While 5G promises the possibility of fast low-cost connections and the ability to support of 100x more devices, the IoT industry can’t wait until those new 5G networks are ready and operating worldwide before deploying the billions of devices that will be online by the end of this decade.
To avoid the saturation of existing cellular networks, 2.4 GHz WiFi, and the cost of licensed spectrum, IoT device manufacturers are looking at new sub-1GHz WiFi standards to provide unlimited, license-free spectrum for their solutions.
802.11af (White-Fi) and 802.11ah (HaLow) are the most sought-after solutions for new connectivity. Both use previously licensed spectrum and do not interfere with traditional WiFi signals in the 2.4GHz and 5GHz bands, nor with 2G and 3G cellular networks. Some of the spectrum is shared with some LTE channels used in the United States.
IEEE 802.11af makes use of the digital dividend of frequencies freed when broadcast television coverage moved to digital terrestrial and some of the previous UHF channels ceased to operate.
Due to the nature of the low-frequency bands, neither technology is suitable for high-speed or high-volume data transmission. They could be used, however, to provide connectivity for a significant number of devices deployed in a wide area. This would again be helpful for long-distance IoT communication and could also be used in business or industrial applications that require long-range communication. Speeds could be acceptable over these distances because of the lack of interference.
Another possibility is using White-Fi to aggregate several TV channels and provide the bandwidths that WiFi uses on 2.4 and 5.6 GHz, making it compatible with billions of devices already using those frequencies.
Sub-1GHz connectivity is also critical for the new generation of low-power consumption devices, with a battery life of several years instead of weeks. That battery performance is necessary for the billions of sensors and monitoring devices deployed in cities around the world.
Future 5G networks could support these IoT devices, adding the possibility of very low latency, but the initial cost for hardware manufacturers to be 5G-ready could be enormous, and it is unlikely that those networks will have a large footprint in many countries until the end of the 2020s.
Moreover, future 5G carriers will need to make costly investments in infrastructure and spectrum licenses, money that they’ll want to recoup through hefty fees and expensive data plans. This cost is something the IoT industry could only afford if they charge for expensive applications such as connected cars or advanced robotics.
Another advantage for 802.11af and 802.11ah is timing. The IEEE is expected to release the final official specifications of 802.11ah HaLow later this month, and the specs for White-Fi around summertime. That will give the green light for semiconductor manufacturers to start putting chipsets in the market later this year, and those could be integrated into the first generation of routers, access points, and connected devices.
Since most current WiFi networks operating in homes and buildings are using the 2.4GHz and 5GHz bands, it’s unlikely that the first applications of the new standards will be indoors.
Many IoT device manufacturers are already using some sub-1GHz systems such as ZigBee, but that’s a proprietary solution, which would make it more expensive to roll out large installations and would compromise future support and compatibility.
The use of unlicensed spectrum does pose some serious security challenges, as it will be easy for hackers -- and this has been demonstrated -- to break into the access points and devices with very basic hardware. Strong authentication and encryption systems will be necessary to avoid unwanted access and potential disruption of the networks and connected systems.
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