Rx-tx time difference generation, measurement and reporting with neighboring base stations

A first base station for a radio access network of a cellular communications system, the first base station comprising:

• processing circuitry in communication with a transceiver, the processing circuitry configured to cause the first base station to:
• receive, at the first base station, a signal transmitted by a second base station;
• estimate a Time of Arrival, TOA, of the received signal at the first base station according to a clock of the first base station;
• determine a delta value that is or is a function of an amount of time between the TOA of the received signal at the first base station according to the clock of the first base station and a time reference at the first base station;
• and
• either (a) provide the delta value to a positioning estimation entity within the cellular communications system or (b) use the delta value at the first base station to reduce a time synchronization error between the first base station and the second base station or (c) pass the delta value to a UE.

A method performed by a positioning estimation entity in a cellular communications system for determining an estimate of a position of a wireless communication device, the method comprising:

• receiving, from a plurality of base stations in a radio access network of the cellular communications system, a plurality of delay values each being a delay value for a different pair of base stations (BS i, BS j), wherein for each pair of base stations (BS i, BS j) the corresponding delay value is or is a function of an amount of time between a Time of Arrival, TOA, of a signal received at BS i from BS j according to a clock of BS i and a time reference at BS i;
• obtaining Time Difference of Arrival, TDOA, measurements for different pairs of base stations (BS i, BS j) made by the wireless communication device;
• and
• computing an estimate of the position of the wireless communication device based on:
• (a) the TDOA measurements, (b) the delay values received for the different pairs of base stations (BS i, BS j) for which the TDOA measurements were made, and (c) known propagation delays for the different pairs of base stations (BS i, BS j) for which the TDOA measurements were made.