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| Chapters |
Abstract |
| Chapter 1 |
Definition of Telecommunications
The Thai telecommunication encyclopedia (2009 edition) presents “telecommunications” as “communication that eliminates distance between persons, equipments, or any automatic system. It is used with any kind of electro-mechanic, light, electromagnetic wave, or
the specific quantum properties, in order to deliver understanding signs, signal, text, sound, picture or multimedia to the receiver.”
This is derived from those of the world’s telecommunication development. Starting from sending smoke, fire, or sound signals, it was
then replaced by mechanical telegraph, copper wires, electromagnetic waves, optical fiber, and so on. Telecommunication significantly
reduces time of those messages transportation over the distances covering person to person communication through the network
level of regional, national, and international connections.
|
| Chapter 2 |
History of World Telecommunications: Telegraphy and Telephony
From a social and culture perspective, the rapid and dependable communications was indispensable to
human life. Systematically,
beginning of communications with telegraph, the world first commercial
service was started in England in 1839 and in the United State
in 1844. Telegraph service was
spanned much in Europe, North America, and Middle East. Its networks connected every continent
except the Antarctica covering every major body of water by submarine cable. Consequently, with the
attempt of combining human
voice into that previous communication system, the telephony was then
born. These both basic telecommunication systems were the
world early important discoveries and
fundamental technologies which sparked lots of latter significant telecommunication systems. |
| Chapter 3 |
History of World Telecommunications: Radio and Wireless
Communications
Evidently, the world’s early discoveries of major communications systems were the telegraphy and
telephony. Another advance in
communications engineering was followed by the radio communications.
It starting was counted on the elegant mathematical
equation of James Clerk Maxwell which was
released during the 1860s. Until 1888, the demonstration of generation and detection
to the
electromagnetic radiation by using Maxwell’s equation was then set up by a German physicist, Heinrich
Hertz. Subsequently,
an Italian researcher named Guglielmo Marconi introduced the wireless signaling
apparatus in 1896. Later, there was the first
wireless link across the Atlantic Ocean consequently in
1901, and then led to the first major application of wireless telegraphy.
Since then, the following
developments were done significantly and came up with other newer systems. There are radio and
television broadcasting, radar, microwave, and radio frequency engineering. Obviously, there are the
world telecommunication
heritages in radio and wireless communication areas. |
| Chapter 4 |
History of World Telecommunications:Optical and Satellite Communications
History of satellite began October 4, 1957, when the Soviet Union launched Sputnik 1, the world’s first
spacecraft. The space race
was on, and in February of 1957, the United States launched Explorer 1.
On August 12, 1960, the United States launched Echo 1, a
passive reflector satellite with no
amplification possibilities. Echo 1 could only reflect the radiation back to earth. In 1966, Charles K.
Kao
and George A. Hockham of the British company Standard Telephones and Cables (STC) were the first
to promote the idea that
the attenuation in optical fibers could be reduced below 20 dB per kilometer,
allowing fibers to be a practical medium for
communication. Both technologies play important roles to
make existence of global network, high-speed services, and particularly for
multimedia-content
communications. |
| Chapter 5 |
History of World Telecommunications: Internet
Generally, the internet is a global system of interconnected computer networks, joining many
government, university, and private
computers together. Prior to that widespread internetworking that
led to the foundation of the internet, several research programs
began to create principles of
networking between separated physical networks, including the development of packet switching
technique. Project participants include Donald Davies (NPL), Paul Baran (RAND Corporation), and
Leonard Kleinrock’s MIT and UCLA
research programs. Consequently, it resulted to the development of
several packet switched networking solutions in the late 1960s
and 1970s, including the ARPANET.
Later, the application of that packet switching guided to develop a protocol for inter-networking,
where
multiple different networks could be joined together into a super-framework of networks. Next by
defining a common network
system, the internet protocol suite (TCP/IP) was then released by Vinton
Cerf, Jon Postel, and Danny Cohen in 1978. This spread of
the inter-network resulting to form the idea
of a global inter-network that then be called internet. |
| Chapter 6 |
History of Thai Traditional Communication Systems
Technically, telecommunication system is defined in this Thai telecommunication encyclopedia
(2009 edition) as “communication
that eliminates distance between persons, equipments, or any
automatic system. It is used with any kind of electro-mechanic, light,
electromagnetic wave, or the
specific quantum properties, in order to deliver understanding signs, signal, text, sound, picture or
multimedia to the receiver”. Systematically, this is based on cleared procedure of implementation
and utilization. Therefore, Thai
telecommunication era is then established when that the first system
was adopted into Thailand. Evidently, the initial communication
was with the telegraphy which
started in the period under the reign of the King Rama V in 1875. Prior to the foundation of Thai
telecommunication, where the earlier history was based on investigated annals, memo, and other
related documents, communication
was generally done though contemporary transportations.
Information was in either form of, for instance, royal letter/ mandate/
document/ and etc could be
delivered via human or other couriers. Not only with those methods, nonsystematic transmission of
any kind of signaling via flag/ sound/ cannon/ light or smoke also could be done for the short
distance communications with their
specific purposes. Those traditional communications were used
randomly in the period before opening to modern
Thai telecommunication era. |
| Chapter 7 |
Thai Telegraph and Teleprinter
Generally, the telegraph was started in Thailand in 1875. Its accomplishment was done with the first
implemented link between
Bangkok and Sumutprakan in 1883 during the reign of the King Rama V. At
the same year, the post and telegraph department then
was established. Basically, Morse code was
used in order to modulate information through telegraph signal. Later, Thai Morse code
was founded
and deployed on November 1,1912 by the post and telegraph department. Continuously, newer and higher efficient
models of telegraph were adopted that moved from the old fashion to be a sound
telegraph model. Next, English version of the
teleprinter was applied with the previous telegraph in
order to improve the communication quality. Until 1953, Thai version of
teleprinter then was invented
through the Bilingual of English and Thai model in the year later. Finally, on April 30, 2008
or 133
years from the first day of telegraph or 125 years after the official opening, telegraph in Thailand is
terminated.
|
| Chapter 8 |
ประวัติการสื่อสารโทรคมนาคมไทย :
องค์การโทรศัพท์แห่งประเทศไทยกับกิจการโทรคมนาคม
An important history of Thailand’s telecommunication development is that the service milestones of the
Telephone Organization of
Thailand or later TOT Public Company Limited. Since telephone services
started in Thailand by the year 1881 under the reign of the
King Rama V, it had been developed
continuously from the basic manual operation of the magneto system to the central battery
system.
Subsequently, this kind of communication service was moved to automatic style of the Step-by-Step
system through those
Cross-Bar systems, and then to modern computerized system of the Stored
Program Control (SPC). All stories regarding those
telephonies represent directly to how
telecommunications in Thailand grew up for a century dominantly under TOT service umbrella.
Later
with the rapid change in Thailand’s telecommunication policy and with the fast growing of related
technologies, Voice over IP
(VoIP), and high speed data communication are not solely served by TOT
as that of the basic telephone service. But those are either
in joint service or operated by other firms. |
| Chapter 9 |
ประวัติศาสตร์การสื่อสารโทรคมนาคมไทย : ยุคเครือข่ายอินเทอร์เน็ต
The internet is the largest computer network with the highest number of users. The internet includes
two main parts. The first part
is over one billion computers linked together. The second part is the
contents in the computers which from any computer in the
network, it is possible to access any and all
of the contents. For understanding to the internet in Thailand, a brief history of the
Internet, Thailand
chapter of the internet society, registration of domain names and IP addresses, Autonomous System
Numbers (ASN),
internet service providers (ISP), internet applications, and computer and internet
milestones in Thailand, are considered. |
| Chapter 10 |
Joint Principle of Telecommunication Technologies with Mass
Communications
Basically, principle of telecommunication technologies and mass communication area can be
considered jointly, although their
developments are constructed on different aspects such as the
first is mainly on discovered technologies and the latter is on wider
view of laws and regulation
events or technology itself. Those developments of telecommunication base on the systematical process
of science. Meanwhile, social culture and media are for those of communication art.
