What Is SigFox?

Specifically, SigFox sets up antennas on towers (like a cell phone company), and receives data transmissions from devices like parking sensors or water meters. 

These transmissions use frequencies that are unlicensed, which in the US is the 915 MHz ISM band; the same frequency a cordless phone uses. (Europe has a narrower band around 868 MHz, and most of the world has some version of this band either like the US or Europe, all with different rules that govern their use.)

SigFox wireless systems send very small amounts of data (12 bytes) very slowly (300 baud) using standard radio transmission methods (phase-shift keying – DBPSK – going up and frequency-shift keying – GFSK – coming down). 

The long range is accomplished as a result of very long and very slow messages. Information theory says that the slower you transmit, the easier it is to “hear” your message.
This technology is a good fit for any application that needs to send small, infrequent bursts of data. Things like basic alarm systems, location monitoring, and simple metering are all examples of one-way systems that might make sense for this network. In these networks, the signal is typically sent a few times to “ensure” the message goes through. While this works, there are some limitations, such as shorter battery life for battery-powered applications, and an inability to guarantee a message is actually received by the tower.

SigFox has faced challenges in moving their technology into the US market. Under FCC Part 15, the law that governs the use of the unlicensed radio spectrum, the maximum time a transmission can be on the air is 0.4 seconds. Since SigFox transmissions are 3 seconds or so, this has required a new architecture, and is the likely reason they have been slower to deploy in the US than promised. The frequency band in the US is also subject to much higher levels of interference than the band SigFox uses in Europe.


Source: LinkLabs