21-09-2012, 12:00 PM
GENERAL VIEWS OF WIRELESS TECHNOLOGY
[attachment=34239]
INTRODUCTION:
Every day, in our work and in our leisure time, we come in contact with and use a variety of modern communication systems and communication media, the most common being the telephone, radio, television, and the Internet. Through these media we are able to communicate (nearly) instantaneously with people on different continents, transact our daily business, and receive information about various developments and events of note that occur all around the world. This communication is based on technology called wireless technology. Wireless means transmitting signals over invisible radio waves instead of wires. Garage door openers and television remote controls were the first wireless devices to become a part of everyday life. Now the cordless keyboard and mouse, PDAs, and digital and cellular phones are commonplace.
DEFINITION:
Technically Wireless is a term used to describe telecommunications in which electromagnetic waves (rather than some form of wire) carry the signal over part or the entire communication path.
HISTORY:
The first wireless transmitters went on the air in the early 20th century using radiotelegraphy (Morse code). Later, as modulation made it possible to transmit voices and music via wireless, the medium came to be called "radio." With the advent of television, fax, data communication, and the effective use of a larger portion of the spectrum, the term "wireless" has been resurrected. It stems from the works of Oersted, Faraday, Gauss, Maxwell, and Hertz. In 1820, Oersted demonstrated that an electric current produces a magnetic field. In 1831, Michael Faraday showed that moving a magnet in the vicinity of a conductor produces an induced current. Thus, he demonstrated that a changing magnetic field produces an electric field. James C. Maxwell in 1864 predicted the existence of electromagnetic radiation and formulated the basic theory. Hertz verified Maxwell’s theory experimentally in 1887. In 1894, a sensitive device that could detect radio signals, called the coherer, was used by its inventor Oliver Lodge to demonstrate wireless communication over a distance of 150 yards.
WORKING OF WIRELESS NETWORK:
Wireless data is predominately transferred over two kinds of networks:
• Wide area networks (WANs) and
• Local area networks (LANs).
These networks are similar to their wired counterparts, but they just use radio waves instead of copper or fiber. WANs can cover areas as large as several countries. AT&T Wireless, Cingular Wireless, Sprint and Verizon and are among the carriers that use wireless WANs.Wireless LANs (WLANs), already popular in airports, coffee shops and hotels, are often used to replace or enhance wired LANs. WLANs can cover 1.25 miles indoors and up to 4.35 miles outdoors in extreme cases, but work best in the 500-foot range. They may service a smaller area than their WAN cousins, but LANs can transfer data much faster, with speeds of 54Mbps now possible. Many companies are switching to WLANs for voice over IP.Thus the combination of WAN’S and LAN’S, wireless technology proved its efficiency (i.e., coverage area and fastness).
WIRELESS SYSTEMS ARE REALLY HELPFUL:
A credit-card-size disposable cell phone will offer an approximately one hour of talk time.
Many businesses use wireless systems to deliver multiple audio programs easily and inexpensively. But most people use wireless systems to help understand speech better. This may be because environmental noise, distance, echo, or a hearing loss make speech intelligibility difficult. Understanding speech in the presence of background noise or echo — or even over a distance — is challenging for everyone. To understand well, we need a good signal-to-noise ratio.
THE LIMITATIONS OF WIRELESS:
When it comes to WANs, bandwidth is still limited. When transmitting data, users must sometimes send smaller bits of data so the information moves more quickly. The size of the device that's accessing the information is also still an issue. Even the most recent phones and PDAs have small screens - often only a couple of inches in diameter - and it is hard to read large documents on them.
Many applications need to be reconfigured if they are going to be used through wireless connections. Most client/server applications rely on a persistent connection, which is not the case with wireless. Transactional systems require safeguards for dropped wireless connections. Remedies for all of these shortcomings cost money.
CONCLUSION:
It is changing. Both devices and network technologies have improved by leaps and bounds in the past year or so. Wireless technology is rapidly evolving, and is playing an increasing role in the lives of people throughout the world. In addition, ever-larger numbers of people are relying on the technology directly or indirectly. Real wireless projects depend on three elements: the device, the network (i.e. the WAN) and the application.
