EURECOM

Displaying 41-80 of 118 results

  • White Papers // Apr 2012

    PRICE: PRivacy preserving Incentives for Cooperation Enforcement

    Many incentive mechanisms have been proposed to foster cooperation among nodes in Peer-To-Peer (P2P) networks. Unfortunately, most of existing solutions rely on the existence of an online centralized authority that is in charge of a fair distribution and transaction of credits (incentives) between peers. Such centralized mechanisms mainly suffer from...

    Provided By EURECOM

  • White Papers // Apr 2012

    Broker-Based Private Matching

    Private matching solutions allow two parties to find common data elements over their own datasets without revealing any additional private information. The authors propose a new concept involving an intermediate entity in the private matching process: they consider the problem of broker-based private matching where end-entities do not interact with...

    Provided By EURECOM

  • White Papers // Apr 2012

    Secure Automotive On-Board Protocols: A Case of Over-the-Air Firmware Updates

    The software running on electronic devices is regularly up-dated, these days. A vehicle consists of many such devices, but is operated in a completely different manner than consumer devices. Update operations are safety critical in the automotive domain. Thus, they demand for a very well secured process. The authors propose...

    Provided By EURECOM

  • White Papers // Apr 2012

    Security Vulnerabilities Detection and Protection Using Eclipse

    After a decade of existence, still, Cross-site scripting, SQL Injection and other of Input validation associated security vulnerabilities can cause severe damage once exploited. To analyze this fact, conducted an empirical study, while OWASP and SANS defined their respective risk-based approaches. Taking these results into consideration, three deficiencies can be...

    Provided By EURECOM

  • White Papers // Apr 2012

    Robust Data Sharing with Key-Value Stores

    A Key-Value Store (KVS) offers functions for storing and retrieving values associated with unique keys. KVSs have become the most popular way to access Internetscale \"Cloud\" storage systems. The authors present an efficient wait-free algorithm that emulates multi-reader multi-writer storage from a set of potentially faulty KVS replicas in an...

    Provided By EURECOM

  • White Papers // Mar 2012

    On the Vulnerability of Automatic Speaker Recognition to Spoofing Attacks With Artificial Signals

    Automatic Speaker Verification (ASV) systems are increasingly being used for biometric authentication even if their vulnerability to imposture or spoofing is now widely acknowledged. Recent work has proposed different spoofing approaches which can be used to test vulnerabilities. This paper introduces a new approach based on artificial, tone-like signals which...

    Provided By EURECOM

  • White Papers // Mar 2012

    HiPoLDS: A Security Policy Language for Distributed Systems

    Expressing security policies to govern distributed systems is a complex and error-prone task. Policies are hard to understand, often expressed with unfriendly syntax, making it difficult to security administrators and to business analysts to create intelligible specifications. The authors introduce the Hierarchical Policy Language for Distributed Systems (HiPoLDS). HiPoLDS has...

    Provided By EURECOM

  • White Papers // Mar 2012

    Large System Analysis of Zero-Forcing Precoding in MISO Broadcast Channels With Limited Feedback

    In this paper, the authors analyze the sum rate of Zero-Forcing (ZF) precoding in MISO broadcast channels with limited feedback, transmit correlation and path loss. Their analysis assumes that the number of transmit antennas M and the number of users K are large, while their ratio remains bounded. By applying...

    Provided By EURECOM

  • White Papers // Feb 2012

    A Practical Precoding Scheme for Multicell MIMO Channels With Partial User's Data Sharing

    In this paper, the authors consider a setting where K Transmitters (TXs) equipped with multiple antennas aim at transmitting to their K respective Receivers (RXs) also equipped with multiple antennas. Without exchange of the user's data symbols, this represents a conventional Interference Channel (IC), while it is a so-called MIMO...

    Provided By EURECOM

  • White Papers // Feb 2012

    Spectrum Sensing for Cognitive Radio Exploiting Spectrum Discontinuities Detection

    This paper presents a spectrum sensing algorithm for wideband cognitive radio exploiting sensed spectrum discontinuity properties. Some work has already been investigated by wavelet approach by Giannakis et al, but in this paper the authors investigate an algebraic framework in order to model spectrum discontinuities. The information derived at the...

