Relay Centric Mobility Management in Mesh Networks

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Solution Overview

Problem

Managing mobility and downlink paging for low power Internet of Things (IoT) devices in wireless communication networks is challenging due to their reliance on sleep cycles to conserve power, especially when they lack a consistent communications channel and need to relay signals through other devices, requiring efficient mobility management and power-saving strategies.

Innovation Solution

The solution involves a method where IoT devices associate with relay devices during common awake periods, monitor for stay alive signals, send link confirmation signals at specific periodic rates, and use discovery broadcasts to select optimal relay devices, ensuring efficient power usage and maintaining communication links while allowing for seamless handovers when links break.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If IoT devices use sleep cycles to conserve power, then energy consumption is reduced, but communication reliability deteriorates due to missed transmissions during sleep periods

Engineering Contradiction:
Improvepower consumptionVSAvoidcommunication reliability
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The patent introduces relay devices as intermediaries between IoT devices and the network. These relay devices remain awake and maintain persistent connections, mediating communications for sleeping IoT devices. The relay devices receive and forward messages during the IoT device's sleep periods, eliminating missed transmissions while the IoT device maintains its power-saving sleep cycle.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system performs preliminary actions by establishing persistent connections and pre-configuring relay devices before the IoT device enters sleep mode. The relay devices are prepared in advance to handle incoming messages and wake-up notifications, ensuring that communication reliability is maintained without requiring the IoT device to stay awake.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If IoT devices frequently wake to check for messages, then communication responsiveness is improved, but power consumption increases

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

Solution Approach 1:

Relay devices serve as intermediaries that monitor for incoming messages during the IoT device's sleep periods. Instead of the IoT device frequently waking to check for messages, the relay device performs this function on behalf of the sleeping device, maintaining communication responsiveness while the IoT device remains in low-power mode.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system implements periodic wake-up cycles for the IoT device rather than continuous monitoring. The device wakes at predetermined intervals to exchange messages with the relay, then returns to sleep. This periodic action balances communication responsiveness with power conservation, as the device only activates its transceivers briefly at scheduled intervals.

Inventive Principle:
Principle #19Periodic action

3Reliability

If relay devices are used to extend communication range, then connectivity is improved, but device complexity increases due to relay selection and coordination

Engineering Contradiction:
ImproveconnectivityVSAvoidrelay selection and coordination
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements self-service mechanisms where IoT devices autonomously discover and select relay devices based on pre-configured parameters such as geographic location and capability information. The devices perform self-configuration and automatic connection establishment without requiring complex manual relay selection or coordination, reducing the perceived complexity while maintaining improved connectivity.

Inventive Principle:
Principle #25Self-service

4Reliability

If IoT devices maintain persistent connections, then communication reliability is improved, but power consumption increases due to continuous transceiver operation

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

Solution Approach 1:

The relay device acts as an intermediary that maintains the persistent connection on behalf of the IoT device. The relay device stays awake and maintains the network connection, while the IoT device can sleep. This approach achieves communication reliability through persistent connections without requiring the power-intensive continuous transceiver operation at the IoT device.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

Instead of maintaining continuous persistent connections, the system uses periodic connection establishment during wake-up cycles. The IoT device establishes connections periodically when awake, then disconnects during sleep periods. The relay device manages these periodic connections, providing reliability through regular re-establishment without the continuous power consumption of persistent connections.

Inventive Principle:
Principle #19Periodic action

Data Source

PatentEP3430843B1Relay centric mobility management in a mesh network
Publication Date: 2020.07.08 QUALCOMM INC
  • EP3430843B1 patent drawingFigure 1
  • EP3430843B1 patent drawingFigure 2
  • EP3430843B1 patent drawingFigure 3

AI summary

Systems and methods are disclosed for efficient signaling between devices. A relay device initiates association with discovery broadcast signals to leaf devices. Each leaf responds with association request signals. After association, the relay periodically sends stay alive signals to the leaf, and the leaf periodically sends link confirmation signals to the relay. If either device fails to send its signal, link breakage is assumed. The leaf device reverts to uplink communication with a base station while searching for another relay. In another embodiment, the leaf foregoes association with a relay, instead forming a device to device (D2D) connection with a relay. A D2D connection is used when the leaf does not expect a link to a relay to be stable enough to justify the association overhead, or when downlink traffic is arriving more frequently than an associated relay is awake. Other aspects, embodiments, and features are also claimed and described.