Therefore, their definitions and history
milestones are usually known to the public on separated
view. Implicitly, there are joint indicators of both areas in order to having
their convergences or joint
development. Those are their principle of system & process (telecommunications) and utilization or
requirement (mass communication), error correction, and accuracy. |
| Chapter 11 |
Basic Telecommunication Law
Telecommunication operation could be defined as providing a communication services with data,
image, sound, or signals. Such
operation may include public telephone services, mobile phone
services or Internet services, etc. The Office of National
Telecommunication Commission (NTC), an
independent regulator established under the Law on Organization for Spectrum Allocation
and
Radio and Television Broadcast and Telecommunication Operation, is responsible for issuing a
license for telecom operator,
specifying the type of telecom services and licenses, as well as
allocating spectrum for the provision of telecommunication services.
The responsibility of the NTC
is mandated by the Telecommunication Operation Act of 2001. The Act contains five sections:
licenses;
interconnection charge; fees and service charges; competition and universal service
obligation.
|
| Chapter 12 |
Electromagnetic Compatibility on Telecommunications
The related principle, definition, meaning, and elements are necessary topics to be understood of
electromagnetic compatibility
(EMC)
with communication system. Therefore, the sample of how the
circuit and power electronics create the electromagnetic
interference is typically considered. In addition,
international and Thai electromagnetic compatibility standard, including the most
important part, the
solution to the electromagnetic compatibility problem for communication, are realized and shown in this
chapter. |
| Chapter 13 |
Principle of Telecommunication Related Tests
The related test of telecommunication equipments is to obtain the confidence of product for
consumers. It is also to test of
compatible devices and others equipments with related standards. Form
overall aspect, telecommunication test could also support
indirectly to the industry for improving its
product quality and service. Those are electromagnetic compatibility, performance test, and
safety test. |
| Chapter 14 |
Principle of Telecommunications Roadmapping
Technology roadmapping is a technique which many organizations selected to support short-, mid-,
or long-term planning and
strategies. Technology roadmapping is also used for connecting to
resource allocation and business management. The roadmap may
be shown in many graphical
formats. T-plan is a generic format composed of at least 3 key layers (1) technology, (2) product/service,
and (3) market/business, along with time dimension explicitly. Technology roadmap is a
systematic technique which ensures that an
organization will move in the right direction to its future
goal. An effective technology roadmap needs to be kept alive and rolling as
usual in order to
maintain up-to-date information contained in the roadmap. Besides getting a technology roadmap,
the roadmapping
process provides an opportunity to communicate and share information among
stakeholders.
|
| Chapter 15 |
Telecommunication Economics
Telecommunications services have developed in a monopoly environment. As competition is
introduced into telecommunications
markets, there are concerns about the continuing exercise of
market power by the market dominance or the incumbent operator. An
effective competition
regulation is required to ensure competitive markets. Telecommunication economics is a tool that
can be used to
foster competitive markets and also to protect consumer rights, especially on six
key issues; competition regulation, price regulation,
spectrum allocation, interconnection, universal
services and consumer protection. |
| Chapter 16 |
Value Chain of Telecommunications Industry
Thai telecommunications industry has been undergoing, both in technology and industry regulation
aspect. Therefore, the value
chain of the telecommunications industry is changed accordingly.
Furthermore, the internet technology becomes a critical part and
influences the structure of
telecommunications value chain. The value chain of Thai telecommunications industry can be
separated
into six levels: equipment-makers layer, network layer, Internet layer, middleware layer,
applications and contents layer, and
customers layer. It plays an important role in order to having a
good related policy and even business plan. |
| Chapter 17 |
Bibliometrics Study of Thai Communication Engineering and
Related Areas-Research Publications
Basically, bibliometrics study is that the method to measure the research publication. It can show
the portrait covering status of the
interested topics/disciplines/journals/institutions/researchers/or
nations of those publications. Focusing on ECTI (electrical
engineering/electronics/computer/
telecommunications and information technology) discipline, results can be seen as one of the R&D
indicator comparing to those of the nearby countries. Generally, data/text mining tool is used to
analyze the dataset from the well-
known ISI: Web of Science database. The samples of the top
instance of Thai affiliations, author, and technical subject areas, can be
used for that purpose.
Moreover, samples of year ranking, top published journal, and correlation map of Thai affiliation
cross keywords,
are those related parameters for the bibliometrics study. |
| Chapter 18 |
Revolution of Radio & Mobile Telephone and Related Standards
The evolution of radio telephone can be described by the related balancing areas among
technologies, standard organizations, and
ability of suppliers to appropriately response the
customer requirements. General perspective of radio telephone evolution from the past
including of
related historical telecommunication standards and organizations, are important. They imply to these
balancing of the
evolution. |
| Chapter 19 |
Electrical Engineering/Electronics, Computer,
Telecommunications and Information Technology Association: ECTI
In order to promote professional carrier in electrical engineering, electronics, computer,
telecommunications and information
technology (ECTI), ECTI association of Thailand was then
established on July 26, 2002. Its activity is similar to those of IEEE (US),
IEE or later IET (UK),
IEICE (Japan), or IEEK (South Korea). The foundation of ECTI association also reflects the centrality
of these technical areas in Thailand. Since 2002, there have been lots of academic activities
serving to students researchers and
faculties. Those are technical conference, seminars, and
publications of transactions, magazines, and books. Technically,
telecommunication is one of the
important areas of ECTI association where Thai telecommunication encyclopedia is highlighted as a
large knowledge portal project that free to access for Thai community. |
| Chapter 20 |
The IEEE Communications Society
The IEEE Communications Society (IEEE ComSoc) is one of the entities within the Institute of
Electrical and Electronics Engineers
(IEEE) that is mainly focused on communications technology.