    Provided By EURECOM

  • White Papers // Feb 2012

    Game Theory-Based Resource Management Strategy for Cognitive Radio Networks

    This paper investigates the application of game theory tools in the context of Cognitive Radio Networks (CRN). Specifically, the authors propose a resource management strategy with the objective to maximize a defined utility function subject to minimize the mutual interference caused by Secondary Users (SUs) with protection for Primary Users...

    Provided By EURECOM

  • White Papers // Feb 2012

    Regional Confidence Score Assessment for 3D Face

    3D shape data for face recognition is advantageous to its 2D counterpart for being invariant to illumination and pose. However, expression variations and occlusions still remain as major challenges since the shape distortions hinder accurate matching. Numerous algorithms developed to overcome this problem mainly propose region-based approaches, where similarity scores...

    Provided By EURECOM

  • White Papers // Feb 2012

    Link Abstraction for Multi-User MIMO in LTE Using Interference-Aware Receiver

    Most of the recent wireless communication systems are interference limited rather than noise limited. In the case of a very strong interferer the conventional assumption of the interference as Gaussian is extremely suboptimal. However, optimal (capacity achieving) receivers utilize some prior knowledge about the interference to reach optimality. The link...

    Provided By EURECOM

  • White Papers // Jan 2012

    Outage Performance of Double Stratospheric Platforms Diversity Systems

    High Altitude Platform Networks (HAPNs) comprise an emerging communication solution promising to exploit many of the best aspects of terrestrial and satellite-based systems. Nevertheless, while offering advantageous propagation characteristics, HAP networks are still subject to large fades due to atmospheric precipitation and especially due to rain, for the allocated high...

    Provided By EURECOM

  • White Papers // Jan 2012

    Sparse Precoding in Multicell MIMO Systems

    In this paper, the authors consider the joint precoding across K distant Transmitters (TXs) towards K single-antenna Receivers (RXs) and they let the TXs have access to perfect Channel State Information (CSI). Instead of considering the conventional method of clustering to allocate the user's data symbols, they focus on determining...

    Provided By EURECOM

  • White Papers // Jan 2012

    Redundancy Management for P2P Backup

    The authors propose a redundancy management mechanism for peer-to-peer backup applications. Since, in a backup system, data is read over the network only during restore processes caused by data loss, redundancy management targets data durability rather than attempting to make each piece of information available at any time. Each peer...

    Provided By EURECOM

  • White Papers // Jan 2012

    Distributed Troubleshooting of Web Sessions Using Clustering

    Web browsing is a very common way of using the Internet to, among others, read news, do on-line shopping, or search for user generated content such as YouTube or Dailymotion. Traditional evaluations of web surfing focus on objectively measured Quality of Service (QoS) metrics such as loss rate or round-trip...

    Provided By EURECOM

  • White Papers // Jan 2012

    Interference Relay Channel in 4G Wireless Networks

    In the next generation cellular systems, such as LTE-A (Release 10 and beyond), Relay Node (RN) deployment has been adopted due to its potentials in enlarging coverage and increasing system throughput, even with primitive relaying functionalities. For example, in LTE-A Release 10 only Type-I (non-transparent) RNs are considered wherein no...

    Provided By EURECOM

  • White Papers // Jan 2012

    Retrospective Interference Alignment for Interference Channels With Delayed Feedback

    The capacity of the most recent network architectures, such as femtocells, is severely limited by interference. This has spurred an intense research on the M-user interference channel, in which M transmitter/receiver pairs interfere with each other. Very striking recent results, though, disproved it by showing that the degrees of freedom...

    Provided By EURECOM

  • White Papers // Jan 2012

    3D Face Recognition: A Robust Multi-Matcher Approach to Data Degradations

    Over the past decades, 3D face has emerged as a solution to face recognition due to its reputed invariance to lighting conditions and pose. While proposed approaches have proven their efficiency over renowned databases as FRGC, less effort was spent on studying the robustness of algorithms to quality degradations. In...

