Four Chirp patterns are applied, each consisting of 4 Chirp pulses (sub-Chirps). The phase shift between the sub-Chirps of consecutive patterns contains the information that is to be transmitted. As interferences change the patterns more or less equally the relative phase difference between the sub-Chirps remains constant, resulting in a high interference resistance.
DBO-CSS was developed for the use in industrial ambience with high interference potential, i.e. the control of manufacturing processes, active RFID. DBO-CSS is defined in IEEE 802.15.4a. Due to its similarity to DSSS it can be integrated into networks working with DSSS.