Patent ID: 8761135

Claim:
A method in a radio base station of a wireless communication system for handling received data units of a stop-and-wait HARQ-process in a multi-carrier operation, the method comprising the steps of: receiving two or more MAC-i/is data units from a user equipment; identifying the Transmission Sequence Number, TSN, of each of the received MAC-i/is data units, said TSN being indicated only in a MAC-is header, and, determining the original transmission order of said two or more received data units using an extended reordering depth, the extended reordering depth being increased compared to the reordering depth of a 6 bit TSN-field, and being based on said identified TSN; wherein the extended reordering depth is further based on the identity of each cell in multi-cell operation, on the identity of each MIMO-stream in MIMO-operation, or on the number of required retransmissions.