    Provided By EURECOM

  • White Papers // Jan 2012

    Moving Face Spoofing Detection Via 3D Projective Invariants

    Face recognition provides many advantages compared with other available biometrics, but it is particularly subject to spoofing. The most accurate methods in literature addressing this problem, rely on the estimation of the three-dimensionality of faces, which heavily increase the whole cost of the system. This paper proposes an effective and...

    Provided By EURECOM

  • White Papers // Dec 2011

    CHECKER: On-Site Checking in RFID-Based Supply Chains

    Counterfeit detection in RFID-based supply chains aims at preventing adversaries from injecting fake products that do not meet quality standards. This paper introduces CHECKER, a new protocol for counterfeit detection in RFID-based supply chains through on-site checking. While RFID-equipped products travel through the supply chain, RFID readers can verify product...

    Provided By EURECOM

  • White Papers // Nov 2011

    High Throughput and Low Power Enhancements for LDPC Decoders

    Modern VLSI decoders for Low-Density ParityCheck (LDPC) codes require high throughput performance while achieving high energy efficiency on the smallest possible footprint. In this paper, the authors present two optimizations to enhance the throughput and reduce the power consumption for these decoders. As a first optimization, they seek to speedup...

    Provided By EURECOM

  • White Papers // Oct 2011

    Combined Compressive Sampling and Distribution Discontinuities Detection Approach to Wideband Spectrum Sensing for Cognitive Radios

    This paper presents a new sensing technique for cognitive radio systems which combines algebraic tools and compressive sampling techniques. The proposed approach consists of the detection of spectrum holes using spectrum distribution discontinuities detector fed by a compressed measurements. The compressed sensing algorithm is designed to take advantage from the...

    Provided By EURECOM

  • White Papers // Sep 2011

    SINR Balancing and Beamforming for the MISO Interference Channel

    In this paper a K user Multi-Input Single-Output (MISO) InterFerence Channel (IFC) is considered where the interference at each receiver is treated as an additional Gaussian noise contribution (Noisy IFC). The authors address the MISO DownLink (DL) beamformer design and power allocation for maximizing the minimum SINR with per base...

    Provided By EURECOM

  • White Papers // Sep 2011

    Spectrum Sensing for Cognitive Radio Exploiting Spectral Masks

    In this paper, the authors will provide a straightforward look at semi blind spectrum sensing technique exploiting spectral masks. The proposed spectrum sensing technique is deployed on two stages. At a first level, the spectral masks database is built during the synchronization phase of the transmission, then in a second...

    Provided By EURECOM

  • White Papers // Sep 2011

    On Optimum End-to-End Distortion in Delay-Constrained Wideband MIMO Systems

    In this paper, the authors analyze the optimum expected End-to-End Distortion (EED) in delay-constrained wide-band Multiple-Input Mulitple-Output (MIMO) systems. They prove that the existence of frequency diversity benefits the EED in delay-constrained systems though it does not impact the ergodic channel capacity. For further analysis, they derive the closed-form expression...

    Provided By EURECOM

  • White Papers // Aug 2011

    The Multiplexing Gain of the Network MIMO Channel With Distributed CSI

    In this paper, the authors discuss the joint precoding across K transmitters (TXs), sharing the knowledge of the data symbols to be transmitted toward K single-antenna receivers (RXs). They introduce a Distributed Channel State Information (DCSI) configuration where each TX has its own local estimate of the overall multiuser MIMO...

    Provided By EURECOM

  • White Papers // Aug 2011

    Two Parallel Approaches to Network Data Analysis

    In this paper, the authors compare two alternative approaches to large-scale analytic applications. They focus on network data analysis and de ne four sample Jobs that operate over a publicly available dataset of a trans-Pacific Internet link. First, they present an approach based on a shared-nothing parallel database and discuss...

    Provided By EURECOM

  • White Papers // Jul 2011

    An Empirical Study of Availability in Friend-to-Friend Storage Systems

    Friend-to-friend networks, i.e. peer-to-peer networks where data are exchanged and stored solely through nodes owned by trusted users, can guarantee dependability, privacy and uncensorability by exploiting social trust. However, the limitation of storing data only on friends can come to the detriment of data availability: if no friends are online,...

