2016 IEEE Global Communications Conference (GLOBECOM), 2016
\textcopyright} 2016 IEEE. As next-generation mobile networks are rapidly taking shape driven by ... more \textcopyright} 2016 IEEE. As next-generation mobile networks are rapidly taking shape driven by the target standardization requirements and initial trial implementations, a range of accompanying technologies prepare to support them with more reliable wireless access and improved service provisioning. Among these are more advanced spectrum sharing options enabled by the emerging Licensed Shared Access (LSA) regulatory framework, which aims to efficiently employ the capacity of underutilized frequency bands in a controlled manner. The concept of LSA promises to equip network operators with the much needed additional spectrum on the secondary basis and thus brings changes to the existing cellular network management. Hence, additional research is in prompt demand to determine the required levels of Quality of Service (QoS) and service provisioning reliability, especially in cases of dynamic geographical and temporal LSA sharing. Motivated by this recent urge and having at our disposal a fully-functional 3GPP LTE cellular deployment, we have committed to implement and trial the principles of dynamic LSA-compatible spectrum management. This paper is our first disclosure on the comprehensive experimental evaluation of this promising technology. We expect that these unprecedented practical results together with the key lessons learned will become a valuable reference point for the subsequent integration of flexible LSA-based services, suitable for inter-operator and multi-tenant spectrum sharing.
2013 36th International Conference on Telecommunications and Signal Processing (TSP), 2013
ABSTRACT This article presents the implementation of a designed model for the simulation of three... more ABSTRACT This article presents the implementation of a designed model for the simulation of three telecommunication services (File Transfer, Video on Demand and Voice over IP) using a queueing theory. The main objective of this article is modelling and simulations of IMS (IP Multimedia Subsystem) network based on single servers (with a Poisson distribution of job arrivals and an exponential job service time) with FIFO queues of unlimited capacity in Matlab environment. Also, for IMS performance improvement new algorithms for S-CSCF selection were designed and implemented in this mathematical model of IMS subsystem. The results of designed algorithms obtained by simulations are evaluated and compared with each other. It was shown that new algorithms improved IMS performance compared with standardized solution.
2015 7th International Congress on Ultra Modern Telecommunications and Control Systems and Workshops (ICUMT), 2015
The operators are deploying heterogeneous networks with LTE base stations covering very small are... more The operators are deploying heterogeneous networks with LTE base stations covering very small areas in locations with high bandwidth demand to address growing clients’ needs. The femto cells and small cells are often installed indoor, to serve the clients of a single building, such as a shopping mall or an office building. In this paper we provide a practical evaluation of RAN modelling in indoor LTE deployment where we benefit from the full access to the real LTE-A (Rel. 10) deployment and complete building documentation. The measured values of Signal to Interference plus Noise Ratio (SINR) and throughput are compared with the results from the radio signal propagation model, implemented in Python. The obtained values are in consequence used for the transmission power configuration to realize the CCO (Coverage and Capacity Optimization) in LTE networks. The results show very good correlation (above 0.8) between even a simple model based on the building maps and the measurements.
Advances in Electrical and Electronic Engineering, 2011
ABSTRACT Hierarchical system of network nodes is suitable solution how to collect and how to pre-... more ABSTRACT Hierarchical system of network nodes is suitable solution how to collect and how to pre-process data from large amount of end-nodes. By contrast to flat (one layer) architecture there are special intermediary nodes used and they are called summarization nodes. These special nodes have to be suitably placed in the network to enable efficient data collection and their number in the hierarchy is one of the key parameters of the architecture. The article deals with the tree architecture design, with its optimisation and with the problem of limited number of summarization nodes.
2015 38th International Conference on Telecommunications and Signal Processing (TSP), 2015
ABSTRACT Today, one of the most engaging challenges for mobile operators is the question how to m... more ABSTRACT Today, one of the most engaging challenges for mobile operators is the question how to manage the data traffic in mobile networks which is increasing exponentially; mainly due to the growing popularity of applications for mobile devices. Mobile data offloading represents the idea of cost-efficient technology to release the overloaded parts of RAN in cellular networks. This emerging solution introduces the concept of offloading the mobile data from primary cellular communication technology to the IEEE 802.11 infrastructure with aim to gain extra capacity (higher throughput) and improve the overall network performance and user experience. The strategy what, when and for how long to offload data from one communication system to another is non-trivial and therefore already active research in this domain should continue to find the answers for open questions. This paper addresses two the most discussed solutions for offloading between the LTE cellular network and WiFi when the performance needs/requirements exceed the threshold for providing the services via LTE network under an agreed-upon QoS (Quality of Services). In detail, the implementation of SNR (Signal-to-Noise Ratio) threshold based handover and network throughput based handover solutions following the 3GPP standard for Access Network Discovery and Selection Function framework for WiFi offloading in simulation environment NS-3 is proposed. Our simulation results confirm that the concept when the SNR and throughput thresholds can be used to control the mobile data offloading process.
