ultra narrow band (UNB)
Ultra Narrow Band (UNB) is a narrowband modulation technique that operates without the use of sidebands. It is a bandwidth efficient modulation for high data rate transmission.
The UNB modulation scheme is also known as Very Minimum Sideband Keying (VMSK), a variant of Phase Shift Key ing( PSK). It is an older modulation method from the 1980s, which was not further developed in the last century due to the lack of filter technologies. The required filters must have extremely high edge steepnesses and must not cause group delay.
UNB modulation is used in some low power WANs( LPWAN) and has the advantage of being very low power, which is crucial for these networks. Ultra narrowband is used in SigFox, Mioty, nWave and Weightless, among others.