    Provided By EURECOM

  • White Papers // Jul 2011

    Wireless Access Mechanisms and Architecture Definition in the MEDIEVAL Project

    Wireless network access and the exchange of multimedia flows over the Internet are becoming more and more pervasive in the everyday life. However, simple technological advances in terms of improved network capacity cannot satisfy the increasing demand of such services, since a paradigm shift from the current Internet architecture is...

    Provided By EURECOM

  • White Papers // Jun 2011

    Sensor Network Aided Agile Spectrum Access Through Low-Latency Multi-Band Communications

    Dynamic spectrum access supported by a low-latency wireless sensor network for spectrum usage monitoring is demonstrated using OpenAirInterface platform. The platform performs secondary communications in bands detected as free, thanks to its multi-band capability. With respect to application scenarios, the main target is to address agile broadband public safety communications....

    Provided By EURECOM

  • White Papers // Jun 2011

    Interference Mitigation in Femto-Macro Coexistence With Two-Way Relay Channel

    Motivated by the femtocell networks where crosstier interference management is crucial to achieve higher system throughput, the authors consider a basic interference model consisting of a MIMO two-way relay communication network in presence of a one-way point-to-point MIMO communication link. They propose an upper-bound on the maximum degrees of freedom...

    Provided By EURECOM

  • White Papers // Jun 2011

    Hash-and-Forward Relaying for Two-Way Relay Channel

    This paper considers a communication network comprised of two nodes, which have no mutual direct communication links, communicating two-way with the aid of a common Relay Node (RN), also known as separated Two-Way Relay (TWR) channel. The authors first recall a cut-set outer bound for the set of rates in...

    Provided By EURECOM

  • White Papers // May 2011

    Interference-Aware Receiver Structure for Multi-User MIMO and LTE

    In this paper, the authors propose a novel low-complexity interference-aware receiver structure for multi-user MIMO which is based on the exploitation of the structure of residual interference. They show that multi-user MIMO can deliver its promised gains in modern wireless systems in spite of the limited CSIT only if users...

    Provided By EURECOM

  • White Papers // Apr 2011

    Performance of LTE in Rural Areas - Benefits of Opportunistic Multi-User MIMO

    This paper focuses on the performance of LTE in rural areas which is based on a channel measurement campaign conducted with the Eurecom OpenAirInterface LTE testbed at 800MHz. This testbed is based on LTE release 8 PHY layer and implements transmission modes 1 (single antenna - SISO), 2 (transmit diversity),...

    Provided By EURECOM

  • White Papers // Apr 2011

    Near Capacity Linear Closed Form Precoders Design With Recursive Stream Selection for MU-MIMO Broadcast Channels

    This paper proposes a novel Closed Form (CF) precoders design for Multi-User Multiple Input Multiple Output Broadcast Channel (MU-MIMO BC). The proposed algorithm constructs stream-wisely the precoders in a recursive manner. It consists in two steps: The first step is a recursive selection of the best streams minimizing the interference...

    Provided By EURECOM

  • White Papers // Apr 2011

    Smart Hybrid-ARQ (SHARQ) for Cooperative Communication Via Distributed Relays in LTE-Advanced

    The work described in this paper proposes two Smart Hybrid-Automatic Repeat ReQuest (SHARQ) schemes with incremental redundancy, that are developed for a dual-hop network of two relays implementing cooperative communication. In a dual-hop network consisting of multiple relays, one of the most challenging tasks is to determine an appropriate trade-off...

    Provided By EURECOM

  • White Papers // Feb 2011

    Interference Sensitivity for Multi-User MIMO in LTE

    A recent idea of exploiting the promised gains of multi-user MIMO for future cellular standards as LTE by intelligent interference aware receivers instead of suboptimal single-user receivers is quite promising. However this detection strategy is based on the exploitation of the structure of interference which necessitates the knowledge of the...

    Provided By EURECOM

  • White Papers // Feb 2011

    The Multiplexing Gain of a Two-Cell MIMO Channel With Unequal CSI

    In this paper, the joint precoding across two distant transmitters (TXs) to two receivers (RXs), each equipped with one antenna is discussed. The authors consider a distributed Channel State Information (CSI) configuration where each TX has a separate local estimate of the channel. The authors assume that no communication is...

