You can get many a fixed wireless system for less than $1,000. Most of these operate at 2.4 GHz and leverage commodity WLAN chipsets to deliver a maximum data rate of 11 Mbps. While these systems can be appealing, they often lack features important for enterprise implementations, including Power-over-Ethernet and flexible management and monitoring capabilities. In addition, because they're based on LAN protocols, they tend to require higher overhead, resulting in throughput that is as low as half the stated rate. Finally, the duty cycle of these products often fails to meet enterprise standards.
That's why many enterprise- and carrier-grade point-to-point products are migrating toward the 5-GHz bands. These systems are typically designed from the ground up for fixed wireless applications. As such, their feature sets, performance and overall reliability are better than lower-cost alternatives. The downside is that many of these systems will cost more than $10,000, though lower-cost options are starting to emerge.
When considering total system cost, factor in not only the cost of the wireless bridges and antennas but costs of components, installation charges and maintenance required for a production system. In the past, system integrators have charged a healthy premium for installation and maintenance, though the trend these days is toward self-installation, at least in enterprise environments where adequate expertise exists (for particulars on six 5-GHz systems see "The Point-to-Point of Wireless Bridging").
Given that ROI models for fixed wireless almost always look good, why isn't the market exploding? It's all about risk management. IT professionals understand the security and reliability attributes of traditional network technologies, but wireless opens up a new set of concerns. Stop worrying--for the most part, the risk is manageable.
In many respects, fixed wireless is the victim of the well-documented security and reliability problems that gave those sexier mobile wireless systems their bad reputations. For example, security problems commonly associated with WLANs have not only garnered lots of attention, they've created a whole industry with companies focused on that specific need. However, the security issues surrounding WLANs, which are intended to propagate signals throughout a building or campus, are not applicable to fixed wireless, where directional antennas mounted high on buildings focus a narrow radio signal between two locations. Even if a snoop could somehow intercept these signals, all the major vendors support sophisticated encryption systems. And because the number of connections is small and centrally managed, key management is not the issue it is with WLANs. In short, don't let security concerns dissuade you from implementing a point-to-point fixed wireless system.
Reliability, on the other hand, is a legitimate concern, though it, too, is usually manageable. Because radio-based fixed-wireless systems operate at relatively low frequencies, you won't experience the weather-related problems with them that are typical of home-satellite systems, which work at much higher frequencies. You can further mitigate risk by turning to a professional installer, who can conduct a thorough path analysis prior to installation. By using directional antennas and building in an appropriate fade margin, professionals can guarantee 99.99 percent reliability in most areas.