Allowing unlicensed networks (e.g., networks which can operate in the shared spectrum or unlicensed spectrum) to effectively use the available spectrum is an attractive approach to increase system capacity. Although the unlicensed spectrum does not match the qualities of the licensed regime, solutions that allow an efficient use of the unlicensed spectrum as a complement to licensed deployments have the potential to bring great value to network operators, and ultimately, to the communication industry as a whole. It is expected that some features in NR may need to be adapted to comply with the special characteristics of the unlicensed band as well as different regulations. The SCS of 15 kHz or 30 kHz may be the most promising candidates for NR-U OFDM numerologies for frequencies below 6 GHz.

For operations in the unlicensed spectrum, a device may be required to sense the medium as free before transmission. This is often referred to as listen-before-talk or LBT for short. There are many different flavors of LBT, depending on which radio technology the device uses and which type of data the device wants to transmit at the moment. Common for all flavors is that the sensing is done in a particular channel (corresponding to a defined carrier frequency) and over a predefined bandwidth. For example, in the 5 GHz band, the sensing is done over 20 MHz channels. Many devices may be capable of transmitting and/or receiving over a wide bandwidth including multiple sub-bands/channels, e.g., LBT sub-band (i.e., the frequency part with bandwidth equal to LBT bandwidth). Typically, a device is allowed to transmit on the sub-bands where the medium is sensed as free. Again, there are different flavors of how the sensing needs to be done when multiple sub-bands are involved.