    Provided By EURECOM

  • White Papers // Mar 2012

    On the Vulnerability of Automatic Speaker Recognition to Spoofing Attacks With Artificial Signals

    Automatic Speaker Verification (ASV) systems are increasingly being used for biometric authentication even if their vulnerability to imposture or spoofing is now widely acknowledged. Recent work has proposed different spoofing approaches which can be used to test vulnerabilities. This paper introduces a new approach based on artificial, tone-like signals which...

    Provided By EURECOM

  • White Papers // Jan 2012

    Outage Performance of Double Stratospheric Platforms Diversity Systems

    High Altitude Platform Networks (HAPNs) comprise an emerging communication solution promising to exploit many of the best aspects of terrestrial and satellite-based systems. Nevertheless, while offering advantageous propagation characteristics, HAP networks are still subject to large fades due to atmospheric precipitation and especially due to rain, for the allocated high...

    Provided By EURECOM

  • White Papers // Feb 2012

    Regional Confidence Score Assessment for 3D Face

    3D shape data for face recognition is advantageous to its 2D counterpart for being invariant to illumination and pose. However, expression variations and occlusions still remain as major challenges since the shape distortions hinder accurate matching. Numerous algorithms developed to overcome this problem mainly propose region-based approaches, where similarity scores...

    Provided By EURECOM

  • White Papers // Jan 2012

    Redundancy Management for P2P Backup

    The authors propose a redundancy management mechanism for peer-to-peer backup applications. Since, in a backup system, data is read over the network only during restore processes caused by data loss, redundancy management targets data durability rather than attempting to make each piece of information available at any time. Each peer...

    Provided By EURECOM

  • White Papers // Jan 2012

    Distributed Troubleshooting of Web Sessions Using Clustering

    Web browsing is a very common way of using the Internet to, among others, read news, do on-line shopping, or search for user generated content such as YouTube or Dailymotion. Traditional evaluations of web surfing focus on objectively measured Quality of Service (QoS) metrics such as loss rate or round-trip...

    Provided By EURECOM

  • White Papers // Feb 2012

    Spectrum Sensing for Cognitive Radio Exploiting Spectrum Discontinuities Detection

    This paper presents a spectrum sensing algorithm for wideband cognitive radio exploiting sensed spectrum discontinuity properties. Some work has already been investigated by wavelet approach by Giannakis et al, but in this paper the authors investigate an algebraic framework in order to model spectrum discontinuities. The information derived at the...

    Provided By EURECOM

  • White Papers // Feb 2012

    Game Theory-Based Resource Management Strategy for Cognitive Radio Networks

    This paper investigates the application of game theory tools in the context of Cognitive Radio Networks (CRN). Specifically, the authors propose a resource management strategy with the objective to maximize a defined utility function subject to minimize the mutual interference caused by Secondary Users (SUs) with protection for Primary Users...

    Provided By EURECOM

  • White Papers // Mar 2012

    Large System Analysis of Zero-Forcing Precoding in MISO Broadcast Channels With Limited Feedback

    In this paper, the authors analyze the sum rate of Zero-Forcing (ZF) precoding in MISO broadcast channels with limited feedback, transmit correlation and path loss. Their analysis assumes that the number of transmit antennas M and the number of users K are large, while their ratio remains bounded. By applying...

    Provided By EURECOM

  • White Papers // Feb 2011

    Deterministic Equivalent for the SINR of Regularized Zero-Forcing Precoding in Correlated MISO Broadcast Channels With Imperfect CSIT

    This paper considers the MISO broadcast channel with different spatial correlations of the user vector channels. The base station implements Regularized Zero-Forcing (RZF) precoding based on an imperfect channel estimation. The authors derive a deterministic equivalent of the Signal-to-Interference plus Noise Ratio (SINR) by applying novel results from the field...

    Provided By EURECOM

  • White Papers // Jan 2011

    Asymptotic Analysis of Regularized Zero-Forcing Precoding in MISO Broadcast Channels With Limited Feedback

    In this paper, the authors analyze the asymptotic sum-rate of Regularized Zero-Forcing (RZF) precoding in MISO broadcast channels with limited feedback, transmit correlation and path-loss. Their analysis assumes that the ratio of the number of transmit antennas M to the number of users K is bounded as (K;M) grow large....

