Throughout history, communication has been a
part of human life that we could not live without. From the
ancient pigeon messages, to fire-communication, to today's
wide flow of telecommunications, net meetings, human's advances
with technology has been enormous. Cord-telephones, mobile
analog, mobile digital and third generation telephones all
act as a symbol of milestone for the human's development in
communication technologies. Even though the invention of landlines
and fax services was a major step in the advancement of communication
technology, it could not escape the limits of the network;
however, wireless technology's development can really achieve
unbounded freedom in communication, allowing more convenience
and comfort in daily life. Below will introduce the progression
of current wireless telephone systems, information sharing,
and the future of wireless telecommunication.
It has been quite awhile since the dawn of mobile phones,
and the history of mobile phones can be categorized into three
different stages: analog communication systems, digital communication
systems, and third generation mobile phone systems. Also,
how do mobile phone systems transmit signals? To understand
signal transmission, we have to investigate the so-called
hexagonal networking structure first.
Hexagon networking structure
Hexagon networking structure is composed of many broadcasting
sites, and every one of the broadcasting sites manages the
local area's wireless communication. The broadcasting sites
have a tower that relates and connects information with neighboring
areas, and that is how a wireless telecommunication web is
formed. Since every tower has their own respective area of
coverage, the map of the network of areas resembles the image
of a hornet's nest, and that's where the name hexagon networking
structure comes from.
In addition, how is the location of these broadcasting sites
determined? Because of the fact that each broadcasting site
can only process a limited amount of signal information, areas
with higher population such as Mongkok, Central, Causeway
Bay have higher usage rates and therefore higher concentration
of broadcasting sites to process the large volume of wireless
telecommunication. As for the less populated areas such as
countryside (Lamma Island, Shek O, Kam Tin) and New Territories
(Tin Shui Wai, Sheung Shui, Tsing Yi), the usage rates are
relatively lower and therefore have less concentration of
broadcasting sites. Thus, the mobile phone accounts that are
located in more remote areas will often experience less signal
receipt than the more populated areas, or sometimes even no
signal at all, and this is all due to the lack of broadcasting
sites.
Signal Processing Mode
Signal processing mode refers to process that
occurs when signal is transferred from one mobile phone account
to another. First let us introduce the process of signal processing.
When two different mobile phones are connected with each other,
the phone will turn the user's voice into a wireless electronic
signal, and then from the broadcasting site's tower, it is
distributed as a form of electronic waves. These processed
signals will then be picked up from neighboring broadcasting
sites and relayed to the other mobile phone and transformed
back into the user's original voice. If two users are in between
great distance that spans numerous broadcasting sites, then
the electronic waves will travel through the web of broadcasting
site network, from one site to another. Utilizing the web
network structure, signals can be sent to many different locations.
After a basic understanding of signal processing, let us go
deeper and discuss the two different modes of signal processing.
Analog Signal Processing
The first generation of mobile phones used analog
signal processing, and in the process of analog signal processing,
the signal take on the form of waves, which is different than
that of the digital signal processing discussed below. In
the process of signal processing, signals are first transformed
into electronic waves and then sent out. Due to interference
with other electronic waves during traveling, the signal that
is received at the destination will be somewhat reduced. Analog
technology shapes the interfered signals back to its original
form. Since the level of interference varies with the different
areas, so the shape of the signal will never be exactly the
same as its original.
Digital Signal Processing
Digital signal processing is branded as the
second generation of mobile phones. Compared to analog signal
processing, they are similar in that they both use electronic
waves to transmit signals, and differ in that digital processing
uses only numbers 1 and 0 to represent the shape of the electronic
waves. In this process, signals also encounter interference,
but since the electronic waves are binary and can only take
on two forms, the reduction in the signal will be much less
and the signal will be shaped back to exactly the same as
its original.
Digitalization
Digitalization refers to the process of turning
signals into digital form. Since the images and sounds are
processed simultaneously in digitalization, it saves a lot
of time. There are also other advantages to digital signal
processing such as being able to completely remove noise and
interference; allowing the combination of different such as
the sound, fax, text, and image in media. With these digital
signal processing advantages, today's mobile phone system
have completely adopted this technology. The two currently
most common systems are GSM and CDMA.
GSM System
GSM system uses the prior mentioned hexagon networking structure
along with a technology called channel reusability. Channel
reusability refers to the idea of repeatedly using the channel
by first splitting one channel into many narrower frequencies,
and then using them as pieces of a puzzle and spread them
onto the different areas. This is the underlying concept of
channel reusability. Using this technology, we can reuse one
channel, thus avoiding a lot of channel establishment as well
as labor and resources.
CDMA System
The difference between CDMA system and GSM system is in the
frequency looping technology. CDMA system not only uses both
hexagon networking structure and channel reusability, it also
uses frequency looping technology, which is using every available
frequency in the vicinity of the area. However, everyone might
wonder about the heavy interference that might come with using
this system, but in reality, there are no such interference
issues. Then what exactly is this frequency looping technology
that the CDMA system uses? When CDMA users receive signal,
the frequency in use will loop with time in attempt to reduce
the probability of other users using the same frequency during
the same time interval. If there are more than one user receiving
the signal, then the frequency that they are using will loop
as well and, in addition, be randomly, thus reducing the interference,
and this is the marvel of frequency looping.
