The wireless networks promise to eliminate cables – A Historic Perspective

King Harald Bluetooth has lived in Denmark since 910 AD until 940 AD. The name Bluetooth (or Blataand in the language of the Vikings) has nothing to do with blue teeth. It means dark color of hair, which was very unusual for Scandinavians. The existence of King Harald Bluetooth would be completely unknown if it had not joined the Nordic countries and if Ericsson had not given his name to the new wireless communication protocol developed together with other major companies in the area.

The area of wireless communications and standards, however, is still in its infancy. The largest companies are divided into groups and develop competitive technologies to sovereignty in a market which is expected within the next two years to skyrocket to billion dollars.

Wireless networks have been available for several years by various manufacturers, but the speed offered (1,5 Mbps) was small and there was no compatibility between them. The new standards provide greater convenience, such as Bluetooth, or higher speeds, such as IEEE802.11b, standardized just a few years ago. But even those not yet formalized, such as IEEE802.11a and HiperLAN2, is equally strong opponents in the battle of prevalence, because of their high potential.

In the last years the area of wireless communication is in height: Analysts say when the one and when the other technology, some companies are changing camps and other companies played in two dashboard. The situation just now seems to be stabilized somewhat and things clarified.

Wireless networks allow electronic devices (from computers to video) to communicate with each other and exchange data without the existence of cables. All new models of wireless networks, apart from the standard IrDA (Infrared Data Association), which is anyway not actually a wireless network, do not require line of sight. In any wireless network there are two parts: the wireless network card (wireless LAN adapter), which communicates either with other devices have wireless network card, either with the transponder-node (Access Point), which serves as a bridge to the wired network . The network card resembles a standard network card (either PCI or ISA for fixed computers, either PC Card for laptops) with a small antenna and the transceiver has dimensions of a book and, apart from the antenna, has appropriate plugs for connecting to a fixed network. With regards to security, most wireless networks also use methods of authorization and encryption-related data. Several models use the technical rotation frequency (frequency hopping) whereby each transponder frequency changes after sending / receiving a packet data avoiding parasites.

The standard Bluetooth created by Ericsson, IBM, Toshiba, Intel, Nokia and Motorola and supported by other 1900 companies, is the de facto standard for wireless networking performance of small electronic devices (mobile, PDA, PC, printers, fax, modem, keyboards, etc.) with low consumption (0,01 W) and low cost. These networks are called PAN (Personal Area Networks, Personal Area Networks) because unlike the LAN, its an area which is covers very few meters. The PAN has been essentially designed to eliminate cables. The speed data transfer is up to 1Mbps while it is possible the simultaneous transfer of sound. The frequency emitted data are 2,4 GHz using the technique rotation frequency. The Bluetooth supports both direct communication between two devices (point to point) and communication equipment with a multi-access point (point to multipoint). The capacity is 8 devices per network, but the method of switching frequencies (1600 rotations per second to 79 channels) allows more than 1 networks to coexist on the same site. The minimum distance between the transmitter and receiver is 10 cm and a maximum 10 meters. In terms of safety, although the Bluetooth does not provide very high level, the short range limits risk.

The movement of devices that support Bluetooth has already begun in the form of mobile phones and network cards for computers. Since the cost of implementation of Bluetooth is very small, by the end of 2010 99% of mobile phones will incorporate Bluetooth. Companies such as Palm and Microsoft have already announced support for Bluetooth in future products.

If the Bluetooth aims to eliminate cables connecting the various gadgets and peripherals among themselves and with the computer, the Protocol IEEE 802.11b aims to eliminate cables between computers. The 802.11 is the name of the project working group of IEEE (Institute of Electrical and Electronics Engineers, Institute of Electrical and Electronics Engineers) for wireless networks. The IEEE 802.11, which was created in June 1997, has speed 2 M bps and is the model followed so far for wireless networks Ethernet. The issuance of IEEE 802.11b (also known as IEEE 802.11 High Rate, or Wi-Fi) was created in July 1998 and has speed 11Mbps while adopting IEEE 802.11a, which is still under development, provides speeds up to 54Mbps. The IEEE802.11 b is essentially the standard in wireless networks, Ethernet and supports contact point to point (which is called ad hoc) and contact point to multipoint. The computers that are on the same site, for example, can be defined in an ad hoc, and to communicate directly with each other. The need for access point occurs when necessary communication with wireline networks and / or regional or in the case of roaming (eg when a user of a mobile computer must be initiated within a building). Part also of 802.11b is the WEP (Wired Equivalent Privacy, secrecy corresponding with wired networks), which uses the RC4 algorithm and offers the possibility of empowering every node and data encryption. Like the Bluetooth, wifi operates at 2,4 GHz and uses the technical rotation frequency. This frequency, is the same used by microwave ovens, chosen because it is free and does not require licensing for devices using them. The use, however, of common frequency by both standards could create problems in coexistence. Such interference can occur if the two networks are very close and are trying to operate simultaneously. Such interference will lead to the wrong transfer of data and will automatically resume the transfer of wasting package to another frequency. The Bluetooth, however, carry smaller packages and testing alternative frequencies 600 times faster than IEEE802.11b, with the result, essentially, the first to block the second dramatically reducing its speed. There was a group IEEE802.15 which was designed to minimize interference between these two standards and the smooth coexistence.

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