Topicality of the problem. GSM mobile networks are very widely used in the world and the number of GSM users exceeds 10^9. In the last decade, the GSM/GPRS network has been very rapidly expanded in Lithuania as well. Coverage of the network has reached 99 % of territory of the country. Load of the network in largest cities reaches up to several hundred Erlangs for square kilometre. Voice traffic still generates the largest part of the network load, however mobile data traffic also grows rapidly. Radio interface between the user of mobile services and the network is not stationary. The received QoS of every user in different places is different. Even in a single cell, radio link characteristics differ in different parts of the cell. The signal level may easily vary about 10–20 dB just within several or tens of meters. Moreover, a mobile user experiences different link conditions while moving in the natural environment within or between cells. However, historically characteristics of QoS of mobile services are measured and evaluated like the ones of the fixed network using statistical methods. Statistically calculated characteristics of QoS do not include information about the received quality of mobile telecommunication services of every individual user. Conception of the received quality of services of individual users (individual QoS – iQoS) in the GSM/GPRS network has not been analysed in the world before. QoS should be measured not only at the network level, as it is... [to full text]

The main purpose of this work is to create information system which would deliver relevant information about flights from airports website to mobile phone. The most important task here is to collect data from Vilnius airport website, organize and put it into our database then deliver it to interested individuals.

Η ΕΕΕ αποτελείται από τέσσερα κεφάλαια και δύο παραρτήματα, ενώ για την καλύτερη κατανόηση και εξοικείωση του αναγνώστη με τις έννοιες και όρους που χρησιμοποιούνται στη βιομηχανία των κινητών επικοινωνιών παρατίθεται ένα σχετικό γλωσσάριο στο τέλος του κειμένου. Το πρώτο κεφάλαιο έχει τίτλο “εισαγωγή στα κυψελωτά συστήματα κινητής τηλεφωνίας” και αποτελεί ουσιαστικά μια εισαγωγή στις βασικές αρχές της κινητής κιυψελωτής τηλεφωνίας. Η εισαγωγή αυτή είναι απαραίτητη προκειμένου να γίνει ομαλά η μετάβαση σε σύνθετες έννοιες που διέπουν την λειτουργία των συστημάτων κινητής τηλεφωνίας. Το δεύτερο κεφάλαιο έχει τον τίτλο “το κανάλι μετάδοσης στις κινητές ραδιοεπικοινωνίες” και αναφέρεται στις ιδιότητες και τα χαρακτηριστικά που λαμβάνουν χώρα κατά την ασύρματη μετάδοση της πληροφορίας. Οι ιδιότητες των ηλ/κων κυμάτων, και της ατμόσφαιρας που αποτελεί το μέσο μετάδοσης στις ασύρματες επικοινωνίες καθώς και η μορφολογία του περιβάλλοντος ραδιομετάδοσης είναι μερικές από τις παραμέτρους που διαδραματίζουν καθοριστικό ρόλο στην ποιότητα των κινητών επικοινωνιών και για τον λόγο αυτό μελετώνται και εν συνεχεία μοντελοποιούνται προκειμένου να επιτύχουμε την μεγαλύτερη δυνατή απόδοση των συστημάτων αυτών. Το τρίτο κεφάλαιο είναι αφιερωμένο αποκλειστικά στο παγκόσμιο σύστημα κινητής τηλεφωνίας G.S.M. Ως γνωστόν, το G.S.M είναι το πιο διαδεδομένο σύστημα κινητών επικοινωνιών και ως εκ τούτου μία εργασία που αναφέρεται σε συστήματα κινητής τηλεφωνίας έχει ως σημείο αναφοράς το G.S.M. Το τέταρτο και τελευταίο κεφάλαιο της ΕΕΕ αναφέρεται στο καθολικό σύστημα κινητών επικοινωνιών UMTS. Το UMTS είναι το σύστημα κινητών επικοινωνιών 3ης γενιάς, το οποίο ουσιαστικά έκανε πραγματικότητα την πάγια απαίτηση από την πλευρά των χρηστών – συνδρομητών για επικοινωνία “οπουδήποτε, οποτεδήποτε, οτιδήποτε”. Η εργασία κλείνει με δύο παραρτήματα. Το παράρτημα Α αποτελεί μία εισαγωγική περιγραφή στο σύστημα σηματοδοσίας Νο 7. Στις περισσότερες περιπτώσεις ο χρήστης κινητής τηλεφωνίας αγνοεί την ύπαρξη του δικτύου σηματοδοσίας το οποίο ουσιαστικά αλλά αφανώς και αθόρυβα «τρέχει» παράλληλα με το δίκτυο μετάδοσης πληροφοριών. Δίνεται λοιπόν η ευκαιρία μέσα από το παράρτημα αυτό να γίνει γνωστή η ύπαρξη του δικτύου σηματοδοσίας Νο 7 (SS#7), όπου περιγράφονται τα λειτουργικά χαρακτηριστικά του (διαστρωματωμένη αρχιτεκτονική, σημεία σηματοδοσίας κλπ.) ενώ γίνεται αναφορά στα είδη των μηνυμάτων σηματοδοσίας και στον τρόπο που ανταλλάσσονται τα μηνύματα αυτά μεταξύ των δομικών στοιχείων του δικτύου SS#7. Στο παράρτημα Β αναφέρονται κάποια βασικά στοιχεία από την «δημοφιλή» τεχνική κωδικοποίησης Linear Predictive Coding (LPC), η οποία στην Ελληνική αποδίδεται ως Γραμμική Προγνωστική Κωδικοποίηση. Η LPC είναι η τεχνική εκείνη που χρησιμοποιείται στο σύνολο σχεδόν των ψηφιακών συστημάτων επικοινωνίας, χάρη στις εγγενείς ιδιότητές της, και επομένως βρίσκει επίσης εφαρμογή και στο G.S.M, ως ένα κατεξοχήν ψηφιακό σύστημα κινητής τηλεφωνίας. Ωστόσο, η εφαρμογή της LPC δεν περιορίζεται μόνο στο G.S.M αλλά εκτείνεται μέχρι τα σημερινά συστήματα 3ης γενιάς. Τέλος, θα ήθελα να αναφέρω δύο λόγια για τις δυσκολίες που συνάντησα καθόλη την διάρκεια συγγραφής της εργασίας αυτής. Η ΕΕΕ, με την παρούσα μορφή, είναι το αποτέλεσμα μιας πολύμηνης προσπάθειας και συνεχούς μελέτης ενός ιδιαίτερα σύνθετου και πολυδιάστατου αντικειμένου έρευνας, όπως είναι τα συστήματα κινητής τηλεφωνίας. Παρά το γεγονός ότι η βιβλιογραφία υπήρξε επαρκής, οι έννοιες και οι τεχνικές δυσκολίες με τις οποίες ήρθα, πολλές φορές, αντιμέτωπος ήταν κάτι το πρωτόγνωρο, το οποίο αρκετές φορές μου έδινε την εντύπωση του ανυπέρβλητου. Θα ήθελα λοιπόν, να ζητήσω εκ των προτέρων την κατανόηση του αναγνώστη για οποιαδήποτε λάθη ή παραλείψεις οι οποίες φυσικά με βαρύνουν στο ακέραιο. / -

