What is Sub-GHz？

Wi-Fi, Bluetooth, and ZigBee technologies are 2.4 GHz protocols widely used in today’s wireless communication applications. The Sub-GHz protocol works in a different radio frequency, below the 1 GHz band.

Sub-GHz is one of the essential technologies for wireless communication. For applications that only require a low data transmission rate, such as smart agriculture, smart homes, smart meters, and more, Sub-GHz gives us many advantages.

Frequency

Sub-GHz technology operates in a frequency band less than 1 GHz, usually around 920 MHz. That’s how Sub-GHz networking gets its name.

Wi-Fi and Bluetooth both use the same 2.4 GHz band everywhere in the world. As for Sub-GHz, countries mainly use the 433 MHz licensed free spectrum. However, because of historical reasons for the frequency bands regulation, a few other bands are used in some regions: North America and Australia (915 MHz), Europe (868 MHz), China (470 MHz & 779 MHz), and Japan 426 (MHz & 920 MHz). By using a spectrum where fewer existing products are on the air, Sub-GHz is less prone to interference from devices using Bluetooth, Wi-Fi, or 2.4 GHz ZigBee.

Range

The lower radio frequencies in Sub-GHz networking are not absorbed by physical matter as much as 2.4 GHz signals. Thus, given the identical antennas and transmission power, the range of Sub-GHz networking is longer than Wi-Fi and Bluetooth.

Another reason for Sub-GHz’s long range is that it typically runs at a slower speed than Wi-Fi and Bluetooth.

Sub-GHz networking can easily reach several hundreds of meters indoors. The long range makes Sub-GHz technology an ideal choice for Internet of Things applications.

Power

Power efficiency and system range are functions of the receiver sensitivity plus the transmission frequency. The sensitivity is inversely proportional to channel bandwidth, so a narrower bandwidth creates higher receiver sensitivity and allows efficient operation at lower transmission rates.

Sub-GHz utilizes a frequency band under 1 GHz, so sensor nodes use significantly less power than 2.4 GHz equivalents.

Application

With less interference, a longer range, and lower power than Wi-Fi or Bluetooth, Sub-GHz networking is the outstanding choice for many IoT applications. There are several markets, such as toys, medical equipment, security systems, and building automation, where both Sub-GHz and 2.4 GHz options can work together optimally.