Patent ID: 8380196

Claim:
A method of performing handover of a user equipment from a source radio base station to a target radio base station in a mobile radio communications system, wherein a handover command comprising information relating to resources reserved for the handover is sent to the user equipment from the source radio base station, wherein the handover command further comprises timing information relating to the timing of the reserved resources; and wherein the timing information is obtained using a frame number offset between a source cell and a target cell, the method comprising: sending information on a first source frame number to the target radio base station in a first message, where the first source frame number is the frame number of the source radio base station upon sending said information on the first source frame number; and receiving a second message from the target radio base station, the second message comprising first target frame number information, wherein the first target frame number information has been obtained by the target radio base station by determining a first target frame number as the frame number of the target radio base station upon receipt of the first message.