Patent ID: 8054836

Claim:
A method for maintaining an order of received data units during a re-establishment procedure in a wireless communication system, the method comprising: receiving a plurality of data units from a source base station according to a sequence prior to re-establishment to a target base station, wherein each data unit includes a sequence number; receiving, from the target base station, at least one data unit having a sequence number after re-establishment; delivering to a higher layer all data units received from the source base station prior to re-establishment and having sequence numbers smaller than the sequence number of the at least one data unit received from the target base station after re-establishment; and delivering, to a higher layer, all data units received prior to starting the re-establishment procedure which are available sequentially, wherein the sequentially available data units respectively have consecutive sequence numbers that are greater than, and immediately sequential to, the sequence number of the at least one data unit received from the target base station after re-establishment.