health-care, education, and safety. Innovative solutions are requested to improve basic services in this scenario. To this end, the community is focusing on smart cities, which refers to an urban transformation...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Jun 2012

    A Cognitive Scheme for Radio Admission Control in LTE Systems

    In order to provide QoS requirements in high speed future communication networks, such as LTE, the operator has to provide a radio admission control algorithm which will guarantee the QoS of different service types (e.g. voice, data, video, ftp) while maximizing radio resource utilization. In this paper, the authors propose...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Jun 2012

    A Cognitive Scheme for Radio Admission Control in LTE Systems

    In order to provide QoS requirements in high speed future communication networks, such as LTE, the operator has to provide a radio admission control algorithm which will guarantee the QoS of different service types (e.g. voice, data, video, ftp) while maximizing radio resource utilization. In this paper, the authors propose...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Jun 2012

    A Learning Theoretic Approach to Energy Harvesting Communication System Optimization

    A Machine-To-Machine (M2M) system composed of low-power embedded devices powered by energy scavenging mechanisms is considered. A learning theoretic approach is introduced for the optimization of said energy harvesting and communication system. The data and energy arrival processes as well as the channel state process are all modeled as finite-state...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Jun 2012

    A Neural Network Based Radio Admission Control Scheme for LTE Systems

    In this paper, the authors propose a radio admission control scheme based on a multilayer feed-forward neural network. According to their scheme, the eNodeB performs radio admission control using a neural network that learns from the past experience how the admission of a new session would affect the QoS of...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Jun 2012

    Joint Pre-Coder Design and Greedy Power Allocation for Compressed Spatial Field Estimation

    In this paper, the authors propose a distributed beam-forming scheme for the estimation of spatial fields (e.g. temperature, moisture) with wireless sensor networks. The pre-coding scheme allows for an over-the-air compressed representation of the correlated set of spatial observations, which are encoded in a number of consecutive sensor-to-GateWay (GW) transmissions....

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Jun 2012

    Optimal Transmission Policy for Distributed Beamforming With Energy Harvesting and Battery Operated Sensor Nodes

    In this paper, the authors consider a scenario where one energy harvesting and one battery operated sensor cooperatively transmit a common message to a distant base station. The goal is to find the jointly optimal transmission (power allocation) policy which maximizes the total throughput for a given deadline. To that...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Jun 2012

    Practical Considerations in the Design of Lossy Cavity Filters

    Lossy filter synthesis is known to minimize the effects of finite resonator Q in filters. In this synthesis approach, the transfer functions are proportional to those attainable with a lossless filter so that, despite having finite resonator Q, the scaled-down transfer functions maintain the properties of insertion loss flatness and...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Jun 2012

    Low Complexity Bit Rate Variable Transponders Based on Optical OFDM With PAPR Reduction Capabilities

    In this paper, the authors propose low complexity bit rate variable transponders for adaptive DC biased optical OFDM systems. The transponders are based on an alternative transform, the Fast Hartley Transform (FHT), and use Adaptively Modulated O-OFDM (AMO-OFDM) to introduce flexibility to optical networks. Additionally, Low Complexity SeLective Mapping (LCSLM)...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Jun 2012

    Experimental Assessment of the Dynamic Provisioning and Restoration of a GMPLS Unified Control Plane in Multi-Layer (MPLS-TP/WSON) Networks

    The paper presents and summarizes the recent advances attained when deploying the GMPLS Unified Control Plane (UCP) for handling Multi-Layer Networks (MLN) within the CTTC ADRENALINE test-bed. Specifically, the goal was to design, implement and validate/evaluate the control functions and protocol improvements (e.g., Forwarding adjacency management) performed by the UCP...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Jun 2012

    Flexible Physical Layer Design Subject to Delay and Energy Constraints

    One of the main problems in transmitting coded data is that the decoder does not know the real number of errors to correct. This issue is critical since it means that the decoders spend much more iterations for correcting them. A paradigm case of this is the Bose-Chaudhuri-Hocquenghem (BCH) code....

