Microwave and
Radio Based Systems
Overview
Many countries use the microwave
and radio based systems as an emergency services, homeland security, public
safety and disaster recovery organizations are heavily reliant on reliable
mobile radio network coverage for mission-critical communications.
Point-to-point digital microwave radio systems are deployed in these networks
to inter-connect mobile radio base stations and backhaul the vital
communications to the central or regional switches. The systems are typically
deployed where distance, difficult terrain or harsh environments mean the speed
or cost of deployment for wired, fiber and satellite communications is not
viable or commercially feasible. But besides of its function there a lot of
people did not know how the microwave radio systems useful. This technology has
been taken for granted over the years. has been taken for granted over the
years.
Possible market share
for microwave products
Service
|
2002
|
2006
|
Point−to−point
microwave radios services
|
$2.5
billion
|
$4 billion
|
Point−to−multipoint
microwave
|
$700
million
|
$2 billion
|
Wireless
LAN microwave products
|
$1.4
billion
|
$4 billion
|
Total
|
$4.6
billion
|
$10
billion
|
Microwave has also become
a vital link in the overall backbone networks over the years. Now, it has
achieved new acclaim in the wireless revolution, relaying thousands of
telephone conversations from place to place, bypassing the local landlines.
Microwaves are between 1 mm and 30 cm long, and operate
in a frequency range from 300 MHz to 300 GHz. Microwaves were first used in the
1930s, when British scientists discovered the application in a new technology called
radar. Microwave radio was used extensively for long−distance telephone
transmission. With the need to communicate over thousands of miles, the cost of
stringing wires across the country was prohibitive. However, the equipment was
both heavy and expensive. the typical microwave radio used 2,100 watts to
generate three groups of radio channels (each group consists of 12 channels), yielding
36−voice−grade−channel capacity. Each voice grade channel operated at the
standard 4 kHz.
Throughout the world,
government−owned and −controlled monopolies are being eliminated. Brazil opened
its doors to international Telecom competition, allowing microwave radio
systems and a mobile telephone system supplied by North American firms. In
Russia, one of the leading systems manufacturers installed an integrated
network along a 3,600−mile gas pipeline.
The cellular and Personal
Communications Service (PCS) industries invested heavily in microwave radios
to interconnect the components of their networks. Where the
interconnection is
used in the cellular world.
Cellular
interconnection of microwave radio:
WinStar
Communications, a Competitive Local Exchange Carrier (CLEC),
pioneered the use of
micro/millimeter wave
radio communications in the 30+ GHz frequency range (actually 28 to 38GHz). This allowed the CLEC to deliver broadband communications to the consumer's door without the use of telephone company wires.
Advantages of Microwave
Radio:
1. Radio
systems do not require a right way acquisition between stations.
2. Each
station requires the purchase or lease of only a small area of land.
3. Because
of their high operating frequencies, microwave radio systems can carry large
quantities of information.
4. High
frequencies mean short wavelengths, which require relatively small antennas.
5. Radio
signals are more easily propagated around physical obstacles such as water and
high mountains.
6. Fewer
repeaters are necessary for amplification.
7. Underground
facilities are minimized.
8. Minimum
delay times are introduced. Minimal crosstalk exists between voice channels.
9. Increased
reliability and less maintenance are important factors.
Disadvantages of
microwave radio:
1. It is
more difficult to analyze and design circuits at microwave frequencies.
2. Measuring
techniques are more difficult to perfect and implement at microwave
frequencies.
3. It is
difficult to implement conventional circuit components at microwave frequencies
like (resistors, capacitors,inductors, ….)
4. Transient
time is more critical at microwave frequencies.
5. It is
often necessary to use specialized components for microwave frequencies.
6. Microwave
frequencies propogate in a straight line, which limits their use to line of
sight applications
http://en.wikipedia.org/wiki/Microwave_transmission
Broadband
Telecommunications Handbook, Second
Edition:
Regis J. (Bud) Bates