LTE-M is the faster of the new cellular variants, capable of megabit speeds, and it’s designed for mobile use, including handoffs from one cell to the next. NB-IoT is slower, at around 250Kbps upstream, but allows for longer battery life. Both have longer range than regular LTE and are better at penetrating walls and floors.
In trials, AT&T’s LTE-M network is being used for trackable shipping containers, smart storage pallets, and soda fountains that report what drinks people choose. Vodafone has demonstrated NB-IoT in parking-space sensors and water meters.
The alternatives to these technologies are already on the ground and are quickly growing.
Ingenu, a U.S.-based startup with a proprietary technology called RPMA (Random Phase Multiple Access), covers about 25 percent of the U.S. population and plans to reach 70 percent this year. In about 30 other countries, partners are building RPMA networks or have contracts to do so. RPMA offers uploads at about 40Kbps and downloads at 10Kbps.
French startup Sigfox has a network in its home country and coverage across five other European nations. Sigfox networks are also being rolled out in more than 20 other countries, including the U.S., Germany, Brazil and Japan. Speeds are measured in hundreds of bits per second, but an efficient protocol can send many small messages and conserves battery life, the company says.
If you need low-power IoT connectivity now, invest in what’s available where you need it, said Tolaga Research analyst Phil Marshall. But speed and coverage aren’t the only factors to consider. There's also:
- Security and predictability: One is how sensitive and critical to business the data going over the network will be. LTE-M and NB-IoT, at least in their current forms, run over licensed spectrum on networks where the carriers control both access and priority. That’s a key advantage for applications where security and reliability matter, and may be worth a higher cost, Schoolar said. By contrast, Ingenu, Sigfox and LoRaWAN all use unlicensed bands where interference from other networks could affect throughput.
- Urgency: Applications that rely on timely data to drive a specific action may need that kind of network. Others, like monitoring crop moisture, may be suited to a network like Sigfox’s, which doesn’t acknowledge whether a message has been received.
- Hardware: Device cost can be a factor, too. Don’t rely solely on the estimated cost of the radio for a particular technology, Marshall at Tolaga Research said. Hardware simplicity and common radio bands, like the widely used 900MHz and 2.4GHz unlicensed bands, are selling points for some LPWANs. But there may be many other parts to an IoT device, like GPS and various sensors, so look at the total cost, he said.
- Longevity: Finally, consider the future, because IoT is a long-term investment and networks are expensive and risky ventures.
“Not all of these technologies are going to make it,” Marshall said.
In that respect, full-service operators have an advantage. “They don’t live and die by IoT,” Schoolar said.
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