ComSoc was established in 1952 (though the current name was adopted
in 1972) with the
mission to promote the advancement technology and applications in communications and related
fields. Activities
organized by the society include publishing transactions, books, magazines, and
also hosting/co-hosting conferences to create
opportunity for members and the technical
community to exchange information and research ideas. The IEEE ComSoc Thailand
chapter was
established in 1994. The mission of the chapter is to promote and support R&D and human
resource development in
communications technology in Thailand. ComSoc Thailand has also
conducted several activities together with other IEEE chapters
internationally. |
| Chapter 21 |
Electromagnetic Spectrum and Radio Frequency Communications
In 1864, James Clerk Maxwell, a Scottish physicist and mathematician discovered that an
“electromagnetic wave” was possible, a
rapid interplay of electric and magnetic field spreading with the
velocity of light at about 3x108 m/s. For communication purpose where
the “radio frequency” is used, it
bases on a form of that electromagnetic radiation with long wavelengths and low frequencies. The
radio
frequency section of electromagnetic spectrum covers on a fairly wide band. It includes waves with
frequencies ranging from
about 10 kilohertz to about 60,000 megahertz corresponding to wavelengths
between about 30,000 m and 0.5 cm. This range of
frequency is adopted for wide applications of
wireless communication, broadcasting systems, satellite communications, etc. Next,
the mode of
propagation of electromagnetic waves in the atmosphere and in free space could be subdivided into
main categories as
ground wave propagation, sky wave propagation, or line of sight (LOS) propagation
for instance. Each mode would be selected
properly for the communication purposes by considering
the obtained distance or quality of signal, and it depends on the atmospheric
factors as well. |
| Chapter 22 |
Basic Radio Resource Management
Radio or wireless communications is the fastest developing technologies. Advancement includes cutting-edge technologies,
customer-centric services and versatile equipments. Nonetheless, there are many constraints, mainly from the spectral bandwidth,
that limit the system capacity. Major consideration focused on the channels assignment every time we considered the capacity
enhancement. Many studies have shown that there are more than just the channel allocation schemes. Radio resource management
plays a key role for efficient utilization of resources to assure the quality of service and to maintain high level of system capacity. RRM
includes, but not limited to, base station assignment, handover, admission control, power control, load control and scheduling
algorithms. |
| Chapter 23 |
Morse Codes
Morse code was invented by Samuel Finley Breese Morse in 1837 in order to represent the messages
for long distance
communications especially for the telegraph by using patterns of short (dots) and
long (dashes) signal. Morse code became the
international standard and was adopted by International
Telecommunication Union (ITU) called the International Morse code. In
Thailand, morse telegraph was
brought in to service for long distance communication since the period of the King Rama V. However,
the original Morse code was based on English alphabet which was not quite suitable for sending Thai
message. Finally, Thai Morse
code was then founded on November 1st of 1912. |
| Chapter 24 |
Principle of Modulation for Communications
Modulation is a technique for transmitting messages over a specific signal called carrier wave. A
signal waveform of the message
called the modulating or baseband signal is encoded into one or
more of the characteristics of the carrier signal to produce a
modulated signal, whose spectrum are
matched to the characteristics of a medium over which it is to be transmitted. The process of
modulation guarantees that the modulated signal has a recognizable pattern of variations in the
characteristics, which the original
baseband signal can be recovered from the modulated signal
detected at the receiver by the process called demodulation. Generally,
its advantages are making
of bandwidth utilization and increasing performance of the communication systems. |
| Chapter 25 |
Error Control Coding for Communication Systems
Error control coding is a technique to reduce error during data transmission of digital
communications and data storage devices.
It is widely used to improve communication system
performance, such as in mobile communications, satellite communications, and
digital video
broadcasting systems. In addition, this technique is also used for the same purpose in data storage
systems. Basically,
the information bit is encoded to be the code word in order to retrieving
detection and correction capability. This codeword is
transmitted through communication systems
or stored in the devices as its purpose. It will then be recovered to be the original form by
decoding with related method. The decoder adapts the detecting and correcting capability of the
coding scheme to reduce some of
error. Using error control coding improves reliability to the
information bits and reduces the consumption of transmitted power. There
are many types of error
control coding scheme, for instance, Hamming code, BCH code, Reed-Solomon (RS) code,
convolution code,
Trellis-Coded Modulation (TCM), turbo codes, and Low-Density Parity Check
(LDPC) code. |
| Chapter 26 |
Fundamental of Spread Spectrum for Communications
Originally, spread spectrum technology to provide vital anti-jamming and low probability of interception,
was invented for military
applications in wireless communications. Other significant advantages are
efficient bandwidth utilization including of high capacity, and
immune to signal distortion from the
multipath propagation or the inter-symbol interference. Typically, there are two spread spectrum
methodologies which are frequency hopping and direct sequence. The first method is that to transmit
signals over normal amount of
bandwidth at a time, the carrier frequency is not constant but changes
periodically by hoping to another frequency in a set of available
frequency spectrum. Next, another is
that a data sequence is encoded by spreading code, which is identical for each user at a higher
rate
than the rate of the data. Therefore, the transmitted data are spread across the wideband spectrum. In
order to reduce detection
error in wireless communications where spread spectrum is applied, RAKE
receiver is usually adopted. In addition,in the cellular mobile
system with that spread spectrum
technique, there is a power control function used to mitigate interference from other users and to
have
a longer battery lifetime. |
| Chapter 27 |
Principle of Code Division Multiple Access: CDMA
Code division multiple access (CDMA) is a form of modulation technique for multiple access to a
physical medium such as a radio
channel. This technique is based on spread spectrum method by
using spreading code for each user. It results in different users use
the spectrum frequency at the
same time. CDMA is a form of spread spectrum signaling since the spreading signal has a much
higher
bandwidth than the data being communicated. CDMA has been developed to be standards
such as CDMA2000 and WCDMA for using in
the third generation mobile communication system. |
| Chapter 28 |
Basic Synchronization for Telecommunications
Synchronization is one of those essential techniques embedding in digital communications. In order
to establishing a communication
linkage between transmitter and receiver, synchronization must
accomplish its scheme acknowledging both sides of “start and stop” of
the data sequence.
Basically, data processing of both ends bases on parallel style and then transmitted through each
other in a single
communication channel by being converted into the serial format. Those
sequences must be referred on the same based-clock signal.
Principle of synchronization also
includes line coding, clock extraction, and time recovery. |
| Chapter 29 |
Principle of Traffi c Engineering in Circuit-Switching and the Numbering
System
Telecommunication network is, in general, operated on the limited number of channels or trunk
circuits. Thus, in order to achieve
high level of system efficiency, the crucial considerations include
acceptable grade of service, numbering plan and the design to
accommodate the traffic
requirements as well as the management of telecommunication traffic or teletraffic. |
| Chapter 30 |
Synchronous Digital Hierarchy: SDH
Synchronous Digital Hierarchy (SDH) is an international standard defined by the International
Telecommunication Union –
Transmission (ITU-T). The synchronous transport method embodied in
these standards not only fulfills all the requirements of
a point-to-point transmission system, they also
satisfy all the requirements of basic telecommunication network – switching,
transmission and network
control. Thus, SDH can be applied, in a seamless and unified manner, in all application sectors – the
local
loop, the inter-exchange network and the long-haul link. With single mode fibers as the
transmission medium, the bandwidth frequency
is to be exploited by going in for wide-band and highspeed
transport in the digital domain. In SDH, multiplexing from a lower to higher
signal hierarchy or
demultiplexing from a higher to lower hierarchy can be done without going through each of the
intermediate steps
as that in Plesiochronous Digital Hierarchy (PDH). The expectations of the users as
well as the operators owing to the rapid advances in
optical transmission, integrated electronics and
software technologies expose the limitations of the existing PDH. Therefore, the need to
transport a
large volume of data over long distance to cater to a multitude service can be fulfilled with SDH system.
With SDH, the
telecommunication network can achieve better quality of service (QoS), more services
and flexibility in multiplexing and demultiplexing
process. |
| Chapter 31 |
Quality of Service (QoS) in Telecommunication Networks
Many networks handling various types of services are demanded to provide their users guarantees
on qualities of delivered services.
Elements of those qualities include reliability, delay, and so on
complying to their stated commitment to their users at reasonable
prices. A typical portion of
network traffic is multimedia that consists of audio and visual data. To serve such requirement,
Quality of
Service (QoS) mechanisms have been required to address and handle multimedia data
packets during transmission and regarded as
one of the most important features in communication
networks. A general model and approaches to the existing standards and network
technologies are
important. Moreover, the fundamental concept and framework of QoS for OSI, QoS in ATM
networks and QoS for IP
networks are necessary to understand this QoS. |
| Chapter 32 |
Local Area Networks: LANs
Basically, networking is a means of connecting computers and other electronic devices together in
order to share information and
also resources, and to communicate with each other. Local area
networking or LAN is one type of that network covers a small
geographical area, typically a building
or an office. Principally, there are two kinds of LAN: wired LANs and wireless LANs. The most
common wired LAN forms include Ethernet LAN and Token Ring. Meanwhile, Ethernet LAN
consists of a central device called switch
with a number of other devices connected to the switch.
