CC BY
103
2. Kim I.I., McArthur Bruce, Korevaar Eric. Comparsion of laser beam propagation at 785nm and 1550nm in fog and haze for optical wireless communications // Proc. of SPIE - vol. 4214, Optical Wireless Communications III. Ed. Eric J. Korevaar. - February. - 2001. - Р. 26-37.
3. Yuksel H., Milner S., Davis C.C. Aperture averaging for optimizing received design and system performance on free-space optical communication links // J. Opt. Netw. - 2005. - Vol. 4, No. 8. - Р. 462-475.
4. Andrews L.C., Philips R.L. Laser Beam Propagation Through Random Media. - 2nd ed. - Bellingham, Washington: SPIE Perss, 2005. - 820 p.
5. Prokes A. Modeling of atmospheric turbulence effects on terrestrial FSO link // Radioengineering. - 2009. - Vol. 18, No. 1. - Р. 42-47.
6. Arun R. Majumadar, Jennifer C. Ricklin Optical and fiber communication reports. Free-Space Laser Communication. - New York: Springer Science + Business Media, LLC, 2008. - 417 p.
7. Архипова Н.В. СО2 лазер с высокочастотным электромагнитным возбуждением I Н.В. Архипова, И.Н. Полухин, В.И. Юдин II Приборы и техника эксперимента. - 2000. - № 1. - С. 1-2.
THE HISTORY OF TELECOMMUNICATIONS DEVELOPMENT AND ITS GOALS
© Нурмухамбетова С.А.*, Умарова Д.М.Ф, Кутлубаева А.Д.*
Астраханский государственный технический университет, г. Астрахань
The Internet has revolutionized the computer and communications world like nothing before. The invention of the telegraph, telephone, radio and computer set the stage for this unprecedented integration of capabilities. The Internet is a medium for collaboration and interaction between individuals and their computers without regard for geographical location.
The necessity to communicate at a distance appeared long ago. When the alphabet was invented, people began to use papyrus and there was something like the modern letter. The first to send letters were the ancient Egyptians. But the best postal system of ancient times was organized by the Romans.
However until the 19-th century there were practically no advances in the means of communication.
The first practical electromagnetic telegraph was invented by Russian scientist Pavel Shilling in 1828, and in 1832 he established telegraph communication
* Старший преподаватель кафедры «Иностранные языки в инженерно-техническом образовании», аспирант кафедры «Общая психология».
* Студент кафедры «Связь». " Студент кафедры «Связь».
between the Winter Palace and the Ministry of Transport in St. Petersburg. B. Yakobi made several improvements in the electromagnetic telegraph and linked St. Petersburg with Tsarskoye Selo. Yakobi invented the telegraph sending key, adopted by the American Samuel Morse. Morse invented the telegraph code of dots and dashes, which is used all over the world to this day.
The telephone is a much younger invention than the telegraph. French mechanic Charles Boursel first suggested the idea of transmitting speech electrically. The first telephone that found application was invented by American Graham Bell in 1876. Russian inventors made several important improvements in the telephone. At present the method of frequency modulation allows to transmit several hundred telephone conversations over the same wire simultaneously.
The telegraph and the telephone were soon followed by the most wonderful invention, which made possible communication without wires. Numerous scientists from different countries contributed to the appearance of wireless communication. In 1895 Russian scientist A.S. Popov demonstrated his first radio receiver. In March 1897 G. Marconi, an Italian inventor, transmitted wireless telegraphy signals over a distance of two miles. However, broadcasting became possible only in 1920s with the introduction of radio receivers in Europe and the USA.
Today radio takes many forms, including wireless networks and mobile communications of all types. Radio communication is the transmission of high frequency energy from the transmitter to the receiver without wires. Radio is a device that transmits and receives signals and programs by electromagnetic waves. The two necessary components of radio are a transmitter and a receiver.
Internet radio or web radio is an audio broadcasting service transmitted via the Internet. Internet radio services are usually accessible from anywhere in the world. This makes it popular among listeners with interests that are not adequately served by local radio stations. Internet radio services offer news, sports, talk and various genres of music - everything that is available on traditional radio stations.
The theory of communication deals primarily with systems for transmitting information from one point to another. The source output might represent a voice waveform, a sequence of binary digits from a magnetic tape, the output of a set of sensors in a space probe, or a target in a radar system. The channel might represent a telephone line, a high frequency radio link, a space communication link, or a storage medium.
In the beginning of 1940's a mathematical theory for dealing with more fundamental aspects of communication systems was developed. The distinguishing characteristics of this theory are the following:
1. the great emphasis on probability theory;
2. the primary concern with the encoder and decoder. In the last 20 years the information theory was extended, made more precise and now it is applied in practical communication systems.
Information technology is the study, design, development, implementation, support or management of computer-based information systems, particularly software applications and computer hardware. Information technology deals mainly with the use of electronic computers and computer software to convert, store, protect, process, transmit and securely retrieve information.
Today the term information technology includes many aspects of computing and technology and covers many fields. Information technology professionals perform a variety of duties that range from installing applications to designing complex computer networks and information databases. The duties of IT specialists may involve data management, networking, engineering computer hardware, database and software design, as well as the management and administration of the whole system. Information technology describes any technology that helps to produce, manipulate, store, communicate and /or disseminate information.
