Wireless Broadband over Unlicensed Spectrum

The FCC set aside several bands of radio frequency spectrum for unlicensed use in the Part 15 rules of Title 47 of the Code of Federal Regulations. Devices ranging from cordless phones to baby monitors to garage door openers have taken advantage of these frequencies. Tiny Wi Fiuses Wi-Fi (“Wireless Fidelity”) equipment operating over 2.4 and 5 GHz bands to avoid expensive spectrum licensing fees and enable affordable connections to end user customers.

The IEEE standards group used the availability of these ranges to develop a wireless alternative to the traditional hardwired local area network (LAN) prevalent in most offices. Standards were developed for the 2.4GHz (IEEE 802.11b) and 5GHz (IEEE 802.11a) ranges and the Wi-Fi Alliance industry group introduced a certification program to guarantee interoperability between various “Wi-Fi” (Wireless Fidelity) devices. Over the last couple of years the ever increasing popularity of Wi-Fi technology for constructing wireless LANs has led to dramatic price decreases, spurred a new generation of improved wireless standards to be developed and led to the introduction of consumer-priced equipment designed for home use.

Although originally designed to offer wireless local area networks over distances of just a few hundred feet, when paired with suitable antennas Wi-Fi technology can also be used to deploy inexpensive metropolitan area networks (MANs) and wide area networks (WANs) without violating the thresholds established by the FCC for legal use of the unlicensed spectrum.

Such low cost MANs and WANs are ideal vehicles for providing cost-effective broadband service to rural communities thus far bypassed by other broadband deployments. A single central tower can typically serve an entire town without a substantial investment in new cabling infrastructure.

Wireless Broadband Enabled Services

The most obvious application for a wireless broadband network is providing fast Internet access to businesses and residents. However, a number of other services are also enabled. Perhaps most significantly, wireless broadband can provide a tremendous augmentation to a community’s emergency response capability and thus homeland security preparedness. Patrol cars can be fitted with special antennas to enable secure broadband connectivity to the central dispatch facility. Besides offering instant access to the main computer system, it could serve as a potential backup to traditional radio dispatch and cellular service. For example, in the weeks after 9/11 in New York City, the Ricochet wireless broadband network was used to allow nearly 1,000 emergency service workers to send building schematics and disaster area photos back to Federal Emergency Management Agency headquarters..

Beyond homeland security applications, broadband wireless can also be used to allow employees to work from home over secure private connections or local corporations to be linked to parent companies in other cities through virtual private networks across a gateway connection to the Internet. As well, government resources ranging from community information to permit applications can be delivered online across the network.

Overcoming the Limitations of Wi-Fi Technology

Due to its original purpose of providing a wired LAN alternative, Wi-Fi was designed to operate over distances of only a few hundred feet. However, the range increases considerably when “line of sight” is available and there is no physical obstruction between two nodes on a Wi-Fi network. Further, Wi-Fi equipment can be attached to external antennas and amplifiers and still operate within FCC limitations. Depending on the type of antenna used, the range can be dramatically increased from hundreds of feet to thousands.