Lifting the limits on high speed wireless data access using antenna arrays

2001 ◽  
Vol 39 (9) ◽  
pp. 156-162 ◽  
Author(s):  
A. Lozano ◽  
F.R. Farrokhi ◽  
R.A. Valenzuela
1999 ◽  
Vol 37 (11) ◽  
pp. 92-98 ◽  
Author(s):  
J. Chuang ◽  
L.J. Cimini ◽  
Geoffrey Ye Li ◽  
B. McNair ◽  
N. Sollenberger ◽  
...  
Keyword(s):  

1994 ◽  
Vol 40 (1) ◽  
pp. 20-27 ◽  
Author(s):  
Tay-Her Tsaur ◽  
Kwang-Cheng Chen ◽  
Chenhsin Lien ◽  
Ming-Tang Shih ◽  
C.P.J. Tzeng

Telecom ◽  
2021 ◽  
Vol 2 (2) ◽  
pp. 167-180
Author(s):  
George K. Varotsos ◽  
Hector E. Nistazakis ◽  
Konstantinos Aidinis ◽  
Fadi Jaber ◽  
Mohd Nasor ◽  
...  

Recent developments in both optical wireless communication (OWC) systems and implanted medical devices (IMDs) have introduced transdermal optical wireless (TOW) technology as a viable candidate for extremely high-speed in-body to out-of-body wireless data transmissions, which are growing in demand for many vital biomedical applications, including telemetry with medical implants, health monitoring, neural recording and prostheses. Nevertheless, this emerging communication modality is primarily hindered by skin-induced attenuation of the propagating signal bit carrier along with its stochastic misalignment-induced fading. Thus, by considering a typical modulated retroreflective (MRR) TOW system with spatial diversity and optimal combining (OC) for signal reception in this work, we focus, for the first time in the MRR TOW literature, on the stochastic nature of generalized pointing errors with non-zero boresight (NZB). Specifically, under these circumstances, novel analytical mathematical expressions were derived for the total average bit error rate (BER) of various system configurations. Their results revealed significant outage performance enhancements when spatial diversity was utilized. Moreover, taking into consideration the total transdermal pathloss along with the effects of stochastic NZB pointing errors, the critical average signal-to-noise ratio (SNR) metric was evaluated for typical power spectral-density values.


Author(s):  
Subhra Prosun Paul ◽  
◽  
Dr. Shruti Aggarwal ◽  

In today’s World sensor networks offer various opportunities for data management applications because of their low cost, reliability, scalability, high-speed data processing, and other versatile advantageous purposes. It is a great challenge to organize data effectively and to retrieve the appropriate data from the large volume of various data sets in ad-hoc network databases, mobile databases, etc. The sensor network is necessary for routing of data, performance analysis of data management activities, and data incorporation for the right application. Data management involves intranet and extranet query handling, data access mechanism, modeling of data, different data movement algorithm, data warehousing, and data mining of network database. Additionally, connectivity, design, and lifetime are important issues for sensor networks to perform all data management activities smoothly. In this paper, we are trying to give a cognitive research tendency of Sensor network data management in the last two decades considering all the challenges and issues of both sensor network database and data management functions using Scopus and Web of Science database. To analyze data, different assessments are done considering various parameters like the author, time, publication and citation number, place, source, document separately for Web of Science and Scopus database in global perspective. It is noticed that there is a significant growth of research in data management for sensor networks because of the popularity of this topic.


2019 ◽  
pp. 158-162
Author(s):  
S. M. Korniiko

The article is devoted to the definition of the content and the system of expert activity in the field of computer technologies, which is based on the results of determining the general system of expert activity. Expert activity should be understood as the implementation by authorized agents on the basis of special knowledge in the field of science, technology, art, crafts, etc. Studies of objects, phenomena and processes in order to provide scientifically substantiated conclusions on the diverse issues that arise in the process of life of society. Such a definition of expert activity includes both judicial and non-judicial expert examination. At present, more than 500 laws are adopted in Ukraine, which in one way or another concern the conduct of expert assessments (most of them are valid at 2019). But no any among that laws directly devoted to the expert work in the field of computer technology. So the system and content of the expert work in the field of computer technology should be established, based on knowledge of the object of expertise – computer technology. It is considered as synonymous with the concept of “information technology” or “information and communication technologies”. Information technology – it is a purposeful organized set of information processes using computer facilities, which provide high speed data processing, rapid information search, dispersal of data, access to information sources regardless of places of their location. The system of expert activity in the field of computer technologies includes examinations belonging to a group of judicial (engineering, commodity, forensic, etc.) and non-judicial (scientific and scientific and technical expertise; examination of issues of quality and conformity of goods (products) to certain requirements; examination of issues of information security; examination of issues of environmental impact and the environment of human life, etc.), as well as presented by different kindsand species examinations that have different goals focused on the study of computer technology in their various aspects and provides solutions to diverse issues.