Thus, Information Communication Technology embraces all technologies for the communication of information. It includes any medium to record information (paper, pen, magnetic disk / tape, optical disks - CD / DVD, flash memory etc.) and also technology for broadcasting information - radio, television. It involves any technology for communicating through voice and sound or images - microphone, camera, loudspeaker, telephone. At present it is apparently culminating to information communication with the help of Personal Computers networked through the Internet, information technology that can transfer information using satellite systems or intercontinental cables.
It should be noted that the history of Internet development revolves around four distinct aspects:
1. the technological evolution that began with early research on packet switching and where current research continues to expand the horizons of the infrastructure along several dimensions, such as scale, performance and higher level functionality;
2. the operations and management aspect of a global and complex operational infrastructure;
3. the social aspect, which resulted in a broad community of internet users working together to create and evolve the technology;
4. the commercialization aspect resulting in an extremely effective transition of research results into a broadly deployed and available information infrastructure.
At present the Internet is a worldwide network of computers and computer networks that can communicate with each other using Internet Protocol. It is a «network of networks» that consists of millions of private and public, academic, business and government networks linked by copper wires, fiber-optic cables, wireless connections and other technologies. The Internet carries various information resources and services, such as electronic mail, on-line chat, file transfer and file sharing, on-line gaming, and the inter-linked hypertext documents and other resources of the World Wide Web.
The Internet can now be accessed virtually anywhere by numerous means. Mobile phones, data cards, handheld game consoles and cellular routes allow users to connect to the Internet from anywhere there is a cellular network supporting that device's technology.
Television is a widely used telecommunication medium for sending and receiving moving images, either monochromatic (black and white) or colour, usually accompanied by sound.
In 1884 Paul G. Nipkow, a 20-year old university student in Germany invented the first electromechanical television system which employed a scanning disk, a spinning disk with a series of holes spiraling toward the centre, for "rasterization", the process of converting a visual image into a stream of electrical pulses. The beginning of the 20-th century brought advances in amplifier tube technology and the use of a rotating mirror-drum scanner to capture the image. Most of the 20-th century televisions depended also upon the cathode-ray tube invented by Karl Braun in 1927.
Telecommunication, a transmission of signals over a distance for the purpose of communication, is an important part of modern society. In telecommunication, a communication system is a collection of individual communications networks, transmission systems, relay stations, tributary stations and data terminal equipment usually capable of interconnection and interoperation to form an integral whole. The components of a communication system serve a common purpose, they are technically compatible use common procedures respond to controls and operate in unison.
The main goals of telecommunication usage in the contemporary world are business and education. Telecommunication business networks - the broad network of partner, customer and supplier relationships and interactions change rapidly and become increasingly dynamic. Plenty of opportunities appear with emerging technologies and advances in consumer electronics. The increasingly global industry landscape can be a competitive challenge, but also a new way to grow business. Addressing these challenges and opportunities requires innovative new services and business models to retain customers lower the capital and operating costs and improve business agility. Working smarter in telecommunications starts with a thorough evaluation of the information technology infrastructure and its relationship to streamlining operations across the entire business network. The modern achievements in the field of telecommunication allow to reduce the time to activate services from days to hours and offer faster problem resolution resulting in improved customer satisfaction levels. Flexible and reliable connectivity and application integration enables an agile foundation for growth, which is critical for handling an increase in the number of subscribers and services without compromising quality and customer satisfaction.
Telecommunications in education for all is a goal that is becoming more achievable as technology extends ever further. Opportunities to learn are provided
to children, women and men through the Internet, computers and CDROMs, email, audio and video teleconferencing, video or television broadcasts and radio. Students and other learners can access the content directly. Teachers can develop their skills and knowledge. Telecommunications help to deliver quality content across wide geographical area. Educating and training youth is one of the major responsibilities of government. Education has always been a foundation for economic and social development. Countries have the opportunity to develop their intellectual capital, and it will become increasingly necessary for all nations to invest wisely to educate and train their citizens, of all ages. Investments in education and learning are crucial. Wise investments that utilize the power and reach of the information and communication technologies available can help to achieve the goal of universal access to education. Information can now travel to any part of the world, across a city or nation, in the same time and at the same cost.
Список литературы:
1. Английский язык для технических вузов: учеб. пособие / В.А. Радо-вель - М. : Дашков и Ко, 2010. - 444 с.
2. Innovation in Telecommunications [Электронный ресурс]. - Режим доступа: http://cyber.law.harvard.edu/commonsbasedresearch/sites/commonsbased-research/images/Telecommunications.pdf.
3. Telecommunications & Education - The Regency Foundation [Электронный ресурс]. - Режим доступа: www.regency.org/t_in_act/pdf/english/edu-cate.pdf.
BLIND DETECTION IN A NONCOHERENT ASYNCHRONOUS DHA FH OFDMA SYSTEM1
© Osipov D.S.*, Seitkulov Ye.N.*
Institute for Information Transmission Problems RAS (Kharkevich Institute),
Moscow
L.N. Gumilyov Eurasian National University, Kazahstan, Astana
In this paper the problem of designing a blind detection technique for a noncoherent DHA FH OFDMA system is considered. Two decision making strategies are introduced. The performance of the proposed strategies in terms of the maximum possible transmission rate is evaluated via simulation for the typical urban model from the 3GPP LTE standard.
1 Dmitry Osipov has been supported by the RFBR grant 12-07-31035
* Старший научный сотрудник лаборатории Информационных технологий передачи, анализа и защиты информации Института проблем передачи информации им. А.А. Харкевича РАН, кандидат технических наук.
* Директор НИИ Информационной безопасности и криптологии, кандидат физико-математических наук.
