Long Distance, Wide Connectivity: How Sub-G RF Modules Are Quietly Rising in the IoT Era
While Wi-Fi, Bluetooth, and other 2.4 GHz technologies dominate short-range communication today, a wireless technology operating in lower frequency bands is carving out its own niche in the vast field of the Internet of Things (IoT) with its irreplaceable advantages. Sub-1GHz (Sub-G for short) wireless modules, much like an unobstructed "suburban expressway," stand in stark contrast to the congested “downtown urban highway" of the 2.4 GHz band, becoming a backbone for achieving wide-area IoT connectivity with their exceptional characteristics of long range and low power consumption. Understanding Sub-G Modules Sub-G modules, short for Sub-1 GHz modules, are wireless radio frequency modules that operate in license-free ISM frequency bands below 1 GHz (such as 169 MHz, 315 MHz, 433 MHz, 470 MHz, 868 MHz, 915 MHz, 920 MHz, etc.). Their technical advantages are rooted in basic physics: The lower the frequency, the lower the propagation loss of the radio wave and the stronger its diffraction capability. This allows Sub-G modules to easily achieve kilometer-level communication distances and powerful wall-penetrating and obstacle-surpassing capabilities, making them particularly suitable for deployment in complex environments and IoT applications requiring large-scale coverage. Network Topology Structures Sub-G modules support flexible network architectures to adapt to ever-changing application scenarios. Star Topology: All end nodes communicate directly with a central gateway or concentrator. It features a simple structure and very low power consumption, making it the preferred choice for LoRaWAN and many proprietary protocols, perfectly suited for large-scale applications like smart metering and environmental monitoring. Point-to-Point Topology: Establishes a direct link between two devices. It is simple and direct, with low latency, often used for remote control and data transparent transmission. Mesh Topology: Each node can act as a relay, automatically forming a network and relaying data transmissions. This can greatly extend network coverage, suitable for areas where gateway deployment is difficult but wide coverage is needed. Core RF Technologies and Chips The implementation of Sub-G modules relies on their underlying chips and communication protocols, mainly divided into the following categories: LoRa (Long Range Radio) This is one of the most representative technologies. It uses Chirp Spread Spectrum (CSS) technology, achieving ultra-long-range communication with very low power consumption and possessing extremely high receiver sensitivity, significantly improving link budget and anti-interference capability. Representative Chips: Semtech's SX1276, SX1262 series. Proprietary Protocols (Private Protocols) Chip manufacturers provide basic RF transceiver chips, based on which developers can customize private protocols. This approach offers controllable cost and high flexibility. Representative Chips: Texas Instruments (TI)'s CC1310, CC1312R, CC135...