A fast handoff scheme for packet data service in the CDMA 2000 system

This paper proposes a fast handoff scheme for a mobile station using packet data service through the CDMA 2000 network. When a mobile station hands off to a cell in which the Packet Data Serving Node (PDSN) is different from that of the previous cell, the CDMA 2000 system performs two stages of handoff in series, a cellular handoff followed by a Mobile IP (MIP) handoff. We propose a fast handoff scheme that reduces signaling latency and user data loss during a handoff. This improvement is achieved by having the source PDSN buffer the user data packets during the handoff procedure and the MIP handoff started concurrently with the cellular. The proposed fast handoff scheme is compatible with the existing protocols, and the two proposed modifications are transparent to mobile stations with the standard Mobile IP and Mobile IP route optimization protocols.