Dissertação (mestrado)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Elétrica, 2008. / Submitted by Jaqueline Oliveira (jaqueoliveiram@gmail.com) on 2008-12-02T16:05:55Z No. of bitstreams: 1 DISSERTACAO_2008_HenriquePVieira.pdf: 1744494 bytes, checksum: e841eb4b8535e79f162f9960278205a1 (MD5) / Approved for entry into archive by Georgia Fernandes(georgia@bce.unb.br) on 2009-02-16T13:53:15Z (GMT) No. of bitstreams: 1 DISSERTACAO_2008_HenriquePVieira.pdf: 1744494 bytes, checksum: e841eb4b8535e79f162f9960278205a1 (MD5) / Made available in DSpace on 2009-02-16T13:53:16Z (GMT). No. of bitstreams: 1 DISSERTACAO_2008_HenriquePVieira.pdf: 1744494 bytes, checksum: e841eb4b8535e79f162f9960278205a1 (MD5) / Com a crescente demanda pelos serviços de pacote de dados sem fio, as operadoras móveis de rede 3G hoje enfrentam o desafio de oferecer novos serviços multimídia com exigências de qualidade de rede ao mesmo tempo em que devem utilizar de forma eficaz a largura de banda que possuem. Esses novos serviços requerem o aumento de banda e de throughput de dados, devido à natureza intrínseca de interatividade que possuem. Essa crescente demanda por banda e throughput fez com que os comitês de padronização das redes de terceira geração trabalhassem no sentido de atender essas necessidades tendo como resultado a especificação de melhores esquemas de modulação e codificação, além da introdução de mecanismos de controle de qualidade dos enlaces (LQC – Link Quality Control) mais avançados. Entre as diversas propostas para a evolução das redes 2G (2ª Geração) para 3G (3ª Geração), o GPRS (General Packet Radio Services) e o EDGE (Enhanced Data Rates for GSM Evolution) aparecem como soluções transitórias (conhecidas como redes 2,5G), mas efetivas, para as redes GSM existentes. Este trabalho propõe apresentar uma proposta de política de adaptação de enlace, que suporte serviços 3G, baseada no modelo GERAN (GSM EDGE Radio Access Network) definido pelo 3GPP (3rd Generation Partnership Project), e que permita controle de admissão de sessão na rede IMS (IP Multimedia Subsystem) utilizando o protocolo de sinalização IP (Internet Protocol) conhecido como SIP (Session Initiation Protocol). Essa proposta é baseada nos resultados teóricos e experimentais, medidos em campo, na rede real de uma operadora GSM/EDGE. _______________________________________________________________________________________ ABSTRACT / With the increasing demand for wireless packet data services, 3G wireless carriers today are faced with the challenge of offering multimedia applications with quality of service requirements while at the same time effectively utilizing precious wireless bandwidth. These new data services require increased bandwidth and data throughput, due to their intrinsic nature. This increasing demand for bandwidth and throughput has driven the work of third generation standardization committees, resulting in the specification of improved modulation and coding schemes, besides the introduction of more advanced link quality control mechanisms. Among the several proposals for the evolution from 2G to 3G, GPRS (General Packet Radio Services) and EDGE (Enhanced Data Rates for GSM Evolution) stand out as transitional solutions for existing GSM networks (it is also referred to as 2.5G system). This work considers to presenting a proposal of politics of link adaptation, that it support services of 3rd generation, based on GERAN model (GSM EDGE Radio Access Network) defined by 3GPP (3rd Generation Partnership Project), and allows to control session admission in subsystem IMS using a IP signaling protocol known as SIP. This proposal is based on the theoretical and experimental results, measured in the field, in a real network.