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Jun 2012

    Joint Source-Channel Coding for the Multiple-Access Relay Channel

    Reliable transmission of arbitrarily correlated sources over Multiple-Access Relay Channels (MARCs) and Multiple-Access Broadcast Relay Channels (MABRCs) is considered. In MARCs, only the destination is interested in a reconstruction of the sources, while in MABRCs, both the relay and the destination want to reconstruct the sources. The authors allow an...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Jun 2012

    Mixed Joint Source-Channel Coding Schemes for Multiple-Access-Relay Channels

    The authors study the transmission of correlated sources over multiple-access-relay channels, in which both the relay and the destination have access to side information arbitrarily correlated with the sources. They propose two new joint source-channel coding schemes based on a novel combination of the Correlation Preserving Mapping (CPM) technique with...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Dec 2011

    A Non-Parametric Statistical Approach for Malicious Users Detection in Cognitive Wireless Ad-Hoc Networks

    In cognitive wireless ad-hoc networks the cooperative sensing achieves more accurate results than non-cooperative ones. However, it also exposes the network to attacks. In this paper an algorithm based on the non-parametric Kruskal-Wallis test is proposed to detect malicious users without having any a priori knowledge. The algorithm makes use...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // May 2011

    An Open GMPLS-Enabled Control Plane Testbed for Remote Development and Experimentation of PCE-Based Path Computation Algorithms

    The deployment of a distributed control plane allows optical transport networks to support the new emerging requirements such as real-time and flexible provisioning, multiple levels of QoS, and required network survivability, through providing a common set of functions and interconnection mechanisms defined under the GMPLS architecture. One of the main...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Jul 2011

    Comparison of Peak Power Reduction Techniques in Optical OFDM Systems Based on FFT and FHT

    In this paper, the authors present different Peak-to-Average Power Ratio (PAPR) reduction techniques, for Optical Orthogonal Frequency Division Multiplexing (O-OFDM) systems based on both the Fast Fourier Transform (FFT) and the Fast Hartley Transform (FHT). They analyze the performance of SeLective Mapping (SLM), interleaving and Partial Transmit Sequence (PTS) techniques...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Jan 2012

    Constant Envelope Coherent Optical OFDM Based on Fast Hartley Transform

    In this paper, the authors discuss the feasibility of a constant envelope optical OFDM based on fast Hartley transform. The digital signal processing output drives an optical phase modulator for obtaining a 0 dB PAPR signal at the transmission side, whereas the use of a Hartley transform increases power efficiency...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // May 2011

    Design and Performance Evaluation of a GMPLS-Enabled MPLS-TP/PWE3 Node With Integrated 10Gbps Tunable DWDM Transponders

    To achieve cost reductions, simplified operations and flexible scalability in optical transport networks, a challenging approach is to replace the TDM aggregation and transport infrastructure, based on legacy SONET/SDH technology, by a new dynamic network infrastructure that delivers the high-bandwidth transport and deterministic performance of the optical circuit technology (i.e.,...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // May 2011

    Eigenbeamforming for Interference Mitigation in GNSS Receivers

    This paper presents a novel beamforming approach for interference mitigation in Global Navigation Satellite Systems (GNSS) receivers. The proposed algorithm is based on a recently developed beamformer but adapted to GNSS particularities, mainly the extremely low power of the received signal (well below the noise floor) and the interest only...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Mar 2011

    Enhanced Dynamic VNT Configuration in GMPLS Controlled Ethernet Over WSON With Timer-Based Lightpath Holding Time

    In this paper, the authors focus on the dynamic Virtual Network Topology (VNT) configuration in a Connection-Oriented (CO) Ethernet over Wavelength Switched Optical Network (WSON), controlled by a single instance of the GMPLS control plane. They propose the usage of a FA (Forwarding Adjacency) link timer, which postpones the release...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Feb 2011

    Expected Distortion With Fading Channel and Side Information Quality

    The authors consider the joint source-channel coding problem of sending a Gaussian source over a Single Input-Single Output (SISO) fading channel when the decoder has additional correlated side information whose quality is also time-varying. They assume a block fading model for both the channel and side information qualities, and assume...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Aug 2011

