Informacja

Drogi użytkowniku, aplikacja do prawidłowego działania wymaga obsługi JavaScript. Proszę włącz obsługę JavaScript w Twojej przeglądarce.

Wyszukujesz frazę "wireless access" wg kryterium: Temat


Wyświetlanie 1-7 z 7
Tytuł:
Road Safety on the Example of Wireless Services – Case Study
Autorzy:
Lizakowski, Piotr
Powiązania:
https://bibliotekanauki.pl/articles/15850349.pdf
Data publikacji:
2023-06-30
Wydawca:
Wydawnictwo Adam Marszałek
Tematy:
wireless access
vehicular environment
IEEE 802.11p standard
modulation
type
service quality
link selection
Opis:
The paper considers organising wireless access in vehicular environments. Such environments are normally affected by Doppler effects, so the IEEE 802.11p standard is expected to ensure an appropriate quality of service for moving objects. Theoretically, the IEEE 802.11p standard compensates for Doppler effects, but it should be ascertained whether 802.11p is still efficient at tiny Doppler shifts and when an object moves at higher speeds. The 802.11p link provides a data rate which is twice as low for 802.11a. Thus, an end-to-end simulation is carried out for the links at wide ranges of signal-to-noise ratio by varying the Doppler shift from 0 Hz to 100 Hz. The simulation also involves 8 modulation types for 128-, 512-, and 1024-bit packet transmissions to cover all possible study cases. The efficiency criterion is the packet-error rate, to which the data rate is additionally considered. The main simulation result is that the 802.11p link is efficient only at not high speeds. The packet length should be shortened to suppress the influence of the object’s speed. Therefore, to enable high-quality wireless access in vehicular environments, a combination of the 802.11p and 802.11a links should be used, where phase shift keying is more effective for 802.11a and quadrature amplitude modulation is more effective for 802.11p. The trade-off herein is a data rate versus margin speed.
Źródło:
Polish Political Science Yearbook; 2023, 2(52); 185-210
0208-7375
Pojawia się w:
Polish Political Science Yearbook
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Expected volumes of requests in systems of the queueing network with a limited number of waiting places
Autorzy:
Zając, P.
Matalytski, M.
Powiązania:
https://bibliotekanauki.pl/articles/121834.pdf
Data publikacji:
2017
Wydawca:
Uniwersytet Humanistyczno-Przyrodniczy im. Jana Długosza w Częstochowie. Wydawnictwo Uczelniane
Tematy:
sieci HM
sieci kolejkowe
system kolejkowy
bezprzewodowy punkt dostępu
HM-networks
queueing network
single-line queueing system
queueing system
queuing time
limited queue
demands total volume
wireless access point
volume of requests
Opis:
We present a method of finding the expected volume of requests in HM-network with homogeneous requests and bypass of the queueing systems of requests. The case was considered when the volume changes associated with the transitions between the states of the network are deterministic functions, depending on the state of the network and time, and the systems are single line. It is assumed that the probability of the states of the network systems, the parameters of the entrance flow of the requests and the service depend on the time.
Źródło:
Scientific Issues of Jan Długosz University in Częstochowa. Mathematics; 2017, 22; 141-160
2450-9302
Pojawia się w:
Scientific Issues of Jan Długosz University in Częstochowa. Mathematics
Dostawca treści:
Biblioteka Nauki
Artykuł
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
Artykuł
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
Artykuł
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
Artykuł
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
Artykuł
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
Artykuł
    Wyświetlanie 1-7 z 7

    Ta witryna wykorzystuje pliki cookies do przechowywania informacji na Twoim komputerze. Pliki cookies stosujemy w celu świadczenia usług na najwyższym poziomie, w tym w sposób dostosowany do indywidualnych potrzeb. Korzystanie z witryny bez zmiany ustawień dotyczących cookies oznacza, że będą one zamieszczane w Twoim komputerze. W każdym momencie możesz dokonać zmiany ustawień dotyczących cookies