Denna rapport är en sammanställning av utfört examensarbete åt CreateIT AB i Junsele. Uppgiften var att utreda hur man kan implementera ett system för att ta reda på en mobils position i CreateITs tidredovisningsapplikation. I rapporten tar vi upp flera teorier för hur en position kan bestämmas, dels GSM-nätets positionsbestämning och dels genom GPS-satelliter. Fördelar och nackdelar med de båda systemen diskuteras i rapporten. Vi granskar de tjänster och produkter som finns på marknaden våren 2002. Slutligen sammanfattar vi systemen, produkterna och skriver rekommendationer till företag som vill positionsbestämma sina anställda. Fakta har hämtats från operatörer i Sverige, mobiltelefonföretag, Internet, artiklar, tillverkare och distributörer av GPS-enheter.

This report describes a bachelor thesis in computer science performed at the system department within the product development unit for GSM (Global System for Mobile communication) at Ericsson in Linköping.GSM can be considered a mature technology but it is still updated with new features on a regular basis. This requires that the technology also continuously is being tested. One technique that is used to perform quality tests is called PESQ (Perceptual Evaluation of Speech Quality). PESQ is a standardized algorithm to perform speech quality tests; it gives a score based on how a human would percept speech quality.The purpose of this thesis was to enhance the speech quality analysis process used when testing the GSM network. One goal was to analyze if it was possible to record and inject sound into a phone call and verify the possibility to execute the PESQ algorithm using a smartphone. Another goal was to develop a smartphone application to perform the described tasks.In order to do so an application for Android was developed. The development process included an investigation whether the Android platform supplies the functionality required. The investiga-tion showed that no general solution for recording and injecting audio into a phone call could be found. Recording was possible on some smartphones, but the characteristics of the recorded audio were not as desired. No solution for injecting audio into a phone call could be found for any of the tested smartphones.However, even though no solution for recording and injecting was found, an application was developed. The application was decided to be more of a proof of concept on how an application of this kind would work. It would also be a good foundation for future development. Suggested future work in order to integrate the application into the existing testing environment is to find alternative solutions for recording and injecting, maybe with the help of smartphone manu-facturers.

This work deals with the principles on which they are based multiband antennas, especially for GSM (900/1800). It then focuses on different ways you can implement these multi-band antennas, mainly deals with structures that can be easily realized using planar technology. These antennas was designed and optimized in electromagnetic simulation software. Selected antenna was practically realized.

No description available.