    Flexible Hybrid Solar/EM Energy Harvester for Autonomous Sensors

    A flexible ElectroMagnetic (EM)/solar energy harvester is proposed that finds application in low power energy autonomous wireless sensor networks and RFID-enabled sensors. A low cost, compact and conformal harvester is implemented on a flexible polyester (PET) substrate combining a rectenna for EM harvesting and a flexible amorphous silicon solar cell...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Jun 2011

    Frequency Offset Compensation Loop for 16-QAM Optical Coherent Systems

    A frequency control loop for 16-QAM (Quadrature Amplitude Modulation) optical coherent systems is proposed and demonstrated. An overall design of the control loop has been evaluated based on simulation results. The proposed frequency control loop enables to estimate, track and compensate frequency offset beyond ?5 GHz. Also, tracking and pull-in...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Apr 2011

    Interference Mitigation Techniques for Asynchronous Multiple Access Communications in SIMO FBMC Systems

    The widespread use of Orthogonal Frequency Division Multiplexing (OFDM) systems relies on the fact that both Inter Carrier Interference (ICI) and Inter Symbol Interference (ISI) are smartly removed by transmitting redundancy in the form of a Cyclic Prefix (CP). Evolved MultiCarrier Modulations (MCM) do not trasmit redundancy and use spectral...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Feb 2011

    Is Transmit Beamforming Robust?

    Transmit beamforming is a simple strategy that uses only one spatial direction in a Multiple-Input Multiple-Output (MIMO) channel. Due to its simplicity, beamforming is usually seen sensitive to inaccuracies of the Channel State Information at the Transmitter (CSIT). In this paper, the authors investigate the robustness of beamforming with respect...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Feb 2011

    Magneto-Inductive Underground Communications in a District Heating System

    Feasibility of underground data communications is investigated by employing magnetic induction as the key technology at physical layer. Realizing an underground wireless sensor network for a district heating plant motivates this research problem. This paper is to find the optimal design for transmitter and receiver coil antennas, assuming predefined wire...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // May 2011

    MIMO Channel Modeling and Transmission Techniques for Multi-Satellite and Hybrid Satellite-Terrestrial Mobile Networks

    The Quality of Service (QoS) in Land Mobile Satellite (LMS) communications drops drastically in the presence of shadowing and multipath fading. This paper studies two promising Multiple-Input Multiple-Output (MIMO) schemes, along with specific transmission techniques, aimed at overcoming this problem. First, specific proposals for a dual-satellite distributed MIMO scheme are...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Oct 2011

    Multicriteria Beamforming in MISO Interference Networks

    The authors investigate the optimal solutions of the MISO interference and weighted wiretap channels. This is done via reformulating the problems within the framework of Multicriteria Optimization. They show that all optimal points are in fact solutions of two different MOP. Indeed, they establish that and are two different scalarization...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Jul 2011

    Network Coding-Based Cooperative ARQ Scheme

    In this paper, the authors introduce a novel Automatic Repeat reQuest (ARQ) scheme for cooperative wireless networks. Their scheme adopts network coding techniques in order to enhance the total bandwidth of the network by minimizing the total number of transmissions. The performance of the proposed approach is evaluated by means...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // May 2011

    Preemption and QoS Management Algorithms for Coordinated and Uncoordinated Base Stations

    This paper addresses the problem of resource allocation and Quality of Service (QoS) management in a downlink communication system where the users are allowed to be attached to and receive data from one or several cooperating Base Stations (BSs) under Orthogonal Frequency Division Multiple Access (OFDMA). Under the assumption that...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Apr 2011

    Requirements and Enhancements for the Evolution of the GMPLS Control Plane of the ADRENALINE Testbed to Support Multi-Layer (MPLS-TP/WSON) Capabilities

    The demand for a higher transport capacity along with the appearance of new packet-based services (e.g., IPTV) is imposing strong requirements on current telecom networks. In the current transport network architecture, IP is the dominant convergence layer used to aggregate packet services. The growth on the bandwidth requirements leads to...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Mar 2011

    Robust Linear Precoding for MSE Minimization in MIMO Broadcast Systems With Channel Gram Matrix Feedback

    In this paper, the authors deal with a Multiple-Input Multiple-Output (MIMO) multiuser Broadcast Channel (BC) featuring linear precoding at the transmitter. The design of such precoder is performed according to the Channel State Information (CSI) sent by the different users through parallel feedback links. A general feedback framework based on...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Jul 2011

