February 14, 2001, 4:12 PM — Fixed broadband wireless access services are wildly attractive to enterprises as an alternative to high-speed, terrestrial metropolitan networks. They also are ripe with potential for use as back-up transmission facilities to cabled networks (think backhoe fiber cuts). Service providers can deliver bandwidth -- and lots of it -- to your doorstep quickly without the costs and labor associated with laying fiber cabling or copper wires, which should translate into faster installation and price benefits for you.
However, actual deployments of much-talked-about last-mile wireless technologies such as multichannel multipoint distribution service (MMDS) and local multipoint distribution services have been relatively few and far between. One reason is that equipment standards are still being defined at Layer 1 for orthogonal frequency division multiplexing (OFDM). OFDM is a generic technology for sending data across spectrum in multiple independent and parallel tones. Fixed-wireless equipment interoperability has been a challenge as various industry camps have pursued OFDM technologies, and, similarly, because there is no officially sanctioned Layer 2 media access control standard for broadband wireless.
For the time being, the various equipment makers are using their own versions of Layer 1 and Layer 2 technologies. Cisco, for example, just launched the WT-2750 broadband fixed wireless system for carriers based on its own OFDM flavor, called Vector OFDM (VOFDM). VOFDM is one technology in the running to become an IEEE standard. It reportedly overcomes the signal distortion and interference caused by "multipath" -- the duplication and echoing of signals caused when they bounce off houses, buildings and other objects. At Layer 2, Cisco and others are using the cable modem DOCSIS standard.
Admittedly, IEEE working groups are making some headway. For example, some technology proposals were presented in November 2000 to the IEEE 802.16.3 committee. The 802.16.3 group is working to build standards for MMDS and other broadband wireless WANs running in the sub-10 GHz frequency range.
Recent reports say that the proposals could result in Layer 1 standards by midyear and commercial services a year or so from now. But Im impatient, and that seems like a long time. My advice would be to sniff out services that are available now if you need them (hint: Sprint and WorldCom hold the most MMDS licenses) and find out from your carrier what it would cost you in pain, money and frustration to upgrade to standards compliance when appropriate. Then get that in writing.