But a significant percentage of rural communities have access today to WISPs (wireless ISPs) that use unlicensed frequency and point-to-multipoint radios to bring a broadband connection to customers. The performance of WISPs varies widely. There are places where WISPs are delivering solid and reliable connections that average between 20 – 40 Mbps download. But unfortunately there are many other WISPs that are delivering slow broadband in the 1 – 3 Mbps range.
The WISPs that have fast data speeds share two characteristics. They have a fiber connection directly to each wireless transmitter, meaning that there are no bandwidth constraints. And they don’t oversubscribe customers. Anybody who was on a cable modem five or ten years ago understands oversubscription. When there are too many people on a network node at the same time the performance degrades for everybody. A well-designed broadband network of any technology works best when there are not more customers than the technology can optimally serve.
But a lot of rural WISPs are operating in places where there is no easy or affordable access to a fiber backbone. That leaves them with no alternative but to use wireless backhaul. This means using point-to-point microwave radios to get bandwidth to and from a tower.
Wireless backhaul is not in itself a negative issue. If an ISP can use microwave to deliver enough bandwidth to a wireless node to satisfy the demand there, then they’ll have a robust product and happy customers. But the problems start happening when networks include multiple ‘hops’ between wireless towers. I often see WISP networks where the bandwidth goes from tower to tower to tower. In that kind of configuration all of the towers and all of the customers on those towers are sharing whatever bandwidth is sent to the first tower in the chain.
Adding hops to a wireless network also adds latency and each hop means it takes longer for the traffic to get to and from customers at the outer edges of one of these wireless chains. Latency, or time lag, in signal is an important factor in being able to perform real-time functions like data streaming, voice over IP, gaming, or functions like maintaining connections to an on-line class or a distant corporate WAN.
Depending upon the brand of the radios and the quality of the internet backbone connection, a wireless transmitter that is connected directly to fiber can have a latency similar to that of a cable or DSL network. But when chaining multiple towers together the latency can rise significantly, and real-time applications start to suffer at latencies of 100 milliseconds or greater.
WISPs also face other issues. One is the age of the wireless equipment. There is no part of our industry that has made bigger strides over the past ten years than the manufacturing of subscriber microwave radios. The newest radios have significantly better operating characteristics than radios made just a few years ago. WISPs are for the most part relatively small companies and have a hard time justifying upgrading equipment until it has reached its useful life. And unfortunately there is not much opportunity for small incremental upgrades of equipment. The changes in the technologies have been significant enough that that upgrading a node often means replacing the transmitters on towers as well as subscriber radios.
The final dilemma faced by WISPs is that they often are trying to serve customers that are in locations that are not ideally situated to receive a wireless signal. The unlicensed frequencies require good line-of-sight and also suffer degraded signals from foliage, rain and other impediments and it’s hard to serve customer reliably who are surrounded by trees or who live in places that are somehow blocked by the terrain.
All of the various issues mean that reviews of WISPs vary as widely as you can imagine. I was served by a WISP for nearly a decade and since I lived a few hundred feet from the tower and had a clear line-of-sight I was always happy with the performance I received. I’ve talked to a few people recently who have WISP speeds as fast as 50 Mbps. But I have also talked to a lot of rural people who have WISP connections that are slow and have high latency that provides a miserable broadband experience.
It’s going to be interesting to see what happens to some of these WISPs as rural telcos deploy CAF II money and provide a faster broadband alternative that will supposedly deliver at least 10 Mbps download. WISPs who can beat those speeds will likely continue to thrive while the ones delivering only a few Mbps will have to find a way to upgrade or will lose most of their customers.