TRANSMISSION TECHNOLOGY FOR WI-FI

There are two technologies for transmission.

1>    Narrowband Technology

2>    Spread Spectrum Technology

1)    Narrowband Technology

A narrowband radio system transmits and receives user information on a specific radio frequency. Narrowband radio keeps the radio signal frequency as narrow as possible just to pass the information. Undesirable cross talk between communications channels is avoided by carefully coordinating different users on different channel frequencies.

A private telephone line is much like a radio frequency. When each home in a neighborhood has its own private telephone line, people in one home can not listen to calls made to other homes. In a radio system, privacy and noninterference are accomplished by the use of separate radio frequencies. The radio receiver filters out all radio signals except the ones on its designated frequency.

From a customer standpoint, one drawback of narrow band technology is that the end-user must obtain an FCC license for each site where it is employed.

2)  Spread Spectrum Technology

Most wireless LAN systems use spread spectrum technology, a wideband radio frequency technique developed by the military for use in reliable, secure, mission critical communications systems. 

Spread spectrum is designed to trade off bandwidth is consumed than in the case of narrowband transmission, but the tradeoff produces a signal that is, in effect, louder and thus easier to detect, provided that the receiver knows the parameters of the spread spectrum signal being broad cast. 

If a receiver is not tuned to the right frequency, a spread spectrum signal looks like background noise. Spread spectrum simply means that data is sent in small pieces over a number of the discrete frequencies available for use at any time in the specified range. 

 

There are further 2 types of this technology.

1>    Frequency Hopping Spread Spectrum Technology

2>      Direct Sequence Spread Spectrum Technology

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THE FUTURE OF WI-FI

Intel put aside $150 million of this fund to invest in Wi-Fi initiatives. Intel expects to introduce its Banias processors for mobile devices during the first half of 2004, said a company spokes woman. Banias is a low power processor designed specifically for mobile devices that includes integrated 802.11a and 802.11b wireless capabilities.

Cometa aims to roll out a nationwide Wi-Fi network and sell exclusively through the channel, said Lawrence Brilliant, CEO of Cometa, in a recent interview with CRN.

Looking to Wi-Fi rather than 3G , BT (British Telco) has installed some 80 Wi-Fi hotspots, called ‘Openzone’ in Hilton hotels, airports and motorway service stations across the UK, and has agreements to put in place another 40.

BT believes that Wi-Fi  which is expected to be half the price of 3G and three times faster is will be the fastest growing mobile technology. 

The Hilton hotel group, which was one of the first business to trial BT open zone, has allowed the installation of wi-fi hotspots in 36 of their hotels across England, Scotland and Wales. Hilton has agreed to install 15 more hotspots at further hotels in the near feature.

The company hopes to have 400 hotspots by summer this year and 4000 by June 2005. In the future it is expected that BT’s wi-fi hotspots will also reach railway stations.

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