Telecommunications engineering
Telecommunications engineering, or
telecom engineering, is an
engineering discipline that brings together
electrical engineering with
computer science to enhance
telecommunication systems.
[1][2] The work ranges from basic
circuit design
to strategic mass developments. A telecommunication engineer is
responsible for designing and overseeing the installation of
telecommunications equipment and facilities, such as complex
electronic switching systems,
copper wire telephone facilities, and
fiber optics. Telecommunication engineering also overlaps heavily with
broadcast engineering.
Telecommunication is a diverse field of engineering which is connected to
electronics,
civil,
structural, and
electrical engineering.
Ultimately, telecom engineers are responsible for providing the method
for customers to have telephone and high-speed data services. It helps
people who are closely working in political and social fields, as well
accounting and project management.
Telecom engineers use a variety of equipment and transport media
available from a multitude of manufacturers to design the telecom
network infrastructure. The most common media used by wired
telecommunications companies today are
copper wires,
coaxial cable, and
fiber optics.
Telecommunications engineers use their technical expertise to also
provide a range of services and engineering solutions revolving around
wireless mode of communication and other information transfer, such as
wireless telephony services, radio and satellite communications,
internet and broadband technologies.
[3]
Telecom engineers are often expected, as most engineers are, to
provide the best solution possible for the lowest cost to the company.
Most of the work is carried out on a project basis with tight deadlines
and well-defined milestones for the delivery of project objectives.
Telecommunication engineers are involved across all aspects of service
delivery, from carrying out feasibility exercises and determining
connectivity to preparing detailed, technical and operational
documentation.
[3]
This often leads to creative solutions to problems that often would
have been designed differently without the budget constraints dictated
by modern society. In the earlier days of the telecom industry, massive
amounts of cable were placed that were never used or have been replaced
by modern technology such as
fiber optic cable and digital
multiplexing techniques.
[4]
Telecom engineers are also responsible for overseeing the companies'
records of equipment and facility assets. Their work directly impacts
assigning appropriate accounting codes for taxes and maintenance
purposes, budgeting and overseeing projects.
History
Telecommunication systems are generally designed by telecommunication
engineers which sprang from technological improvements in the telegraph
industry in the late 19th century and the radio and the telephone
industries in the early 20th century. Today, telecommunication is
widespread and devices that assist the process, such as the television,
radio and telephone, are common in many parts of the world. There are
also many networks that connect these devices, including computer
networks,
public switched telephone network (PSTN),
[5]
radio networks, and television networks. Computer communication across
the Internet is one of many examples of telecommunication.
[6]
Telecommunication plays a vital role in the part of world economy and
the telecommunication industry's revenue has been placed at just under
3% of the gross world product.
[7]
Telegraph and telephone
Alexander Graham Bell's big box telephone, 1876, one of the first
commercially available telephones - National Museum of American History
Samuel Morse
independently developed a version of the electrical telegraph that he
unsuccessfully demonstrated on 2 September 1837. Soon after he was
joined by
Alfred Vail
who developed the register — a telegraph terminal that integrated a
logging device for recording messages to paper tape. This was
demonstrated successfully over three miles (five kilometres) on 6
January 1838 and eventually over forty miles (sixty-four kilometres)
between
Washington, D.C. and
Baltimore on 24 May 1844. The patented invention proved lucrative and by 1851 telegraph lines in the
United States spanned over 20,000 miles (32,000 kilometres).
[8]
The first successful
transatlantic telegraph cable
was completed on 27 July 1866, allowing transatlantic telecommunication
for the first time. Earlier transatlantic cables installed in 1857 and
1858 only operated for a few days or weeks before they failed.
[9] The international use of the telegraph has sometimes been dubbed the "
Victorian Internet".
[10]
The first commercial telephone services were set up in 1878 and 1879 on both sides of the Atlantic in the cities of
New Haven and
London.
Alexander Graham Bell
held the master patent for the telephone that was needed for such
services in both countries. The technology grew quickly from this point,
with inter-city lines being built and
telephone exchanges in every major city of the United States by the mid-1880s.
[11][12][13]
Despite this, transatlantic voice communication remained impossible for
customers until January 7, 1927 when a connection was established using
radio. However no cable connection existed until
TAT-1 was inaugurated on September 25, 1956 providing 36 telephone circuits.
[14]
In 1880, Bell and co-inventor
Charles Sumner Tainter conducted the world's first wireless telephone call via modulated lightbeams projected by
photophones.
The scientific principles of their invention would not be utilized for
several decades, when they were first deployed in military and
fiber-optic communications.
Radio and television
Over several years starting in 1894 the Italian inventor
Guglielmo Marconi built the first complete, commercially successful wireless telegraphy system based on airborne electromagnetic waves (
radio transmission).
