Selecting the Right LPWAN Modules for... | EEWeb Community
By EEWeb | Thursday, August 27, 2020
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In an earlier blog, we looked at the certification costs of and differences between LTE and LoRaWAN low-power wide-area network (LPWAN) technologies. Here, we’ll explore 10 modules from leading suppliers for both the LTE and LoRaWAN LPWAN technologies.
When it comes to selecting the right modules for a new design, many factors influence the final choice. The transmission range, the geographic regions that support the modules, and the available band frequencies must be considered. Also taken into account are the volume of data throughput, power consumption, and the module’s operational temperature range.
 (Image: MultiTech)
Here is an example of how LPWAN is used. As shown in the figure above, the LPWAN device will receive data from energy, retail, health care, and/or remote monitoring input and then connects the data wirelessly to different types of platforms including remote servers. Users can access the information using a platform such as the asset management platform. By using a module, the end-device design can be simplified.
LTE-M/NB-IoT modules
Because LTE-M /NB-IoT modules leverage the mobile carrier networks, their range will be as extensive as the networks. Leveraging the carrier networks also means that LTE-M/NB-IoT modules have many band choices. The networks enable the LTE-M modules to transmit significantly more data and more quickly than LoRaWAN modules can.
However, the carrier networks also determine a module’s usability in a specific geographic region. Successfully deploying a module in a particular region requires choosing one that is certified and compatible with the network that has coverage in that region.
For example, the Nimbelink, Digi, and Sequans modules (see table below) are compatible with carriers such as AT&T, Verizon, and Telus, and they can all be deployed in the areas covered by these companies. However, only the Nimbelink and Sequans modules have been certified with Orange, a French carrier, so Digi’s module cannot be used in an area not covered by Orange. On the other hand, only Sequans’s module is certified with NTT Docomo, the predominant mobile operator in Japan, so Nimbelink’s and Sequans’s modules are much less likely to receive coverage in Japan.
 NimbeLink’s NL-SWN-LTE-NRF9160 offers LTE-M (CAT M1) and NB-IoT (NB1, NB2) connectivity for global applications and also includes an integrated GPS receiver. (Image: NimbeLink)
 Sequans’s Monarch GM01Q module combines LTE-M and NB-IoT into one compact LGA package. It has ultra-low PSM power consumption at 1 µA. (Image: Sequans)
Lastly, all the LTE-M /NB-IoT modules mentioned here have low battery voltage, which ensures low energy consumption and high energy conservation. That way, the module can operate for a long time without the need for battery replacement. The modules also have a comparably broad range of temperature tolerance, which enables them to operate reliably in harsh environments.
LoRaWAN modules
LoRaWAN technologies typically cover the range (or distance) of 10 to 20 km. For example, Würth Elektronik’s AMB2220’s range is 500 m to 5 km. However, Miromico’s FMLR-72-x-STL0Z supports a theoretical line-of-sight range of up to 100 km. The longer the range of a module, the fewer modules are needed to cover an area. As a result, range affects the number of modules and the related costs.
Overall, LoRaWAN modules have access to fewer band choices than LTE-M/NB-IoT modules. The bands may also vary for LoRaWAN. For example, Würth Elektronik’s AMB2220 has ultra-high-frequency bands, and Insight SiP’s ISP4520 has ultra-high-frequency bands as well as mid-frequency bands.
MultiTech’s long-range LoRa modules, Microchip’s RN2483, Miromico’s FMLR-72-x-STL0Z, SG Wireless’s SGW2828, and Würth Elektronik’s AMB2220 can transmit only tens of kilobits per second. The exception is Insight SiP’s ISP4520, which can transmit 1,000 to 2,000 kbps. Typically, a company will choose to provide either the LTE or LoRaWAN modules. But MultiTech offers solutions for both LTE and LoRaWAN.
 Multitech’s xDot is LoRaWAN 1.0.2-compliant, providing bidirectional data communication up to 10 miles/15 km line-of-sight and 1–3 miles/2 km into buildings, using sub-gigahertz ISM bands in North America, Europe, Australia (AU915), Asia Pacific (AS923), India (IN865), and Korea (KR920). (Image: MultiTech)
Because the LoRaWAN modules are certified through the LoRa Alliance certification process, they have more standardization. Additionally, the LoRaWAN modules do not depend on carrier networks and so are not tethered to the specific geography a carrier supports. As a result, the users do not need to worry about the LoRaWAN module interoperability problem in a specific location once the devices have been certified by the LoRa Alliance.
Lastly, LoRaWAN modules are similar to LTE-M /NB-IoT modules in terms of temperature tolerance and energy efficiency, as they all have to operate for a long time in the field with minimal battery changes.
Below are 10 examples of LTE-M/NB-IoT and LoRaWAN modules from leading manufacturers. Keep in mind that this comparison chart is provided as a reference only. When selecting a specific module, make sure the most updated specifications are obtained from the suppliers. Moreover, be aware that some of the performance parameters stated in the chart have to be accomplished with an external antenna attached to the module. There is a design tradeoff consideration of higher performance using external antenna versus lower performance with an integrated compact antenna.
 Conclusion
Both the LTE-M/NB-IoT and LoRaWAN modules need to function reliably in harsh, outdoor environments with infrequent battery changes. While LTE-M and NB-IoT have an advantage in transmission range, data transmission rate, and the numerous choices of bands, they are limited by the carrier network that supports them. While LoRaWAN modules lag in transmission range, data transmission, and the number of band choices, they can operate in areas independent of network coverage.
The first decision will be choosing LTE or LoRaWAN. Then compare the parameters and select the one that best fits your design needs, including the dimension of the modules. Here are the general guidelines for module selection:
- Determine the distance or range to be covered to see if LTE or LoRaWAN would be a better fit.
- Calculate the volume and frequency of data to be transmitted. If infrequent or small amounts of data will be transmitted, LoRaWAN will be an easy choice.
- Geographical region will determine which modules to use. In North America, the typical carriers are AT&T, Verizon, and T-Mobile. But in Europe or Japan, each country will have his own carrier, and therefore, certification by that particular carrier is very important.
- Some applications require the use of both LTE-M and NB-IoT. In this case, choose those modules that offer a combination of technologies. Keep in mind that only one protocol is required. It is cheaper to select the single protocol module, such as LTE-M only.
- Availability of interfaces. For example, Telit’s module provides USB two-point zero HS, UART, SPI, GPIO, ADC, 1.8 SIM interface, and I2C. This may be convenient for some designs.
Finally, most suppliers provide reference designs as well as development kits. These tools are very useful and can save quite a bit of development time. Additionally, test the modules to ensure that their performance will meet your design goals.
By John W. Koon |