    Provided By EURECOM

  • White Papers // Nov 2011

    High Throughput and Low Power Enhancements for LDPC Decoders

    Modern VLSI decoders for Low-Density ParityCheck (LDPC) codes require high throughput performance while achieving high energy efficiency on the smallest possible footprint. In this paper, the authors present two optimizations to enhance the throughput and reduce the power consumption for these decoders. As a first optimization, they seek to speedup...

    Provided By EURECOM

  • White Papers // May 2011

    Interference-Aware Receiver Structure for Multi-User MIMO and LTE

    In this paper, the authors propose a novel low-complexity interference-aware receiver structure for multi-user MIMO which is based on the exploitation of the structure of residual interference. They show that multi-user MIMO can deliver its promised gains in modern wireless systems in spite of the limited CSIT only if users...

    Provided By EURECOM

  • White Papers // Dec 2010

    Hardware Optimized Sample Rate Conversion for Software Defined Radio

    The evolution towards applications with increasing functionalities leads to the need of high flexible systems that support a high number of different standards while decreasing the required hardware space. Therefore, a high configurable platform being able to handle a multitude of standards is needed. One main issue is the tradeoff...

    Provided By EURECOM

  • White Papers // Sep 2010

    A Scalable Interest-Oriented Peer-to-Peer Pub/Sub Network

    There has been a big challenge in structured peer-to-peer overlay network research area. Generally, a structured overlay network involves nodes evenly or based on their resource availabilities, and gathers nodes' resources to achieve some bigger tasks. The challenge here is to gather resources based on nodes' interests, and only interested...

    Provided By EURECOM

  • White Papers // Nov 2010

    Bag of Soft Biometrics for Person Identification New Trends and Challenges

    In this paper, the authors seek to provide insight on the general topic of soft biometrics. They firstly present a new refined definition of soft biometrics, emphasizing on the aspect of human compliance, and then proceed to identify candidate traits that accept this novel definition. They, then address relations between...

    Provided By EURECOM

  • White Papers // Apr 2009

    Hierarchical Codes: A Flexible Trade-Off for Erasure Codes in Peer-to-Peer Storage Systems

    Redundancy is the basic technique to provide reliability in storage systems consisting of multiple components. A redundancy scheme defines how the redundant data are produced and maintained. The simplest redundancy scheme is replication, which however suffers from storage inefficiency. Another approach is erasure coding, which provides the same level of...

    Provided By EURECOM

  • White Papers // Jul 2009

    Analysis of User-Driven Peer Selection in Peer-to-Peer Backup and Storage Systems

    In this paper, the authors present a model of peer-to-peer backup and storage systems in which users have the ability to selfishly select remote peers they want to exchange data with. In their work, peer characteristics (e.g., on-line availability and dedicated bandwidth) play an important role and are reflected in...

    Provided By EURECOM

  • White Papers // Apr 2010

    Honeybot, Your Man in the Middle for Automated Social Engineering

    Automated social engineering poses a serious information security threat to human communications on the Internet since the attacks can easily scale to a large number of victims. The authors present a new attack that instruments human conversations for social engineering, or spamming. The detection rate is low, which becomes manifest...

    Provided By EURECOM

  • White Papers // Sep 2008

    Large Scale Malware Collection: Lessons Learned

    In order to assure accuracy and realism of resilience assessment methods and tools, it is essential to have access to field data that are unbiased and representative. Several initiatives are taking place that offer access to malware samples for research purposes. Papers are published where techniques have been assessed thanks...

    Provided By EURECOM

  • White Papers // Aug 2011

    Two Parallel Approaches to Network Data Analysis

    In this paper, the authors compare two alternative approaches to large-scale analytic applications. They focus on network data analysis and de ne four sample Jobs that operate over a publicly available dataset of a trans-Pacific Internet link. First, they present an approach based on a shared-nothing parallel database and discuss...

