What’s the Difference Between IEEE 802.11ah and 802.11af in the IoT? (.PDF Download)

The IEEE standard 802.11 usually defines what we all know as Wi-Fi. Multiple versions of this standard exist, but not all are designated as Wi-Fi despite their being a part of the family. Specifically, consider two relatively recent versions of the standard: 802.11af, now referred to as White-Fi, and 802.11ah, otherwise known as HaLow. Both versions, which are more suited to Internet of Things (IoT) applications, offer benefits beyond traditional Wi-Fi, including longer range and lower power consumption.

This article takes a closer look at these standards, either of which could be the solution to your next design.

IoT Requirements

Most IoT applications involve sensors transmitting minimal data from remote locations over short distances. A core requirement is low power consumption—most applications are battery-operated, so long battery life is a must. 

Another burgeoning need is longer range. Most IoT applications cover short range from 10 to say 100 meters. However, many others need to extend that range from 100 meters to many kilometers. Low data rates (less than 1 Mb/s) are typical.

Traditional wireless technologies such as Wi-Fi, Bluetooth, ZigBee, and others can easily handle the short-range applications, but their operating frequency limits that range. Power consumption may be an issue, too.

The distance traveled by a radio wave of a given power, antenna gain, and receiver sensitivity directly relates to the operating frequency. The physics of radio indicates that the range is inversely related to frequency. In other words, lower-frequency signals naturally travel farther than higher-frequency signals.