Error Correcting Code
During the process of signal transfer, some interference
and errors are bound to occur, and mobile phone systems have
a method to correct such errors. To avoid mistakes in information,
signals are transferred repeatedly for multiple times. When
a interference occurs during the process of transfer, mobile
phone systems can correct the signals received. Below are
two methods of such Error Correcting Code.
The actual method is pretty simple. If the system
was to transfer a "1", this signal during transfer
process will repeatedly transfer for multiple times such as
five times. Because of interference, the signal received will
have an error such as receiving a "0" instead of
the "1" that was transferred. When the system discovers
that the signal does not follow the repeated "1"
pattern, it will recognize the mistake and make the correction,
by using the majority as the correct signal. As the figure
shows, when the signal transfer shows the amount of "1"
is the majority when compared to "0", then the "0"
will be corrected. Using this method, the system can correct
signal errors such as the other example shown in the figure.
Through this Error Correcting Code, the errors will be corrected.
(Error Correcting Code)
Currently, mobile phone transferring messages is already
very common and widespread, and using mobile phones to transfer
e-mails will become a daily habit. We will be able to use
mobile phones to accommodate many personal services such as
shopping and making payments. To achieve such demand, there
must be a creation of a new mobile phone web system. This
system must have instant web-connection capabilities, allowing
the user to access different services instantly. Also, the
network should also be able to provide abundant multi-media
services. These are the roles of the third generation mobile
phone systems.
Third Generation Mobile Phone
Systems-3G
3G is short for Third Generation and it uses a newly created
wireless telecommunication technology, allowing mobile phone
users to instantly access high speed internet services. As
a result, we can connect to the internet with high speed anywhere
and anytime, and enjoy the abundant content of recreation
and entertainment information as well as search capabilities.
We are not limited to depending on television, personal or
family computers to access internet services. In business,
electronic business activity will also expand, such as acquiring
information and holding conferences through the internet.
Through 3G technology, users' access speed can be raised to
up to two mega bytes per second(2Mbits/s), which is forty
times faster than GSM system. Also, the system's processing
capabilities are also increased, allowing the system to deliver
better quality services. Because of these, 3G technology is
more advanced than traditional telecommunication network systems.
Overall speaking, what new functions has 3G technology brought
us? 3G technology's trademark lies with the compatibility
with technology advances, user friendly and ergonomically
designed mobile phones, capable of delivering fast multi-media
information, and global positioning system functions. Other
than those, it also allows user to have high speed internet
connection and e-mail functions. Even though 3G technology
in Hong Kong has not developed completely, it has already
reached a very mature stage in Japan. In the near future,
when 3G technology formally adapts into Hong Kong mobile phone
systems, we will be able to take advantage of the new services
made available through the third generation mobile phone systems.
Blue Tooth Technology
A kind of wireless telecommunication technology that has
been heard of few years ago, but was only associated with
electronics fans in the eyes of the public, is not an ordinary
technology. Imagine this; you pressing a button on your mobile
phone and the air conditioning in your house will turn on
before you arrive home. Or through your hand held computer
you are able to find out what you have in your refrigerator
at home when you are out grocery shopping, allowing you to
decide what to purchase. The above can all become reality
through Blue Tooth technology. Before discussing the applications,
let's first look at what is Blue Tooth technology. Blue Tooth
technology is a kind of electronic wave-proof wireless telecommunication
technology. With this type of technology, Blue Tooth products
can conduct wireless communication in a short distance. The
origin of the name Blue Tooth came from a tenth century Norway
king. This king ruled Denmark, and if you translate his name
to English, it becomes ¡§Blue Tooth¡¨.
This technology was named after him in hopes of the technology
will one day become the standard throughout the world.
In the earliest stages of wired-network, every component
is connected by a wire that provides the information transfer,
which greatly reduced the flexibility and reach of communication.
In the recent years, Infrared (IR) communication's implementation
removed the inconvenience of wires, but had a big drawback
of relying on the position of the IR sensor to provide communication,
similar to a television remote. The user has to be in short
distance of the device's sensors and in range of its line
of sight for it to control it properly. When Blue Tooth products
are introduced, it will solve the problems mentioned above;
allowing communication in a distance of up to ten meters and
are not restricted to direction and wires. Currently on the
market, there have already been some manufacturers who introduced
electronic products that contain Blue Tooth technology, such
as the recently popular wireless headphones. The headphones
are popular with users because it does not need a cable to
achieve its purpose, and with the support of other Blue Tooth
products such as noting a destination phone number on a hand-computer,
the Blue Tooth wireless headphones will automatically dial
the number fast and conveniently.
To put it simply, as long as electronic products incorporate
this type of advanced Blue Tooth technology, the transfer
of information will not be restricted to geography, environment,
signal processing mode and network. Even though the current
Blue Tooth technology development and application has not
become widespread, with the continuous introduction of a wide
variety of Blue Tooth products, users can purchase and apply
Blue Tooth products into their daily lives. In the not distant
future, we will be able to witness a limitless communication
world that will receive the fastest information anywhere and
anytime, brining us the real convenience through wireless
telecommunication.
Through the above article, everyone has a deeper understanding
and comprehension of wireless telecommunication. The actual
development of wireless telecommunication is boundless, and
what will it become in the future? That can only be discovered
from everyone's further inquiry.
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