Reliability of Communication Systems Used in Offshore Wind Farms, Journal of Telecommunications and Information Technology, 2022, nr 4

In the era of renewable energy, offshore wind farms play a very important role. The number of such installations in Europe is increasing rapidly. With the growing capacity of wind turbines installed in these farms (3, 5, 10 MW), the profitability of this type of energy systems plays an increasing role. The number of wind energy turbines installed at offshore wind farms is growing constantly as well. Once installed, the power plants must be under constant technical supervision, with reliability of electronic communication systems being a particularly important aspect in the operation of offshore wind farms. Considerations focusing on this subject form the very core of this paper. After an introduction to offshore wind farms, the following aspects will be discussed: redundant topologies, e.g. multiple HiPERRings, redundant switches and routers within the backbone networks, redundancy of the transmission media used, alternative transmission technologies, e.g. WLANs (IEEE 802.11h, IEEE 802.11g). Finally, requirements applicable to reliable electronic communication systems used in offshore wind farms will be formulated

Suitability of Transport Techniques for Video Transmission in IP Networks

The paper discusses the problem of video transmission in an IP network. The authors consider the ability of using the most popular video codecs that use both the MPEG2 Transport Stream and Dynamic Adaptive Streaming over Hypertext Transfer Protocol (DASH). The main emphasis was given to ensuring the quality of service and quality assessment methods, taking into account not only the service- or network provider’s point of view but also the end user’s perspective. Two quality assessment approaches were presented, i.e. objective and subjective methods. The authors presented the results of the quality evaluation for H.264/MPEG-4, H.265/HEVC and VP9 codecs. The objective measurements, proved by statistical analysis of user opinion scores, confirmed the ability of using H.265 and VP9 codecs in both real time and streaming transmissions, while the quality of video streaming over HTTP with the H.264 codec proved inadequate. The authors also presented a connection between the dynamics of network bandwidth changing and MPEG-DASH mechanism operation and their influence on thequality experienced by users

A New Parameterized Model for Determining Quality of Online Video Service Using Modern H.265/HEVC and VP9 Codecs, Journal of Telecommunications and Information Technology, 2020, nr 4

This paper describes a new measurement method (VS model) for determining the quality of online video services relying on modern H.265/HEVC and VP9 codecs. The said method has been developed on the basis of VQuad-HD curves (according to ITU-T J.341). This model does not refer to signal analysis, but protocol analysis instead. The parameters used are: type of video codec, encoding rate, transport technique, packet loss and burst size. The method may be implemented quickly and easily, which is one of the great advantages when using this method to measure Qo

New Tool for Investigating QoS in the WWW Service, Journal of Telecommunications and Information Technology, 2015, nr 1

The subject of this paper is the QoS measurement in the World Wide Web (WWW) service. It will begin with a brief presentation of methods currently used to measure QoS in the WWW service before going on to describe in detail the new tool QoSCalc(WWW). Following that, the potential of the new tool will be put to the test in a series of analysis scenarios. The results and insights obtained will then be presented in several diagrams, and interpreted

Video Streaming over IP using the DASH Technique, Journal of Telecommunications and Information Technology, 2018, nr 2

Modern Internet serves as a high-performance platform for an ever-increasing number of services. Some of them – video services in particular – are of the broadband variety. So, it is not surprising that segments of networks can rapidly become congested, which may lead to a deterioration in quality. It is hoped that the new MPEG-DASH technique will alleviate congestion. This paper contains an analysis of the new technology’s impact on the quality of service in IP networks. It also explains a new numerical tool QoSCalc(DASH) that has been used to analyze the DASH method in different scenarios. The results are presented graphically and interpreted

A Comparison Study of DASH Technique by Video Streaming over IP with the Use of RTP and HTTP Protocols, Journal of Telecommunications and Information Technology, 2020, nr 1

Today’s Internet knows no bounds. New applications are marketed every single day. Many of them incorporate video sequences. These must be transported over the Internet quickly (often in real time). However, the Internet has not been designed for live communications and, regrettably, this may become apparent all too quickly. Countermeasures are required in the form of new, efficient transport techniques facilitating online video services. MPEG-DASH is one of such modern techniques. But how good is this new technique really? This paper delves into the matter. The paper contains an analysis of the impact that the new technology exerts on the quality of video streaming over IP networks. It also describes a new numerical tool – QoSCalc (DASH-HTTP) which has been used to analyze MPEG-DASH under different use scenarios. The results are presented graphically and their interpretation is provide

New Tool for Examining QoS in the VToIP Service, Journal of Telecommunications and Information Technology, 2014, nr 1

This paper is dedicated to the subject of measuring QoS in the Video Telephony over IP (VToIP) service. QoS measurement models in general and then models designed specifically for measuring QoS in the VToIP service are presented. A new numerical tool for examining the quality of VToIP video streams VToIP is described. The tool’s functionality is then put to the test in a number of analysis scenarios. The results and insights gained from the analyses are then presented in several diagrams, and interpreted. The paper concludes with a summary and an outlook on further areas of work

New Metric for World Wide Web Service Quality , Journal of Telecommunications and Information Technology, 2014, nr 2

The main topic of this paper is the quality of the WWW service evaluation. The authors present well-known measurement methods, and present the new “Power” metric for quality, advocating it as a method of assessing the quality of such service. This metric is based on the most important network parameters that affect any assessment of the WWW service, i.e. Web page opening time and download data transfer rate. The new method is easy to implement, fast in operation, and provides stable and repeatable result

Concept for a Measurement Management System for Access Service to the Internet, Journal of Telecommunications and Information Technology, 2016, nr 3

This paper describes the problems associated with the provision of quality of service over an access connection to the Internet, i.e. the Internet Access Service (IAS). The paper has something of an overview character. Following a comprehensive introduction to the subject of “Changing Network Technologies” the paper focuses on the topic “Quality of IAS” in the light of regulatory directives of the European Parliament and the latest recommendations of ITU-T and ETSI. The focus will then shift to “Measurement Points and Measurement Scenarios for Determining QoS”. This topic will be described in detail and illustrated with several graphics. The final chapter has a pronounced scientific character and contains, among other things, a suggestion for a so-called Measurement Management System (MMS) to aid the design, execution and evaluation of efficient, automatic QoS measurements in networks

Quantifying the Suitability of Reference Signals for the Video Streaming Analysis for IPTV, Journal of Telecommunications and Information Technology, 2016, nr 1

IP networks are indispensable nowadays and they are some of the most efficient platforms. The constantly growing number of users and new services in these networks – the largest being the Internet – require a satisfactory quality of service from any application they use. So, determining the QoS in real-time services is particularly important. This work shows how to quantify the suitability of reference signals for analyzing the quality of video streaming in IPTV. The assessment relies on two different algorithms: PEVQ and VQuad-HD. Three different reference signals – two real ones and an artificial one – are used in this study, and a numerical measurement system is used, which simulates mean network impairments. These measurements provide valuable information for determining the QoS of actual IPTV services in practice