Don't fear the U-NII

As wary as some wireless carriers might be of operating in an unlicensed band, their concerns might be squelched by the potential benefits of this untapped spectrum

As the debate surrounding the best alternatives for broadband wireless access spectrum intensifies, most RBOCs, competitive local exchange carriers and ISPs seem dead set on either local multipoint distribution service or multichannel multipoint distribution service. Both LMDS and MMDS are capturing the greatest attention - and the most dollars - from carriers because their spectrums offer the promise of regulated security, which presumably can reduce risk.

But what about the unregulated unlicensed-national information infrastructure (U-NII)? This group of three frequency bands, each consisting of 100 MHz in the 5 GHz band, was set aside by the FCC in January 1997 to support a future family of high-speed, low-power wireless voice and data devices. Today more than ever, the benefits of U-NII overshadow the drawbacks. Yet, in the rush to build killer applications in two-way broadband wireless transport, many carriers have overlooked the benefits of U-NII. Many more, perhaps, have overestimated the dangers of working in an unlicensed band.

The story behind U-NII

When the U-NII band first was made available, it opened a new medium for wireless data transport. At the time, access to the NII was limited to monopoly service providers that were charging high prices for limited options. Then U-NII came along, offering consumers the promise of a more affordable and flexible method of connecting to the NII by creating a competitive access option - one that would operate without any single gatekeeper.

This band (250 MHz of spectrum at 5.10 to 5.35 GHz) was requested from the FCC by the Wireless Information Networks Forum in May 1995. At approximately the same time, Apple Computer requested the allocation of 300 MHz in the 5.10 to 5.35 GHz and 5.725 to 5.875 GHz ranges to establish a new unlicensed radio service to promote full deployment of the U-NII.

In January 1997, the FCC agreed that a new approach to last-mile bandwidth was needed and provided 300 MHz of spectrum for U-NII devices. Specifically, it provided access to three 100 MHz bands: 5.15 to 5.25 GHz (for indoor use only); 5.25 to 5.35 GHz; and 5.725 to 5.825 GHz. According to the FCC, this would "facilitate rapid and inexpensive wireless access to information resources by educational institutions, business, industry and consumers."

The FCC suggested that access to the U-NII band would "permit educational institutions to form inexpensive broadband wireless computer networks between classrooms, thereby providing cost-effective access to an array of multimedia services on the Internet." The FCC also added that the U-NII band would help improve medical care by allowing medical staff to rapidly and inexpensively obtain patient data, such as X-rays and medical charts.

Now what?

It has been four years since the FCC's initial U-NII ruling, and the commission has since issued new rules that it says will "foster the development of a broad range of new devices and communications options that will stimulate economic development and the growth of new industries."

Has the FCC's prediction proved true? Not yet. First, the public simply has not paid much attention to U-NII. Leading equipment manufacturers such as Nortel Networks and Newbridge Networks continue to focus on higher-frequency, licensed millimeter wave spectrum, such as LMDS, instead of microwave.

Many carriers also have not embraced U-NII. They have concerns about the band being unlicensed, thus having the potential for interference, and about the U-NII band's limited power. As a result, leading carriers are quickly buying MMDS licenses for a guaranteed licensed spectrum.

Perhaps the weak perception of U-NII is interfering with their actions. Certainly, the issues are peace of mind and security. The carriers that most worried about reliability, such as RBOCs and interexchange carriers (IXCs), say that they may deploy U-NII first but will move to a licensed spectrum as it becomes available.

Yes, the U-NII bands are unlicensed, but is interference really such an issue? The 2.4 ISM band has been around for years, with scores of communications equipment vendors providing devices operating within the same unlicensed band. True, this equipment must be designed to operate in a spread-spectrum mode to minimize interference with other devices in the vicinity, but the basic physics of the situation limit the number of bits that can be accommodated within a given frequency. Spreading doesn't increase this number, it just makes spectrum management much easier.

The FCC has chosen a different approach with U-NII. The effective power radiated by each transmitter is limited, confining the range of the device to around 5 kilometers. Compared with a potential range of 50 kilometers for an ISM radio, this fact would argue that the number of potential interferers would be limited by a factor of 100 (essentially the ratio of the areas of coverage). Another way to look at this scenario is that a U-NII system would support 100 times the aggregate data rate of an ISM system, albeit with more hub sites.

