Patent ID: 8599786

Claim:
A method for base station handover of a mobile station (MS) from a source cell of a source base station to a target cell of a target base station in a cellular radio network, wherein the base stations transfer packet switched communications between the mobile station and the network, the method comprising: by the source base station while the MS is in the source cell: receiving a handover command message from a source support node, stopping reception and acknowledgement of uplink packets from the MS; stopping transmission of downlink packets towards the MS; sending a context message to the source support node without indicating which buffered downlink packets have been discarded; transmitting to the MS, the handover command message ordering the MS to connect to the target cell; and transmitting to the MS, information regarding a sequence number of a next expected uplink packet that is expected by the source support node for a packet flow subject to lossless packet switched handover; and by the MS upon arrival and synchronization of the MS in the target cell: transmitting to the target base station, information regarding a sequence number of a next expected downlink packet that is expected by the MS for the packet flow subject to lossless packet switched handover; and starting uplink data transmission to the target base station beginning with the next expected uplink packet that is expected by the source support node.