A New Approach to the Link Budget Concept for an OAM Communication Link

Following on from the increasing interest for electromagnetic waves carrying Orbital Angular Momentum (OAM), different configurations of antenna systems able to generate such beams have been proposed. However, in our opinion, a traditional radiation pattern approach does not provide the right picture of an OAM-based communication link. For this reason we propose a new general concept, the "OAM-link pattern", which takes into account the peculiar phase structure characterizing these waves. Focusing on OAM transmissions between antenna arrays, we introduce a formula for the link budget evaluation which describes the whole communication link and directly leads to a "classically shaped" main lobe pattern for a proper rephased reception in the case of uniform circular arrays.Comment: 4 pages, 3 figure

OAM multiple transmission using uniform circular arrays: numerical modeling and experimental verification with two digital television signals

In this work we present the outcomes of a radio-frequency OAM transmission between two antenna arrays performed in a real-world context. The analysis is supplemented by deep simulative investigations able to provide both a preliminary overview of the experimental scenario and a posteriori validation of the achieved results. As a first step, the far-field OAM communication link is tested at various frequencies and the corresponding link budget is studied by means of an angular scan generated by the rotation of the receiving system. Then, on the same site, two digital television signals encoded as OAM modes ($\ell$=1 and $\ell$=-1) are simultaneously transmitted at a common frequency of 198.5 MHz with good mode insulation.Comment: 16 pages, 14 figure

Using compact GML to deploy interactive maps on mobile devices

As users get connected with new-generation smart programmable phones and Personal Digital Assistants, they look for geographic information and location-aware services. In such a scenario, developers need infrastructures and standards in order to provide geographic data and cartographic tools to a wide set of applications and small mobile devices. GIS market offers a rich set of powerful tools for geographic information management, but a simple and lightweight protocol to easily add cartographic functionalities to mobile applications is still missing. This paper presents the compact Geographic Markup Language (cGML), a custom version of GML tailored for mobile devices. By using small tags, server side pre-projected and pre-scaled coordinates, it allows development and deployment of map-based software for mobile phones and PDAs with strong constraints on connection, CPU and memory

Local anaesthesia efficacy as postoperative analgesia for open shoulder instability surgery. a prospective randomised controlled study

Background and objectives: The aim of present study was to evaluate for the first time, the clinical effect of local anaesthetic infiltration as postoperative analgesia in open shoulder surgery for anterior-inferior instability. The comparison of the local infiltration and interscalenic brachial plexus block to a control group test the local anaesthetic efficacy in this surgery. Methods: 78 patients scheduled for open shoulder surgery were enrolled and randomly assigned to one of three groups: local infiltration anaesthesia (LIA), interscalenic brachial plexus block (IBPB) and control (C). All patients received standardized general anaesthesia and all injections were performed with the same dose and volume of anaesthetic. The number boluses delivered by a PCA pump applied at the end of surgery and the visual analogue score (VAS) at 0, 2, 4, 6, 12, 18 and 24 hours after intervention were recorded. A patient satisfaction score was also assessed. Results: Mean bolus consumption of the rescue analgesic, compared to C, was significantly less both in the LIA and IBPB groups (P<0.05). The IBPB group showed VAS scores that were significantly better than C group at all time points (P<0.05). The VAS scores for LIA group were clinically comparable to IBPB, and only at the 2 and 6 hours, postoperative time points there were no significant differences found in respect to the C group. IBPB and LIA showed comparable patient satisfaction scores. Conclusion: The local anaesthetic infiltration as postoperative analgesia appears to be a clinically valid alternative, statistically comparable to IBPB, with no clinical meaningful adverse effects

Lightweight client-pull protocol for mobile communication

Consumer mobile devices, such as cellular phones and PDAs, rely on TCP/IP as main communication protocol. However, cellular networks are not reliable as wired and wireless LAN, due to both users mobility and geographical obstacles. Moreover, limited bandwidth outside urban areas requires an application level data priority management, in order to improve user experience and avoid communication stack deadlocks. This paper presents early specification and first prototype of the LCPP (Lightweight Client-Pull Protocol), a UDP-based communication protocol specially designed to provide better performance, fast responsiveness and save processing power on mobile devices. Using some concepts adopted in the field of P2P file sharing, LCPP provides data priority management approach, which enables application to negotiate concurrent access to communication channel and to be notified about delaying, network congestion or remote device inability to process data

