Patent ID: 9237541
Filing Date: 2016-01-12
CPC Classification: G01S,H04W

Claim Text:
1. A method in a first network node for estimating a first timing offset difference between a first timing offset of a first base station and a second timing offset of a second base station, wherein the first network node, first base station, and second base station are comprised in a cellular network, and wherein the method comprises: receiving Uplink Time Difference Of Arrival, UTDOA, measurements from a second network node, which UTDOA measurements relate to a first UTDOA time difference between a first measured receiving time when an uplink signal from a user equipment is received at the first base station, and a second measured receiving time when the uplink signal from the user equipment is received at the second base station; receiving Observed Time Difference Of Arrival, OTDOA measurements from a third network node, which OTDOA measurements relate to a first measured OTDOA time difference between a third receiving time when a downlink signal from the first base station is received at the user equipment and a fourth receiving time when a downlink signal from the second base station is received at the user equipment; and estimating a first timing offset difference between a first timing offset of the first base station and a second timing offset of the second base station, based on the first UTDOA time difference and the first measured OTDOA time difference.