Stable Relay Route via Sequential RSSI Average

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Solution Overview

Problem

Conventional wireless multihop relay routing protocols are unstable due to fluctuations in the propagation channel, leading to frequent route restructuring and increased network load, as they do not account for temporal changes in RSSI, resulting in unreliable relay routes.

Innovation Solution

A communication system that calculates a reception power evaluation value using a sequential average of RSSI values over multiple routing packets, stabilizing the relay route by incorporating the average values into the routing metric, thereby reducing the impact of RSSI fluctuations and improving route stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If conventional minimum path loss routing uses Bellman-Ford algorithm with RSSI metric, then routing calculation is simple, but the route becomes unstable due to RSSI fluctuation

Engineering Contradiction:
Improverouting calculation complexityVSAvoidroute stability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent applies preliminary action by pre-calculating and storing multiple alternative routes (primary route, secondary route, tertiary route) before actual communication needs arise. When RSSI fluctuation causes the primary route to become unstable, the system can immediately switch to pre-prepared alternative routes without performing complex real-time recalculations, thus maintaining route stability while avoiding complex computational processes.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes the routing metric from simple RSSI to a composite metric that incorporates both RSSI and route stability parameters. By introducing a stability threshold and using multiple metrics (RSSI, stability, alternative route availability), the system transforms the single-parameter RSSI-based routing into a multi-parameter decision framework, resolving the contradiction between simple calculation and stable routing.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If routing protocol frequently restructures routes due to propagation channel fluctuation, then route adapts to channel changes, but network load increases

Engineering Contradiction:
Improveroute adaptability to channel changesVSAvoidnetwork load
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The system performs preliminary actions by pre-establishing multiple alternative routes during idle periods when network load is low. These pre-computed routes are stored and ready for immediate use, allowing the system to adapt to channel fluctuations without triggering frequent real-time routing recalculations, thus reducing network load while maintaining adaptability.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback mechanisms by continuously monitoring RSSI values and comparing them against stability thresholds. When fluctuations exceed the threshold, the system triggers route switching to pre-prepared alternative routes rather than initiating full routing protocol re-executions. This feedback-based approach enables adaptive response to channel changes while minimizing unnecessary routing updates and reducing network load.

Inventive Principle:
Principle #23Feedback

3Device complexity

If hop count is used as routing metric, then routing algorithm is simple, but route stability decreases due to use of far-apart node links

Engineering Contradiction:
Improverouting algorithm complexityVSAvoidroute stability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent changes the routing metric from simple hop count to a composite metric that includes both hop count and link quality (RSSI) components. By introducing additional parameters (link quality threshold, route stability factor) into the routing decision process, the system maintains algorithmic simplicity while improving route stability through multi-parameter evaluation rather than relying solely on hop count.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The system applies preliminary action by pre-evaluating and selecting routes that satisfy both hop count constraints and link quality requirements. During the route discovery phase, the system pre-filters candidate routes based on RSSI thresholds and stability criteria, so that when routing decisions are made, only pre-validated stable routes are considered, avoiding the need for complex real-time stability assessments.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2541989B1Communications system, slave node, route building method, and program
Publication Date: 2018.04.11 KYUSHU UNIV
  • EP2541989B1 patent drawingFigure 1
  • EP2541989B1 patent drawingFigure 2
  • EP2541989B1 patent drawingFigure 3

AI summary

Provided are a communication system and the like capable of making a stable relay route even when a propagation channel is fluctuated by the fluctuation of RSSI. For making a tree-type communication route whose root is a core node, each slave node, after the reception of the latest reset routing packet from a node, judges if the transmission source node should be the parent of the tree-type structure based on the sequential average of the reception power of n routing packets received from the same transmission source node. As the reception power is log-normally distributed in general, an asymptotically stable relay route can be obtained, especially by using the sequential average.