Okay, let's take a little time to discuss some LPWAN protocols. These are protocols that are really designed for much longer range communication from a building into a neighborhood, city wide communications, those kind of things. You'll recognize some of these, we've mentioned before, but now we're going to dig into and compare how and why you would select them, what the characteristics are of the different protocols. The three that we're going to focus on are cellular technologies where there's actually two good choices for IoT devices, LTE-M and NB-IoT. Then we're going to look at LoRa and the corresponding LoRaWan, which is another good technology for Wide Area Network communication. And then, a specialized one that's out there called SigFox, a little bit of difference and all these solutions. The cellular protocols, as you know, because we all carry a cell phone in our pockets these days, their technology's changed fairly rapidly. And we've seen recently where the different carriers are reaching to try to push into 5G and get the benefits of those technologies. For a technologist using these technologies, you have to be aware that there is such rapid change. And you have to be careful that understanding what the different technologies might be and how available they really will be for your devices. Lots of choices out there for chipsets and approaches to putting these systems together using this connectivity. And usually as you increase the volume, and you use more common protocols, the cost of applying these protocols also decreases. We started off when solar protocols first arrived with 1G. We're up to 5G now. It was common even a few years ago to still see 2G devices out there, devices that had cellular or modems. 2G is essentially sunset at this point, the protocols not supported. Most those devices that were using 2G moved on to 3G, which gave higher data rates and a little bit more standard approach to the protocols. When we moved into 4G and LTE, we started to get to speeds that supported multimedia and video applications. These protocols in these native forms LTE, 5G. These are really not the target protocols that we would want to use for IoT devices where we're trying to use extremely low power, and much much lower data rates. Luckily, within these protocols, there were alternative protocols for IoT developed. LTE-M and NB-IoT are the two primary ones. LTE-M is again an IoT optimized cellular approach that allows you to use a lower cost connection that has moderate throughput. It's very common in the US. Certainly, the first IoT optimized cellular protocol that became available. NB-IoT really was more popularly used in Europe. And it's designed to be less mobile and lower throughput. So really, these are NB-IoT modems would be used for static devices that have very low data rates. It started to drift into the US in late 2018. The feature of these protocols, LTM is an example, is long battery life. The protocols allow for power saving modes, where periods the device enters into extended sleep. And the device during that period is unreachable. There's a number of different technologies that are used. Extended Discontinuous Reception is one that allows the device to extend the time interval that it'll be using for listening for synchronization messages. Using these types of approaches, these cellular modems can extend battery life to up to over 10 years use. So again, for a sensor that you want to place on the wall and connect to a network and then not think about again. It would be great to have something like a 10 year battery life and still have the benefits of this communication. If you compare LTE-M and NB-IoT to other communications choices, like LTE, satellite or WiFi, you'll see that again, these LTE-M and NB-IoT approaches are optimized for IoT, lower costs, longer battery life. Extended coverage for indoor and underground penetration. Certainly, not providing some of the features like voice communication or mobility that you would see with an LTE based design. So, again, this is a matter of selecting the right protocol for the right application. For IoT devices, these are certainly ones to consider. When you compare across the entire suite of cellular protocols, NB-IoT is certainly the one that's the least complex and lowest cost. LTE-M isn't too far behind. But if you get into the points where you're trying to transfer sound and video, etc. Then you start moving up into the LTE and 5G type protocols. If you do some of this development on your own, you'll find that there is development kits out there from the manufacturers. AT&T provides an LTE-M development suite that includes a freedom board and an LTE-M board that provide connectivity into their network so that you can test programming these devices. In this particular application, there's a flow framework that lets you visually program simple transactions. You can check these tools out. There's a lot more out there. LoRa is an alternative to cellular IoT. It's an interesting protocol. It's an end to end protocol using LoRaWAN that actually takes the LoRa communications from End Nodes, brings them into Gateways, and then uses TCP/IP to communicate the network servers and application servers. Throughout that whole process, the payload of the message that you're using is secured through AES. It is a nice long range of alternative to cellular. One of the one of the benefits to LoRa is it does have really strong indoor coverage and underground performance, very capable of moving through basement floors, etc. And again, provides that long battery life of 10 to 20 years for LoRa based devices. In North America, it uses the unlicensed bands, the 900 megahertz bands, same in the EU. Although those bands are managed a little differently. The data rates generally run from 250 bits per second to 50k bits per second. There's a lot of prototyping systems out there. For the Raspberry Pi, there's a LoRa Hat that you can plug on to a Pi, from a company called Dragino, that would let you try out these LoRa connectivities. SIGFOX is another low power WAN alternative. It's interesting, SIGFOX uses a custom chip and a custom network to create its devices. So, you basically have a SIGFOX chip on your device that connects into a SIGFOX network, into the SIGFOX cloud, and eventually out to your application. But the entire end to end up to your application is controlled by SIGFOX. So, it's a very different architecture. It's also designed for very small messages, 12 byte messages, optimized for sensor type data. It depends on this proprietary network being available. And there is a subscription cost model for paying for these devices. Again, if that's a good fit for you, it's fine. It's certainly true that SIGFOX provides that low energy cost, it's out of box connectivity is good. The tricky bit is to make sure that the area that you're in supports it. It has some install base in the EU, especially in France. Not quite as much in the US, although it's being built out over time. Again, if you're using devices that have small data sets with relatively low rates of connectivity, SIGFOX might be a good alternative for you. For all these things, there's different considerations, the sleep modes of the devices. Can you use a device that has a sleep mode, or are you going to be in a situation where because of a life safety issue, you need to guarantee your communication? What data rates are you going to be using? Can you be dependent on unlicensed bands versus the licensed LTE networks? Regardless, all of these systems are certainly supported by silicon from the larger vendors like Qualcomm. So, it's fairly easy for you to find these chips, prototype your applications and look at how you're going to provide for IoT communications over long ranges.
