Why You Should Consider Cellular Narrowband IoT as the Backbone of Your Mainstream IoT Product

Cellular Narrowband IoT technology is going to lead all other Low Power Wide Area (LPWA) technologies for obvious reasons.

Global mobile Suppliers Assocation (GSA) reported the NB-IoT and LTE-M global ecosystem market status in April this year that the continued commitment poured in by the mobile industry to these standards has witnessed a dramatic growth in the number of networks supporting NB-IoT and LTE-M networks and substantial growth in the number of Cat-NB1 and Cat-M1 compliant devices.

The sheer size of the network operators investment in the NB-IoT and LTE-M network deployment in the number of countries globally will convince you that this technology will not fade away, but will flourish as time goes by delivering the growth that many will taste and enjoy.

The below coverage map will boost your confidence and provides you with the excitement to take the plunge and be part of this incredible journey into the future.

Another key indicator is the IoT equipment that joined the market. GSA has identified a significant rise in devices supporting the NB-IoT and LTE-M IoT standards in the past six months at the point of reporting.

The above table just meant that IoT products adopting this promising technology is growing very rapidly. The rapid rise in the number of devices supporting Cat-NB1, Cat-NB2 and Cat-M1 is in step with the increasing maturity of the IoT services being provided by operators. It would be intriguing to learn how this Narrowband IoT technology is used. Following is the target application breakdown of the IoT equipment.

Module forms over half of the total number IoT equipment launched as it has its role in the marketplace - to ease the market adoption of this technology. What’s interesting is next two key applications – asset tracker and router/gateway. Both these applications will need something more than just the NB-IoT or LTE-M backhaul – GPS for location position and possible a short-range wireless like BLE to support gateway bridge and product configuration features.

This is where the Avnet’s AES-CELLIOT-AVT9152MOD, cellular IoT module with BLE fits perfectly. AVT9152 combines all three LTE-M (Cat M1)/NB-IoT (Cat NB), GPS and BLE wireless technologies into a module targeting broad range of IoT applications where low power and small size matters. This module uses industry-leading, low-power devices from Nordic Semiconductor, the nRF9160 LTE- M/NB-IoT with Arm® Cortex®-M33 64 MHz processor includes 1 MB Flash and 256 KB RAM, Arm TrustZoneTM for trusted execution, and Arm CryptoCell 310 for application layer security; and nRF52840 BT5.0, Arm® Cortex®-M4 32-bit processor with FPU, 64 MHz, 1 MB Flash and 256 KB RAM. This combination equips the module with ample computational power to support a range of complex and processor intensive IoT applications with the necessary IoT security needs included. The broad range of 17 cellular frequency bands supported along with the FCC, CE, RCM and BQB certification obtained enable ideal IoT equipment to be created for the global market.

Designing an IoT equipment is never a trivial matter. Many a times it will be powered by battery and expected to last over a long period of time in between charged cycle like a tracker device but still need to be responsive to the external world in reporting its position and status. The AVT9152 module inherited all the low-power DNA that comes from the Nordic nRF9160 low-power SiP NB- IoT/LTE-M modem integrated with GPS. Generally, in any RF SoC device, the wireless communication interface is where the most power is consumed. Therefore, it is of utmost important that the wireless interface is optimized for low-power design. The information below here shows you how nRF9160 is faring against the competitions – it’s a leapfrog lead!

Power Saving Mode (PSM) is using when the IoT equipment can sleep for long period, up to 413days without communicating with the network.

eDRX is Extended Discontinuous Reception, suitable for IoT equipment that wakes up often (few seconds to tens of minutes) to listen to the network. The parameters in the table refer to nRF9160 wakes up every 81.92s to for paging time window duration of 2.56s to capture the single paging occurrence from the network base station.

In addition to the low-power feature, Narrowband IoT equipment can be complex with respect to the networking protocols that it needs to support. As an example, a Cat-M1 IoT equipment may need to setup MQTT for data transfer to Azure cloud, HTTPS for application firmware upgrade over the air (FOTA) and LwM2M for device management with the telco server. On top of these, it might need to implement advanced security scheme like TLS or DTLS.

Most competitions out there will require some of these protocols to be implemented in the external host application microcontroller and communicate over AT commands to the NB-IoT or Cat-M1 modem. This will involve considerable extra engineering effort and cost.

Conversely, the nRF9160 SDK has all these major protocols implemented shown in the block diagram below here.