Thus, the issue of limited power capability at U-NII is not an issue but rather a benefit, and it is consistent with the high data rate applications that U-NII was designed to support. It also turns out that U-NII base station separations are roughly comparable with cell site separations, thus making co-location of base station equipment convenient and economical.

Furthermore, any interference now can be managed by building frequency-agile mitigation capabilities into the transceiver, such as with Adaptive Broadband's AB-Access product. When such a device is first turned on, it scans the available frequency range to find which of 10 available channels has the best signal from a base station and tunes to that channel. If several devices or the base station itself subsequently detects "noise" in the channel, the base station controller intelligently moves the entire group of affected subscribers to another channel to avoid the interference (Figure 1).

The potential of U-NII

The U-NII band allows any service provider to deploy equipment today without any spectrum cost or approval by the FCC. The U-NII band will provide opportunities in a number of areas. For example, schools will be able to create low-cost, wireless LANs. The U-NII band also is ideal for the competitive telecommunications marketplace. It's free and allows instant provisioning. Both are huge benefits to emerging service providers seeking to claim their stake of the last mile by being first-to-market with a completely packet-based network that seamlessly converges Internet, data and voice traffic over the same pipe.

As schools get connected to the Internet and campus networks are built out, commercial applications also stand to benefit from the U-NII band. Because user access fees are inexpensive, the U-NII frequency spectrum will undergo a similar explosion once the benefits are understood. It is hard to argue against the use of a resource that is virtually free to anyone and can be used any time, anywhere. There is no need to pay for licenses or get permission to use it. For the CLECs and wireless ISPs that are just initiating business, the U-NII band may be their only choice for spectrum. For the IXCs and RBOCs, U-NII will provide the capability to provide ubiquitous service, even in areas where they have no licenses.

Service providers today are scrambling to offer access to the last mile for their bandwidth-hungry customers. For example, the RBOCs are interested in using wireless technology to complement their DSL offerings. They have large investments in copper, but in reality, they are unable to serve two out of three customers because of the technological inadequacies ofDSL. Wireless technology can enable them to overlap their DSL service and provide 100% coverage.

Meanwhile, a new breed of service provider is moving wireless technology quickly into the vacant U-NII band. Two such companies are Fuzion Wireless Communications, a Boca Raton, Fla.-based CLEC, and I3S, an Irving, Texas-based provider of high-speed Internet access via cable modem, Ethernet, DSL and wireless technologies. Both companies initially will deploy in the unlicensed U-NII band, which is instrumental in meeting the demand for affordable, high-speed Internet access (see sidebar on page 58). Using AB-Access, the companies will deliver Internet access at 25 Mb/s, a speed up to 400 times faster than dial-up service over a 56 kb/s modem. The technology will allow for simultaneous transmission of such applications as Web browsing, file transfers, interactive remote applications, real-time video conferencing and full-motion streaming video over a single high-speed Internet connection.

As with most technological advancements, broadband wireless access will not involve a single solution. But in addition to the now common deployment of LMDS and MMDS, look for more service providers to use the U-NII band to get the job done.

Fuzion Wireless Communications plans to become the first carrier to launch a sizeable application of high-speed broadband wireless data services. The recently licensed competitive local exchange carrier will deliver high-speed wireless Internet access to thousands of businesses across Florida in early October, with a national rollout scheduled for 2000.

The CLEC plans to leverage its Melbourne, Fla.-based international gateway to offer global solutions for Internet access, voice over IP, long-distance and local exchange services in early 2000. Fuzion also plans to merge its global broadband distribution system with a business-to-business portal to deliver bandwidth-intensive Web-based business applications.

In another rollout, I3S has contracts with independent apartment owners and residential real estate investment trusts to provide high-speed wireless Internet access to multidwelling units (MDUs) nationwide. According to company officials, the ISP's current network reaches more than 1.5 million MDUs in 25 markets, and a growing number of these deployments will use wireless technology.

As a next step, I3S will work with Adaptive Broadband to develop the U.S. market for both fixed and portable applications of broadband wireless technology such as AB-Access. The aim is to give users high-speed, wireless connections to the Internet for laptop computers and other mobile devices.