Over-the-air frequency and time synchronization for small cells

A network node enabling transmit timing synchronization for base stations, comprising:

• at least one processor;
• and
• memory containing software executable by the at least one processor whereby the network node is operative to:
• obtain a time offset between a transmit timing of a first base station and a reference timing;
• obtain a time offset between a transmit timing of a second base station and the transmit timing of the first base station;
• compute a time offset between the transmit timing of the second base station and the reference timing based on the time offset between the transmit timing of the first base station and the reference timing and the time offset between the transmit timing of the second base station and the transmit timing of the first base station;
• and
• provide the time offset between the transmit timing of the second base station and the reference timing to another base station for assistance in time synchronization of the other base station.

A method of operation of a base station to measure and report a transmit timing offset for one or more pairs of base stations detected by the base station, comprising:

• measuring a transmit timing of a first base station;
• measuring a transmit timing of a second base station;
• computing a time offset between the transmit timing of the first base station and one of a group consisting of:
• the transmit timing of the second base station and a reference timing as determined by the transmit timing of the second base station and a known difference between the transmit timing of the second base station and the reference timing;
• and
• reporting the time offset to a network node.

A base station enabled to report transmit timing offsets of other base stations to a network node, comprising:

• a radio unit;
• a network interface;
• at least one processor;
• and
• memory containing software executable by the at least one processor whereby the base station is operative to:
• measure, via the radio unit, a transmit timing of a first base station;
• measure, via the radio unit, a transmit timing of a second base station;
• compute a time offset between the transmit timing of the first base station and one of a group consisting of:
• the transmit timing of the second base station and a reference timing as determined by the transmit timing of the second base station and a known difference between the transmit timing of the second base station and the reference timing;
• and
• report, via the network interface, the time offset to a network node.