Balanced Network Objective Function for LLN Traffic Distribution
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Solution Overview
Problem
Current routing protocols in Low-Power and Lossy Networks (LLNs) fail to proactively balance network traffic distribution, leading to unbalanced battery consumption and network lifetime issues, especially under non-uniform node distribution and dynamic network changes.
Innovation Solution
Introducing a Balanced Network Objective Function (BNOF) that uses Routing Table Size (RTsize) and Packet Processed Rate (PPR) as metrics to determine the most balanced path for traffic distribution, sent in the DAG metric container of the DIO message, allowing nodes to select and switch parents based on minimum path cost and workload, ensuring all nodes share traffic equally.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If ETX-based routing metric is used to optimize transmission efficiency, then packet delivery performance is improved, but network traffic distribution becomes unbalanced
Solution Approach 1:
The patent introduces a new routing metric that combines ETX with a load balancing factor. This metric dynamically changes based on the current traffic load and battery status of intermediate nodes, allowing the routing protocol to select paths that balance both transmission efficiency and traffic distribution. The load balancing factor is calculated based on the number of active routes through each node, creating a parameter that reflects network congestion and guides balanced traffic distribution.
2Productivity
If network formation prioritizes transmission optimization, then packet delivery is improved, but battery consumption becomes unbalanced across nodes
Solution Approach 1:
The routing metric incorporates a battery status parameter that reflects the energy levels of intermediate nodes. When selecting parent nodes for routing, the protocol considers both the transmission quality (ETX) and the battery status of candidate nodes. This dual-parameter approach ensures that traffic is routed through nodes with sufficient energy reserves, preventing premature node failure and extending overall network lifetime while maintaining packet delivery performance.
3Device complexity
If routing paths are selected based on minimum hop count, then network formation is simplified, but traffic load becomes concentrated on specific nodes
Solution Approach 1:
The patent extends the traditional hop count metric by adding a load weighting factor. Instead of simply counting hops, the new metric weights each hop based on the current traffic load of the intermediate node. This allows the routing protocol to prefer paths with fewer hops when load is balanced, but automatically redirect traffic through alternative paths when certain nodes become congested, achieving load distribution without significantly increasing formation complexity.
4Device complexity
If a single border router serves thousands of sensors, then network infrastructure is simplified, but individual nodes experience high battery consumption
Solution Approach 1:
The patent implements a hierarchical routing structure where the network is segmented into multiple intermediate routing tiers between sensor nodes and the border router. Instead of all sensors communicating directly with a single border router, the protocol dynamically selects intermediate parent nodes at different hierarchical levels. This segmentation distributes the routing burden across multiple nodes, reducing the traffic load on any single node and extending battery life while maintaining simplified infrastructure with a single border router.
Data Source
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AI summary
In one implementation, the present invention provides a mechanism for balanced ad-hoc network formation. To achieve the for balanced ad-hoc network formation, the present invention sends the metric information with DIO control message. A new metric container type is introduced in RPL to hold the metric information, and select the parent with minimum path cost, and switch the parent with minimum path cost, as per the defined logic. A stateless metric considers that the average traffic flow from each node is approximately same. The stateless metric directly uses the number of routing table entries (RTsize) to decide which path to use. A stateful metric, wherein the node keeps a track of packets processed per second by itself. For stateful metric, the node maintains packets processed rate (PPR) variable, which is then used as the metric.