Il cgml: una soluzione basata su xml per la rappresentazione di mappe vettoriali su dispositivi mobili

L’evoluzione tecnologica dei dispositivi mobili, in termini di potenza di calcolo, capacità di visualizzazione e memorizzazione, e il proliferare di sistemi di connessione a banda larga su rete locale wireless (WiFi) e cellulare (UMTS), permette la gestione di dati complessi quali le mappe vettoriali e l’accesso ai Location Based Service (LBS) per mezzo di un telefono cellulare o un palmare. L’uso di linguaggi XML nel settore dei LBS condiziona la struttura delle funzionalità e dei dati ma garantisce l’interoperabilità dei servizi. Un esempio è il linguaggio GML (Geographic Markup Language) standard de facto nello scambio dei dati tra sistemi GIS e nella rappresentazione dell’informazione geografica. Il GML non è orientato alla rappresentazione di mappe vettoriali, è quindi necessario trasformarlo in un altro linguaggio XML, ad esempio il linguaggio grafico SVG (Scalable Vector Graphics). Per evitare la separazione tra il dato geografico (GML) e la sua visualizzazione (Mobile SVG) ma usando comunque le mappe vettoriali su dispositivi mobili, abbiamo definito il cGML (compact Geographic Markup Language). La rappresentazione di un dato tramite cGML è una mappa vettoriale e come tale può essere utilizzata nella presentazione grafica, ma allo stesso momento è anche un contenitore di insiemi di dati geo-riferiti, omogenei per semantica, utilizzabili in elaborazioni locali sul dispositivo mobile.Enhanced mobile device performances, in terms of CPU power, memory capacity, display capabilities and adoption of wideband connectivity based on local wireless (WiFi) and cellular (UMTS) networks, bring interactive mapping and access to Location Based Services (LBS) to mobile phones and PDAs. The use of XML language in the LBS influences data structure, functionalities and performances; although it could be time and memory expensive, it guarantees service interoperability. The GML language (Geographic Markup Language) is "de facto" standard in data exchanging between Geographic Information Systems. The GML has not been designed to represent vector map: it has to be transformed into another XML language, for example the graphical-oriented XML language Mobile SVG. To avoid the separation between the geographic data (GML) and its visualization (Mobile SVG), keeping vector mapping on mobile devices, we have designed the cGML (compact Geographic Markup Language). The data encoded using cGML is a vector map, so that it can be used in the graphic representation, but at the same time it is a container of geographical related data set, homogenous for semantic and usable in local processing on the mobile device

Compact gml: merging mobile computing and mobile cartography

The use of portable devices is moving from "Wireless Applications", typically implemented as browsing-on-the-road, to "Mobile Computing", which aims to exploit increasing processing power of consumer devices. As users get connected with smartphones and PDAs, they look for geographic information and location-aware services. While browser-based approaches have been explored (using static images or graphics formats such as Mobile SVG), a data model tailored for local computation on mobile devices is still missing. This paper presents the Compact Geographic Markup Language (cGML) that enables design and development of specific purpose GIS applications for portable consumer devices where a cGML document can be used as a spatial query result as well

The cgml: a xml language for mobile cartography

Increasing processing power and storage capabilities encourage systematic adoption of high-end mobile devices, such as programmable cellular phones and wireless-enabled PDA to implement new exciting applications. The performances of modern mobile devices are bringing innovative scenarios, based on position awareness and ambient intelligence paradigms. The market is moving from old 'Wireless Applications' approach to Mobile Computing, which aims to exploit mobile host capabilities. This paper presents the compact Geographic Markup Language (cGML), an XML-based language defined to enable design and development of LBS applications specific for mobile devices, and an example of client-server architecture using it

Modeling Orbital Angular Momentum (OAM) Transmission in Waveguides with the COMSOL Multiphysics® Software

The recent years have witnessed a growing interest in the possibility of enhancing the information transfer per unit bandwidth by exploiting the Orbital Angular Momentum (OAM) of light in both free-space and guided scenarios. In the proposed paper, the propagation of suitable OAM superpositions of waveguide eigenmodes in guiding structures with a circular symmetry is analyzed both theoretically and with the aid of the software COMSOL Multiphysics®, leading to the estimation of the power attenuation constants due to the finite conductivity of the metallic guide walls