[15] In December 1901, he would go on to established wireless communication between Britain and Newfoundland, earning him the
Nobel Prize in physics in 1909 (which he shared with
Karl Braun).
[16] In 1900
Reginald Fessenden was able to wirelessly transmit a human voice. On March 25, 1925, Scottish inventor
John Logie Baird publicly demonstrated the transmission of moving silhouette pictures at the London department store
Selfridges. In October 1925, Baird was successful in obtaining moving pictures with
halftone shades, which were by most accounts the first true television pictures.
[17] This led to a public demonstration of the improved device on 26 January 1926 again at
Selfridges. Baird's first devices relied upon the
Nipkow disk and thus became known as the
mechanical television. It formed the basis of semi-experimental broadcasts done by the
British Broadcasting Corporation beginning September 30, 1929.
Satellite
The first U.S. satellite to relay communications was
Project SCORE in 1958, which used a tape recorder to
store and forward voice messages. It was used to send a Christmas greeting to the world from U.S. President
Dwight D. Eisenhower. In 1960
NASA launched an
Echo satellite; the 100-foot (30 m) aluminized
PET film balloon served as a passive reflector for radio communications.
Courier 1B, built by
Philco,
also launched in 1960, was the world's first active repeater satellite.
Satellites these days are used for many applications such as uses in
GPS, television, internet and telephone uses.
Telstar was the first active, direct relay commercial
communications satellite. Belonging to
AT&T as part of a multi-national agreement between AT&T,
Bell Telephone Laboratories, NASA, the British
General Post Office, and the
French National PTT (Post Office) to develop satellite communications, it was launched by NASA from
Cape Canaveral on July 10, 1962, the first privately sponsored space launch.
Relay 1 was launched on December 13, 1962, and became the first satellite to broadcast across the
Pacific on November 22, 1963.
[18]
The first and historically most important application for communication satellites was in intercontinental
long distance telephony. The fixed
Public Switched Telephone Network relays
telephone calls from
land line telephones to an
earth station, where they are then transmitted a receiving
satellite dish via a
geostationary satellite in Earth orbit. Improvements in
submarine communications cables, through the use of
fiber-optics,
caused some decline in the use of satellites for fixed telephony in the
late 20th century, but they still exclusively service remote islands
such as
Ascension Island,
Saint Helena,
Diego Garcia, and
Easter Island,
where no submarine cables are in service. There are also some
continents and some regions of countries where landline
telecommunications are rare to nonexistent, for example
Antarctica, plus large regions of
Australia,
South America,
Africa,
Northern Canada,
China,
Russia and
Greenland.
After commercial long distance telephone service was established via
communication satellites, a host of other commercial telecommunications
were also adapted to similar satellites starting in 1979, including
mobile satellite phones,
satellite radio,
satellite television and
satellite Internet access. The earliest adaption for most such services occurred in the 1990s as the pricing for commercial
satellite transponder channels continued to drop significantly.
Computer networks and the Internet
Symbolic representation of the Arpanet as of September 1974
On 11 September 1940,
George Stibitz was able to transmit problems using
teleprinter to his Complex Number Calculator in New York and receive the computed results back at
Dartmouth College in
New Hampshire.
[19] This configuration of a centralized computer or
mainframe computer
with remote "dumb terminals" remained popular throughout the 1950s and
into the 1960s. However, it was not until the 1960s that researchers
started to investigate
packet switching
— a technology that allows chunks of data to be sent between different
computers without first passing through a centralized mainframe. A
four-node network emerged on 5 December 1969. This network soon became
the
ARPANET, which by 1981 would consist of 213 nodes.
[20]
ARPANET's development centered around the Request for Comment process and on 7 April 1969,
RFC 1
was published. This process is important because ARPANET would
eventually merge with other networks to form the Internet, and many of
the
communication protocols that the Internet relies upon today were specified through the Request for Comment process. In September 1981,
RFC 791 introduced the
Internet Protocol version 4 (IPv4) and
RFC 793 introduced the
Transmission Control Protocol (TCP) — thus creating the TCP/IP protocol that much of the Internet relies upon today.
Optical fiber
Optical fiber can be used as a medium for telecommunication and
computer networking because it is flexible and can be bundled as
cables.
It is especially advantageous for long-distance communications, because
light propagates through the fiber with little attenuation compared to
electrical cables. This allows long distances to be spanned with few
repeaters.
In 1966
Charles K. Kao and
George Hockham proposed optical fibers at STC Laboratories (STL) at
Harlow,
England, when they showed that the losses of 1000 dB/km in existing
glass (compared to 5-10 dB/km in coaxial cable) was due to contaminants,
which could potentially be removed.
