No network platform is best for every application and use case and that appears to be the case for internet of things use cases as well. That applies both to the type of edge computing as well as the untethered access platform.
Connectivity can use fixed networks; unlicensed wide area networks or mobile networks optimized for internet of things use cases.
Connectivity cost per device also matters: some networks cost more, per device. Also, some use cases require mobility; others do not. Battery life often is a key consideration, and each network might have different strengths in that area as well. Consider three 4G-based standards, Cat-M1, NB-IoT and Cat-1.
In practice, it is possible to buy devices using a dual-mode connectivity option, including both Cat-M1 and NB-IoT. Also, many original differences in features have lessened, or been eliminated.
Cat-M1 often is necessary for wearable use cases, such as fitness bands and smartwatches, asset tracking and health monitors, largely because Cat-1 supports mobility. It also is essential if voice communications are a requirement. Cat-M1 latency is 10 to 15 milliseconds.
It also is used for automated teller machines, alarms, metering applications, security monitoring and building monitoring systems.
NB-IoT is more commonly used for lower-bandwidth use cases that also are stationary. Smart gas, water, and electricity meters, smart street lighting and parking sensors provide examples. One of the characteristics of these use cases is that data transmission is infrequent and small amounts of data are transferred.
Heating, ventilation and air conditioning use cases, industrial monitors and agricultural sensors that monitor irrigation systems and detect leaks are use cases suited to NB-IoT networks.
Cat-M1 supports 1.4 MHz bandwidth and also supports over-the-air firmware, software and security updates, as well as being designed to support Linux operating systems.
Cat-M1 supports full and half-duplexing, which can lower power consumption and increase their battery life when sensors are operated in half-duplex mode
NB-IoT supports uplink speeds of 66 kbps and download speeds of 26 kbps in half-duplex mode. Latency ranges between 1.6 to 10 seconds.
But NB-IoT occupies a very narrow bandwidth of 180 kHz and can be deployed in the guard band portion of an LTE network, meaning NB-IoT uses unoccupied portions of the LTE network.
NB-IoT also tends to offer better coverage inside buildings and wider coverage of outdoor areas as well.
Cat-1 was designed for IoT devices with low and medium bandwidth needs, supporting bandwidth of 5 Mbps for uploads and 10 Mbps for downloads. Latency is low, at 50 to 100 milliseconds, and Cat-1 supports tower handoff, making it a viable option for asset tracking deployments.
However, it consumes more power and its signal range is a bit shorter than NB-IoT and Cat-M1.
As always, choices are a compromise between cost, battery life, coverage, bandwidth and other requirements such as voice support or mobility.
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