    Secure Lossless Aggregation Over Fading & Shadowing Channels for Smart Grid M2M Networks

    Whilst security is generally perceived as an important constituent of communication systems, this paper offers a viable security-communication-tradeoff particularly tailored to smart grids. These systems, often composed of embedded nodes with highly constrained resources, require e.g., metering data to be delivered efficiently whilst neither jeopardizing communication nor security. Data aggregation...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Jul 2011

    On the Impact of Shadowing on the Performance of Cooperative Medium Access Control Protocols

    Accurate representation of the physical layer is instrumental for a sound design and optimization of Medium Access Control (MAC) protocols for cooperative wireless networks. However, the vast majority of MAC protocols are designed and analyzed by considering simplified physical layer and channel models, which often lead to too optimistic performance...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Jun 2011

    Prototyping With SDR: A Quick Way to Play With Next-Gen Communications Systems

    In the past, real-world prototyping of communication systems were not very common due to high financial costs and long development times derived from the use of dedicated HardWare (HW) such as Field Programmable Gate Arrays (FPGA), Application Specific Integrated Circuits (ASICs) and Digital Signal Processors (DSPs). Nonetheless, this implementation is...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Sep 2011

    Real-Time Broadcasting Over Block-Fading Channels

    Broadcast transmission from a Base Station (BS) to a group of users is studied. It is assumed that the BS receives data at a constant rate and tries to broadcast these messages to the whole set of users within a certain deadline. The channels are assumed to be block fading...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Sep 2011

    Recent Advances in Reconfigurable Microwave Filters

    In today?s communication systems the demand for tunable filters with high performance and with independent control of the filter parameters has been growing. In this paper an overview of several tunable filters that have been proposed over the last years is presented, focused on recent developments involving independent frequency, bandwidth...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Nov 2011

    Source-Channel Coding for the Multiple-Access Relay Channel

    This paper considers reliable transmission of general correlated sources over the Multiple-Access Relay Channel (MARC) and the Multiple-Access Broadcast Relay Channel (MABRC). In MARCs only the destination is interested in a reconstruction of the sources, while in MABRCs both the relay and the destination want to reconstruct the sources. The...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Sep 2011

    Use of Turbo Codes With Low-Rate Convolutional Constituent Codes in Fingerprinting Scenarios

    The authors discuss the use of turbo codes in fingerprinting schemes. More precisely, they present a family of turbo codes that are secure against attacking coalitions of size 2. This family is build upon a class of low-rate convolutional codes with maximum free distance. Low rate convolutional codes are commonly...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Oct 2011

    Yet Another Entropy Power Inequality With an Application

    In this paper, the authors derive a generalization of the vector Entropy Power Inequality (EPI) recently put forth in, which was valid only for diagonal matrices, to the full matrix case. Next, they study the problem of computing the linear precoder that maximizes the mutual information in linear vector Gaussian...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Jul 2011

    A Dynamic Path Computation Algorithm for E2e Dedicated Protection in a GMPLS Controlled Multilayer (Ethernet/WSON) Network

    In this paper, the authors focus on end-to-end (e2e) 1+1 dedicated path protection in a Connection-Oriented (CO) Ethernet over Wavelength Switched Optical Network (WSON) controlled by a unified GMPLS control plane. They propose a multi-layer protection scheme in which a path computation algorithm for both, working and protecting path is...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Jul 2011

    Distributed Point Coordination Function for IEEE 802.11 Wireless Ad Hoc Networks

    The Distributed Point Coordination Function (DPCF) is presented in this paper as a novel Medium Access Control Protocol (MAC) for wireless ad hoc networks. DPCF extends the operation of the Point Coordination Function (PCF) defined in the IEEE 802.11 Standard to operate over wireless networks without infrastructure. In PCF, a...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Jul 2011

    Femtocell Systems With Self Organization Capabilities

    In this paper, the authors present a self-organization technique to manage interference in femtocell networks. They model femtocells as a multiagent system implementing a form of Reinforcement Learning (RL) known as Q-Learning (QL) to solve the aggregated interference problem originated due to the macro-femtocell systems coexistence. They discuss this approach...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Jan 2012

