Link Layer Assisted Handoff for Seamless Mobility
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Solution Overview
Problem
Current handoff techniques in wireless communication systems, such as Fast Mobile IP, suffer from significant latencies and packet loss, leading to performance degradation in real-time applications due to Layer 2 and Layer 3 handoff delays, which negatively impact user experience and TCP throughput.
Innovation Solution
Implementing OSI layer 2-originated indications for imminent, ongoing, and completed handoffs, allowing applications to proactively buffer data and manage network resources, thereby reducing the impact of handoff disruptions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If standard Mobile IP handoff is used, then network layer mobility is supported, but significant handoff latency and packet loss occur
Solution Approach 1:
The patent applies preliminary action by having the mobile node proactively detect handoff conditions through Layer 2 indications (such as changes in access point signal strength or connection status) before the actual handoff occurs. The mobile node pre-configures Layer 3 routing information and initiates Layer 3 handoff procedures in advance, allowing the handoff to be completed seamlessly without significant latency or packet loss.
2Loss of time
If Fast Mobile IP handoff is used, then network layer handoff latency is improved, but Layer 2 handoff latency remains a limiting factor
Solution Approach 1:
The patent segments the handoff process into distinct Layer 2 and Layer 3 components, allowing independent optimization of each layer. By detecting Layer 2 handoff conditions and triggering Layer 3 handoff procedures separately, the system can optimize Layer 3 handoff latency through Fast Mobile IP while addressing Layer 2 latency through proactive detection and coordination, thereby improving overall handoff performance.
3Adaptability or versatility
If handoff procedures are implemented, then mobility between access points is enabled, but packet loss and TCP performance degradation occur
Solution Approach 1:
The patent implements feedback mechanisms where the mobile node continuously monitors Layer 2 connection status and access point signal quality. When handoff conditions are detected, the system provides feedback triggers that initiate Layer 3 handoff procedures. This feedback loop ensures timely handoff execution, minimizing packet loss and preventing TCP performance degradation by maintaining continuous connectivity awareness throughout the mobility process.
Data Source
AI summary
Various embodiments are described to address the need for an apparatus and method that improves upon known handoff techniques, such as Mobile IP and Fast Mobile IP, to improve the mobility experience of an end user. OSI layer 2-originated indications of a handoff being imminent (301, 501, 502), a link down for handoff (307, 509, 510), and a new link up after handoff (309, 511, 512) are introduced. These indications can be used by applications (such as real-time/streaming applications on the mobile (101)) to take suitable proactive measures prior to an actual handoff. Examples of such measures include the buffering of data to be used during the handoff interval in a way that improves the seamless mobility experience of the end user.