2. UNB associated MAC

2.1 General

The SigFox network uses open access bands (ISM (Industrial, Scientific and Medical Band)). These bands differ according to geographical area:

• in ETSI-compliant countries, the band used is between 868 and 870 MHz ;

• in the rest of the world, the band used is between 902 and 928 MHz, in compliance with local regulatory restrictions.

These bands are freely accessible, but only on condition that the signals transmitted meet certain properties defined by standard EN 55011. In particular, the standard limits transmission power (25 mW at 868 MHz), as well as transmission time. Another criterion is the duty cycle, which limits the percentage of time a node can transmit....