This article deals with "Wireless Technologies", that is, how they have evolved, what role they play in the life or development of companies, types of wireless devices, applications, among many other aspects related to the area.
INTRODUCTION
At present the issue of "wireless networks" has taken on great importance since this technology has aroused the interest of many in terms of how to communicate different computer equipment without the need to use wired networks; that is, how to establish communication between computers wirelessly.
This technology facilitates the operation of computers that cannot be in the same place or that are separated at a distance.
This does not mean that wireless technology will replace wired networks in the future; since the latter reach a higher transmission speed than that offered by wireless technology.
However, wireless systems provide greater user comfort because it is not necessary to use so many cables for the installation of wireless equipment, as well as they provide greater ease of movement for computers or systems with this technology. But even so, we cannot rule out anything since the advancement of technologies "is an unknown world for man", that is, we do not know what new technologies we will be using tomorrow.
"DEVELOPMENT OF THE TOPIC"
Wireless networks allow or facilitate communication between workstations that are in different locations. This is because they do not need a physical means of interconnection, that is, there are no cables that connect the different work teams to establish communication.
There are basically two types of wireless networks:
* Long distance: They are used to transfer information between computers that are in different geographic areas; that is to say, in surrounding or remote spaces or places (better known as MAN Metropolitan Area Network, metropolitan area networks) their transmission speeds are relatively low, from 4.8 to 19.2 Kbps.
* Short distance: They are used to transfer information between computers that are separated by a small space; for example, in company computers that are in the same building (they are known as LAN Local Area Network, local area networks) their speeds are of the order of 280 Kbps to 2 Mbps.
There are two types of long distance networks:
- Packet-switched networks (public and private). Cellular telephone networks. The latter are used to transmit high-cost information, since modems are currently more expensive due to the special circuitry, which allows to maintain the signal loss. This loss of signal is not a problem for voice communication because the delay in switching lasts a few hundred milliseconds, which is not noticeable, but in the transmission of information it can cause defects.
Disadvantages of cell transmission are:
- Charging of phones is easily terminated Cellular transmission is easily intercepted Transmission speeds are low.
All these disadvantages mean that cellular communication is little used. But it is hoped that advances in data compression, security, and error-checking algorithms will allow cellular networks to be a good option in some situations.
The other option that exists in long distance networks are the so-called:
- Public Radio Packet Switching Network. These networks do not have signal loss problems because their architecture is designed to support data packets instead of voice communications.
Private packet-switched networks use the same technology as public ones, but under radio frequency bands restricted by the organization of their computer systems.
Main advantages of wireless networks:
- Allow mobility Facilitate relocation of workstations avoiding the need to lay cables Quick installation Lower maintenance costs
PUBLIC RADIO NETWORKS.
Public networks have two main players: "ARDIS" (a partnership of Motorola and IBM) and "Ram Mobile Data" (developed by Ericcson AB, called MOBITEX). These networks allow transmission through radio channels in metropolitan areas that can be used as long distance networks. The infrastructure of these networks includes area controllers and Base Stations, fault-tolerant computing systems, these systems support the X.25 packet switching standard, as well as their own packet structure. These networks provide flexibility at the application layers, allowing the customer to develop software applications.
Public radio networks such as ARDIS and MOBITEX will play a significant role in the local area network (LAN's) market due to their large size. For example, OTIS elevators uses ARDIS for their service organization.
INFRARED NETWORKS
Infrared light networks are limited by space and are almost generally used by networks in which the stations are in a single room or floor, some companies that have their offices in several buildings carry out the communication by placing the receivers / emitters in the windows of the buildings. Infrared transmission does not have this drawback, therefore it is currently an alternative for Wireless Networks.
The same principle is used for network communication, a "transceiver" is used that sends a beam of Infrared Light to another that receives it. Light transmission is encoded and decoded on sending and receiving in an existing network protocol. One of the pioneers in this area is Richard Allen, who founded Photonics Corp. in 1985 and developed an "Infrared Transceiver". In addition, the technology has been improved using a transceiver that spreads the beam throughout the room and is collected by other transceivers.
