Can Broadband Fixed Wireless Improve Your Bottom Line? 

By David M. Piscitello
Core Competence, Inc.

Reducing the time to market in a product-based economy is a sure way to improve one's bottom line. In the services-based market, broadband local access follows the same economic principle: consistently reduce the time from service order placement to that moment when an access circuit is in service and billable, and the profits will follow.

If only it were this straightforward for data CLECs. Depending on your market play, as a CLEC, service order fulfillment of access circuits can be routinely hampered by your competitor-providers, and the incumbent copper farmers who have little incentive to turn facilities over to you, other than to avoid litigation and possible FCC intervention. In fairness, T-carrier and copper-pairs for data service orders are now being placed in such volumes that ILECs may legitimately have reached the point where they can't meet the demand for installs. 

Perhaps you are a facilities-based CLEC. A local government may be disputing a right-of-way that interferes with your ability to install copper or fiber that's needed to deliver service to not one but many broadband customers. Since customer expectations are such that any service order fulfillment ought to be satisfied in Internet time, CLECs often find themselves in a situation where the customer threatens to walk out of frustration, and the fulfillment process is in someone else's hands. Can wireless offer a solution to CLECs?

Since precious few CLECs hold licenses in spectral areas assigned for broadband (LMDS/MMDS), wireless may not be viable. However, products like the Western Multiplex Lynx microwave radios apply a spread-spectrum coding technique to the 2.4 and 5.8 GHz ISM (Industrial, Scientific, and Medical) bands. With these, service providers can offer T-1 and T-3 bandwidth over distances up to fifty miles (see Title 47 of the Code of Federal Regulations, Part 15.247). You won't need an FCC license. And while you may require line-of-sight, you can often avoid right-of-way encumbrances. You also avoid the recurring charges for access to ILEC facilities, and maintain operational control.

Spread-spectrum technology
Spread-spectrum was developed as a military application. It's a way of encoding digital information into a signal so that it looks like noise to any but the intended receiver. The trick here (greatly simplified) is that the signal is spread over a wider frequency band than you would typically need to transmit the information content. You combine the information content (signal) with a pseudorandom signal to produce what appears to be white noise to conventional receivers. 

The intended receiver possesses the pseudorandom spreading code, so it can recover the original information content. Signal spreading is performed either by direct sequence or frequency hopping. Direct sequence combines or multiplies the user data stream with a pseudorandom spreading code to create a "chip". The receiver knows the pseudorandom spreading code, so it can derive the user data from the chip. Direct sequence signals may be hidden from any receiver, and these systems can communicate below the ambient noise level, but it sacrifices data rate, and is vulnerable to strong interference anywhere within the wideband channel. 

By contrast, frequency hopping, as the name implies, leaves the information content intact, but changes the carrier frequency at which the information signal is transmitted according to a pseudorandom sequence. Fast frequency-hopping systems change frequencies rapidly, so are least vulnerable to interference and jamming, but expensive. Most commercial systems are slow frequency hoppers: less expensive and tuned to meet FCC Rules Part 15.247 average channel occupancy requirements. 

Optical Wireless
I've focused on microwave wireless thus far. There are other laser-based or optical wireless systems. Laser communications systems from companies like LSA Photonics operate in the near-infrared waveband to provide full-duplex transmission data rates up to 155 Mbps over a distance of 9 miles. Short wavelength infrared technology from companies like LightPointe Communications can be used to deliver 20 Mbps up to 2.5 miles, and a whopping 622 Mbps up to 1.25 miles. Like the fixed wireless radio systems, these line-of-sight systems do not interfere with RF sources, and the narrow laser beam width precludes interference with other communication systems as well. Vendors claim high-speed laser communications tolerate inclement weather (fog and rain) admirably. 

Fixed Wireless Applications
Many fixed wireless systems use the 2.4 GHz ISM frequency to support full-duplex wireless IP services from 56 Kbps to 2xT1/E1, and the 5.8 GHz frequency to support 8xT1, 4xE1 and even DS3. In situations where you can't get facilities to a customer-on time, or ever-but where you can establish a line-of-sight between your customer and your POP, and you can install wireless terminals and antennas, you should be able to retain a customer who would otherwise cancel an order, or fulfill orders more quickly. 

You may wish to consider the 5Ghz ISM and optical wireless systems instead of Telco copper or fiber facilities to provide backhaul facilities from multi-tenant units to your POP; WAN link diversity for customers who insist on high-availability and redundancy; or temporary connectivity for companies that find themselves victim to a disaster, to quickly complement your own backbone bandwidth needs.

What about cost? Vendors claim the payback of wireless deployment is best evaluated by determining the additional revenue obtained by rapid order fulfillment plus elimination of Telco recurring facilities charges. This claim seems especially true for high bandwidth (45 Mbps and up) services, where payback is often estimated at less than one year. 

Implementation
Broadband wireless access systems require careful planning before implementation. First determine the locations to be wirelessly linked, and the capacity requirements of that link; some vendors conveniently offer online path calculators to help you estimate link performance, and vendors are more than willing to assist with this and every aspect of product selection and installation. 

Next perform site surveys. Evaluate climate and terrain, and verify line-of-sight. Determine where you will locate radio or optical equipment and wiring, whether you will need shelter, and how you will access power. Distance between sites affects technology choice, antennae size and mounting selection. Remember, the promising aspect of this technology is rapid order fulfillment, so the system design process, equipment procurement, installation and testing must be timely and efficient.

Conclusions
I've touched on only some of the wireless solutions. I haven't discussed sub-rate products like the Digital Wireless SsurfNet and Ricochet, designed for residential subscribers, nor fixed wireless products that require licensing. And as service provider interest in wireless grows, technology innovations will be unveiled, including non-line-of-sight solutions (Cisco WT2700). 

Today, unlicensed, fixed wireless solutions have become more attractive. Pricing for wireless broadband solutions is considerably more competitive today precisely because CLECs and ISPs greatly expand the potential market for broadband solutions. Still, the decision to "go wireless" is not a slam dunk. Obtain quotes from local Telcos and any alternative facilities providers that serve the area where you seek to offer service, then do your own cost-benefits analysis. Choose the solution that allows you to declare the customer "up and billable" with the shortest fulfillment time possible. 

David Piscitello is president of Core Competence, Inc., a network consulting firm and founder of The Internet Security Conference.