In Token Ring, there is no such central node. Thus, the devices are arranged
in the form of a ring. |
| Chapter 33 |
Asynchronous Transfer Mode: ATM
Asynchronous Transfer Mode, abbreviated ATM, provides a high-speed low-delay multiplexing and
switching network to support
any type of traffics such as voice, data and video applications. ATM
segments and multiplexes user traffics into small and fixed-length
units called cells. The cell is 53
octets, with 5 octets is reserved for the cell header. Each cell is identified by virtual circuit identifiers
which contained in the cell header. An ATM network uses these identifiers to relay the traffic
through high-speed switches from the
sending customer premises equipment (CPE) to the
receiving CPE. ATM provides no error detection operations on the user payload
inside the cell. It
provides no retransmission services and a few of operations are performed on the small header.
These cells with
minimal services are performed to implement and support multi-megabit transfer
rates. The ITU-T, ANSI and the ATM Forum have
selected ATM to be a part of the broadband
ISDN (B-ISDN) specification to provide for the multiplexing and switching operations. ATM
resides
on top of the physical layer of a conventional layered protocol. The physical layer could be
implemented with SONET/SDH, DS3,
FDDI, CEPT4 and others. However, large public networks
are usually uses SONET/SDH for physical layer. |
| Chapter 34 |
Internet Protocol Version 6
Internet Protocol version 6 (IPv6) was developed and standardized to solve the address space
problem in the current Internet
Protocol version 4 (IPv4). The IPv6 address is 128 bits long.
Supporting many as 2128 IP addresses. In addition, IPv6 improves
efficiency of network operation
over IPv4. The migration from IPv4 networks to IPv6 networks can be done in three manners: dual
stacks, IPv6-in-IPv4 tunnel, or IP protocol translation. |
| Chapter 35 |
Next Generation Network: NGN
Telex or telegraphy exchange was the most common text transmission service in the past before
transferring to the newer
telecommunication systems. It is refered to that the service of providing a
documentary record. Also, it was developed as the latter
generation of the teleprinter which could
be used as the unattended machine (semi or automatic) for serving most to press and travel
agencies, airlines, or embassies in general. Telex was adopted into service in Thailand at the same
time as the US’s service
enhancement of the teleprinter to telex in 1962. At the end of August
1982, there was a record of 3,016 telex customers in Thailand,
meanwhile about 1.7 million
subscribers all around the world were reported in 1988. Until the application of facsimile and other
higher efficiented communication technologies, the number of telex users had been decreased
rapidly worldwide and then its services
in the United States were terminated in 1992. |
| Chapter 36 |
Principle of Transmission Lines for Communications
Significantly, transmission lines play an important role in a wide range of communications. They are
used for carrying information
from one place to others. There are various types of transmission lines
such as two-wire open air, two-wire ribbon, twisted pair,
coaxial cable, and optical fiber types.
Those are applied for various purposes of communications. Generally, application criterion based
on characteristics of the transmission lines are considered on their application bandwidth,
transmission distance, installation budget,
and physical environment. For example, an ADSL
technology uses twisted pair transmission line, LAN technology bases on coaxial cable,
and longdistance
communication such as SONET technology relies on the optical fiber. |
| Chapter 37 |
Principle of Telephony and Its Network
Generally, the telephone or basic voice service system is the most popular type of communications.
In general, a basic structure of
telecommunication network consists of the telephone exchange,
signaling and transmission system, controller and terminal equipments.
Signal transmission over the
public telephone network is based on that sending voice signal between two or more of remote
parties.
That connection starts from a caller connecting to the public telephone network through the
local switching or exchange in order to link
with another user. There are many types of those
connections, such as star topology and mesh topology. Utilization of those topology
depends on
various factors such as the size of network or the number of end-user. Finally, a hierarchy network
which consists of the
international telephone switching center, a tertiary center, a secondary center,
a primary center, and the local exchange, is that
implemented to serve for telephone services in
Thailand.
|
| Chapter 38 |
Basic Telephone Switching Technology
A telephone exchange or a switching system is used to connect the telephone signal between two
end-users. Basically, there are
two types, a circuit switch and a packet switch system. Later,
telephone exchange has been developed and moved to another
advanced step to be operated for
the next generation network (NGN) system (software switching system). This newer type of
switching could operate covering basic telecommunication service by using the application of
internet protocol (IP) or with
asynchronous transfer mode (ATM) system. In addition, they are not
only to serve for voice service on this soft switching system, but
also with many type of enhanced based on data communications. That works on digital signal format instead of old fashion of
analog
(voice). |
| Chapter 39 |
Basic Telephone Line Testing System
Line testing system (LTS), as a part of basic telephone fault management system, is used to
investigate any fault that occurs and
interrupts (land line) telephone operation. It is a necessary tool
using to yield the quality of service. Generally, LTS is considered into
two types. Those are internal
and external system working in similar manner as an electrical measurement meter. Measured
results
over the cable lines are related to those fault types, therefore, they can be interpreted to
figure out for their causes. Thus, solutions to
fix each fault can be dispatched accordingly. LTS can
be also used to preventively maintain the network. Pretest, routine test, or
surveillance test are the
instances of benefit of this system as well. |
| Chapter 40 |
Principle of Telex
Telex or telegraphy exchange was the most common text transmission service in the past before
transferring to the newer
telecommunication systems. It is refered to that the service of providing a
documentary record. Also, it was developed as the latter
generation of the teleprinter which could
be used as the unattended machine (semi or automatic) for serving most to press and travel
agencies, airlines, or embassies in general. Telex was adopted into service in Thailand at the same
time as the US’s service
enhancement of the teleprinter to telex in 1962. At the end of August
1982, there was a record of 3,016 telex customers in Thailand,
meanwhile about 1.7 million
subscribers all around the world were reported in 1988. Until the application of facsimile and other
higher efficiented communication technologies, the number of telex users had been decreased
rapidly worldwide and then its services
in the United States were terminated in 1992. |
| Chapter 41 |
Principle of Facsimile Machine
Facsimile or fax machines is regarded as telecopy machine and functioned basically as a
combination of a copy machine (which
scans the original textual and graphic material as images as
well as printing documents from the receiving information) and a modem
(which converts the data
into signals). It transmits via a telecommunication link, usually telephone lines, to the destination
which is a
receiving fax machine. The reproduced document is a copied version of the original
document at the receiver side. Through a long
history, facsimiles are still in use despite of other
replaceable equipment. |
| Chapter 42 |
Digital Subscriber Line: DSL
The classical data communications over the public phone network is usually done via the dial-up
modem connections. However, the
rapidly increasing demand of high data rates and low usage
cost leads to the development of technologies which still exploit the existing
copper-wire
infrastructure such as plain old telephone service (POTS). That is a modem-based technology,
digital subscriber line (DSL),
which utilizes much higher bandwidth than those of voice modem.