    Provided By EURECOM

  • White Papers // Feb 2010

    Password Strength: An Empirical Analysis

    It is a well known fact that user-chosen passwords are somewhat predictable: by using tools such as dictionaries or probabilistic models, attackers and password recovery tools can drastically reduce the number of attempts needed to guess a password. Quite surprisingly, however, existing literature does not provide a satisfying answer to...

    Provided By EURECOM

  • White Papers // Jan 2009

    Optimally DoS Resistant P2P Topologies for Live Multimedia Streaming

    Using a peer-to-peer approach for live multimedia streaming applications offers the promise to obtain a highly scalable, decentralized and robust distribution service. When constructing streaming topologies, however, specific care has to be taken in order to ensure that quality of service requirements in terms of delay, jitter, packet-loss and stability...

    Provided By EURECOM

  • White Papers // Jun 2009

    On the Characterization of MU-MIMO Channels

    In this paper, the authors study the divergence of different links in wide-band Multi-User Multiple-Input Multiple-Output (MUMIMO) channels. The divergence is measured on several levels: spatial separation of the user's correlation matrices, co-linearity of the MIMO channel matrices, and correlation of large scale fading. The measurement data has been acquired...

    Provided By EURECOM

  • White Papers // Oct 2008

    Long Term Study of Peer Behavior in the KAD DHT

    Distributed Hash Tables (DHTs) have been actively studied in literature and many different proposals have been made on how to organize peers in a DHT. However, very few DHTs have been implemented in real systems and deployed on a large scale. One exception is KAD, a DHT based on Kademlia,...

    Provided By EURECOM

  • White Papers // Oct 2010

    Comparison Between Viterbi Detectors for Magnetic Recording Channels, Based on Regressive and Autoregressive Noise Models

    A recent work presents a regressive noise model for the data-dependent correlated noise, at the output of a magnetic recording channel detector. This paper generalizes this channel model, considering digital equalization and a more efficient correlation matrix, in order to make a comparison with the usual detector in a more...

    Provided By EURECOM

  • White Papers // Jun 2012

    Android Stack Integration in Embedded Systems

    Smartphone usage has increased manifold upon introduction of Google's Android. Since its introduction, Android has evolved at an outstanding pace in terms of application development, commercialization and market share of Android powered devices. Although originally developed for Smartphones, now the embedded system industry has realized the capabilities of Android. Due...

    Provided By EURECOM

  • White Papers // Sep 2010

    Beamforming for the Underlay Cognitive MISO Interference Channel Via UL-DL Duality

    SINR duality is shown in a Multi-Input Single-Output (MISO) DownLink (DL) InterFerence Channel (IFC) and its UpLink (UL) Single-Input Multi-Output (SIMO) dual with linear Transmit (Tx) BeamFormers (BF). While UL-DL duality under the sum power constraint is well-established between the Broadcast Channel (BC) for the SINR balancing (max min SINR)...

    Provided By EURECOM

  • White Papers // Sep 2010

    Distribution Discontinuities Detection Using Algebraic Technique for Spectrum Sensing in Cognitive Radio

    In this paper, the authors propose a new Spectrum Sensing technique for spectrum distribution discontinuities detection using Algebraic Detection (AD). The presented mathematical background leading to such technique is based on operational calculus and differential algebra which offers a new stand point in sensing theory. Even if this background is...

    Provided By EURECOM

  • White Papers // May 2012

    CSI Feedback Allocation in Multicell MIMO Channels

    In this paper, the authors consider the joint pre-coding across K Transmitters (TXs), sharing the knowledge of the user's data symbols being transmitted to K single-antenna Receivers (RXs). They consider a Distributed Channel State Information (DCSI) configuration where each TX has its own local estimate of the overall multiuser MIMO...

    Provided By EURECOM

  • White Papers // May 2012

    On Enhancing Inter-User Spatial Separation for Downlink Multiuser MIMO Systems

    In practical downlink multiuser MIMO channels, users' channels are non-orthogonal, which results in inter-user interference and in turn degrades system performance. In this paper, a new subspace-domain linear transmit preprocessing technique is proposed in enhancing users' spatial separation and suppressing inter-user interference. The authors show by simulations that sum rate...

