Temat: access networks - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Performance and Limitations of VDSL2-based Next Generation Access Networks
Autorzy:: Heliotis, G.
Dimos, L.-P.
Kordoulis, I.
Agapiou, G.
Powiązania:: https://bibliotekanauki.pl/articles/307882.pdf
Data publikacji:: 2013
Wydawca:: Instytut Łączności - Państwowy Instytut Badawczy
Tematy:: DSL networks
impulse noise
VDSL2 next generation access networks
crosstalk
Opis:: In this paper, we first briefly review the main operational aspects of FTTC (xPON)/VDSL2 access networks. Then, we present performance measurements with respect to network sub loop operating length and VDSL2 operational profiles (8b, 12a, 17a), studying the rates that can be achieved at different scenarios. We then provide results of the effect of stationary crosstalk and non-stationary impulse noise on the provisioned service in an operating VDSL2 access network.
Źródło:: Journal of Telecommunications and Information Technology; 2013, 1; 98-102
1509-4553
1899-8852
Pojawia się w:: Journal of Telecommunications and Information Technology
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: RoFnet - Reconfigurable Radio over Fiber Network Architecture Overview
Autorzy:: Medeiros, M.
Avó, R.
Laurencio, P.
Correia, N.
Barradas, A.
Powiązania:: https://bibliotekanauki.pl/articles/308954.pdf
Data publikacji:: 2009
Wydawca:: Instytut Łączności - Państwowy Instytut Badawczy
Tematy:: optical access networks
optical single sideband
radio over fiber
reflective semiconductor optical amplifiers
wavelength division multiplexing
Opis:: This paper introduces the basic operational concepts of the RoFnet - reconfigurable radio over fiber network, which is a project supported by the Portuguese Foundation forScience and Technology. This project proposes an innovative radio over fiber optical access network architecture, which combines a low cost base station (BS) design, incorporating reflective semiconductor optical amplifiers, with fiber dispersion mitigation provided by optical single sideband modulation techniques. Optical wavelength division multiplexing (WDM) techniques are used to simplify the access network architecture allowing for different BSs to be fed by a common fiber. Different wavelength channels can be allocated to different BSs depending on user requirements. Additionally, in order to improve radio coverage within a cell, it is considered a sectorized antenna interface. The combination of subcarrier multiplexing with WDM, further simplifies the network architecture, by using a specific wavelength channel to feed an individual BS and different subcarriers to drive the individual antenna sectors within the BS.
Źródło:: Journal of Telecommunications and Information Technology; 2009, 1; 38-43
1509-4553
1899-8852
Pojawia się w:: Journal of Telecommunications and Information Technology
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Ubiquity of Client Access in Heterogeneous Access Environment
Autorzy:: Gierłowski, K.
Powiązania:: https://bibliotekanauki.pl/articles/308576.pdf
Data publikacji:: 2014
Wydawca:: Instytut Łączności - Państwowy Instytut Badawczy
Tematy:: handover
mesh networks
mobility
technological networks
ubiquitous access
wireless networks
Opis:: With popularization of mobile computing and diverse offer of mobile devices providing functionality comparable to personal computers, the necessity of providing network access for such users cannot be disputed. The requirement is further reinforced by emergence of general purpose mobile operating systems which provide their full functionality only with network connectivity available and popular XaaS (Everything as a Service) approach. In this situation and combined with the fact that most Internet-based services are able to function efficiently even in best effort environment, requirement of ubiquity of network access becomes one of the most important elements of today’s computing environment. This paper presents a general overview of the the vast group of mechanisms and technologies utilized in modern attempts to efficiently provide ubiquity on network access in heterogeneous environment of today’s access systems. It starts with division of users interested in ubiquitous network access into broad groups of common interest, complete with their basic requirements and access characteristics, followed by a survey of both already popular and new wireless technologies suitable to provide such access. Then a general discussion of most important challenges which must be addressed while attempting to fulfill the above goal is provided, addressing topics such as handover control and mobility management.
Źródło:: Journal of Telecommunications and Information Technology; 2014, 3; 3-16
1509-4553
1899-8852
Pojawia się w:: Journal of Telecommunications and Information Technology
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Protocols for Wireless Sensor Networks: A Survey
Autorzy:: Kochhar, A.
Kaur, P.
Singh, P.
Sharma, S.
Powiązania:: https://bibliotekanauki.pl/articles/958098.pdf
Data publikacji:: 2018
Wydawca:: Instytut Łączności - Państwowy Instytut Badawczy
Tematy:: cross-layer
Medium Access Control
protocols
Wireless Sensor Networks
Opis:: This paper presents a survey on the MAC and network layer of Wireless Sensor Networks. Performance requirements of the MAC layer are explored. MAC layer protocols for battery-powered networks and energy harvesting-based networks are discussed and compared. A detailed discussion on design constraints and classification of routing protocols is presented. Several routing protocols are compared in terms of such parameters as: energy consumption, scalability, network lifetime and mobility. Problems that require future research are presented. The cross-layer approach for WSNs is also surveyed.