RADIO FREQUENCY NETWORKS
Wireless Radio Frequency Networks are used mainly in military applications, they consist of a transmission signal technique called spread-spectrum modulation, which has a maximum transmission power of 1 Watt. The idea is to take a conventional band signal and distribute its energy over a wider frequency domain.
Thus, the average energy density is lower in the equivalent spectrum of the original signal. In military applications the goal is to reduce the energy density below the ambient noise level in such a way that the signal is not detectable. The idea in networks is that the signal is transmitted and received with a minimum of interference. There are two techniques to distribute the conventional signal in an equivalent spread spectrum:
- Frequency hopping: This method is a technique in which the receiving and transmitting devices move synchronously in a certain pattern from one frequency to another, both jumping at the same time and on the same predetermined frequency. As in the direct sequence method, the data must be reconstructed on the basis of the frequency hopping pattern. This method is viable for wireless networks, but the current assignment of the ISM bands is not adequate, due to competition with other devices, such as the 2.4 and 5.8 Mhz bands that are used by microwave ovens.
LOCAL AREA NETWORK HYBRID ethernet (coaxial / infrared)
En una implementación «Ethernet CSMA/CD», una estación con un paquete listo para enviar, retarda la transmisión hasta que «cense» o verifique que el medio por el cual se va ha trasmitir, se encuentre libre o desocupado. Después de comenzar la transmisión existe un tiempo muy corto en el que una colisión puede ocurrir, este es el tiempo requerido por las estaciones de la red para «censar» en el medio de transmisión el paquete enviado. En una colisión las estaciones dejan de transmitir, esperan un tiempo aleatorio y entonces vuelven a censar el medio de transmisión para determinar si ya se encuentra desocupado.
In an Ethernet cabling the coaxial medium is divided into segments, a maximum of 5 segments is allowed between 2 stations. Of these segments only 3 can be coaxial, the other 2 must have a point-to-point link. The coaxial segments are connected by means of repeaters, a maximum of 4 repeaters can be installed between 2 stations. The maximum length of each segment is:
- 500 meters for 10 Base5185 meters for 10 base2.
The function of the repeater is to regenerate and retransmit the signals that travel between different segments, and to detect collisions.
INFRARED RADIATION MODES
- Stations with infrared technology can use three different modes of radiation to exchange Optical energy between transmitter-receivers: point-to-point quasi-diffuse and diffuse (Fig. 1, 2, 3).
- In point-to-point mode: the radiation patterns of the emitter and receiver must be as close as possible, that is, the emitting and receiving stations must be practically opposite each other for their alignment to be correct. As a result, point-to-point mode requires a line-of-sight between the two stations to communicate. This mode is used for the implementation of Wireless Infrared Token-Ring networks. The physical "Ring" is built by the individual point-to-point wireless link connected to each station. The quasi-diffuse and diffuse mode, unlike the point-to-point mode, are radio broadcast, that is, when a station broadcasts an Optical signal, this can be received by all stations at the same time in the cell. In quasi-diffuse mode the stations communicate with each other, through reflective surfaces.The line-of-sight between two stations is not necessary, but must be with the reflection surface. It is also recommended that the stations are close to the reflection surface, this can be passive or active. In cells based on passive reflection, the reflector must have high reflective and dispersive properties, while those based on active reflection require a reflective output device, known as a satellite, which amplifies the optical signal. Passive reflection requires more energy, by stations, but is more flexible to use. Diffuse mode, the output power of a station's optical signal, should be sufficient to completely fill the entire room, through multiple reflections, on walls and obstacles in the room.Therefore line-of-sight is not necessary and the station can be oriented to either side. The diffuse mode is the most flexible, in terms of location and position of the station, however this flexibility comes at the cost of excessive optical emissions.
