Patent ID: 8229365

Claim:
A method for use in a cellular access system, said system comprising a first plurality of base stations, each of which controls the traffic to and from at least one cell in the system, in which system the communication between users in a cell and the base station of the cell is divided into an up link period (UL) during which users may transmit to their base station, and a down link period (DL) during which a base station may transmit to users in the cell of the base station, the method further comprising the steps of letting a controlling node in the system send instructions to a first base station and a second base station in said first plurality of base stations, wherein the instructions to the first base station comprises information regarding: at least a first point (T 1 ) in time when the first base station should start transmitting a control signal, and wherein the instructions to the second base station comprises information regarding: at least a second point (T 2 ) in time when the second base station should start to listen for control signals from other base stations, and measure their time of arrival and signal strength, at least a third point (T 3 ) in time when the second base station should cease listening for control signals from other base stations, at least a fourth point (T 4 ) in time when the second base station should transmit the measurements results to the controlling node, said results comprising the time of arrival and signal strength of the received control signals, wherein the controlling node uses the measurement results in order to set individual guard periods for the second base station or for a group of base stations in the system in which the second base station is comprised.