Television broadcasting over IP networks (IP-TV) is one of a number of network applications that ... more Television broadcasting over IP networks (IP-TV) is one of a number of network applications that are except of media distribution also interested in data acqui-sition from group of information resources of variable size. IP-TV uses Real-time Transport Protocol (RTP) protocol for media streaming and RTP Control Protocol (RTCP) protocol for session quality feedback. Other applications, for example sensor networks, have data acquisition as the main task. Current solutions have mostly problem with scalability -how to collect and process information from large amount of end nodes quickly and effectively? The article deals with optimization of hierarchical system of data acquisition. Problem is mathematically described, delay minima are searched and results are proved by simulations.
Today there are numerous active filter circuit solutions employing current or voltage conveyors. ... more Today there are numerous active filter circuit solutions employing current or voltage conveyors. There are also a number of current and voltage conveyors of specific types. In the initial stages of the design they are considered in their idealized form, when their idealized models are used, which are made up of controlled current and voltage sources. To be able to assess whether the proposed structures are or are not suitable, it is necessary to have the possibility of realizing the designed circuits using real components, and also to have, already at the design stage, the most faithful models of real components so that the properties of the filter under consideration can be assessed as early as the design stage and the design of the envisaged filter made as effective as possible. The paper deals with the idea of so-called universal multifunction conveyor, which would enable realizing a certain group of both current and voltage conveyors, thus forming a multipurpose experimental ele...
This work deals with the procedure of filter design using modern active circuit elements called v... more This work deals with the procedure of filter design using modern active circuit elements called voltage conveyors. Like in the case of current conveyors, various kinds of voltage conveyors can be designed and used for frequency filter synthesis. As the voltage conveyors have not been manufactured in the form of real electronic devices yet, the paper shows how to construct the design network structures using the available electronic device AD844. Results of the simulations of ideal filter structures and of using the AD844 are presented.
2007 Third International Conference on Wireless and Mobile Communications (ICWMC'07), 2007
... TREE ESTABLISHMENT ALGORITHM In this section, we introduce a tree organization algorithm for ... more ... TREE ESTABLISHMENT ALGORITHM In this section, we introduce a tree organization algorithm for the RTCP feedback transmission within a multicast session ... in Europe, see Figure 7. This leads to a difference in the feedback-level (or application-level) overlaying topology and ...
Sixth International Conference on Networking (ICN'07), 2007
The real time protocol (RTP) and its accompanying real time control protocol (RTCP) are employed ... more The real time protocol (RTP) and its accompanying real time control protocol (RTCP) are employed in multicast applications. The RTCP protocol is used to distribute feedback on multimedia transmission among session members. The feedback is reported by sending, among others, RR (receiver report) and SR (sender report) packets. With the specific-source multicast, the hierarchical aggregation is used as a method of feedback distribution. The hierarchical aggregation allows a significant reduction of the feedback transmission delay in case of large-scale sessions such as IPTV broadcasting. This paper deals with a tree structure of session members for the feedback distribution with the hierarchical aggregation used. The tree concerned consists of end nodes and summarization nodes. A summarization node aggregates feedback produced from end nodes, which are situated on the lowest tree level only. The tree is applied to an IPTV broadcasting multicast session. The video format used is SD-DVB (standard definition-digital video broadcasting) with the MPEG-2 standard. Also, bandwidth requirements for the feedback distribution in case of the IPTV application described are discussed.
This article focuses on the performance evaluation of the response time for signalling through a ... more This article focuses on the performance evaluation of the response time for signalling through a home Internet Protocol based Multimedia Subsystem (IMS), separately for each of IMS core nodes (Proxy-Call Session Control Function, Interrogating-CSCF, Serving-CSCF and Home Subscriber Server) and then on the investigation of the trend-line functions and their equations to describe these delays for various measured intensity of signalling generated load by high-performance tool - IxLoad. In this article, we have found out the trend-line function of response times for each measured message. Thanks to the showed results, some performance parameters like delay in selected IMS core node and their behaviour can be predicted and evaluated.
A sensing system utilizing a standard optical fiber as a distributed sensor for the detection and... more A sensing system utilizing a standard optical fiber as a distributed sensor for the detection and localization of mechanical vibrations is presented. Vibrations can be caused by various external factors, like moving people, cars, trains, and other objects producing mechanical vibrations that are sensed by a fiber. In our laboratory we have designed a sensing system based on the Φ-OTDR (phase sensitive Optical Time Domain Reflectometry) using an extremely narrow laser and EDFAs.
