With IDCC personnel helping set the standards for 802.16 this could be interesting.
Briefing: Wi-fi Wi-max explained
New technologies could end the short range of most wireless hot spots – and spell doom for wireline carriers.
January 12, 2004
Wireless networking is one of the Holy Grails of computing. While wi-fi makes a good effort at reaching this tech nirvana, it also comes with a built-in downside. Wi-fi access points, or hot spots, are still tightly tethered to a wired infrastructure – conventional DSL, cable-modem, leased-line, or dial-up links to an Internet service provider. That makes for a short wireless leash in a world that demands greater access than the few hundred feet (in optimal conditions) provided by a wi-fi hotspot.
But the leash is about to be broken, thanks to two emerging technical standards for wireless services that can cover metropolitan areas. The standards are being developed by The Institute of Electrical and Electronics Engineers (IEEE), the vendor-neutral technical standards organization. Once implemented by telephone carriers, these networking schemes have the potential to revolutionize the last-mile service delivery for broadband to homes and businesses.
The new broadband wireless specs are known by numbers matching their specific IEEE working groups. The first, 802.16, is for metro fixed-point wireless, and will compete against DSL, cable, and dial-up for homes and businesses. The second, 802.20, is for wireless data services for mobile users, and could compete with cellular, 3G, and other similar services.
Most of the industry attention, however, has been focused on 802.16, because it represents a potential breakthrough in provisioning broadband services to consumers and small businesses.
The 802.16 family of specifications is for fixed-point wireless services operating either between 2 and 11Ghz, or 10 and 66GHz. These frequencies are located in the upper end of the microwave range, and are primarily line-of-sight, meaning connection points cannot be physically blocked.
Using the 802.16 networking protocol, a provider could deliver data from its antennas to rooftop antennas at subscriber sites (see diagram). What is more, the standard allows for different channels, to reduce contention and make the most of the available bandwidth, thus permitting a maximum of 75Mbps per transceiver. Individual subscribers gobble up only a small portion of that huge broadband pipe, roughly estimated to be about 2Mbps. Today’s DSL and cable-modem services range from about 0.4 Mbps to 2Mbps, while a common business-class, T-1 leased line is roughly 1.5Mbps (a dial-up modem is about 0.05Mbps).
The standard receiving the most attention is 802.16a, which focuses on the unlicensed portions of the 2 to 11GHz radio band that runs at either 2.4GHz or 5GHz.
A group of equipment makers, including Atheros, Fujitsu, Intel, Nokia, and Proxim, have started using the name wi-max to brand the technology, and have formed the Wi-Max Forum vendor consortium to promote it. Products compliant with the specification, which was approved by the IEEE in early 2003, should begin appearing in 2004. The 802.16b specification, which covers the licensed 11-66GHz band, is still under development by the IEEE.
The range of a wi-max service, which uses a directional antenna, is estimated to be as much as 30 miles under ideal conditions; in practical terms, it could be far less, depending on the terrain and location of other buildings in the area. Wi-fi, meanwhile, has a range of around 100 feet.
The wi-max protocols make efficient use of bandwidth, and also allow it to carry many different types of traffic: not only ethernet and TCP/IP, but also ATM and voice traffic, if desired. The protocol also allows for strong encryption to ensure that each subscriber's data is kept private.
Costs and hidden tradeoffs for wi-max are still for the most part unknown. There are, no doubt, huge advantages for businesses or even consumers. Provisioning wired broadband data services is slow and expensive, especially for enterprises – and can take months if new cable must be laid.
With wireless, adding new services can be as easy as putting up an antenna and making a phone call to a service provider. Even homeowners who move to a new location can simply take the wi-max receiver with them and install it without having to reconfigure the system. There is no doubt wi-max will be a boon for equipment makers, content providers, and consumers in the next few years. And considering the ease of deployment, as well as the potential for new carriers to enter the market, metro wireless could be devastating for wireline carriers who ignore the threat.