Typically, its data rate is started at about 128 kbps and up to
1.5 Mbps for most home users over
an existed twisted-pair telephone network. In order to utilize higher frequency range of the copper
lines, specific DSL equipment called Digital Subscriber Line Access Multiplexer (DSLAM) must be
installed on both ends between user
and the service provider. Up on the specific purposes, there
are various types of DSL those include ADSL, SDSL, HDSL, RADSL, and
VDSL. |
| Chapter 43 |
Power Line Communications
Power line communications (PLC) has been around for decades since the 1920s. Its applications
include automatic meter reading
(AMR) and automatic protection switching in power grids, as well as
remote controls of various home appliances. However, PLC has
received renewed attention. Due to
the explosive growth of Internet usages, availabilities of very large scale integration (VLSI)
chip sets
capable of complex digital signal processing (DSP) functions, and deregulation of telecommunication
markets, several power
utilities plan to provide Internet services through their power distribution
networks. Compared to existing applications of PLC, the
requirements for broadband Internet services,
known as Broadband over Power Line (BPL), pose several technical challenges as such
services have
higher bit rates and are offered to multiple users through a shared network. Two technologies have
been proposed as
effective solutions. Firstly, orthogonal frequency division multiplexing (OFDM) is
used to overcome various non-ideal channel properties
of power lines, including frequency selective
channel response and multi-path propagation. Secondly, carrier sense multiple access
with collision
avoidance (CSMA/CA) is used as a multiple access control (MAC) protocol. Regarding using BPL as
an Internet access
technology, there are concerns about its potential interference with existing wireless
communication services including amateur radio,
shortwave radio, and military applications. In addition,
it is not clear whether BPL is more cost effective than its competing technologies
such as digital
subscriber line (DSL) and cable modems. The most likely application for broadband PLC is in-home
networking, where
power lines serve as an infrastructure for a communication network among electrical
appliances. For such applications, there are
several industrial standards as well as equipments
available in the market. |
| Chapter 44 |
Optical or Visual Telegraph
Before the beginning of telecommunication era, increasing distance for communications was based
on that of lifting up the signal
sources of for the further sight. That was called the “semaphore”. This
semaphore was then developed to have a shape similar as like
the tower or the clock tower. This
tower-liked was named as Tachygraphe and the sign on its can be changed accordingly to the
sending signals. It was invented by a French, “Abbey Claude Chappe”, who became the developer
of the latter optical telegraph system.
This tachygraphe can represent signals with 99 different
words at the beginning, through 9,999 words, and up to 40,000 words of late development.
Optical telegraph had been used widespread for more than a century, especially during the
revolution in France. It is also
the origin of “hop” style communication, using in microwave
communication system. Officially the first message sent on August 15,
1794 is the beginning of
“Telecommunication Era” and Claude Chappe is also named as the “father of telecommunications”. |
| Chapter 45 |
Principle of Optical Communications
Optical communication is one of the most advanced communications by using electromagnetic
waves (of light form). It differs from
radio and microwave communication in that the wavelengths
employed are shorter (or higher frequency). Light as the transmission
medium, the system employs
its beam of modulated monochromatic light to carry information from the transmitter to the receiver.
As a result, the transmission of speech, data, video, and other information by means of the visible
and the infrared portion of the
electromagnetic spectrum can be deployed. Basically, an optical
communication system consists of a transmitter, which encodes a
message into an optical signal, a
channel of either free space or optical fiber, which carries the signal to its destination, and a
receiver, which reproduces the message from the received optical signal. Obviously, the advantage
of communication at high frequency
of the optical carrier permits much more information to be
transmitted over a single channel than it is possible with a conventional
radio or microwave system.
In addition, the very short wavelength of the optical carrier permits the realization of very small
compact
components. |
| Chapter 46 |
Fiber optic Communication System
Fiber optic communication system is a kind of lightwave communications that utilize the optical fiber
as a waveguide. Generally, its
basic structure composes of electro-optic (E/O) converter, optical
fiber, and optic-electronic (O/E) converter. The fiber structure
consists of “core” and “cladding”
which their index profile and propagation mode represent to their types. Its related applications are
for
medical and sensor purpose, sensor, and for high speed communication as well. |
| Chapter 47 |
Fiber To The Home: FTTH
Fiber to the Home (FTTH) is an optical signal communication that utilizes an optical fiber to connect
from the central network to the
subscribers or end users in order to achieve a high-speed access.
This system provides a high bandwidth communication channel and
supports multiple communication
services, those are high-speed internet, Cable TV, and broadband communication.
It could be
provided simultaneously for each user via only a single or a pair of fiber optic cable. |
| Chapter 48 |
Dense Wavelength Division Multiplexing
Dense wavelength division multiplexing (DWDM) refers to a technology for a fiber-optic transmission
that exploits multiple
wavelengths of light within the 1550-nm band on a single fiber. In contrast to
the communication over copper wires which deploys
another technology called time division
multiplex (TDM), it employs multiple optical carrier signals with different wavelengths of laser
light
whose spacing is less or denser than that of conventional wavelength division multiplexing (WDM),
to carry different data for each
channel on a single. This technology is regarded as a crucial
component of optical networks that allows the transmission of various
types of data communicated
with protocols or systems such as asynchronous transfer mode (ATM), and synchronous optical
network/synchronous digital hierarchy (SONET/SDH) over an optical layer. |
| Chapter 49 |
Fundamental of Radio Antenna
The antenna is a transducer designed to transmit and to receive electromagnetic wave. In the same
hand, transmitted antenna
converts electrical impulse to be electromagnetic wave and vice versa
for the received antenna. According to various kind of wireless
communication systems, antennas
are designed appropriately with their applications and frequency band. They are for such as radio
and television broadcasting, wireless LAN, radar, space exploration, and etc. |
| Chapter 50 |
Smart Antenna
Smart antennas have been used for improving the performance of wireless radio systems. They
consist of an antenna array,
combined with signal processing in both space and time domain. The
objective is to enhance the received signal, to suppress all
interfering signal, and to increase
capacity. This chapter provides basic information about smart antenna system including its types
and applications. |
| Chapter 51 |
Bluetooth and ZigBee
Short range communication is the communication technology that utilizes wireless communications
or radio wave communications. It
is intended for communications between small electronic or
electrical devices such as mobile phones, Personal Digital Assistant (PDA),
Pocket Personal
Computer (Pocket PC), digital music player, and other small electronic devices. The devices that
are in a personal area,
which radius of coverage area should be less than 50 meters, can form a
network and communication with each other. The important
objective of the short range
communication technology is that it should be commodity and can be embedded in any small
electronic and
electrical devices. There short range communication technologies are Bluetooth and
ZigBee. |
| Chapter 52 |
Bluetooth Technology
Bluetooth is a kind of wireless personal area network (WPAN) technology that operates in 2.4 –
2.483 GHz frequency band. This
communication will forms temporary small network called piconet
with data transmission rate is up to 1 Mbps (max). Bluetooth is
available for small and low power
devices such as personal digital assistant (PDA), laptop, and portable devices. There are three
basic technologies inside bluetooth system that includes frequency hopping spread spectrum
(FHSS), service discovery protocol (SDP),
and application protocols. Its application are for all types
of communication, those are picture, voice, and data. |
| Chapter 53 |
Radio Frequency Identifi cation: RFID
RFID technology allows for remote wireless information storage and access by modulating
information signal on to electromagnetic
wave carriers. In an RFID communication system, the
information is normally exchanged between RFID interrogators/readers and RFID
tags. The
information typically stored in an RFID tag is for the purpose of identification. Generally, RFID
applications of interest include
book identification in a library system, animal identification in
livestock management, access control for office security, and payment
media in transportation
systems. |
| Chapter 54 |
Principle of WiFi Networks
WiFi is an attractive networking solution due to the ability of computing and communication devices
(e.g., PDA, PC, notebooks)
equipped with appropriate WiFi Network Interface Cards (NICs) to
communicate with each other without encumbering the users with
cabling and its limitations. WiFi
changes the way people work. It allows people to stay connected or share data anywhere, anytime
under the service areas. Wireless deployments have increased dramatically due to the maturity of
the WLAN technologies and their
reduction in cost. WiFi is not intended to replace wired networks,
but rather complement them, for enhancing efficiency and
productivity. |
| Chapter 55 |
Amateur Radio
Amateur radio is a scientific hobby, carried on by duly authorized persons with three license
classes, the novice, the intermediate,
and the advanced. The radio communication shall be done in
accordance with the rules and regulation set out by the administrative
authority, such as call sign,
communication channels, Q-codes, and transmission powers. The operations shall comply with
the international standards in order to achieve an efficient communication with worldwide radio
amateurs. |
| Chapter 56 |
Principle of Wireless Sensor Networks
The military needs for monitoring battle fields have pushed for the introduction of wireless sensor
technology. It then has been
further developed for civilian and commercial applications. Some
important factors that demand the use of wireless sensor technology
over wireline sensor
technology include : (1) the deployment cannot or hardly be realized with cable lines; (2) the
requirement to
monitor or surveillance large areas; and (3) the need for monitoring not only
temporal but various spatial data such as temperature,
humidity, and water supply. Wireless sensor
network consists of a group of sensor nodes joined together into network. These sensor
nodes are
located where signal are collected. The signal is relayed and finally collected by the server node to
be further analyzed.
