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Even if the noise is large, LoRa can cope with it calmly. After the LoRa modem is configured, the range that can be divided is 64-4096 chips/bit, and the highest spreading factor (12) in 4096 chips/bit can be used up to. Relatively speaking, industrial iot gateway ZigBee can only divide the range of 10-12 chips/bit.

By using a high spreading factor, LoRa technology can transmit small-capacity data through a wide range of radio spectrum. Actually, when you measure it through a spectrum analyzer, the data looks like noise, but the difference is that the noise is uncorrelated, whereas the data has correlation, and based on that, the data can actually be extracted from the noise. The higher the spreading factor, the more data can be extracted from the noise. In a well-functioning GFSK receiver, a minimum signal-to-noise ratio (SNR) of 8dB is required to demodulate the signal reliably. By configuring AngelBlocks, LoRa can demodulate a signal with a signal-to-noise ratio of -20dB. The GFSK method is the same as this The resulting difference is 28dB, which is equivalent to a lot of expansion in range and distance. In an outdoor environment, a 6dB gap can achieve twice the original transmission distance.

Super link budget, let the signal fly farther In order to effectively compare the performance of the transmission range between different technologies, we use a quantitative indicator called "link budget". The link budget includes every variable that affects signal strength at the receiver, which in its simplified form includes transmit power plus receiver sensitivity. The transmit power is 100mW (20dBm), the receiver sensitivity is -129dBm, and the total link budget is 149dB. In comparison, GFSK wireless technology, which has a sensitivity of -110dBm (which is already an excellent figure), requires 5W of power (37dBm) to achieve the same link budget. In practice, the receiver sensitivity of most GFSK wireless technologies can reach -103dBm. In this case, the transmitter frequency must be 46dBm or about 36W to achieve a link budget similar to LoRa. serial to wifi converter Therefore, using LoRa technology, we can obtain wider transmission range and distance with low transmission power. This low-power wide-area technology is exactly what we need.