Fixed Wireless Business

WISP Heresies

Although the WISP industry is still very young, one wireless pundit says that the industry is already mired in groupthink on several key business issues.

by Steve Stroh Editor of FOCUS On Broadband Wireless Internet Access [December 27, 2004]

As a writer who watches the Wireless ISP and Broadband Wireless Service Provider industry, I observe from "30,000 feet". Because I'm purely an observer and not an operating WISP or otherwise affiliated with a vendor, service provider, or analyst firm, I've developed some "unconventional" perspectives.

When I jokingly (I thought) offered to present a list of what I called "WISP Heresies" during my time on a panel discussion at the Fall 2004 Wi-Fi Planet Conference & Expo WISP session, moderator Alex Goldman said "Great! I'll look forward to it!" In my presentation I discussed a total of Ten WISP Heresies, but space only permits an extended discussion of what I consider to be the three most compelling "Heresies."

WISP Heresy #10: Invest In Better Systems Up Front
WISPs typically build systems that they can afford, typically based on Wi-Fi. They do their homework - conducting site surveys and construct their systems to avoid known interference, and commence service. But, interference almost inevitably happens and to deal with it you have go visit the rooftop or the tower and "tweak" until you can mitigate the interference.

But what if you spend more money up front to buy radios that deal with interference automatically, such as:

• Choosing antenna element diversity (antenna has an upper and lower set of elements)
• Choosing antenna polarity (each element has a horizontal and vertical antenna)

A radio that:

• Automatically chooses a channel with the least interference and automatically moves the base station and the associated CPEs to the new channel
• Incorporates Link Layer Retransmission (ARQ) so that TCP/IP doesn't have to retransmit packets damaged in transit with corresponding drop in throughput
• Increases or decreases transmit power as needed (base station and associated CPE)
• Changes forward error correction (none, some, a lot) as needed
• Changes packet length as appropriate
• Changes modulation (good signal, no interference uses high-order modulation for best throughput, poor signal and/or interference uses lower-order modulation for most robust connection)

A number of other parameters
With the system being able to change these parameters iteratively and automatically, the result is very good automatic compensation for interference, but also surprisingly good Non Line Of Sight (NLOS) operation in urban settings where such a system can take advantage of multipath.

The system I describe already exists—Aperto PacketWave. Some of those features are present in the more advanced products from a number of vendors, but PacketWave is a good illustration of just how much can be done to automatically mitigate interference issues. PacketWave has been deployed by TowerStream as their primary last-mile links for its deployments in Providence, Boston, Chicago, New York City, Los Angeles, and soon San Francisco and an number of other cities in the next year. It's instructive that PacketWave works so well that TowerStream, which markets primarily to businesses, offers a Service Level Agreement to its customers, which many in the WISP industry have flatly stated is an impossibility if license-exempt spectrum is used.

WISP Heresy #7: Competition From… Where?!?!?!
WISPs are facing competition from surprising directions—not the usual DSL and cable modem providers, but increasingly they'll see competition from Municipal Wireless Networks, Wireless Telephony Service Providers, and their customers themselves.

There are two factors driving the deployment of Municipal Wireless Networks. The first is that governments have come to view Broadband Internet Access as at least an economic development issue, if not a "quality of life" issue. If Broadband Internet Access isn't already universally available to every citizen at reasonable prices, then the government may feel compelled to get involved. They're emboldened to do so by the increasing number of successful (admittedly, varying degrees of "successful") deployments of such systems.

Go to page two: Heresy #5: WiMAX Isn't Almost Here