Communications Technologies

 

Communication describes an activity whereby a connection is created or a message or information is transmitted, and it may be performed naturally, as in face-to-face conversation, or through technological means.

 

The topic of technologically-based communication embraces a whole world today.  It may be said that modern communication of all types – wired communication, wireless and cellular communication, and data transfer – is a variegated 'salad' of infrastructures, technologies, instruments and systems that are interconnected and mutually supportive.

 

Some scenarios from daily life may illustrate the complex interconnections of modern communications technologies:

  • Telephone communication: line telephone conversation from one city to a mobile phone user in another city. The conversation starts from a wired network, is relayed to a cellular network through a switch center, and from there to a cellular site nearest to the recipient of the conversation
  • Use of multimedia: transmission of photographs through a communications network.  A photograph taken with a communication device in one city is transmitted to a nearby cellular site, relayed by the cellular communications network to a cellular site in another city or country, and transmitted from there to the recipient.

 

 

Global Communication

Global Communication

 

From natural to technological communication

Communication describes an activity or process of transmission of information and messages. Information may travel from one point to another point, from a single point to several points and vice versa, or from several points to other points. Communication takes place between all living organisms, including at the molecular and intercellular levels.  In nature an infinite number of types of communication exists, ranging from those taking place in the living body, such as the transmission of genetic information by means of molecular structures, or transmission of messages in the brain through electric connections and chemical agents, through communication of sound such as bird song, or visual or 'aromatic' communication between flowers and insects, up to and including gestures and speech between humans.

 

In humans, communication takes place between two or more people, and when we use technological means we use artificial signals, such as coded signals and digital messages, and the information is converted into electrical signals and then back again to information.  Communication activity includes the sender, the content of the message, and the recipient, and necessitates cooperative communication between the sender and the recipient.  Information may pass between the active collaborators in real time, as in conversation, or with a delay, such as in sending a letter by post or by e-mail, as a result of which the transmission of the message and its reception may occur at different points in time.

 

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Development of Technological systems

 

Communication between humans developed along with the developments in science and technology, both in quality and in quantity.  Ancient communication was based on messages transmitted verbally, even over distances, through messengers, on smoke signals or drums.  Following this, symbolic communication appeared- transmission of messages through symbols engraved or painted on stones and rocks, such as in cave drawings.  The first signs of writing appeared about 5.500 years ago, engraved in stone and clay, or imprinted in mud or mortar. Animal skins and papyrus made from reeds were also used.

  Ancient Sumerian cuneiform script (26 B.C)

Ancient Sumerian cuneiform script (26 B.C)

 
 

The development of writing into an accepted system of symbols provided uniformity in a language and enabled the transmission of messages and information over greater distances.  When postal services were established and began to operate in an organized and institutionalized fashion (over the course of history postal services employed messengers on foot, horsemen, carriages, and homing pigeons) it was possible to transmit written messages relatively more rapidly, in an organized fashion, and over greater distances.  The invention of printing in the mid-15th Century naturally led to a tremendous revolution in the field of transmission of information and messages.  The ability to transmit and receive information ;by electronic means, a process initiated with the invention of the telegraph in the 18th Century, followed by the telephone and radio, altered the nature of communication forever, and in fact transformed it into mass communication.  Modern communication systems – including TV, Internet and mobile phones – enable fast and efficient mass communication.

 

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Communication technologies and systems – types

Today's communication systems and networks are spread throughout the world, and depend on different types of technologies and infrastructures that are interconnected and able to communicate reciprocally and dynamically through switching and connecting centers, local and global.  This complex communication system of infrastructures and technologies consists of the following strata:

  • Technologies of wired communication systems (telephone lines and optic fibers), including the sub-system of verbal communication
  • Technologies of wireless and cellular communication
  • Technologies of data transfer systems, such as computers (see details below)
  • Sub-systems of multimedia communication  that combine picture, movement and sound 
     

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Types of infrastructures and the wireless network

Infrastructures supporting communication networks

  • Wireless networks
  • Data transfer networks by cable
  • Telephone networks

 

The Wireless Network

A wireless network enables the user to establish wireless connection over great distances without the need for cables.  Wireless connection operates through technologies using electromagnetic waves, such as radiofrequency radiation, microwave, and infrared light.  The ranges of wireless communication are restricted by the range of frequencies and communication technology used.  The typical restrictions are, for instance, strength of the signal, fading of the signal along its course, or by the line-of-sight.  The wireless network is used in devices and installations such as computers, and personal digital accessories (PDAs) such as palm computers, tablets and mobile phones.

