Radio Base Station Accommodation Apparatus Handoff Sequence Management
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Solution Overview
Problem
In the CDMA 2000 1xEV-DO system, data transmission stops and jitter occur during hand-off due to route changes, leading to packet order issues and annulment when the transmission delay between the hand-off destination base station and Packet Data Serving Node (PDSN) is shorter than that between the hand-off source base station and PDSN.
Innovation Solution
Managing sequence numbers independently for radio packets transmitted to both the hand-off source and destination base stations, ensuring that RLP packets from a single IP packet are not split across routes during hand-off, and using these sequence numbers to restore data at each base station.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If route change by RSP is performed during hand-off, then data transmission continuity is improved, but packet order cannot be maintained and packets are annulled when transmission delay between hand-off destination base station and PDSN is shorter
Solution Approach 1:
The patent applies preliminary action by having the hand-off source base station transmit a notification to the PDSN before the hand-off occurs. This notification contains information about the hand-off and allows the PDSN to prepare for receiving packets from the new base station, preventing packet annulment due to route changes. The PDSN stores this notification and uses it to correctly process packets arriving from the hand-off destination base station.
2Adaptability or versatility
If RLP packets from one IP packet are transmitted through different routes during hand-off, then route flexibility is improved, but packet order is disrupted and restoration fails
Solution Approach 1:
The patent implements feedback by having the PDSN send an acknowledgment (ACK) back to the mobile device when packets are successfully restored. This ACK confirms that the packets have been correctly received and restored despite being transmitted through different routes during hand-off. The feedback mechanism ensures that packet order information is maintained and allows the system to verify successful restoration.
Data Source
AI summary
A radio communication method in which, when hand-off of the down direction is performed while a radio mobile device subjects one application packet of the up direction to fragmentation to divide the one application packet into a plurality of radio packets and transmits the plurality of radio packets, sequence numbers of radio packets managed by a first radio base station to the plurality of fragmented radio packets of the one application packet even after the hand-off of the down direction is performed and to apply sequence numbers of radio packets managed by a second radio base station to fragmented radio packets of the application packet transmitted subsequently after completion of transmission of the plurality of fragmented radio packets of the one application packet; and making a radio base station accommodation apparatus identify a radio base station and restore data for each radio base station.