Geometric Interpretation of Theoretical Bounds for RSS-based Source Localization with Uncertain Anchor Positions

The Received Signal Strength based source localization can encounter severe problems originating from uncertain information about the anchor positions in practice. The anchor positions, although commonly assumed to be precisely known prior to the source localization, are usually obtained using previous estimation algorithm such as GPS. This previous estimation procedure produces anchor positions with limited accuracy that result in degradations of the source localization algorithm and topology uncertainty. We have recently addressed the problem with a joint estimation framework that jointly estimates the unknown source and uncertain anchors positions and derived the theoretical limits of the framework. This paper extends the authors previous work on the theoretical performance bounds of the joint localization framework with appropriate geometric interpretation of the overall problem exploiting the properties of semi-definiteness and symmetry of the Fisher Information Matrix and the Cram{\`e}r-Rao Lower Bound and using Information and Error Ellipses, respectively. The numerical results aim to illustrate and discuss the usefulness of the geometric interpretation. They provide in-depth insight into the geometrical properties of the joint localization problem underlining the various possibilities for practical design of efficient localization algorithms.Comment: 30 pages, 15 figure

Generic Multiuser Coordinated Beamforming for Underlay Spectrum Sharing

The beamforming techniques have been recently studied as possible enablers for underlay spectrum sharing. The existing beamforming techniques have several common limitations: they are usually system model specific, cannot operate with arbitrary number of transmit/receive antennas, and cannot serve arbitrary number of users. Moreover, the beamforming techniques for underlay spectrum sharing do not consider the interference originating from the incumbent primary system. This work extends the common underlay sharing model by incorporating the interference originating from the incumbent system into generic combined beamforming design that can be applied on interference, broadcast or multiple access channels. The paper proposes two novel multiuser beamforming algorithms for user fairness and sum rate maximization, utilizing newly derived convex optimization problems for transmit and receive beamformers calculation in a recursive optimization. Both beamforming algorithms provide efficient operation for the interference, broadcast and multiple access channels, as well as for arbitrary number of antennas and secondary users in the system. Furthermore, the paper proposes a successive transmit/receive optimization approach that reduces the computational complexity of the proposed recursive algorithms. The results show that the proposed complexity reduction significantly improves the convergence rates and can facilitate their operation in scenarios which require agile beamformers computation.Comment: 30 pages, 5 figure

Analysis of Reconfigurability, Control and Resource Management in Heterogeneous Wireless Networks

Modern communications networks integrate different access technologies that require interoperability for seamless and user-transparent transfer of multimedia-reach content. Latest standardization activities in this area pinpoint the IEEE 802.21 standard as an enabler of media independent handovers in various scenarios. Additionally, the implementation of the heterogeneous network paradigm yields optimized and efficient resource management techniques emphasizing the need for reconfiguration and interoperability capabilities within future wireless networks. This paper analyzes a combination of reconfigurability, interoperability and resource management aspects in heterogeneous wireless networks based on the IEEE 802.21 standard. It introduces a novel platform for wireless heterogeneous communication systems and a prototype of a reconfigurable mobile terminal that rely on the IEEE 802.21 standard. The introduced platforms are extensively validated through simulations and laboratory experiments showcasing that the IEEE 802.21-backed interoperability is able to support uninterrupted content delivery across multiple communication technologies with high performance

Исследование ультрадисперсных оксидов меди, полученных плазмодинамическим методом

The synthesis of copper oxides has a great importance due to the fact these materials are widely used in superconductors manufacturing. It’s known that properties of materials in nanodispersed conditions are improved. In this article, an analysis of ultradispersed plasmodynamic synthesis product obtained using coaxial magnetoplasma accelerator with copper electrodes was carried out. The obtained powder was analyzed by X-ray diffractometer Shimadzu XRD 7000 using the temperature consoles Anton Paar TTK450. Using this analysis such phases as copper Cu, copper oxide (I) Cu2O, copper oxide (II) CuO, and copper hydroxide hydrate Cu(OH)[2]•H[2]O were identified in the product. By gradually heating, the powder to the temperature of 800 °С the phase change was observed. The mass of copper oxide increased up to 96% and copper hydroxide hydrate

D6.2 - Prototype description and field trial results

Deliverable D6.2 del projecte FARAMIRPostprint (published version

Policies for efficient spectrum sharing

This chapter presents a paradigm for policy based networking that assumes separation of policies from radio firmware allowing policy management in a dynamic way. The approach is specifically tailored for cognitive radio environments where intelligent resource management and flexible behavior of radio networks and nodes can be facilitated. A novel policy reasoning architecture was proposed that may be used for various network scenarios, centralized or decentralized, in order to achieve specific management goals or simply to accommodate user preferences. Also, the chapter discussed the potential security threats for policy based cognitive radio systems and proposed ways for their mitigation.JRC.G.6-Digital Citizen Securit