Determining a centre frequency in an unlicensed frequency band to use

A network node (l) for determining a centre frequency in an unlicensed frequency band to use for downlink communication in a cellular network, the network node comprising:

• a processor;
• and
• a memory storing instructions that, when executed by the processor, causes the network node to:
• perform a coarse pre-scan when the network node is in a transmit time slot, yielding a coarse measurement of signal levels for a plurality of frequencies in the unlicensed frequency band;
• perform an accurate measurement when the network node is in a receive time slot, yielding an accurate measurement of signal levels for a plurality of frequencies in the unlicensed frequency band;
• and
• determine at least one frequency to use as a centre frequency for a downlink communication channel in the unlicensed frequency band.

A network node comprising:

• means for performing a coarse pre-scan when the network node is in a transmit time slot, yielding respective coarse measurement of signal levels for a plurality of frequencies in an unlicensed frequency band;
• means for performing an accurate measurement when the network node is in a receive time slot, yielding respective accurate measurement of signal levels for a plurality of frequencies in the unlicensed frequency band;
• and
• means for determining at least one frequency to use as a centre frequency for a downlink communication channel in the unlicensed frequency band in a cellular network.

A non-transitory computer readable storage medium having program code stored therein for determining a centre frequency in an unlicensed frequency band to use for downlink communication in a cellular network, the program code which, when run on a network node, causes the network nodes to perform operations comprising:

• performing a coarse pre-scan when the network node is in a transmit time slot, yielding a coarse measurement of signal levels for a plurality of frequencies in the unlicensed frequency band;
• performing an accurate measurement when the network node is in a receive time slot, yielding an accurate measurement of signal levels for a plurality of frequencies in the unlicensed frequency band;
• and
• determining at least one frequency to use as a centre frequency for a downlink communication channel in the unlicensed frequency band.