Advantages of Lan's over Fixed Networks
- Mobility: Wireless networks provide users on a LAN with access to information in real time anywhere within the organization or public environment Simplicity and speed of installation: Installation of a LAN is quick and easy and eliminates need to run cables through walls and ceilings Installation flexibility: Wireless technology enables the network to reach points that are difficult to access for a wired LAN Reduced cost of ownership: while the initial investment required for a wireless network can be higher than the hardware cost of a LAN, the investment
of the entire installation and the cost over the life cycle can be significantly lower. The long-term benefits are superior in dynamic environments that require frequent actions and movements. Scalability: WLAN systems can be configured in a variety of topologies to meet the needs of specific installations and applications. The configurations are very easy to change and it is also very easy to add new users to the network.
"WIRELESS DEVICES"
Wireless devices began to gain place in the preferences of computer users, both for offices and for the home. Their main advantages are that since they are not tied to a socket, they are much more comfortable and preserve the aesthetics of any environment by not having cables.
It is possible to get any accessory to plug into the PC: Mouse, keyboard, printers, cameras, gamepad, etc.
It is even possible to connect several machines on a network and with Internet access without the use of any cable.
These computers allow almost total freedom of movement for the user, since one can sit down to write several meters from the monitor, play from an armchair away from the computer, and even talk on a cell phone with headphones without the need for cables that many of the time they bother us.
There is an incredible assortment of keyboards and mice, with ergonomic designs and keys that respond to minimal contact. For them to work it is necessary to connect the receiver to the USB port. Both the keyboards and the mouse need two batteries to work. In the case of keyboards, they can last up to four months and Mouse half.
Games
The biggest offer in this area is for game consoles. They are identical devices to the original but wireless.
phones
There are those exclusively for cell phones and those used to chat on the computer.
The latest craze in cell phones are headsets known as "hands-free." Since they are placed on the ear, and they come with a screen that informs the name or number of who is calling. They come with a series of keys so you don't have to take the phone out of your pocket.
Of course, there are many more wireless devices, but I have only mentioned the best known.
ADVANTAGES AND DISADVANTAGES OF A DEVICE CONNECTED BY CABLE OR WIRELESS.
Nowadays there are many devices that can be connected to the PC both by cable and wirelessly. From keyboards and mice to printers, IP cameras, speakers…
On the left, an HP Deskjet 460cb printer (for notebook computers). On the right, an HP Photosmart C7180 printer, one of the most complete printers on the market.
The list is very extensive, as well as the systems used to make this connection.
Image of a USB IrDa receiver. On the right, a Desktop (keyboard + mouse) by radio frequency.
ADVANTAGE
- Absence of cables in the installation The mobility acquired by the devices installed wirelessly. Installs quite clean and relatively easy to do.
DISADVANTAGES
- Mobility is limited by the scope of the system used High cost They are less secure Possibility of greater misconfiguration Loss of connectivity Exposed to interference High power consumption
Despite all the above drawbacks, a wireless connection is very useful for many devices, such as printers for laptops, radio note readers, and ultimately whenever we need to place these devices in a place that is problematic to access by wiring.
"SOME WIRELESS TECHNOLOGIES".
Bluetooth and Wi Fi technologies
These two technologies do not compete with each other, but rather complement each other. Bluetooth is much newer. It is the wireless equivalent of USB connectivity. Due to its short range and low power consumption it is used to connect all kinds of devices to the computer. Also for cell phones and palmtops. The maximum coverage it reaches is 20 meters.
Wi Fi technology for its part is ideal for building computer networks. With this you can move large files. Data transmission is performed ten times faster than Bluetooth and has a range of 100 meters in closed spaces. This technology allows various wireless connections to the
Wi-Max Internet
"Specifically, 802.16 technology, often referred to as WiMAX, complements WLAN by connecting 802.11-enabled hotspots to the Internet and offers a wireless alternative to next-generation broadband connectivity to businesses and homes."
