The Towering Heights of Wireless Backhaul

For those who haven't mentally stepped through the process of building a wireless PtP or PtMP link, let me give you a heads up, literally: if your building isn't tall or the terrain doesn't lends itself to some kind of unnatural elevation, you're going to have to seriously consider building a tower.

During a recent conversation with a small bank that has half-dozen or so branches I learned that one of their sites was unable to lease a T1 because the incumbent local exchange carrier didn't have sufficient copper pairs.

As I described the idea of transporting the traffic wirelessly to a larger town 8 miles away it quickly became obvious that the bank's IT manager had no stomach for building two modestly sized towers, even though it would likely cost less than the annual fees they pay their auditors.

Point-to-point, fixed-wireless vendor BridgeWave issued a press release regarding an ISP in Kentucky that upgraded their existing wireless network topping out at 45 Mbps to a speedy GigE. For a service provider that's feeling the bandwidth pinch and looking toward future growth, GigE is clearly the way to go. What this press release understates is the distinct advantage that the ISP, QX.net, had in being able to use their existing sites. With perhaps with a little modification, they mounted another set of antennas and supporting radios and off they went. Most organizations looking at wireless backhaul options aren't likely in those circumstances.

The reality is that erecting a tower, even in a friendly area, has its share of challenges. First there's finding a site. If your own property isn't suitable, you may need to transport your network to the base site wirelessly, an additional complexity. Even if you can build on your own property, it will require an electrician and likely some ground work to provide the power. You need to bring your network there, too, but Ethernet over Cat5E has a distance limitation of 100 meters and copper is not a good choice for outside use due to lightning. If you choose fiber you'll likely need assistance in trenching conduit, running and terminating the fiber, and unless the radios have fiber interfaces, you'll need to put the fiber transceiver in a weather-proof cabinet near the base of the tower to convert the signal back again to copper. And there's more with the actual tower construction: soil boring to ascertain ground stability, local zoning bylaws to consider, permits to be filled, state historical societies to satisfy (i.e. SHPO), contractors to find, etc. And then there's the costs: surveyors, permits for the tower itself, wireless equipment, and of course assembly and installation. Compared to ordering a wireline circuit, setting up a wireless link requires sweat equity!Due to the complexity, it's advisable to hire a firm that installs wireless backhaul for a living. They'll be able to provide the necessary consulting, engineering and installation to ensure that the link is reliable, within your specifications. With the potential upfront costs and complexities, many organizations are reticent in considering wireless backhaul, but if that's the only option, or if circuit costs are eating you alive, pencil it out and see if it doesn't pay.