Wireless Mesh Node Bloom Filter Fill Rate Management

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Solution Overview

Problem

In wireless mesh networks with a large number of nodes, Bloom filters used for packet routing become overly filled, leading to increased false positives and reduced reachability, especially when the fill rate exceeds 50%, limiting the number of hops and requiring larger filter sizes that increase packet size and power consumption, particularly affecting low-power IoT devices.

Innovation Solution

A mesh node acts as an intermediate gateway by creating a new advertisement message with a reduced fill rate Bloom filter when the original Bloom filter reaches a maximum fill rate, allowing further hop information to be added and extending the path to the gateway without increasing packet size, thereby reducing the risk of false positives and improving forwarding efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the Bloom filter size is increased to accommodate more hops, then the reachability and number of supported hops are improved, but the packet size and power consumption increase

Engineering Contradiction:
ImprovereachabilityVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent segments the routing information by creating multiple advertisement messages, each containing a Bloom filter with a reduced fill rate (e.g., below 50%). Instead of using one large Bloom filter that would require more power, the system divides the routing information into multiple smaller, more efficient advertisement messages that can be processed with lower power consumption while maintaining the same reachability.

Inventive Principle:
Principle #1Segmentation

2Area of stationary object

If the Bloom filter fill rate is increased to include more mesh nodes, then the coverage and number of supported hops are improved, but the false positive rate increases

Engineering Contradiction:
ImprovecoverageVSAvoidfalse positive rate
Core Design Contradiction:
Area of stationary objectVSReliability

Solution Approach 1:

The patent applies dynamics by adjusting the fill rate parameter of the Bloom filter based on the network conditions and path length. Instead of using a static high fill rate that causes false positives, the system dynamically maintains the fill rate below a threshold (e.g., 50%) to optimize the balance between coverage and false positive rate, thereby improving reliability while maintaining adequate coverage.

Inventive Principle:
Principle #15Dynamics

3Reliability

If the Bloom filter fill rate is reduced to decrease false positives, then the reliability is improved, but the number of hops and coverage are limited

Engineering Contradiction:
Improvefalse positive rateVSAvoidnumber of hops
Core Design Contradiction:
ReliabilityVSLength of moving object

Solution Approach 1:

The patent ensures continuity of useful action by periodically retransmitting advertisement messages with updated Bloom filters along the same path to the gateway. This continuous retransmission allows the routing information to be maintained and propagated throughout the network over time, enabling packets to reach the gateway through multiple hops even though each individual advertisement message has a reduced fill rate.

Inventive Principle:
Principle #20Continuity of useful action

Data Source

PatentEP3811678B1Method and mesh node for enabling communication in a wireless mesh network
Publication Date: 2024.08.07 TELEFONAKTIEBOLAGET LM ERICSSON (PUBL)
  • EP3811678B1 patent drawingFigure 1~2
  • EP3811678B1 patent drawingFigure 3~4
  • EP3811678B1 patent drawingFigure 5A

AI summary

A method and a mesh node (200) for enabling communication of packets in a wireless mesh network with multiple mesh nodes. When receiving (2:2) an original advertisement message with a Bloom filter initiated by an original gateway (204), it is detected that a predetermined maximum fill rate is reached in the received Bloom filter. The mesh node (200) starts to act as an intermediate gateway and creates a new advertisement message (2:3) comprising a new initiated Bloom filter with a reduced fill rate. The new advertisement message is then transmitted (2:4) with the new Bloom filter while indicating that the new advertisement message originates from said original gateway (204).