Zigbee Proxy Network Ad-Hoc Link Management

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Solution Overview

Problem

Wireless control networks with resource-restricted devices face challenges in maintaining correct communication due to single point failures and high power consumption, especially in energy-harvesting devices, where parent link failures are not detected, leading to network overload and reduced reliability.

Innovation Solution

A method involving a resource-restricted device transmitting a frame with a source identifier to proxy devices, which construct and forward packets with derived source-related information, including a sequence number and delay, without pre-configuration, allowing for ad-hoc proxy assignment and minimizing power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a parent-child relationship is established between resource-restricted devices and parent routers, then communication can be forwarded to final destination, but single point of failure is created and communication reliability deteriorates when parent link is broken

Engineering Contradiction:

Improvecommunication forwardingVSAvoidcommunication reliability

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The patent applies local quality by enabling individual resource-restricted devices to establish direct communication links with multiple potential parent routers rather than relying on a single parent-child relationship. Each device can independently select and switch between different parent routers based on link quality, creating localized redundancy that eliminates the single point of failure while maintaining efficient communication forwarding.

Inventive Principle:

Principle #3Local quality

2Reliability

If broadcast/multicast features are used to detect parent link failure and find new parent router, then communication reliability is improved, but bandwidth consumption increases and network overload occurs

Engineering Contradiction:

Improvecommunication reliabilityVSAvoidbandwidth consumption

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent implements partial action by having resource-restricted devices perform selective parent link failure detection only when necessary, rather than continuous broadcast/multicast monitoring. Devices transmit data frames and monitor for acknowledgments or duplicate frames from other devices, triggering failure detection and parent router switching only when communication anomalies are detected, thus maintaining reliability while minimizing bandwidth consumption.

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The patent applies self-service by enabling resource-restricted devices to autonomously detect parent link failures and discover alternative parent routers through analyzing data frame transmissions and acknowledgments without requiring network-wide broadcast/multicast protocols. Each device independently monitors its own communication status and performs self-healing by switching to alternative parents when failures are detected.

Inventive Principle:

Principle #25Self-service

3Reliability

If energy-harvesting devices perform complete search for new parent router when communication is lost, then communication reliability is improved, but power consumption exceeds available energy resources

Engineering Contradiction:

Improvecommunication reliabilityVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent implements partial action by having energy-harvesting devices perform limited, targeted parent router searches rather than exhaustive complete searches. When communication is lost, devices selectively probe for alternative parent routers based on existing network knowledge and link quality metrics, finding sufficient alternative parents with minimal energy expenditure that fits within harvested energy constraints while restoring communication reliability.

Inventive Principle:

Principle #16Partial or excessive action

4Reliability

If resource-restricted devices equip receiving circuit to detect parent link failure, then communication reliability is improved, but device complexity and power consumption increase

Engineering Contradiction:

Improvecommunication reliabilityVSAvoiddevice complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies self-service by enabling resource-restricted devices to detect parent link failures through their existing data transmission and acknowledgment reception functions, without requiring dedicated receiving circuits. Devices monitor the presence or absence of expected acknowledgments and duplicate frames from other devices to infer link status, achieving failure detection using already-present hardware and minimizing device complexity.

Inventive Principle:

Principle #25Self-service

Data Source

PatentEP2499788B1Method for communicating in a network comprising a batteryless zigbee device, network and device therefor

Publication Date: 2017.05.24 SIGNIFY HOLDING BV

Figure 1

AI summary

A method for wireless communication in a network comprising a resource- restricted device, and at least one proxy device, wherein the method comprises the following steps: -the resource-restricted device(ZGPD) transmitting a frame containing source identifier to be forwarded to a destination device in the network, -the proxy device (ZP5) receiving the frame, -the proxy constructing, from the frame, a packet to be forwarded to the destination device, -the router device associating a delay to the packet and scheduling forwarding of the packet after this delay, wherein the step of constructing a packet from the frame comprises deriving source- related information from the received packet and including this information in the packet.