The BSD Socket API architecture really stands out comparing to competitions that are using AT Commands to communicate with the NB-IoT or LTE-M module. This basically simplifies software development with seamless integration to the application code and faster time to market.

The similar level of integration is available over the short range wireless BLE where multi-protocol is supported for BLE, Bluetooth Mesh, Thread and Zigbee inclusive of concurrent multi-protocol feature. This allows sophisticated IoT equipment like gateway or router to be developed.

The DFU/FOTA features included mitigates risk of all the firmware used in the AVT9152 module as these can now be easily updated in the field. This will certainly protect the investment made for the longer term.

All these great things introduced can be readily evaluated using the AES-CELLIOT-AVT9152KIT IoT evaluation and development kit that has been put together for this intention.

Here is the complete list of items in the kit.

An AVT9152 EVB kit includes:

1. AVT9152 evaluation board
2. External LTE paddle antenna
3. Active GPS/GALILEO ceramic patch antenna
4. Global eUICC plastic SIM card
5. Wall mount universal AC-DC 5V power adaptor
6. Six-pin rainbow jumper cable
7. 10-pin header J-Link ribbon cable

The AVT9152 evaluation kit has flexibility catered to the critical antenna piece for the three wireless technologies in the system. BLE antenna is onboard the AVT9152 module with detail antenna radiation pattern information available for packaging design. During evaluation or development phase, SMA or μ.FL LTE-M/NB-IoT antenna can be considered and both passive or active GPS antenna can be connected directly to the μ.FL connector in the AVT9152 module. Wide range of target antenna can be evaluated easily during product development.

Developer has the extra flexibility to scale their applications, be it adding of new sensors, wired connectivity or user interfaces by using the Arduino connectors available in the evaluation kit.

The development kit is created to be powered by battery directly. The actual system power consumption can be easily measured and analyzed. In power sensitive application, it is necessary that every part of the system circuit is optimized for low-power design. The evaluation kit facilitates this by allowing the AVT9152 module power rail to be totally isolated from the rest of the system power. This way, any impact on the AVT9152 module power due to the NB-IoT or LTE-M network behavior can be easily measured and analyzed. It is important to check this factor with the actual network signal during development or power optimization design.

This sensor rich kit comes complete with preprogrammed SDK, factory provisioned eUICC micro SIM card with free subscription plan; and Avnet’s 24 x 7 IoTConnect cloud platform inclusive of dashboard; offers unprecedented end-to-end IoT out of box connection experience over LTE-M network.

eUICC SIM technology is another sought after value proposition that is offered here. Some IoT equipment will have to operate under harsh environment where the equipment is completely sealed with the internal make of the system inaccessible to the outside world. In this case, the only way to enable ODMs to take the full advantage of the best subscription plan offered in the future market is to offer a mean to swap the telco/carrier profile in the SIM by doing it over the air. The ODMs are dying to have this feature included in their IoT equipment.

The eUICC SIM provided here comes with FREE subscription plan. This plan expires 3 months after first connection to the network or when 50MB of data quota is consumed whichever comes first. This will need to be activated through here.

It provides LTE CAT-M1 coverage in these regions:

Please source your own SIM card if your region is not covered or you would want to test using LTE CAT-NB1 network.

Already onboard sensor from TE Connectivity, MS4 Series AmbiMate sensor module provides temperature, relative humidity, motion and ambient light sensing. In addition, there are barometric pressure, accelerometer and gyroscope sensors available too. All these measured sensors data together with the GPS position information from the NB-IoT/LTE-M modem can be displayed on the IoTConnect dashboard upon login after doing registration. This is truly an enabling platform for IoT equipment development that saves significant development time and money.

Here is how it looks like, the latest measured information.

Please note that the PIR sensor and GPS tracking function can be user controlled. This command is sent down to the evaluation kit over the NB-IoT or LTE-M network from the IoTConnect server. Besides this text command can also be sent down to the evaluation kit in the similar way for evaluation purpose. This command is then piped out through the USB virtual COM-port of the evaluation kit.

As mentioned earlier in the above text on the supported FOTA feature, the NB-IoT and LTE-M modem and the application firmware in the system is upgradeable over the cellular IoT network using the same IoTConnect platform. This will enable future product enhancement or bug fixes to take place after product has been shipped.

If you're interested in learning more about or purchasing the new AVT9152 module and evaluation kit, click here.