Optical fiber was successfully developed in 1970 by
Corning Glass Works, with attenuation low enough for communication purposes (about 20
dB/km), and at the same time GaAs (Gallium arsenide)
semiconductor lasers were developed that were compact and therefore suitable for transmitting light through fiber optic cables for long distances.
After a period of research starting from 1975, the first commercial
fiber-optic communications system was developed, which operated at a
wavelength around 0.8 µm and used GaAs semiconductor lasers. This
first-generation system operated at a bit rate of 45
Mbps
with repeater spacing of up to 10 km. Soon on 22 April 1977, General
Telephone and Electronics sent the first live telephone traffic through
fiber optics at a 6 Mbit/s throughput in Long Beach, California.
The first wide area network fibre optic cable system in the world
seems to have been installed by Rediffusion in Hastings, East Sussex, UK
in 1978. The cables were placed in ducting throughout the town, and had
over 1000 subscribers. They were used at that time for the transmission
of television channels,not available because of local reception
problems.
The first
transatlantic telephone cable to use optical fiber was
TAT-8, based on Desurvire optimized laser amplification technology. It went into operation in 1988.
In the late 1990s through 2000, industry promoters, and research
companies such as KMI, and RHK predicted massive increases in demand for
communications bandwidth due to increased use of the
Internet, and commercialization of various bandwidth-intensive consumer services, such as
video on demand.
Internet protocol data traffic was increasing exponentially, at a faster rate than integrated circuit complexity had increased under
Moore's Law.
[21]
Concepts
Basic elements of a telecommunication system
Transmitter
Main article:
Transmitter (information source) that takes information and converts it to a signal for transmission. In
electronics and
telecommunications a transmitter or radio transmitter is an
electronic device which, with the aid of an
antenna, produces
radio waves. In addition to their use in
broadcasting, transmitters are necessary component parts of many electronic devices that communicate by
radio, such as
cell phones,
Transmission medium
Transmission medium over which the signal is transmitted. For example, the transmission medium for
sounds is usually air, but solids and liquids may also act as transmission media for sound. Many transmission media are used as
communications channel. One of the most common physical medias used in networking is
copper wire. Copper wire to carry signals to long distances using relatively low amounts of power.Another example of a physical medium is
optical fiber,
which has emerged as the most commonly used transmission medium for
long-distance communications. Optical fiber is a thin strand of glass
that guides light along its length.
The absence of a material medium in
vacuum may also constitute a transmission medium for
electromagnetic waves such as
light and
radio waves.
Receiver
Receiver (
information sink) that receives and converts the signal back into required information. In
radio communications, a radio receiver is an electronic device that receives
radio waves and converts the information carried by them to a usable form. It is used with an
antenna. The information produced by the receiver may be in the form of sound (an
audio signal), images (a
video signal) or data (a
digital signal).
[22]
Wired communication
Wired communications make use of underground communications cables
(less often, overhead lines), electronic signal amplifiers (repeaters)
inserted into connecting cables at specified points, and terminal
apparatus of various types, depending on the type of wired
communications used.
[23]
Wireless communication
Wireless communication involves the transmission of information over a
distance without help of wires, cables or any other forms of electrical
conductors.
[24]
Wireless operations permit services, such as long-range communications,
that are impossible or impractical to implement with the use of wires.
The term is commonly used in the
telecommunications
industry to refer to telecommunications systems (e.g. radio
transmitters and receivers, remote controls etc.) which use some form of
energy (e.g.
radio waves, acoustic energy, etc.) to transfer information without the use of wires.
[25] Information is transferred in this manner over both short and long distances.
[26]
Roles
Telecom equipment engineer
A telecom equipment engineer is an electronics engineer that designs
equipment such as routers, switches, multiplexers, and other specialized
computer/electronics equipment designed to be used in the
telecommunication network infrastructure.
Network engineer
A network engineer is a computer engineer that is in charge of
designing, deploying and maintaining computer networks. In addition,
he/she oversees network operations from a
network operations center, designs
backbone infrastructure, or supervises interconnections in a
data center.
Central-office engineer
A central-office engineer is responsible for designing and overseeing the implementation of telecommunications equipment in a
central office (CO for short), also referred to as a wire center or
telephone exchange[27]
A CO engineer is responsible for integrating new technology into the
existing network, assigning the equipment's location in the wire center,
and providing power, clocking (for digital equipment), and alarm
monitoring facilities for the new equipment. The CO engineer is also
responsible for providing more power, clocking, and alarm monitoring
facilities if there are currently not enough available to support the
new equipment being installed. Finally, the CO engineer is responsible
for designing how the massive amounts of cable will be distributed to
various equipment and wiring frames throughout the wire center and
overseeing the installation and turn up of all new equipment.
