Wireless Handoff Buffering for Mobile Endpoint Reliability

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Solution Overview

Problem

In wireless networks, the handoff of mobile endpoints between base stations often results in packet loss and latency due to signal strength changes, leading to a poor user experience.

Innovation Solution

A method that involves multicasting data to both the serving and target base stations, buffering data at the target base station, and using sequence numbers to ensure seamless handoff with minimal latency or data loss, allowing the target base station to take over data transmission smoothly when the signal strength exceeds predetermined thresholds.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If data is routed through a single base station, then device complexity is reduced, but reliability deteriorates due to packet loss during handoff

Engineering Contradiction:

Improvedata transmission reliabilityVSAvoiddata routing complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The system performs preliminary actions by buffering data at the target base station before the handoff is complete. This ensures that when the mobile endpoint transitions from the first base station to the second base station, the data is already available at the new base station, eliminating packet loss and latency associated with real-time data transfer during handoff.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent introduces an intermediary mechanism using sequence numbers to track and manage data packets during handoff. The sequence number system acts as a mediator between the multiple base stations and the mobile endpoint, ensuring proper data delivery and retransmission without requiring complex coordination between base stations.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If handoff between base stations is performed, then adaptability is improved for mobile users, but loss of information increases due to packet loss

Engineering Contradiction:

Improvemobile endpoint mobilityVSAvoiddata packet loss

Core Design Contradiction:

Adaptability or versatilityVSLoss of information

Solution Approach 1:

Data is buffered at the target base station in advance of the handoff completion, ensuring that when the mobile endpoint switches from the first base station to the second base station, the data is already available and no packets are lost during the transition.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system employs sequence numbers to provide feedback mechanisms for tracking data packet delivery. This allows the system to detect missing packets and trigger retransmissions, ensuring complete data delivery despite the mobility-induced handoffs between base stations.

Inventive Principle:

Principle #23Feedback

3Adaptability or versatility

If handoff between base stations is performed, then adaptability is improved for mobile users, but loss of time increases due to latency

Engineering Contradiction:

Improvemobile endpoint mobilityVSAvoidhandoff latency

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

By buffering data at the target base station before the handoff is complete, the system eliminates the latency that would otherwise occur during the handoff transition. The data is ready to be transmitted immediately when the mobile endpoint connects to the new base station, making the handoff imperceptible to the user.

Inventive Principle:

Principle #10Preliminary action

4Reliability

If data is multicast to multiple base stations, then reliability is improved during handoff, but use of energy increases

Engineering Contradiction:

Improvehandoff reliabilityVSAvoidnetwork energy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The system uses preliminary buffering at the target base station rather than continuous multicasting to multiple base stations. This approach maintains reliability by ensuring data availability during handoff while reducing energy consumption by eliminating the need to continuously transmit duplicate data to multiple base stations.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS7782824B2Method and system for handling a mobile endpoint in a wireless network

Publication Date: 2010.08.24 CISCO TECHNOLOGY INC

AI summary

A method of handling a mobile endpoint in a wireless network includes routing data for a mobile endpoint through a first base station. The mobile endpoint is wirelessly connected to the first base station and has a first signal strength at the first base station. The method also includes routing data for the mobile endpoint through the first base station and a second base station. The mobile endpoint is wirelessly connected to the first base station and has a second signal strength at the second base station. The second signal strength is above a first level. The method also includes routing data for the mobile endpoint through the second base station. The mobile endpoint is wirelessly connected to the second base station and has a third signal strength at the second base station. The third signal strength is above a second level.