A lot of recent hype around the Internet of Things (IoT) and low power, wide-area networks (LPWANs) is based on claims of citywide, region-wide, or nationwide IoT coverage. Easy ubiquitous coverage sounds good—but what does it really mean for you as the application developer? Below, we’ve detailed a few pieces of advice around this topic.
Be wary of the hype.
M2M network developers may claim to have public IoT coverage of a particular geographic area, and that may be somewhat true depending on the number of base stations they have (as well as what link margin they’re using to assume coverage). But that doesn’t necessarily mean you’re going to get coverage inside a building, between buildings, underground, in an urban area, etc., for your application. It's vitally important that when you seen the siren call of an operator advertising complete coverage, you take into consideration what "complete" really means.
Here’s a tongue-in-cheek example: If we decided to put a gateway on a hot air balloon and float it across the U.S. over the course of a week, I would technically have (nearly) nationwide coverage. It’s not going to be consistent, and it certainly won’t cover most of the “things” developers would inquire about. But even so, I could put out a press release and boast of my ubiquitous coverage. (This obviously would never happen, but you get the idea.)
Here’s a more realistic example. We have a Symphony Link basestation on a 700-foot tower near our office, and we get up to 25 miles of range from that tower. But we would never promise that amount of coverage to application developers, because it wouldn’t be realistic for many use cases. Once you start getting to the edges of the link, nodes would drop in and out of coverage—and due to the height of the gateway, there is a lot of interference and noise from other ISM band applications.
With this in mind, it’s important for application developers to get beyond the hype when they see press releases for ubiquitous public coverage.
Understand what coverage your application requires.
If a public network appeals to you, it’s important to understand that coverage will vary depending on your application. A node in a streetlight will get different coverage than a node in wireless water meter that’s below ground. And both will have different coverage from something that will live inside a building. This is particularly important in or around a city and in urban areas, where unlicensed band interference from other 900 MHz or 2.4 GHz devices makes it notoriously difficult to deploy LPWAN networks.
If you’re set on putting your application on a public M2M network, there are a few steps you’ll want to take. First, you’ll need to find out if the network is actually there or not! A press release announcing a forthcoming public network isn’t something to hang your hat on—but a public network that’s been in place for years (and has worked for deployments similar to yours) may be.
You’ll also want to determine the detailed answers to the following questions:
- How much will it cost for you to join the network?
- How much will the endpoints cost?
- What hardware is available?
- How do you get your data from that network?
- Have other companies used the network successfully?
- Can you roam from one area to another, or are you required to have static nodes?
- Can your device pass all the regulatory requirements for that network?
A final word of advice: If you plan on joining a particular public IoT network, you’ll want to take a look at a coverage map. You’d carefully review network coverage if you were investing in an AT&T or Vodafone cellular plan for your organization, and you should definitely review purported coverage from your IoT network provider.