Several applications include agriculture environment control, vehicular traffic
monitoring and control, air and voice pollution control,
and public safety control.
|
| Chapter 57 |
Ultra-wideband for Wireless Communications
Ultra-wideband signal is a technology with high potential for high-speed multimedia wireless
communications. It takes different
approach in electromagnetic communications compared to
fundamental of narrowband wireless communications. Moreover, ultra-
wideband requires no carrier
signal in order to communicate. Ultra-wideband technology offers several advantages such as
resistance to jamming, large channel capacity, and simple transceiver architecture compare with
fundamental of narrowband
communication technology. As a result, this kind of is deployed to
access a wide range of information for higher capacity and support
many users of wireless
communications. |
| Chapter 58 |
470 MHz. Cellular Mobile Telephone System
The first generation of mobile telephone system in Thailand is that the 470 MHz cellular system.
Basically, it is that the Nordic mobile
telephone (NMT-450 MHz). After the operating first for
Scandinavian countries in 1981 by using 450 MHz band, it was then adopted to
Thailand in 1986
by moving technically to available frequency 470 MHz band. This analog mobile telephone system
was popular at the
beginning, however, its service fades down after the present of newer digital
based mobile telephone system.
|
| Chapter 59 |
Water Surface Communications
Communications over surface of the water is a kind of wireless communications, which is important
as much as communications
over the ground. Due to the major part of the world covers by water,
this communication system plays an important role for the long
distance connection. The water
surface communication are separated into five categories. Those are done on transmission through
ground wave, satellite link, scattering to the troposphere, and reflecting from Ionosphere.
|
| Chapter 60 |
Submarine Cable Network in Thailand
Alternative high capacity communication channel called submarine cable, is that the development of
wired communications by laying
it underwater. Basically, it is used to deliver high speed or high
capacity data of long distance communications purpose. Copper and
coaxial cable are those
original types of cable which used for the submarine cable network. Later in digital communication
era, optical fiber is replaced which more advantage than that of the previous metal cables. For
Thailand, there are lots of submarine
cable projects. The initial one was done by the former
Communication Authority of Thailand (CAT) in 1964. It was a joint project with
Japanese agency to
link for Thailand-the Philippine-and Japan. Continuously, newer projects such as ASEAN Cable
System, Thai-
Malaysia Link, SEW-ME-WE3, and FLAG were implemented. |
| Chapter 61 |
Television Broadcasting
Television Broadcasting is a type of picture and voice transmission. There are two categories of TV
broadcasting which are on
analog and digital technology. The principle of TV broadcasting is that
the transmitter will send the picture and voice signal that got
modulated with the radio wave and
then spread in the air in the form of the electromagnetic wave. The receiver then demodulates the
signal for the picture and voice to appear on the monitor. The principle of the TV broadcasting
composes of scanning and systems of
television signaling such as NTSC system, PAL system,
and SECAM system, etc. For these types of TV broadcasting, there are many
transmission
methods such as sending through the cable transmission line, satellite, and ground radio
frequency wave. |
| Chapter 62 |
Broadcasting Television 3
Thai TV Color Channel 3 started broadcasting at 1970 on VHF Low Band PAL-B system, to serve
the Bangkok and surrounding area.
In 1987, Thai TV Color Channel 3 networks were setup
together with the Mass Communication Organization of Thailand (MCOT) TV
networks. The
coverage area extended to 89.7 % of the whole country or covered over 96.3 % for the total
population in Thailand.
After that, in 2005, the Bangkok master station and all VHF Low Band PALB
system of Channel 3 TV stations were changed to the UHF
frequency band PAL-G system.
Resulting to good receiving signal, higher picture quality is achieved. Thai TV Color Channel 3
involves in
digital broadcasting system. Those are done by setting up related transmitters that
support the Digital Terrestrial Broadcasting DVB-T
into both of Bangkok master station and at other
bases nationwide. |
| Chapter 63 |
Teletext
Generally, teletext is a newspaper sent over a television network system. It was developed in the
United Kingdom in 1970 before the
invention of internet. The teletext data, such as stock exchange
data, weather forecast data, and international news, is sent by
modulating its signal into the
television signal. This modulated signal is then sent to the receiver over a television broadcasting.
Finally, the end user can view a newspaper by using the teletext decoding machine such as SETTOP
BOX. This kind of service fades
down after the present of the internet network and short
message service (SMS) via mobile phone, and etc. |
| Chapter 64 |
Broadband Communications
Broadband communications are referred to a group of technologies in both telecommunications
and data communications that can
provide high-speed digital data transfer and can support multiple
services such as voice, still picture, motion picture or video, and text
data or multimedia at the
same time on the same network. Broadband communications are relative term used to differentiate
a group of systems from narrowband communications. In broadband communications, the systems
normally use wider spectrum or
larger bandwidth and transfer faster digital data rate than traditional
narrowband communications. They can be used to deliver
different types of services over single
network. Generally, both wired and wireless broadband technologies are identified and
categorized.
Their applications and basic characteristics are described. |
| Chapter 65 |
Broadband over Power Lines
In the early stages of Power Line Communications (PLC) technology, it was applied by power
utilities for controlling and ensuring
efficient energy distribution system. Its application also includes
automatic controls of various home appliances. Due to the dramatic
increasing of high-speed
internet usages demand, and the dense power supply infrastructures in most area, Broadband over
Power Lines (BPL) technology has received high attention for providing high-speed internet service.
The physical components of BPL
consist of high-voltage level, medium-voltage level, and lowvoltage
level transmission lines interconnected with transformers.
Consequently, the common
topologies of distribution grid (bus, star, and ring topologies) play an important roll in the PLC
network design when considering network cost, network reliability, and network efficiency. There
are several network architectures
for providing BPL, for instance, fiber-optic and low voltage lines
network architecture, medium and low voltage lines network
architecture, and medium voltage lines
and wireless network architecture, which are suitable for the different situations. Nevertheless,
BPL technology poses an important technical limitation about its interference with amateur radio system,
military communication system
and aviation control radio. The rules and standards have been set |
| Chapter 66 |
Wireless Sensor Network
From the development of technology in sensor, microprocessor, and wireless communications
fields lead to a new method of data
gathering which is small in size with low power consumption
and low cost. By distribution of many small size sensor nodes embeds into
the intended
environment for gathering information, each sensor node is one unit of a network. All nodes
collaborates each other to
create a wireless sensor network for communication and sending
information. Each sensor node and the whole wireless sensor
network have ability of self-organize,
so they can operate unintentionally from operator or human. Because of many limitations, the
form
of wireless sensor network is changed and adapted to accomplish its goal in the real world.
|
| Chapter 67 |
Integrated Services Digital Network: ISDN
The communication system had been changed from sending and receiving the sound or analog
signal to be the digital signal,
because of the limited of the information flow rate in the
communication line. Consequently, the method using digital signal is called
Integrated Services
Digital Network or ISDN, was introduced which combined both sending and receiving data
(including pictures and
sound). Next, the broadband ISDN has been developed with higher sending
and receiving data rate in order to get more effective
system. ISDN is not only used in telephone
system, but it also applied to other information system such as for security system or
multimedia
purpose. |
| Chapter 68 |
Virtual Private Network: VPN
Virtual private network (VPN) is a kind of technology that allows users to access remotely through
internet to the local or company
network as if it is working in the same place. For instance, users
who stay far beyond the service area may need to use those functions
or resources of the office
network. This is possible by using VPN technologies. Basically, the internet is a public network
which can be
intercepted by unwanted users. For this reason, VPN provides the key mechanisms
to create secure connection by using tunneling,
encryption, and authentication. There are many
VPN applications such as remote access VPN, Intranet VPN and Extranet VPN. All of
these
applications could be supported by point-to-point tunneling protocol (PPTP), layer 2 tunneling
protocol (L2TP), and IP security
(IPsec). |
| Chapter 69 |
Thailand School Net
Thailand school communication network or “School Net” was found in 1995 by the National
Electronic and Computer Technology
Center (NECTEC). Its objectives are to support self education
of Thai students by using the information technology or IT, and also to
establish another
communication channel among teachers and students in order to improving education atmosphere.