2016 IEEE Global Communications Conference (GLOBECOM), 2016
\textcopyright} 2016 IEEE. As next-generation mobile networks are rapidly taking shape driven by ... more \textcopyright} 2016 IEEE. As next-generation mobile networks are rapidly taking shape driven by the target standardization requirements and initial trial implementations, a range of accompanying technologies prepare to support them with more reliable wireless access and improved service provisioning. Among these are more advanced spectrum sharing options enabled by the emerging Licensed Shared Access (LSA) regulatory framework, which aims to efficiently employ the capacity of underutilized frequency bands in a controlled manner. The concept of LSA promises to equip network operators with the much needed additional spectrum on the secondary basis and thus brings changes to the existing cellular network management. Hence, additional research is in prompt demand to determine the required levels of Quality of Service (QoS) and service provisioning reliability, especially in cases of dynamic geographical and temporal LSA sharing. Motivated by this recent urge and having at our disposal a fully-functional 3GPP LTE cellular deployment, we have committed to implement and trial the principles of dynamic LSA-compatible spectrum management. This paper is our first disclosure on the comprehensive experimental evaluation of this promising technology. We expect that these unprecedented practical results together with the key lessons learned will become a valuable reference point for the subsequent integration of flexible LSA-based services, suitable for inter-operator and multi-tenant spectrum sharing.
2013 36th International Conference on Telecommunications and Signal Processing (TSP), 2013
ABSTRACT This article presents the implementation of a designed model for the simulation of three... more ABSTRACT This article presents the implementation of a designed model for the simulation of three telecommunication services (File Transfer, Video on Demand and Voice over IP) using a queueing theory. The main objective of this article is modelling and simulations of IMS (IP Multimedia Subsystem) network based on single servers (with a Poisson distribution of job arrivals and an exponential job service time) with FIFO queues of unlimited capacity in Matlab environment. Also, for IMS performance improvement new algorithms for S-CSCF selection were designed and implemented in this mathematical model of IMS subsystem. The results of designed algorithms obtained by simulations are evaluated and compared with each other. It was shown that new algorithms improved IMS performance compared with standardized solution.
2015 7th International Congress on Ultra Modern Telecommunications and Control Systems and Workshops (ICUMT), 2015
The operators are deploying heterogeneous networks with LTE base stations covering very small are... more The operators are deploying heterogeneous networks with LTE base stations covering very small areas in locations with high bandwidth demand to address growing clients’ needs. The femto cells and small cells are often installed indoor, to serve the clients of a single building, such as a shopping mall or an office building. In this paper we provide a practical evaluation of RAN modelling in indoor LTE deployment where we benefit from the full access to the real LTE-A (Rel. 10) deployment and complete building documentation. The measured values of Signal to Interference plus Noise Ratio (SINR) and throughput are compared with the results from the radio signal propagation model, implemented in Python. The obtained values are in consequence used for the transmission power configuration to realize the CCO (Coverage and Capacity Optimization) in LTE networks. The results show very good correlation (above 0.8) between even a simple model based on the building maps and the measurements.
Advances in Electrical and Electronic Engineering, 2011
ABSTRACT Hierarchical system of network nodes is suitable solution how to collect and how to pre-... more ABSTRACT Hierarchical system of network nodes is suitable solution how to collect and how to pre-process data from large amount of end-nodes. By contrast to flat (one layer) architecture there are special intermediary nodes used and they are called summarization nodes. These special nodes have to be suitably placed in the network to enable efficient data collection and their number in the hierarchy is one of the key parameters of the architecture. The article deals with the tree architecture design, with its optimisation and with the problem of limited number of summarization nodes.
2015 38th International Conference on Telecommunications and Signal Processing (TSP), 2015
ABSTRACT Today, one of the most engaging challenges for mobile operators is the question how to m... more ABSTRACT Today, one of the most engaging challenges for mobile operators is the question how to manage the data traffic in mobile networks which is increasing exponentially; mainly due to the growing popularity of applications for mobile devices. Mobile data offloading represents the idea of cost-efficient technology to release the overloaded parts of RAN in cellular networks. This emerging solution introduces the concept of offloading the mobile data from primary cellular communication technology to the IEEE 802.11 infrastructure with aim to gain extra capacity (higher throughput) and improve the overall network performance and user experience. The strategy what, when and for how long to offload data from one communication system to another is non-trivial and therefore already active research in this domain should continue to find the answers for open questions. This paper addresses two the most discussed solutions for offloading between the LTE cellular network and WiFi when the performance needs/requirements exceed the threshold for providing the services via LTE network under an agreed-upon QoS (Quality of Services). In detail, the implementation of SNR (Signal-to-Noise Ratio) threshold based handover and network throughput based handover solutions following the 3GPP standard for Access Network Discovery and Selection Function framework for WiFi offloading in simulation environment NS-3 is proposed. Our simulation results confirm that the concept when the SNR and throughput thresholds can be used to control the mobile data offloading process.