This is a very expensive network that Microsoft applies. We will truly be able to have broadband and not just bandwidth, where the transmission speed will be higher.
Difference between a Wi-Fi and Wi-Max network
A Wi-Fi, ad hoc network can be established by anyone to connect the home with the office, while Wimax is designed to cover an entire city through base stations scattered around the metropolitan area.
GPRS technology
GPRS is the acronym for General Packet Radio Services (General Packet Radio Services). It is often described as "2.5G", that is, a technology between the second (2G) and third (3G) generation of digital mobile technology. It is transmitted over mobile phone networks and sends data at a speed of up to 114 Kbps. The user can use the mobile phone and the pocket computer to surf the Internet, send and receive mail, and download data and media. It allows you to video conference with your colleagues and use instant messages to chat with your family and friends, wherever you are. In addition, it can be used as a connection for the laptop or other mobile devices.
3G technology
Like GPRS, 3G technology (third generation wireless technology) is a wireless communication service that allows you to be permanently connected to the Internet through your mobile phone, pocket computer, tablet PC or laptop. 3G technology promises better quality and reliability, higher data transmission speed, and higher bandwidth (which includes the ability to run multimedia applications). With data speeds of up to 384 Kbps, it is almost seven times faster than a standard phone connection.
IrDA technology
This technology, based on light rays that move in the infrared spectrum.
IrDA standards support a wide range of electrical, computing and communications devices, allowing bidirectional communication between two extremes at speeds ranging between 9,600 bps and 4 Mbps.
This technology is found in many notebook computers, and in a growing
number of cell phones, especially those from leading manufacturers such as Nokia and
Ericsson.
"INTERNET TOPOLOGY"
One of the most important topologies in wireless networks today is the Internet topology, which shows how large workgroups interconnect to share information. Fig. 5
Several individual computers connected to each other form a local area network (LAN). The Internet consists of a series of interconnected networks (LANs). Personal computers and workstations can be connected to a local area network using a modem through an ISDN or PSTN connection, or directly to the LAN. There are also other forms of connection to networks, such as the T1 connection and the dedicated line. Bridges and hubs link multiple networks to each other. A router transmits the data over the networks and determines the best transmission path.
IMPORTANCE OF WIRELESS TECHNOLOGIES IN BUSINESSES
Wireless technologies provide a number of benefits to companies, that is, they provide wireless and mobile solutions that improve business processes, allowing companies to do their jobs better, faster and more economically. In addition, mobile solutions allow them to achieve results within their business that were previously impossible to achieve.
Wireless technology is another tool that competitive companies can benefit from in this process of change.
It does not matter if a company is large or small, nor the sector in which it operates, at any time new technologies, the internet and electronic commerce will affect or have already affected your business, whether in the way you work, in your relationships commercial or to a greater or lesser extent in mobile devices, since these represent another means available to those companies that know that in order to grow, to be more competitive and improve their processes, they must approach new technologies and incorporate them into their business to the extent that is fair and necessary for them to facilitate business development.
"CONCLUSION"
This article tries to give the reader a broad knowledge in the area of wireless technologies that are one of the main tools in business development since it is one of the technologies that are most outstanding today due to its easy installation, mobility among others of its extensive and much-cited characteristics, in addition to providing us with greater comfort in the use of wireless devices or devices. Wireless technology is very important since new ways of wirelessly sharing information over long and short distances are presented every day, making our work easier and putting us at the forefront.
"BIBLIOGRAPHY"
es.wikipedia.org/wiki/Red_inalámbrica
www.monografias.com/trabajos/redesinalam/redesinalam.shtml
www.maestrosdelweb.com/redeswlan/
http: //www.configurarequipos. com / doc516.html
Encarta Encyclopedia
0CE5E4431A61C3FFC1256DBA002E0B76 / $ File / Wireless.pdf