This project has
been developed follow the eighth national economic and social development plans
(1997 – 2001). In addition, it is responsible to the
national information technology policy of the
year 2000 (IT 2000). SchoolNet’s evolution has been seen in its four periods of time.
Those are
the beginning years, the time of schoolnet@1509, the project expanding period, and the transition
time from NECTEC to the
ministry of education. |
| Chapter 70 |
เทคโนโลยีการสื่อสารสำหรับระบบควบคุมการจำหน่ายไฟฟ้า
Basically, distribution automation system (DAS) for electricity services consists of three major subsystems.
Those are controlling
system of the master station, communication system via any
purposed channel such as mobile communications/ trunked radio/
microwave communication/
copper wire & phone lines/ powerline communications or fiber optic communication, and the
remote
terminal unite (RTU) for remote measurement and operations. This DAS is used in order to
improve power distribution efficiency and
stability, to reduce the SAIDI (System Average Interruption
Duration Index), and to provide the efficient maintenance & safety with less
human operation
and on-site cost. These are done by the operation of master station to communicate with RTU
in order to switch
on/off and to do other functions via specific or selected communication systems. |
| Chapter 71 |
Basic Communication Systems for Power Grid Network
Grid systems is an important part for transmitting electric energy from power plants to customers.
In practical, power plants may
located away from customers in range of several hundred
kilometers. For this reason, grid system controls are a necessary function for
power system
management (i.e., optimal power flow, transmission and distribution operation, system stability, etc.).
Furthermore,
operations of a component in a grid system may cause various consequences to
other parts. Hence, for efficiently managing grid
systems, an appropriate and reliable
communication channel for system operators must be installed. Those details are an overview of
components in power systems and their remote control systems, structure of supervisory control
and management system (SCADA),
related standards, and the history of electric industry. |
| Chapter 72 |
Traffic Information Through FM Radio Broadcasting
Transmission of traffic information through FM radio broadcasting is one of data transmission
channels for the Intelligent Transport
System (ITS). Its coverage is for wide area utilization
meanwhile its investment cost is considered. Significantly, traffic information is
utilized in order to
making a decision in type and travel route with the most updated traffic status. Traffic information is
mixed with FM
broadcasting signal in order to the utilization this existing communication channel as
the benefit. Generally, broadcasting system of
traffic information, related communication standards,
and its procedures, are the important factors of this communication system. |
| Chapter 73 |
Principle of Communication System for Water Resource Management
Communication systems play an important role in order to manage water resource of various
watersheds over Thailand and nearby.
Related data among those meteorological and hydrology
agencies need to be transferred and managed efficiently. Consequently, that
would impact directly
to other concerns in order to supply adequate water for agriculture and industries, and also to
prevent the
disaster of flood and others. Basically, the development of those communication
systems has been moved from the manual mode of
using basic telephone and radio
communication through the telemetering system. Moreover, meteorological radar and satellite
communication are applied in to this kind of resource management as well. Significantly, they could
support real time scenario of
concerned information. In addition, communications via mobile
telephone (GPRS) channel is another effective channel where real time
multimedia (data, voice, and
picture) could be reported from on-site directly and individually. |
| Chapter 74 |
Telemetering System for Irrigation
In Thailand, the telemetering system is widely used in automatic remote data measurement.
Transmission of irrigation information
such as water level and quantity including its salinity and
oxygen, rainfall quantity and water gate control, are those necessary datum.
As a result, it
tremendously enhances water management efficiency. First, after data collection the results are
transmitted to the
master station in both images and numeric forms. These transmission channels
include radio wave, fiber optics, and public phone
network (for leased line). Next, the data is
processed through a forecast system in order to support decision making at the final. The
Royal
Irrigation Department leverages the water level and rainfall quantity identified by the telemetering
and a water forecast systems
in water management at various river basins. For instance of
telemetering utilitation, water level at a remote station can be captured
by the telemetering system.
The captured images of water quantity are transmitted to the master station, while the textual data
is sent
to recipients via short-messaging services over mobile devices. |
| Chapter 75 |
Communication Systems for Tsunami Warning
Dart Buoy or Tsunami warning system was installed at various sites in the oceans around the world.
Basically, changes in sea-water
level will be measured by sea-water pressure gauge which installed
at the ocean floor and then transmitted to the Tsunami Warning
Center via satellite within few
seconds after the earthquake. Next, the center will bring the sea level data and others in order to
evaluate. Finally, in case of the event warning information would be then distributed via SMS, FAX,
OPENCARE, call center, warning
tower, and television broadcasting. |
| Chapter 76 |
Global Maritime Distress and Safety System: GMDSS
In order to prevent marine disaster, communication systems play a very important note to save
human life / ship / properties during
its journey in the sea. After the disaster of the Titanic in 1939,
the SOLAS (Safety of Life at Sea) was then established (1941) to
cooperative on these safety.
Consequently, the international Maritime Organization (IMO) was formed to responsible for
organizing and
releasing safety rules for the marine safety. Later in 1988, with the assistant of the
international Radio Consultative Committee (CCIR) /
world Meteorological Organization (WMO) /
international Hydrographic Organization (IHO) / INMARSAT and others, the GMMDS (Global
Maritime Distress and Safety System) was then formed. Starting on February 1st of 1992, GMDSS
was adopted and completed in seven
years late with the compulsory to all about 300 Gross tonship
(with assumption to war ship and some specialties ships) |
| Chapter 77 |
Warning Tower and Its Communication Systems
Warning tower is used in Thailand as one of the important tools in disaster risk areas to
disseminate information and notify people
to escape from the disaster which might occur in the
area such as tsunami, flash flood, land-slide, and etc. The towers, excluding those
installed by Krabi
province, are controlled by the National Disaster Warning Center (NDWC) (2008). Information
about the disaster
which may generate into the area, will be distributed by NDWC. Generally, the
warning towers could work automatically after receiving
transmitted data via satellite, and also
through the local community via radio frequency (FR) communication. It would be functioned
even
in an emergency situation which causes destruction in a rest area and subject of the failure of
power generation system or
ground communication systems. |
| Chapter 78 |
Telecommunication Network for the Greater Phuket Digital Paradise Project
Phuket is the biggest island in Thailand, there is about 544 square kilometers of the area located
on the Andaman coast of the west
of the south of Thailand. The highest elevation of the island is
422 meter above sea level. Though the tin mining business has played
a specially role in the
economic development of the province, but in early 1985 the price of the tin fell by half and tin
mining became
unprofitable to continue the operation. The tin mining business gradually ceases
operation. The decline has also due to the decrease
in deposit after centuries of exploitation.
Therefore, Phuket has to look for new business on which to base its future economic
development.