Television broadcasting over IP networks (IP-TV) is one of a number of network applications that ... more Television broadcasting over IP networks (IP-TV) is one of a number of network applications that are except of media distribution also interested in data acqui-sition from group of information resources of variable size. IP-TV uses Real-time Transport Protocol (RTP) protocol for media streaming and RTP Control Protocol (RTCP) protocol for session quality feedback. Other applications, for example sensor networks, have data acquisition as the main task. Current solutions have mostly problem with scalability -how to collect and process information from large amount of end nodes quickly and effectively? The article deals with optimization of hierarchical system of data acquisition. Problem is mathematically described, delay minima are searched and results are proved by simulations.
Today there are numerous active filter circuit solutions employing current or voltage conveyors. ... more Today there are numerous active filter circuit solutions employing current or voltage conveyors. There are also a number of current and voltage conveyors of specific types. In the initial stages of the design they are considered in their idealized form, when their idealized models are used, which are made up of controlled current and voltage sources. To be able to assess whether the proposed structures are or are not suitable, it is necessary to have the possibility of realizing the designed circuits using real components, and also to have, already at the design stage, the most faithful models of real components so that the properties of the filter under consideration can be assessed as early as the design stage and the design of the envisaged filter made as effective as possible. The paper deals with the idea of so-called universal multifunction conveyor, which would enable realizing a certain group of both current and voltage conveyors, thus forming a multipurpose experimental ele...
This work deals with the procedure of filter design using modern active circuit elements called v... more This work deals with the procedure of filter design using modern active circuit elements called voltage conveyors. Like in the case of current conveyors, various kinds of voltage conveyors can be designed and used for frequency filter synthesis. As the voltage conveyors have not been manufactured in the form of real electronic devices yet, the paper shows how to construct the design network structures using the available electronic device AD844. Results of the simulations of ideal filter structures and of using the AD844 are presented.
2007 Third International Conference on Wireless and Mobile Communications (ICWMC'07), 2007
... TREE ESTABLISHMENT ALGORITHM In this section, we introduce a tree organization algorithm for ... more ... TREE ESTABLISHMENT ALGORITHM In this section, we introduce a tree organization algorithm for the RTCP feedback transmission within a multicast session ... in Europe, see Figure 7. This leads to a difference in the feedback-level (or application-level) overlaying topology and ...
Sixth International Conference on Networking (ICN'07), 2007
The real time protocol (RTP) and its accompanying real time control protocol (RTCP) are employed ... more The real time protocol (RTP) and its accompanying real time control protocol (RTCP) are employed in multicast applications. The RTCP protocol is used to distribute feedback on multimedia transmission among session members. The feedback is reported by sending, among others, RR (receiver report) and SR (sender report) packets. With the specific-source multicast, the hierarchical aggregation is used as a method of feedback distribution. The hierarchical aggregation allows a significant reduction of the feedback transmission delay in case of large-scale sessions such as IPTV broadcasting. This paper deals with a tree structure of session members for the feedback distribution with the hierarchical aggregation used. The tree concerned consists of end nodes and summarization nodes. A summarization node aggregates feedback produced from end nodes, which are situated on the lowest tree level only. The tree is applied to an IPTV broadcasting multicast session. The video format used is SD-DVB (standard definition-digital video broadcasting) with the MPEG-2 standard. Also, bandwidth requirements for the feedback distribution in case of the IPTV application described are discussed.
This article focuses on the performance evaluation of the response time for signalling through a ... more This article focuses on the performance evaluation of the response time for signalling through a home Internet Protocol based Multimedia Subsystem (IMS), separately for each of IMS core nodes (Proxy-Call Session Control Function, Interrogating-CSCF, Serving-CSCF and Home Subscriber Server) and then on the investigation of the trend-line functions and their equations to describe these delays for various measured intensity of signalling generated load by high-performance tool - IxLoad. In this article, we have found out the trend-line function of response times for each measured message. Thanks to the showed results, some performance parameters like delay in selected IMS core node and their behaviour can be predicted and evaluated.
A sensing system utilizing a standard optical fiber as a distributed sensor for the detection and... more A sensing system utilizing a standard optical fiber as a distributed sensor for the detection and localization of mechanical vibrations is presented. Vibrations can be caused by various external factors, like moving people, cars, trains, and other objects producing mechanical vibrations that are sensed by a fiber. In our laboratory we have designed a sensing system based on the Φ-OTDR (phase sensitive Optical Time Domain Reflectometry) using an extremely narrow laser and EDFAs.
Uploads