[attachment=34239]
INTRODUCTION:
Every day, in our work and in our leisure time, we come in contact with and use a variety of modern communication systems and communication media, the most common being the telephone, radio, television, and the Internet. Through these media we are able to communicate (nearly) instantaneously with people on different continents, transact our daily business, and receive information about various developments and events of note that occur all around the world. This communication is based on technology called wireless technology. Wireless means transmitting signals over invisible radio waves instead of wires. Garage door openers and television remote controls were the first wireless devices to become a part of everyday life. Now the cordless keyboard and mouse, PDAs, and digital and cellular phones are commonplace.
DEFINITION:
Technically Wireless is a term used to describe telecommunications in which electromagnetic waves (rather than some form of wire) carry the signal over part or the entire communication path.
HISTORY:
The first wireless transmitters went on the air in the early 20th century using radiotelegraphy (Morse code). Later, as modulation made it possible to transmit voices and music via wireless, the medium came to be called "radio." With the advent of television, fax, data communication, and the effective use of a larger portion of the spectrum, the term "wireless" has been resurrected. It stems from the works of Oersted, Faraday, Gauss, Maxwell, and Hertz. In 1820, Oersted demonstrated that an electric current produces a magnetic field. In 1831, Michael Faraday showed that moving a magnet in the vicinity of a conductor produces an induced current. Thus, he demonstrated that a changing magnetic field produces an electric field. James C. Maxwell in 1864 predicted the existence of electromagnetic radiation and formulated the basic theory. Hertz verified Maxwell’s theory experimentally in 1887. In 1894, a sensitive device that could detect radio signals, called the coherer, was used by its inventor Oliver Lodge to demonstrate wireless communication over a distance of 150 yards.
WORKING OF WIRELESS NETWORK:
Wireless data is predominately transferred over two kinds of networks:
• Wide area networks (WANs) and
• Local area networks (LANs).
These networks are similar to their wired counterparts, but they just use radio waves instead of copper or fiber. WANs can cover areas as large as several countries. AT&T Wireless, Cingular Wireless, Sprint and Verizon and are among the carriers that use wireless WANs.Wireless LANs (WLANs), already popular in airports, coffee shops and hotels, are often used to replace or enhance wired LANs. WLANs can cover 1.25 miles indoors and up to 4.35 miles outdoors in extreme cases, but work best in the 500-foot range. They may service a smaller area than their WAN cousins, but LANs can transfer data much faster, with speeds of 54Mbps now possible. Many companies are switching to WLANs for voice over IP.Thus the combination of WAN’S and LAN’S, wireless technology proved its efficiency (i.e., coverage area and fastness).
WIRELESS SYSTEMS ARE REALLY HELPFUL:
A credit-card-size disposable cell phone will offer an approximately one hour of talk time.
Many businesses use wireless systems to deliver multiple audio programs easily and inexpensively. But most people use wireless systems to help understand speech better. This may be because environmental noise, distance, echo, or a hearing loss make speech intelligibility difficult. Understanding speech in the presence of background noise or echo — or even over a distance — is challenging for everyone. To understand well, we need a good signal-to-noise ratio.
THE LIMITATIONS OF WIRELESS:
When it comes to WANs, bandwidth is still limited. When transmitting data, users must sometimes send smaller bits of data so the information moves more quickly. The size of the device that's accessing the information is also still an issue. Even the most recent phones and PDAs have small screens - often only a couple of inches in diameter - and it is hard to read large documents on them.
Many applications need to be reconfigured if they are going to be used through wireless connections. Most client/server applications rely on a persistent connection, which is not the case with wireless. Transactional systems require safeguards for dropped wireless connections. Remedies for all of these shortcomings cost money.
CONCLUSION:
It is changing. Both devices and network technologies have improved by leaps and bounds in the past year or so. Wireless technology is rapidly evolving, and is playing an increasing role in the lives of people throughout the world. In addition, ever-larger numbers of people are relying on the technology directly or indirectly. Real wireless projects depend on three elements: the device, the network (i.e. the WAN) and the application.