Subroles
As
structural engineers,
CO engineers are responsible for the structural design and placement of
racking and bays for the equipment to be installed in as well as for
the plant to be placed on.
As
electrical engineers, CO engineers are responsible for the
resistance,
capacitance, and
inductance (RCL) design of all new plant to ensure telephone service is clear and crisp and data service is clean as well as reliable.
Attenuation or gradual loss in intensity
[28]
and loop loss calculations are required to determine cable length and
size required to provide the service called for. In addition, power
requirements have to be calculated and provided to power any electronic
equipment being placed in the wire center.
Overall, CO engineers have seen new challenges emerging in the CO environment. With the advent of Data Centers,
Internet Protocol
(IP) facilities, cellular radio sites, and other emerging-technology
equipment environments within telecommunication networks, it is
important that a consistent set of established practices or requirements
be implemented.
Installation suppliers or their sub-contractors are expected to
provide requirements with their products, features, or services. These
services might be associated with the installation of new or expanded
equipment, as well as the removal of existing equipment.
[29][30]
Several other factors must be considered such as:
- Regulations and safety in installation
- Removal of hazardous material
- Commonly used tools to perform installation and removal of equipment
Outside-plant engineer
Outside plant
(OSP) engineers are also often called field engineers because they
frequently spend much time in the field taking notes about the civil
environment, aerial, above ground, and below ground.
[31]
OSP engineers are responsible for taking plant (copper, fiber, etc.)
from a wire center to a distribution point or destination point
directly. If a distribution point design is used, then a
cross-connect box is placed in a strategic location to feed a determined distribution area.
The
cross-connect box, also known as a
serving area interface,
is then installed to allow connections to be made more easily from the
wire center to the destination point and ties up fewer facilities by not
having dedication facilities from the wire center to every destination
point. The plant is then taken directly to its destination point or to
another small closure called a terminal, where access can also be gained
to the plant if necessary. These access points are preferred as they
allow faster repair times for customers and save telephone operating
companies large amounts of money.
The plant facilities can be delivered via underground facilities,
either direct buried or through conduit or in some cases laid under
water, via aerial facilities such as telephone or power poles, or via
microwave radio signals for long distances where either of the other two
methods is too costly.
Subroles
Engineer (OSP) climbing the telephone pole.
As
structural engineers,
OSP engineers are responsible for the structural design and placement
of cellular towers and telephone poles as well as calculating pole
capabilities of existing telephone or power poles onto which new plant
is being added. Structural calculations are required when boring under
heavy traffic areas such as highways or when attaching to other
structures such as bridges. Shoring also has to be taken into
consideration for larger trenches or pits. Conduit structures often
include encasements of slurry that needs to be designed to support the
structure and withstand the environment around it (soil type, high
traffic areas, etc.).
As
electrical engineers,
OSP engineers are responsible for the resistance, capacitance, and
inductance (RCL) design of all new plant to ensure telephone service is
clear and crisp and data service is clean as well as reliable.
Attenuation or gradual loss in intensity
[28]
and loop loss calculations are required to determine cable length and
size required to provide the service called for. In addition power
requirements have to be calculated and provided to power any electronic
equipment being placed in the field. Ground potential has to be taken
into consideration when placing equipment, facilities, and plant in the
field to account for lightning strikes, high voltage intercept from
improperly grounded or broken power company facilities, and from various
sources of electromagnetic interference.
As
civil engineers, OSP engineers are responsible for drafting plans, either by hand or using
Computer-aided design
(CAD) software, for how telecom plant facilities will be placed. Often
when working with municipalities trenching or boring permits are
required and drawings must be made for these. Often these drawings
include about 70% or so of the detailed information required to pave a
road or add a turn lane to an existing street. Structural calculations
are required when boring under heavy traffic areas such as highways or
when attaching to other structures such as bridges. As civil engineers,
telecom engineers provide the modern communications backbone for all
technological communications distributed throughout civilizations today.
Unique to telecom engineering is the use of air-core cable which
requires an extensive network of air handling equipment such as
compressors, manifolds, regulators and hundreds of miles of air pipe per
system that connects to pressurized splice cases all designed to
pressurize this special form of copper cable to keep moisture out and
provide a clean signal to the customer.
As political and social
ambassador,
the OSP engineer is a telephone operating company's face and voice to
the local authorities and other utilities. OSP engineers often meet with
municipalities, construction companies and other utility companies to
address their concerns and educate them about how the telephone utility
works and operates.
[31][32]
Additionally, the OSP engineer has to secure real estate to place
outside facilities on, such as an easement to place a cross-connect box
on.
source : https://en.wikipedia.org/wiki/Telecommunications_engineering