 

Types of technologies in wireless data transfer

  • The Wi-Fi network (wireless transmission of data through radiofrequency) - typical ranges for a wireless access points are 35 meters indoors and 100 meters outdoors
  • Bluetooth technology – this technology is relatively inexpensive and may be used over relatively long distances.  In a Personal Area Network (PAN) the range is up to 100 meters, but with Bluetooth earphones it is limited to a few meters.
  • Satellite Microwave technology –  This technology enables communication over long distances – up to tens of kilometers between cellular sites and hundreds of kilometers with satellites. Although this technology requires a large initial investment, it can be utilized immediately.
  • Infrared technologies – inexpensive, but restricted to short distances of a few meters, for example, in remote control devices.
  • Near Field Communication (NFC) technologies – used mainly in smart phones situated within reach, or close to this, for radio communication according to a communication standard (protocol) appropriate to the transmission of documents and data (e.g. telephone directories) and for coordination between devices.

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Cellular communication networks

A mobile (cell) phone is a bi-directional radio that can transmit and receive simultaneously using the radiofrequency range of the electromagnetic radiation spectrum. Cellular communication technology enables the use of mobile phones, and it is based on the geographic subdivision of the communication technology's coverage area into cells, each with a given number of frequencies (or channels), allowing a large number of subscribers to communicate simultaneously.

Illustration of Cellular CommunicationIllustration of Cellular Communication

 

 

 

 

 

 

 

 

 

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Data communication networks

Data communication is a process of direct digital transfer of data between computers (such as portable computers, notepads, tablets, and smart phones) without intermediate storage.  The process is conducted through a physical platform of linear communication networks (such as telephone lines and optical fibers) or through wireless networks (such as communication through radiofrequency waves or the cellular network) or through a combination of the two.

 

Types of data communication networks:

  • Personal Area Network (PAN) – a personal computer network for individual use or for a household network
  • Local Area Network (LAN) – local networks in a single household or group of buildings (such as a university campus)
  • Metropolitan Area Network (MAN) – intended for a geographical area of the size of a city or metropolis
  • Wide Area Network (WAN) – networks spread over a large unlimited area, linking cities and countries.

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Scenarios to illustrate the combination of different communication systems

As previously mentioned, the different types of communication systems – linear communication, wireless and cellular communication, and data communication – are interconnected and work together. 

The complexity of communicationThe complexity of communication

 

  • A conversation between a person in his or her home, using a line phone, and someone in another town speaking on a mobile phone while driving through an open area. The conversation goes out from the home of the sender through the telephone line, reaches the switchboard of the line network, is relayed to the cellular network of the mobile station center (MSC) nearest to the recipient, and the station center directs the conversation to the cellular base station nearest to the recipient, who is driving on the open road.
  • An individual in his home sends a photograph (multimedia messaging service – MMS) to a recipient in a shopping center. A multimedia photo may be transmitted in one of two ways:

1. Directly through the cellular network of an advanced mobile phone (Generation 3+):  The photo is transmitted from the mobile device to the cellular site nearest to the sender, through the appropriate generation communication network, from where it is transmitted by MSC – the cellular switch responsible for routing the transmitted media signals – to the cellular site nearest to the shopping center where the recipient is located.  If the recipient is situated in the electromagnetic shade relative to the nearest site, i.e. there is no direct reception from the site, the picture is relayed to a microcellular system deployed in the shopping center, and from there to the microcell nearest to the recipient, and then to his mobile phone.

2. Through an in-house communication network by Wi-Fi technology: The photo is sent through the in-house Wi-Fi network from the sender's mobile phone in his home, and transmitted through the modem in his home to the Internet transmitter through the LAN and WAN networks – these networks, that are woven through the cellular network, relay the photo to the MSC and to the cellular site nearest to the shopping center where the recipient is located.  Here, too, if the recipient is situated in the electromagnetic shade relative to the nearest site, i.e. there is no direct reception from the site, the picture is relayed to a microcellular system deployed in the shopping center, and from there to the microcell nearest to the recipient, and then to his mobile phone.

 

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References

  • Communication Technology Update and Fundamentals, 14th edition (Grant AE, Meadows JH, editors In association with Technology Futures, Inc). Focal Press, New York and London. 2014.
  • Jones S, Kovac RJ, Groom FM. Introduction to Communications Technologies: A Guide for Non-Engineers, 2nd Edition, December 16, 2008

 

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