As is well known, in the field of IoT wireless communication , LoRa modules have technical characteristics such as low power consumption, long transmission distance, and strong anti-interference ability. They can effectively solve problems such as short device battery life, weak signal coverage in remote scenarios, and easy interference in complex environments (such as industrial plants and urban building clusters) in low power wide area networks (LPWAN). They are one of the communication infrastructures in fields such as smart agriculture, smart cities, and industrial IoT.

For example, HOPERF's independently developed RFM95 is a LoRa SPI module that adopts an advanced mixed-signal design, is based on a unique adaptive rate algorithm, and supports multiple frequency bands and multiple modulation methods (LoRa, (G)FSK, (G)MSK, OOK). It can not only effectively improve the wireless communication link performance of IoT devices, but also cover communication scenarios from long distance and low speed to medium and short distance and medium and high speed, and its current consumption is significantly lower than other devices in the industry.

The core advantage of the RFM95 lies in its industry-leading communication range achieved through a maximum link budget of 164dB. This performance stems from the combination of a constant RF output power of +20dBm (100mW) and a receiver sensitivity as low as -144dBm. By adopting LoRa modulation, it achieves a breakthrough in the "distance, anti-interference, and power consumption" triangle trade-off, ensuring stable wireless signal transmission even in complex environments.

How to balance power consumption, speed and range in RFM95?

As shown in the figure below, the RFM95 is a half-duplex, low-IF wireless transceiver. It has a built-in standard frequency shift keying (FSK) modem and a long-range spread spectrum (LoRa™) modem, which allows users to flexibly select/switch between various signal modulation methods such as OOK, FSK, and LoRa according to their actual needs.

LoRa SPI Module RFM95 - Simplified Functional Block Diagram

Among them, the LoRa™ modem uses spread spectrum modulation and forward error correction technology, which increases the distance and robustness of the radio communication link compared with traditional FSK or OOK-based modulation methods ; the spread spectrum factor and error correction rate are design variables that allow designers to optimize the trade-off between bandwidth usage, data rate, link budget improvement and interference immunity.

Another important feature of LoRa™ modems is their enhanced anti-interference capability, which enables co-channel GMSK rejection of up to 25 dB. This anti-interference capability allows LoRa™ modulation systems to coexist easily in spectrum-intensive bands or in hybrid communication networks, and LoRa™ can be used to extend range when conventional modulation schemes fail.

It is important to note that different modulation methods differ significantly in key performance dimensions: for example, LoRa focuses on long-distance transmission and low power consumption, FSK has an advantage in data rate, and OOK is characterized by simple structure and low cost. The three are clearly distinguished in terms of transmission distance, data rate, power consumption level and implementation complexity.

This multi-mode support capability allows the RFM95 to cover communication needs ranging from simple scenarios (such as short-distance, low-speed data transmission) to complex scenarios (such as long-distance, low-power IoT communication), and effectively avoids the limitations of a single modulation technology in application scenarios, significantly improving the module's adaptability and practicality.

RFM95, an efficient communication solution in LPWAN

It is worth mentioning that, due to the RFM95's receiving current as low as 10.3mA and the register holding current as low as 200nA in sleep mode, and the integration of a +14dBm high-efficiency PA, it can significantly reduce operating power consumption while ensuring communication distance. It is especially suitable for battery-powered IoT terminals (such as wireless sensors and automatic meter reading systems), and can greatly extend the device's battery life.

In addition, the RFM95 has strong anti-interference capabilities. Its front-end IIP3 (third-order input intercept point) can reach -12.5dBm, which has excellent anti-blocking ability. Combined with the inherent advantages of LoRa modulation technology in terms of selectivity and anti-blocking, it can work stably in strong interference environments and solve the problem that signals are easily affected by co-channel interference in traditional modulation technology.

The RFM95 also features a built-in 256-byte data packet engine that supports CRC check, preamble detection, and bit synchronization. Combined with Automatic Radio Frequency Induction (CAD) and Automatic Frequency Correction (AFC) functions, it can further improve the communication stability and data transmission accuracy of IoT devices.

In terms of compatibility, the RFM95 supports multiple standard protocols such as WMBus and IEEE 802.15.4g, and has been specially calibrated for ISM bands such as 868MHz and 915MHz to meet the regulatory requirements of different regions. In addition, the RFM95 also integrates a temperature sensor, which can monitor the module's operating status in real time, facilitating system power consumption management and fault diagnosis.

By combining ultra-long communication range, low power design, flexible modulation modes and high reliability, the RFM95 provides a wireless communication solution that balances performance and practicality for low power wide area network (LPWAN) devices, and is one of the key bridges connecting the physical world and digital platforms.