A movable feast

Wireless technology, and specifically WiFi (an interoperability standard agreed on by vendors of wireless offerings, called IEEE 802.11), rate among the hottest topics in IT. Wireless, it is agreed, could become a huge combined growth area in IT, telecoms and mobile, industries that have seen hard times of late.

In every area of hype, however, a complete understanding of the technology is often lacking, and as if to further complicate the issue, legalities constrain vendors and users from having the clear and plentiful benefits of a really promising technology.

[Intel] is desperate to lobby for legal provisioning of WiFi.

Carel Alberts, technology editor, ITWeb

The odd result of these realities has been that vendors have until recently trumpeted their wireless offerings (this obviously being a Good Thing, as anyone can see) and shut up about their implementations (such as Cisco`s reported Johannesburg International Airport hot spot). Sometimes, driven by a curious mix of hype and poor public understanding, they even offer equipment that is not strictly speaking compatible with WiFi standards (see 802.11g further down).

In turn, this means corporate and home users, instead of deriving benefits from a technology untrammelled by legalities, are buying wireless devices and networks that may or may not interoperate, or operating them in a limited sphere that does not include public places - this being Telkom`s domain.

Talk to any wireless provider, and you will hear that their main problem is "the last mile", being the short distance from the user accessing public networks from his or her PDA, laptop or other wireless device.

But the noise against this restrictive regime is growing. Wireless hotspots are mushrooming to such an extent that there will be more than 118 000 such high-activity spots around the world by 2005, according to research group IDC. These will typically be at airports, malls, hotels and other busy places. And to add to the clamour, Intel has just upped the ante considerably with its integrated wireless chip on the latest mobile Centrino processor.

It is clear from conversations with the vendor that it is desperate to lobby for legal provisioning of WiFi (sometimes also called WLAN, or wireless local area networking), which could have us roaming campuses, even across public roads, all the while downloading files without dropping connectivity, at decent data rates of 11Mbps or even 54Mbps. With such devices, we need never be out of reach of our e-mail. Productivity will increase and this country would generally be a better place to do business in.

If Intel does not succeed in its rather aggressive plans to highlight its plight and that of other vendors, providers and users, its sales could just nosedive on Centrino when compared with the rest of the world. Of course, Centrino is the very embodiment of cool, and people will still buy it, since they can use it around their corporate or home networks.

So what is WiFi? Purveyors of the technology concentrate on the 802.11b standard, a microwave technology operating in the unlicensed 2.4GHz spectrum that transmits data at 11Mbps. This is totally compelling technology for a mobile user.

Incongruously, the b flavour of the standard came out before a, which is much faster, but operates in the regulated 5GHz spectrum band. Vendors can offer both, as Intel will, with no interference between the two transmissions.

Another standard, g, an evolution of b and backward compatible with it, has not been ratified yet, and users should probably focus on b, which is the most stable and most well-understood of the three radio frequency technologies.

The 802.11b standard operates 13 channels in the band mentioned above. Non-adjacent channels (eg 1, 6 and 11) can operate in harmony and sequentially, theoretically ad infinitum.

In terms of data rate, it compares well with infrared (4Mbps), Bluetooth (1Mbps) and even classic Ethernet (10Mbps, but now up to 1Gbps). The b standard has a self-protection mechanism in that the further the recipient moves from the access point, the lower the data rate, for the sake of maintaining a good connection.

Although access points, operating as a wireless hub, often claim unlimited numbers of users, no more than 20 at one time is advised if decent throughput is required, say the experts.

Clearly, the type of application also influences the throughput, as do the nature of radio (it can be erratic), building construction, a dynamic radio environment, placement of the access point and the presence of people and plants.

Error correction occurs on the transport level (layer 4 of the Open Systems Interconnect model). If a packet is dropped, it is resent. Some applications being more time-sensitive than others (such as video), the advisability or otherwise of using wireless will soon become apparent.

People worried about radiation can take heart from the fact that wireless` typical power output (100 milliWatt) is far less than cellular (600 milliWatt to 3 Watt). Perhaps this makes them worry more about cellular than before, but would this stop them talking?