Seamless Handover via Packet Caching and Fetch Requests
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Solution Overview
Problem
Current mobile communication technologies face challenges in achieving seamless handover between heterogeneous networks, particularly in supporting both unicast and multicast communication, leading to packet losses and service degradation during user mobility, with existing solutions either increasing latency, reducing traffic performance, or introducing excessive signaling overhead.
Innovation Solution
A method and apparatus utilizing caching and buffering mechanisms to enable seamless handover by storing packets in mobile nodes and access network elements, allowing continuous data flow during handover and packet recovery after handover, with predictive resource reservation to prepare the new access nodes, thereby minimizing packet losses and optimizing resource usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If tunnel construction is used to minimize delay and losses during handover, then packet loss is reduced, but signaling overhead and network resource waste increase excessively
Solution Approach 1:
The patent applies preliminary action by having the mobile node send a Fetch Request message before handover completes, requesting packets that are predicted to arrive during the handover period. The target access node prepares and buffers these packets in advance, so they are ready for immediate delivery after handover, eliminating the need for complex tunnel construction while minimizing packet loss.
Solution Approach 2:
The patent extracts the packet buffering function from the tunnel mechanism and places it directly at the target access node. Instead of using tunnels to forward packets during handover, the system extracts and buffers only the necessary packets at the target node based on prediction, reducing signaling overhead while maintaining reliability.
2Adaptability or versatility
If existing mobility management solutions are applied, then seamless handover is partially achieved, but they cannot simultaneously support both unicast and multicast communication
Solution Approach 1:
The patent applies universality by designing a handover mechanism that works for both unicast and multicast communication types. The Fetch Request message and packet buffering mechanism are generic and can handle any packet type, allowing the same infrastructure to support multiple communication modes without sacrificing seamless handover performance.
Solution Approach 2:
The patent segments the handover process into distinct phases: prediction of packets to be received during handover, buffering at the target access node, and selective retrieval after handover. This segmentation allows the system to handle different communication types (unicast/multicast) through the same framework while maintaining reliability.
3Reliability
If packets are buffered during handover, then packet loss is reduced, but latency increases during the handover process
Solution Approach 1:
The patent applies preliminary action by predicting and buffering packets before handover completes. The target access node identifies packets that will arrive during handover and buffers them in advance, so they are ready for immediate delivery after handover without causing latency.
Solution Approach 2:
The patent uses feedback through the Fetch Request message mechanism. The mobile node provides feedback about its handover status and packet reception state, allowing the target access node to optimize buffering and delivery timing, minimizing latency while ensuring complete packet delivery.
Data Source
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AI summary
A method for performing a seamless handover of a mobile node on which an application is running which receives data from a first access node to a second access node, said method comprising: receiving data by a buffer of said mobile node; consuming by said application the data stored in said buffer during handover while no new data is received by said buffer; after handover, requesting by said mobile node data which have been received by a cache of said second access node to request therefrom the missing packets that arrived during the handover.