Author(s):  
Anatoliy Soltus ◽  
◽  
Maksym Rud ◽  

The article examines the problems of navigation and communication with the use of satellite technologies in road transport in the context of the growth of globalization processes in the world economy and the transformations of freight transport technologies caused by a large-scale transition to transport with zero emissions and the development of unmanned vehicles. The paper discusses the principles of building a global high-speed broadband satellite Internet with low latency. Potential capabilities of technologies such as digital antenna arrays and laser communication channels used in such systems are analyzed. Also considered are the existing and potential problems, both technical with electromagnetic compatibility with existing satellite communication systems and between systems under construction or planning, and legal caused by changes in the principles of information transfer at the interstate level. The main players in the emerging market of high-speed satellite communications are considered and the parameters of the systems declared by them are described. The comparison of the current state of building satellite constellations of individual projects is carried out and the ability to implement the announced plans by individual companies is analyzed. The disadvantages that create obstacles for the introduction of high-speed satellite communications in road transport at the moment and the directions of their overcoming are highlighted. Considering the potential of satellite Internet systems, the current state of construction, as well as existing technical and legal restrictions, the introduction of reliable satellite communications will significantly speed up the transition to autonomous unmanned vehicles. In this regard, the most successful opportunities for the new communication technology will be able to realize the transport companies, which will simultaneously update the fleet of vehicles towards zero emissions and with unmanned technologies.


Author(s):  
Ю.Г. Пастернак ◽  
В.А. Пендюрин ◽  
К.С. Сафонов

Решение задачи связи в Арктике, а также в тундре, в тайге, в лесу, в море, на полях возможно только с использованием мобильных систем спутниковой связи. ФГУП «Космическая связь» (г. Москва) располагает группировкой спутников, которая постоянно расширяется. Для надежной связи в Арктике и в северных широтах, помимо геостационарных спутников, запущены спутники, движущиеся по высокоорбитальным траекториям. Для переключения со спутника на спутник, входящий в зону видимости абонента, необходимо использовать антенные решетки. Проблема заключается в том, что в настоящее время отсутствуют мобильные терминалы высокоскоростной спутниковой связи, а стоимость зарубежных аналогов препятствует широкому их использованию (достигает 50 тысяч долларов). Обычно радиолокационная связь (РЛС) с фазированной антенной решеткой используется для наблюдения за тысячами угловых точек, для отслеживания сотни целей. Такие требования могут быть выполнены только путем сканирования луча в пространстве в течение микросекунды. Ясно, что необходимо электронное управление лучом, поскольку механически вращать антенну не представляется возможным. Лишь некоторая часть вышеуказанных проблем будет затрагиваться в этой статье, ниже будут представлены электронная модель антенной решетки и её математическая модель The solution of the communication problem in the Arctic, as well as in the tundra, in the taiga, in the forest, in the sea, in the fields is possible only with the use of mobile satellite communication systems. FSUE "Space Communications" (Moscow) has a constantly expanding group of satellites. For reliable communication in the Arctic and Northern latitudes, in addition to geostationary satellites, satellites moving along high-orbit trajectories were launched. To switch from one satellite to the other included in the subscriber's visibility area, it is necessary to use antenna arrays. The problem is that currently there are no mobile terminals for high-speed satellite communication, and the cost of foreign analogues prevents their widespread use (up to 50 thousand dollars). Typically, a phased array radar is used to track thousands of corner points to track hundreds of targets. Such requirements can only be met by scanning the beam in space for a microsecond. It is clear, that electronic beam control is necessary since it is not possible to mechanically rotate the antenna. Only some of the above problems will be touched upon in this article. An electronic model of the antenna array and its mathematical model is presented


Author(s):  
Xiongwei Fei ◽  
Kenli Li ◽  
Wangdong Yang ◽  
Keqin Li

Heterogeneous and hybrid computing has been heavily studied in the field of parallel and distributed computing in recent years. It can work on a single computer, or in a group of computers connected by a high-speed network. The former is the topic of this chapter. Its key points are how to cooperatively use devices that are different in performance and architecture to satisfy various computing requirements, and how to make the whole program achieve the best performance possible when executed. CPUs and GPUs have fundamentally different design philosophies, but combining their characteristics could avail better performance in many applications. However, it is still a challenge to optimize them. This chapter focuses on the main optimization strategies including “partitioning and load-balancing”, “data access”, “communication”, and “synchronization and asynchronization”. Furthermore, two applications will be introduced as examples of using these strategies.


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