BLE Mesh Path Selection Using Link Quality Metrics
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Solution Overview
Problem
Existing methods for selecting paths in Bluetooth Low Energy (BLE) mesh networks fail to account for unacknowledged links, heterogeneous node capabilities, receiver sensitivities, and interference, leading to suboptimal data delivery rates and increased traffic congestion.
Innovation Solution
A method for calculating a link quality metric that considers RSSI, success probability, channel occupancy, and repetition numbers to determine the optimal path between nodes, using path discovery messages to update and broadcast path quality parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If flooding mechanism is used to forward packets through the mesh network, then packet delivery is achieved, but traffic congestion and interference increase significantly
Solution Approach 1:
The patent extracts the harmful flooding mechanism from the network and replaces it with targeted unicast transmission along selected paths. Instead of having all nodes forward all packets, only specific relay nodes on selected paths forward packets to their destination, eliminating unnecessary traffic and interference while maintaining delivery reliability.
Solution Approach 2:
The patent applies local quality by selecting paths based on local link quality metrics (RSSI, ETX) at each hop. Each node evaluates the quality of outgoing links and selects paths that maintain high quality throughout, ensuring that packet forwarding occurs only through high-quality local segments rather than uniform flooding across the entire network.
2Productivity
If path selection is based on simple hop count or RSSI, then implementation is simple, but data delivery rate is suboptimal
Solution Approach 1:
The patent changes the path selection parameters from simple metrics (hop count, RSSI) to a composite metric that includes ETX (Expected Transmission Count) and link quality measurements. This parameter transformation allows the system to optimize data delivery rate by considering actual transmission efficiency rather than just distance or signal strength, while the complexity is managed through standardized measurements at each node.
Solution Approach 2:
The patent implements feedback mechanisms where nodes continuously measure link quality (RSSI, ETX) and use this feedback to dynamically select and update paths. The path selection process incorporates real-time measurements of transmission success and link conditions, allowing the system to adapt to changing network conditions and maintain optimal data delivery rates.
3Use of energy by moving object
If unacknowledged links are used in BLE mesh, then energy consumption is reduced, but link reliability becomes difficult to assess
Solution Approach 1:
The patent applies preliminary action by having nodes perform link quality measurements (RSSI, ETX) before actual data transmission. These preliminary assessments allow nodes to predict link reliability and select optimal paths in advance, compensating for the lack of acknowledgments during actual data transfer while maintaining energy efficiency.
Solution Approach 2:
The patent uses link quality metrics (RSSI, ETX) as intermediaries to assess link reliability without requiring acknowledgments. These metrics serve as indirect indicators of link quality, allowing nodes to evaluate and compare path options based on measured parameters rather than direct feedback, thus maintaining both energy efficiency and reliability assessment capability.
4Reliability
If packet repetitions are used to increase reliability, then successful delivery probability increases, but channel occupancy and collision risk increase
Solution Approach 1:
The patent applies partial action by using packet repetitions selectively rather than uniformly across all transmissions. Nodes determine the number of repetitions needed based on link quality measurements (ETX, RSSI), applying just enough redundancy to achieve reliable delivery without excessive repetitions that would waste channel resources and increase collision risk.
Solution Approach 2:
The patent changes the transmission parameters dynamically based on measured link quality. Instead of fixed repetition counts, nodes adjust the number of packet repetitions according to actual link conditions (ETX values, RSSI measurements), optimizing the balance between delivery reliability and channel resource consumption for each specific transmission.
Data Source
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AI summary
A method for supporting the establishment of a path for transmitting a message in a mesh network, wherein said message is to be transmitted from a source node in said mesh network to a destination node, via one or more intermediary nodes, in said mesh network. The method comprises the steps of receiving, by an intermediary node in said mesh network, a path discovery message originating from said source node in said mesh network, said path discovery message comprising a path quality parameter, updating, by said intermediary node, said path quality parameter based on a quality of link associated with a node from which said intermediary node received said path discovery message, and broadcasting, by said intermediary node, said path discovery message wherein said broadcasted path discovery message comprises said updated path quality parameter. A complementary method and corresponding node are also presented herein.