Fortunately, its natural beauty was soon discovered and there was explosion of tourism industry in
1980’s which has
lasted until the 21st century. The tourism industry has bought in more than
50,000 million baht at early 2000s. The population of the
province is around 287,000 in 2004,
but there are more than three million tourists destining to Phuket a year. The government has
emphasized the development of Phuket and surrounding areas to attract more foreign visitors. For
the development of Knowledge
Based Economy, Thai Government has set up and Action Plan
(1999 – 2011) to develop Phuket as the international city by making use
of ICT. The government
strategy for ICT development is called the Greater Phuket Digital Paradise Project. It aims to
facilitating the
Greater Phuket area, which includes Phuket and its four neighboring provinces of
Krabi, Phangnga, Trang and Satun, which share the
coastline along the Andaman Sea.The National
Electronics and Computer Technology Center under the National Science and
Technology
Development Agency has the responsibility to implement the strategy in cooperation with the Office
of the National
Economic and Social Development Board (NESDB), Phuket Provincial Governor’s
Office and the other related sectors. The objective of
Greater Phuket Digital Paradise Project is to
enforce international competitiveness in business and industry. |
| Chapter 79 |
Thai Military Communications System
Thai military communications system is generally applied both at to state of normality and state of
war. It is used for
communications between battalion and other institution implicated of transnational
security. Basically, it composes of three systems.
There are military communication system, tactical
communication system, and support functions system. Each of them is configured
specifically and
would work synchronizingly for those supposes. |
| Chapter 80 |
Principle of Satellite Communications
From the origination idea of a synchronous communications satellite in 1984 of Arthur C. Clarke, a
British writer and author of “2001:
A Space Odyssey”, it was later developed to be the satellite
communication system. Communications via satellite play a major role in
broadcasting, computer
and internet communications, and many others. Starting from launching of SPUTNIK I on October
4, 1957
through the first commercial satellite of INTELSAT on April 6, 1965, satellite
communication has been developing significantly combining
together with many kinds of
technologies. Basically, satellite communications engineering covers such a lot of topics as radio
wave
propagation, antenna technologies, orbital mechanics, communication techniques (such as
signal processing, modulation and coding),
and related electronics. Importantly, aspects of satellite
communication design are complicated where those parameters are, for
instance, lightweight and
minimum power consumption, considered large number of communication channels requirement,
enormous
path loss of long number of communication, powerful transceivers, or even the
compliant with each government licensing and
regulatory requirement (e.g. geosynchronous orbit). |
| Chapter 81 |
History and Development of Satellite Communication Systems
From the 1945 article describing of the possible use of communication relay implemented in the
space, satellite communication was
then developed from this origin of Author C. Clarke’s idea.
Since the beginning of launching the world first satellite, SPUTNIK of USSR
in 1957 and following
by the first US’s satellite, Explorer I, in 1958, satellite communication has been developing
continuously and
playing a very important role in world-wide telecommunications. In Thailand, this
kind of wide coverage area communications was
started with the Intelsat in 1967 for the basic
international telephone services. Later in 1993, the first Thai communication satellite,
ThaiCom, was
launched. Following with Thai Micro-SATellite (TMSAT), it has been operating since 1997. Under
the cooperation of
Thai-French government, Thailand Earth Observation Satellite (THEOS) project
was then established in 2004. |
| Chapter 82 |
THEOS Satellite
THEOS satellite is the first optical remote sensing satellite for Thailand which is fully operated by the
Geo-Informatics and Space
Technology Development Agency (GISTDA), Ministry of Science and
Technology. It was developed on LEOSTAR 500 XO platform
where concerned technologies have
been used in former French observation programs. Those are SPOT (Le Systeme Probatoire d’
Observation de la Terre 5: SPOT5) and PLEIADES. Technically, its communication system bases on
both frequency range of S-band
(2-4 GHz) and X-band (8-12 GHz). With the assigned function, that
s-band frequency is used for ground communication purpose.
Meanwhile for payload data
management, X-band frequency channel is selected. |
| Chapter 83 |
Thai Mrico-SATellite: TMSAT
Thaipat is a Thailand’s first microsatellite designed and built by Thai engineers. The technology
transfer and training was a one
year program under the corporation between university of Surrey
(UK), Mahanakorn university of Technology (MUT) and united
communication company limited
(UCOM). The objective was to transfer the knowledge and expertise of the designing, testing, and
building a small satellite. The program was commenced in April 1996, and completed in April
1997. The original title of program and
spacecraft was the TMSAT (Thai Micro-SATellite). Thaipat
was a name given by His Majesty The King Bhumibol Adulyadej, in October
1998. The main
payload on boarded Thaipat was a multi-spectral Earth observation cameras with 65 metre
resolution. The other
payloads were digital store-forward communications payload (DSP payload
and GPS receiver). On 10 July 1998, Thaipat was launched
by the Zenith-II launcher into Sun
synchronous orbit at 815 km altitude and 98 degree inclination.
|
| Chapter 84 |
THailand Earth Observation Satellite: THEOS
Having utilized satellite data in various applications for more than two decades and realizing the
importance of earth observation,
Thailand has decided to develop its own satellite. Through the
Cooperation Agreement between the Governments of Thailand and
French Republic, the THEOS
(Thailand Earth Observation System) Programme has been established. The French company,
EADS
Astrium, which has extensive experience in this field such as SPOT series of satellites was
chosen as the prime contractor. The contract
includes development and launch of THEOS satellite,
as well as the development of the ground segment both for satellite operation and
control. THEOS
satellite is the first high-resolution earth observation satellite for Thailand which is fully operated by
the Geo-Informatics
and Space Technology Development Agency (GISTDA), Ministry of Science
and Technology and will provide worldwide geo-referenced
image products and image reception
and processing capabilities for applications in cartography, land use, natural disaster assessment
and mitigation, environmental monitoring, agriculture and forest management, coastal zone
monitoring and flood risk management.
THEOS will provide timely imaging of any part of Thailand in
less than three days. The THEOS satellite payload features both high
resolution in panchromatic
mode and wide field of view in multispectral mode which has been tailored to Thailand’s specific
needs with
a worldwide imaging capability. The launch of THEOS is scheduled in 2008 in a sun
synchronous orbit at an altitude of about 822
kilometers. |
| Chapter 85 |
Global Positioning System for Surveying and Mapping
In aspect of navigation purpose, GPS or Global Positioning System becomes commonplace and
user-friendly for all. The principle of
GPS for positioning is like compass back-azimuth techniques
but instead compass direction sighting to two or three key terrains, from
the space, 2 of 24
satellites emit signals to a receiver for positioning and other implements accuracy of receiver
position. Generally,
there are two types of receivers: navigation and surveying purposes. Two
techniques of measurement are conducted: kinematics and
static techniques. In Thailand GPS and
another Satellite Positioning Systems, however, for surveying and mapping have been operated
since 1960. The Royal Thai Survey Department is the initiators of GPS operation for such purpose
as construction and extension of
national mapping ground control-point network by using static
measurement techniques. This activity has been operated annually. For
the kinematics
measurement techniques, the department of city planning and public work installed the GPS-based
station for correction
signals broadcasting purpose throughout Thailand. Finally, GPS is integrated
with IT technology and becomes a necessary part of daily
life activities. |
| Chapter 86 |
Marine Environmental Monitoring System Using Buoy Network and
Satellite Technology
An important system of marine environmental monitoring for various purposes can be utilized of
buoy networks. As of year 2007,
there are eleven buoy locations Thailand, where nine are in the
gulf of Thailand and two locate in the Andaman Sea. Desired data form
this buoy network is
measured and collected, then transmitted via satellite link through ground station. Those include
sea surface
temperature, salinity, conductivity, significance wave height & period, current speed &
direction, light attenuation at 470, 550 and
650 nm, wind speed & direction, air temperature and
air pressure. Generally, this system is operated twenty four repeats a day and
functioned as a
nearly real time system. |
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