Within the last year I have been a victim, twice. The first time, a thief stole two catalytic converters off my car parked in my driveway. The second time, a thief stole a package from my mailbox. Okay, in the grand scheme of things, these probably aren’t the worst crimes that could have occurred; but they still got me thinking. Barring installing an expensive security system, welding rebar over my new catalytic converters, or picking up my mail directly from the post office, was there anything I could do to potentially prevent these crimes from happening again in the future? As it turns out, there may be, and it will likely come in the form of a low-power wide area network (LPWAN) technology known as Narrowband-IoT (NB-IoT).
NB-IoT is one of the Cellular IoT (CIoT) technologies defined under the 3GPP umbrella to enable IoT connectivity using the licensed frequencies and to co-exist with legacy cellular broadband technologies like LTE, UMTS, and GSM. By reusing the cellular infrastructure, it enables devices to connect directly to operator networks, providing access to improved nationwide coverage with value-added services like mobility, roaming, security, and authentication. The target for NB-IoT is to provide sufficient coverage for smart meters and other IoT appliances typically located in basements and similarly deep inbuilding locations.
That makes NB-IoT suitable for commercial applications like home lighting, security control, and maybe even keeping tabs on my catalytic converters and mail. It also opens the door to new opportunities for industrial IoT (IIoT) applications like energy and utility management (e.g., a smart grid), asset tracking, and machine-to-machine communication. After all, NB-IoT can provide robust coverage and is scalable to very large numbers of devices—two hallmarks for the IIoT.
But, succeeding in the IIoT with NB-IoT devices and systems will require critical attention to three key challenges.
Battery Life. In NB-IoT, the maximum battery life expected is in the range of 10+ years; however, to avoid costly maintenance, the battery should last for the lifecycle of the device. Unfortunately, battery life is impacted by coverage.
In low coverage, more repetitions are needed to transfer data. The more repetitions, the longer the duty cycles of the IoT modems and the higher the power consumption. Excess repetitions due to network misconfiguration or network implementation also have a similar impact. In a deep inbuilding location there may be a difference of tens of dBs in coverage between operators, and that can take years off the battery life of an IoT device deployed in that location.
To ensure a long battery life, manufacturers will need to characterize the current consumption of the device under active, idle, standby, and sleep modes. Device vendors will need to recreate operating conditions to better understand how much current is drawn in each scenario (e.g., a remote software update versus a device that is unable to connect to server).
Coverage. NB-IoT is expected to enable a coverage gain of 23 dB (max.) over regular LTE. The real gain may be less, depending on the deployment method and configuration. The challenge with NB-IoT coverage is that it is heavily dependent on the field performance of the commercial network equipment and IoT devices, interoperability between the equipment, and the network design and configuration.
To ensure extreme coverage, manufacturers will need to simulate different RF environments (e.g., at remote locations, basement installations, hidden installations, behind concrete walls, and industrial environments). And, they will need to perform transmitter and receiver characterization to understand device performance under these different RF conditions. Once the IoT network is live, the service provider will need to perform field measurements to ensure the simulated tests match real-life conditions.
Low Cost. The NB-IoT module target price is below $5.00. Initially, the cost is expected to be comparable to that for GSM/GPRS. However, the underlying NB-IoT technology is much simpler and its cost will likely decrease as demand increases. An unreliable NB-IoT device can add to the module price, with its associated service and/or recall cost, as can the cost of test during the device’s development and production.
To achieve a low NB-IoT device cost, manufacturers can use lower priced components or simplify the hardware design, but the performance of the device must be properly characterized to ensure these cost-cutting measures don’t compromise device reliability. Manufacturers must also carefully select the right test equipment to reduce the cost of test. An integrated solution that can cover the whole product lifecycle, from design to manufacturing to conformance test, can help minimize test equipment capital cost.
A Final Thought
Without a doubt, NB-IoT holds great promise for the rapidly expanding IIoT. For those who can overcome its challenges, opportunities abound. Does that mean a nifty way of keeping track of my mail is around the corner? Perhaps. Telia, a Swedish mobile operator, recently teamed up with the Finnish postal service Posti to develop smart mailboxes for just that purpose. And, Borgs Technologies now offers a NB-IoT tracker for pets. Maybe a tracker for my catalytic converters will be next? In the meantime, I’ll be sure to set my car alarm and keep my driveway lights on!
If you are interested in finding out how Keysight’s solutions can help address your NB-IoT device and system challenges, check out the following links:
· To monitor current drawn at sub-circuits with much higher bandwidth and dynamic range for the most demanding applications, check out the CX3300 Device Current Waveform Analyzer
· To perform parallel testing of multiple devices under test to get the maximum throughput for the production line, check out the EXM Wireless Test Set