    Small Cells, Wireless Backhaul and Renewable Energy: A Solution for Disaster Aftermath Communications

    In this paper, the authors propose a network infrastructure to be deployed in the aftermath of a disaster with the aim of providing communication services to both emergency responders and civilians. The proposed infrastructure is a Network of Small Cells powered by renewable energy that features an all-wireless multi-hop backhaul...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Jul 2011

    SWAP Project: Beyond the State of the Art on Harvested Energy-Powered Wireless Sensors Platform Design

    The main goal of the SWAP project is that of designing, implementing and ultimately testing a new breed of wireless sensor nodes with energy scavenging capabilities. The authors' design will include novel energy scavenging hardware as well as network protocols and algorithms. In this paper, they summarize the outcomes of...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Aug 2011

    VITRO Architecture: Bringing Virtualization to WSN World

    This paper presents the architecture of the VITRO system concept developed under the VITRO project for the realization of Virtual Sensor Networks. The aim of the proposed architecture is to enable the realization of scalable, flexible, adaptive, energy-efficient and trust-aware Virtual Sensor Network platforms, focusing on the reduction of deployment...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Oct 2011

    Antenna Array Based GNSS Signal Acquisition: Real-Time Implementation and Results

    The use of Global Navigation Satellite System (GNSS) technology in safety- and mission-critical services has raised the concern in recent times about possible GNSS Denial of Service (DoS) situations. In that sense, the GNSS vulnerability to interferences could become a real threat to the entire service integrity. In this paper,...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Jun 2011

    Characterizing WLAN Medium Utilization for Radio Environment Maps

    This paper explores the possibility to use the medium utilization as a metric to be included in Radio Environment Maps (REMs) of WLAN networks. The main objective is to build REMs that go beyond the spectrum use and that can be used to improve deployment and operation of WLANs. Specifically,...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Apr 2011

    Dynamic Distributed Spectrum Allocation in GMPLS Controlled Elastic Optical Networks

    The authors propose and experimentally evaluate a distributed spectrum assignment approach for GMPLS-controlled elastic networks based on collecting the frequency slot availability information during the signaling phase and performing efficient spectrum allocation at the destination node. Current Wavelength Switched Optical Networks (WSON) are based on a fixed ITU-T DWDM wavelength...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Jan 2012

    Experimental Evaluation of a Full-Meshed Domain Abstraction Design Model for Reduced State Information Dissemination in Multi-Domain PCE-Based WSONs

    A novel full-meshed domain abstraction model for scalable state information in PCE-based WSONs is presented. The authors experimentally evaluate the state information update reduction and the blocking improvement with regard to a shortest path model. The hierarchical Path Computation Element (PCE) architecture has arisen as the leading standard for inter-domain...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Apr 2011

    Experimental Investigation of PCE-Based Path Computation for OSNR-Aware Dynamic Restoration in GMPLS-Enabled Multi-Domain Translucent WSON

    The authors experimentally demonstrate PCE-based path computation for OSNR-aware dynamic restoration in GMPLS-enabled multi-domain translucent WSON, assessing the overall feasibility and quantitatively evaluating the service disruption time and path computation latency during end-to-end lightpath restoration. Translucent Wavelength Switched Optical Networks (WSON), with sparse 3R regenerators to alleviate the Wavelength Continuity...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Aug 2011

    GNSS-SDR: An Open Source Tool for Researchers and Developers

    This paper introduces GNSS-SDR, an open source Global Navigation Satellite System software-defined receiver. The lack of reconfigurability of current commercial-of-the-shelf receivers and the advent of new radionavigation signals and systems make software receivers an appealing approach to design new architectures and signal processing algorithms. With the aim of exploring the...

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)

  • White Papers // Oct 2011

    MAC Protocols With Cross-Layer Design

    The proliferation of wireless and mobile networking and the increased demand for higher performance requirements has leveraged the need for more flexibility in network design. A promising way to achieve this is through the collaboration between the various layers of the protocol stack, a trend known as Cross-Layer (CL) design....

    Provided By Centre Tecnològic de Telecomunicacions de Catalunya (CTTC)