Źródło:: Journal of Telecommunications and Information Technology; 2018, 1; 77-87
1509-4553
1899-8852
Pojawia się w:: Journal of Telecommunications and Information Technology
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Simulating capture behaviour in 802.11 radio modems
Autorzy:: Ware, C.
Wysocki, T. A.
Chicharo, J.
Powiązania:: https://bibliotekanauki.pl/articles/309552.pdf
Data publikacji:: 2001
Wydawca:: Instytut Łączności - Państwowy Instytut Badawczy
Tematy:: wireless local area networks
ad hoc networks
capture models
medium access control protocol
fairness
Opis:: Simulation plays an important role in the performance evaluation of MAC protocols. Building simulation models which are able to accurately model physical behaviour is fundamental to the outcome of such techniques. Through both qualitative and quantitative comparison of experimental trace data against simulation results obtained using delay, power, and hybrid capture models, this paper investigates the performance of various packet capture models in the simulation analysis of the 802.11 PHY and MAC layer protocols. We illustrate these models are unable to accurately describe the fairness properties of the experimental data. A new model is proposed, Message Retraining, to describe the operation of an 802.11 receiver. We illustrate that the Message Retraining reception model is able to model the fairness characteristics obtained with an IEEE 802.11 radio modem more accurately than the previous capture models.
Źródło:: Journal of Telecommunications and Information Technology; 2001, 3; 46-54
1509-4553
1899-8852
Pojawia się w:: Journal of Telecommunications and Information Technology
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: How the Role-Based Trust Management Can Be Applied to Wireless Sensor Networks
Autorzy:: Felkner, A.
Powiązania:: https://bibliotekanauki.pl/articles/307588.pdf
Data publikacji:: 2012
Wydawca:: Instytut Łączności - Państwowy Instytut Badawczy
Tematy:: access control
role-based trust management
trust
wireless sensor networks
Opis:: Trust plays an important role in human life environments. That is why the researchers has been focusing on it for a long time. It allows us to delegate tasks and decisions to an appropriate person. In social sciences trust between humans was studied, but it also was analyzed in economic transactions. A lot of computer scientists from different areas, like security, semantic web, electronic commerce, social networks tried to transfer this concept to their domains. Trust is an essential factor in any kind of network, whether social or computer. Wireless sensor networks (WSN) are characterized by severely constrained resources, they have limited power supplies, low transmission bandwidth, small memory sizes and limited energy, therefore security techniques used in traditional wired networks cannot be adopted directly. Some effort has been expended in this fields, but the concept of trust is defined in slightly different ways by different researchers. In this paper we will show how the family of Role-based Trust management languages (RT) can be used in WSN. RT is used for representing security policies and credentials in decentralized, distributed access control systems. A credential provides information about the privileges of users and the security policies issued by one or more trusted authorities.
Źródło:: Journal of Telecommunications and Information Technology; 2012, 4; 70-77
1509-4553
1899-8852
Pojawia się w:: Journal of Telecommunications and Information Technology
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Evolutionary paths in wireless communication systems
Autorzy:: Michalski, W.
Powiązania:: https://bibliotekanauki.pl/articles/309042.pdf
Data publikacji:: 2005
Wydawca:: Instytut Łączności - Państwowy Instytut Badawczy
Tematy:: cellular mobile radio systems
wireless local area networks
wireless personal networks
wide area wireless packet data systems
satellite-based mobile systems
paging/messaging systems
cordless telephones
access points
switches
GPRS
Mobile IP
WLAN cellular integration
Opis:: The paper contains a review and analysis of evolutionary paths of seven most important, from network development strategy point of view, wireless communication systems, especially the WLAN operating according to the IEEE 802.11 standard. With respect to WLAN, trends related to evolution toward mobile network and self organizing network as well as toward integration of WLAN and GSM using GPRS are presented. Concerning WLAN architecture development, evolution paths toward distributed controlled network as well as centrally coordinated and controlled network are described. Moreover, analysis includes cellular mobile radio systems, wireless personal networks, wide area wireless packet data systems, satellite-based mobile systems, paging/messaging systems and cordless telephones. With respect to these systems, general evolution process and trends associated with this process are described.
Źródło:: Journal of Telecommunications and Information Technology; 2005, 3; 105-111
1509-4553
1899-8852
Pojawia się w:: Journal of Telecommunications and Information Technology
Dostawca treści:: Biblioteka Nauki

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