INTER-RAT HANDOVER CONTROL USING SEQUENCE NUMBERS

摘要

An empty GRE packet along with a sequence number provides in-order delivery of data packets for a session to a UE during inter-RAT handover. In particular, an empty GRE packet sent from a source gateway in a source RAN (Radio Access Network) to a target gateway in a target RAN includes a sequence number to indicate to the target gateway the end of forwarded data packets from the source gateway. The target gateway sends data packets received from the source gateway to the UE until the empty GRE packet with the expected sequence number is received. Upon receipt of the empty GRE packet containing the expected sequence number, the target gateway begins sending data packets received directly from a home network gateway to the UE.