This thesis deals with methodology for measuring transmission parameters of internet connection. The aim of the thesis is to cover and compare known methods used for testing. Based on the research then design and realize an application that will provide those kind of measurements.

This masters theses deals with standard detection methods of speech/pause - voice activity detectors are based on the principles of short-time energy, real spectrum, short-time intensity and on a combinations of these three detectors. In the next parts, there are mentioned other voice activity detectors based on hidden Markovov‘s models and a detector described in the ITU-T G.729 standard. All the detectors, mentioned above, were implemented in research environment MATLAB. Further there was created an user interface for testing functions of the implemented detectors. Finally, there was done an evaluation by ROC characteristics according to the results of the testing.

Polarization mode dispersion PMD becomes the most limiting factors for achieving high-speed optical transmission. The size of the dierencial group delay between the polarization plane is influenced by many different factors and therefore accurate measurement of PMD should be done in all phases of building and operating optical path.

This thesis deals with description of lossy video compression. Theoretical part of the work describes the fundamentals of the video compression and standarts for lossy as well lossless video and still image compression. The practical part follows up with design of Java program for simulation of MPEG codec.

This diploma work describes the software-defined network focusing on optical networks. Subsequently designed their own software network that is implemented in the environment OMNeT ++. This work deals with SDN (software-defined network), and impact on current communications environment in the world of telecom-munications services.

Les recommandations (normes) élaborées par l'UIT (l'Union Internationale de Télécommunications) précisent avec rigueur les conditions dans lesquelles les tests subjectifs de qualité visuelle doivent avoir lieu: la salle de test, les conditions de visualisation, le protocole d'évaluation, les méthodes de post-traitement des scores accordées par les évaluateurs, etc... Pourtant, les études de l'état de l'art mettent en évidence que des nombreuses inadvertances perdurent au niveau théorique et expérimental: (1) la modélisation statistique précise des scores attribués par les observateurs humains à un certain type de contenu reste encore inconnue, (2) la différence théorique et applicative entre les évaluations sur des échelles discrètes et continues ne fait pas encore l'objet d'une étude dédiée et (3) l'impact sémantique (psycho-cognitif) des étiquettes associées à l'échelle d'évaluation est toujours invoqué mais jamais évalué. Notre thèse offre un cadre méthodologique et expérimental permettant de: 1. Modéliser avec précision statistique la distribution des scores attribués par les observateurs et évaluer l'impact pratique d'une telle modélisation, 2. Établir la relation théorique entre les scores attribués par les observateurs sur une échelle continue et une échelle discrète, 3. Établir le cadre statistique permettant de quantifier l'impact sémantique induit par les étiquettes sémantiques associées à l'échelle d'évaluation, 4. Spécifier et réaliser un cadre expérimental de référence, à vocation d'utilisation ultérieure par les instances de l'UIT / Quality evaluation is an ever-fascinating field, covering at least a century of research works emerging from psychology, psychophysics, sociology, marketing, medicine… While for visual quality evaluation the IUT recommendations pave the way towards well-configured, consensual evaluation conditions granting reproducibility and comparability of the experimental results, an in-depth analysis of the state-of-the-art studies shows at least three open challenges related to the: (1) the continuous vs. discrete evaluation scales, (2) the statistical distribution of the scores assigned by the observers and (3) the usage of semantic labels on the grading scales. Thus, the present thesis turns these challenges into three research objectives: 1. bridging at the theoretical level the continuous and the discrete scale evaluation procedures and investigating whether the number of the classes on the discrete scales is a criterion meaningful in the results interpretations or just a parameter; studying the theoretical influence of the statistical model of evolution results and of the size of the panel (number of observers) in the accuracy of the results are also targeted; 2. quantifying the bias induced in subjective video quality experiments by the semantic labels (e.g. Excellent, Good, Fair, Poor and Bad) generally associated to the discrete grading scales; 3. designing and deploying an experimental test-bed able to support their precision and statistical relevance. With respect to these objectives, the main contributions are at theoretical, methodological and experimental levels

Progressive download video services, such as YouTube and podcasts, are responsible for a major part of the transmitted data volume in the Internet and it is expected, that they will also strongly affect mobile networks. Streaming video quality mainly depends on the sustainable throughput achieved during transmission. To ensure acceptable video quality in mobile networks (with limited capacity resources) the perceived quality by the customer (QoE) needs to be monitored by estimation. For that, the streaming video quality needs to be measured and monitored permanently. For TCP based progressive download we propose to extract the the video timestamps which are encoded within the payload of the TCP segments by decoding the video within the payload. The actual estimation is then done by play out buffer fill level calculations based on the TCP segment timestamp and their internal play out timestamp. The perceived quality for the user is derived from the number and duration of video stalls. Algorithms for decoding Flash Video, MP4 and WebM Video have already been implemented. After deriving the play out time it is compared to the timestamp of the respective TCP segment. The result of this comparison is an estimate of the fill level of the play out buffer in terms of play out time within the client. This estimation is done without access to the end device. The same measurement procedure can be applied for any TCP based progressive download Internet service. Video was simply taken as an example because of its current large share in traffic volume in operator networks.

This master's thesis describes process of design and development of the system for calculating the coverage of wireless networks, it is implemented as a web portal and written in the Java programming language. The text of the thesis describes the work with the used platforms, a description of the ITU-R calculation method P.1812, which is used for calculation electric field strength and basic information about electromagnetic waves. The main function of the system is to calculate and display coverage of wireless networks and customer management information.

This thesis deals with the measurement of transmission parameters in the new generation access networks NGA. The aim of the thesis is to build and configure a test network and scenarios for the measurement of service quality parameters and then verify the transmission stability. The theoretical part describes general functioning of NGN networks, the requirements of different telecommunications services on quality parameters, methodology and recommendations for measuring transmission parameters in packet networks. The practical part deals with the configuration of scenarios using mainly MPLS technology and methodology of their testing. Measurements were performed according to recommendations IETF RFC 2544, IETF RFC 6349 with the ExacTCP test and ITU-T Y.1564 with the EtherSAM test. For measurements were used measuring instruments of EXFO brand. In conclusion, the measurement results according to the mentioned standards were evaluated and also the advantages of using the measurement according to the given standard in NGA access networks were discussed.

Progressive download video services, such as YouTube, are responsible for a major part of the transmitted data volume in the Internet and it is expected, that they also will strongly affect mobile networks. Streaming video quality mainly depends on the sustainable throughput achieved during transmission. In order to achieve an acceptable video quality in mobile networks (with limited capacity resources), traffic engineering mechanisms have to be applied. For that, the streaming video quality needs to be measured and monitored permanently. Therefore, the video timestamps which are encoded within the payload of the TCP segments have to be extracted. For that it is necessary to decode the video within the transported payload. Algorithms for decoding Flash Video, MP4 and WebM Video have already been implemented as a demonstration implementation in support of the network based measurement contribution to SG12 by Chemnitz University for TCP encoded progressive download Internet services. In the demonstration, the derived play out buffering from the monitored traffic is being output internally. A second application is then used to graphically display the estimation result. The measurement and estimation is solely done within a measurement point of an operator network without access to the client’s end device.