    Provided By EURECOM

  • White Papers // Feb 2011

    Mixed CSIT DL Channel: Gains with Interference Aware Receivers

    The Broadcast Channels (BC), a single transmitter transmitting data to multiple receivers, has been widely studied in literature mostly with and sometimes without the availability of Channel State Information at the Transmitter (CSIT). The authors study a very practical version of the BC where the transmitter has CSIT of some...

    Provided By EURECOM

  • White Papers // Feb 2011

    Interference Sensitivity for Multi-User MIMO in LTE

    A recent idea of exploiting the promised gains of multi-user MIMO for future cellular standards as LTE by intelligent interference aware receivers instead of suboptimal single-user receivers is quite promising. However this detection strategy is based on the exploitation of the structure of interference which necessitates the knowledge of the...

    Provided By EURECOM

  • White Papers // Apr 2011

    Performance of LTE in Rural Areas - Benefits of Opportunistic Multi-User MIMO

    This paper focuses on the performance of LTE in rural areas which is based on a channel measurement campaign conducted with the Eurecom OpenAirInterface LTE testbed at 800MHz. This testbed is based on LTE release 8 PHY layer and implements transmission modes 1 (single antenna - SISO), 2 (transmit diversity),...

    Provided By EURECOM

  • White Papers // May 2010

    Relative Channel Reciprocity Calibration in MIMO/TDD Systems

    Channel State Information at the Transmitter (CSIT) can greatly improve the capacity of a wireless MIMO communication system. In a Time Division Duplex (TDD) system CSIT can be obtained by exploiting the reciprocity of the wireless channel. This however requires calibration of the Radio Frequency (RF) chains of the receiver...

    Provided By EURECOM

  • White Papers // Sep 2009

    Optimal Linear Precoder for Multiuser MIMO for Discrete Alphabets

    In this paper, the authors study the effect of discrete constellation alphabets on linear pre-coding for the downlink of Multi-User (MU) MIMO. They underline the fundamental difference in the approach of pre-coding if the alphabets are assumed to be discrete constellations rather than the idealized Gaussian assumption. They derive the...

    Provided By EURECOM

  • White Papers // Jun 2010

    Making Multiuser MIMO Work for LTE

    Underlining the viability of Multi-User (MU) MIMO for future wireless communications as Long Term Evolution (LTE), the authors propose in this paper a pre-coding strategy based on the low resolution LTE pre-coders which necessitates 2 bits feedback from the User Equipment (UE). The proposed strategy encompasses geometrical interference alignment at...

    Provided By EURECOM

  • White Papers // Jun 2010

    Online Data Backup: A Peer-Assisted Approach

    In this paper, the authors study the benefits of a peer-assisted approach to online backup applications, in which spare bandwidth and storage space of end-hosts complement that of an online storage service. Via simulations, they analyze the interplay between two key aspects of such applications: data placement and bandwidth allocation....

    Provided By EURECOM

  • White Papers // Sep 2011

    On Optimum End-to-End Distortion in Delay-Constrained Wideband MIMO Systems

    In this paper, the authors analyze the optimum expected End-to-End Distortion (EED) in delay-constrained wide-band Multiple-Input Mulitple-Output (MIMO) systems. They prove that the existence of frequency diversity benefits the EED in delay-constrained systems though it does not impact the ergodic channel capacity. For further analysis, they derive the closed-form expression...

    Provided By EURECOM

  • White Papers // Jun 2011

    Interference Mitigation in Femto-Macro Coexistence With Two-Way Relay Channel

    Motivated by the femtocell networks where crosstier interference management is crucial to achieve higher system throughput, the authors consider a basic interference model consisting of a MIMO two-way relay communication network in presence of a one-way point-to-point MIMO communication link. They propose an upper-bound on the maximum degrees of freedom...

    Provided By EURECOM

  • White Papers // Jun 2011

    Hash-and-Forward Relaying for Two-Way Relay Channel

    This paper considers a communication network comprised of two nodes, which have no mutual direct communication links, communicating two-way with the aid of a common Relay Node (RN), also known as separated Two-Way Relay (TWR) channel. The authors first recall a cut-set outer bound for the set of rates in...

    Provided By EURECOM