This dissertation investigates the development of new Global system for mobile communications (GSM) improvement algorithms used to solve the nondeterministic polynomial-time hard (NP-hard) problem of assigning cells to switches. The departure of this project from previous projects is in the area of the GSM network being optimised. Most previous projects tried minimising the signalling load on the network. The main aim in this project is to reduce the operational expenditure as much as possible while still adhering to network element constraints. This is achieved by generating new network configurations with a reduced transmission cost. Since assigning cells to switches in cellular mobile networks is a NP-hard problem, exact methods cannot be used to solve it for real-size networks. In this context, heuristic approaches, evolutionary search algorithms and clustering techniques can, however, be used. This dissertation presents a comprehensive and comparative study of the above-mentioned categories of search techniques adopted specifically for GSM network improvement. The evolutionary search technique evaluated is a genetic algorithm (GA) while the unsupervised learning technique is a Gaussian mixture model (GMM). A number of custom-developed heuristic search techniques with differing goals were also experimented with. The implementation of these algorithms was tested in order to measure the quality of the solutions. Results obtained confirmed the ability of the search techniques to produce network configurations with a reduced operational expenditure while still adhering to network element constraints. The best results found were using the Gaussian mixture model where savings of up to 17% were achieved. The heuristic searches produced promising results in the form of the characteristics they portray, for example, load-balancing. Due to the massive problem space and a suboptimal chromosome representation, the genetic algorithm struggled to find high quality viable solutions. The objective of reducing network cost was achieved by performing cell-to-switch optimisation taking traffic distributions, transmission costs and network element constraints into account. These criteria cannot be divorced from each other since they are all interdependent, omitting any one of them will lead to inefficient and infeasible configurations. Results obtained further indicated that the search space consists out of two components namely, traffic and transmission cost. When optimising, it is very important to consider both components simultaneously, if not, infeasible or suboptimum solutions are generated. It was also found that pre-processing has a major impact on the cluster-forming ability of the GMM. Depending on how the pre-processing technique is set up, it is possible to bias the cluster-formation process in such a way that either transmission cost savings or a reduction in inter base station controller/switching centre traffic volume is given preference. Two of the difficult questions to answer when performing network capacity expansions are where to install the remote base station controllers (BSCs) and how to alter the existing BSC boundaries to accommodate the new BSCs being introduced. Using the techniques developed in this dissertation, these questions can now be answered with confidence. / Dissertation (MEng)--University of Pretoria, 2008. / Electrical, Electronic and Computer Engineering / unrestricted

Ces dernières années, nombreux travaux dont l’objectif est de conduire à l’interopérabilité ferroviaire ont permis l’émergence d’un système paneuropéen de contrôle-commande ferroviaire. Ce système exploite des radiocommunications sol-trains fonctionnant selon le protocole GSM-R (Global System for Mobile communications – Railways. La bonne marche de l’exploitation ferroviaire dépend, pour une part, du bon acheminement des données entre sol et trains. Il s’avère donc nécessaire d’assurer un fonctionnement efficace de cette radio sol-trains en dépit de perturbations électromagnétiques intentionnelles ou non intentionnelles qui pourraient la perturber. Ce travail de thèse s’intéresse à cette seconde catégorie de perturbations. Nous développons des méthodes de détection de brouilleurs électromagnétiques afin de mettre en oeuvre rapidement des contre-mesures efficaces contre ces brouillages, à différents niveaux de l’architecture radio. Nous mettons en oeuvre un système de détection supervisé permettant de détecter la présence de signaux de brouillage intentionnels, voire de les reconnaître. Fondé sur l’analyse des signaux échangés, nous développons et évaluons deux méthodes distinctes. L’une exploite les signaux en quadrature mis en évidence par le récepteur dans le canal de communication employé. L’autre méthode considère la densité spectrale de puissance des signaux recueillis dans une bande de fréquence plus large, centrée dans la gamme allouée aux communications GSM-R, et s’étendant de part et d’autre de celle-ci. Ces méthodes sont successivement évaluées par simulation, sur des données issues d’un banc de mesure puis, sur un site ferroviaire réel. / In recent years, numerous studies whose ultimate goal is to drive the railway interoperability have allowed the emergence of a pan-European train control system. This system uses ground-to-train radio operating on the GSM-R (Global System for Mobile communications - Railways) protocol, currently being deployed on a large scale along railway lines. The smooth running of railway operations depends, in part, of the proper routing of radio communications between trains and ground. Therefore, it is necessary to ensure the effective operation of this ground to train link in presence of intentional or unintentional electromagnetic interference that could disrupt communication. This thesis focuses on this second category of disturbances. We develop methods for detecting electromagnetic interference superimposing their signals to GSM-R signals. Then, this detection will promptly set off effective countermeasures against such interference at different levels of the radio architecture, the physical layer, the higher protocol layers. We implement a supervised detection system to detect the presence of jamming signals and, for potentially to recognize them. Based on the analysis of signals exchanged, we develop and evaluate two methods. One considers the quadrature signals recovered by the receiver in the used communication channel. The second method exploits the power spectral density of the signals collected in a wider frequency band, centered in the range allocated to the GSM-R communications and extending on either side thereof. These methods are successively evaluated by simulation, on data obtained using a test bench, and on a real railway site.