RPL Downlink Reliability via Dual Path Generation
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Solution Overview
Problem
RPL routing technology in industrial wireless networks faces challenges in maintaining reliable downlink traffic to mobile devices due to mobility, leading to packet loss and network degradation, as existing protocols were not designed to handle mobile devices effectively.
Innovation Solution
The solution involves dual path generation and redundant packet retransmission, utilizing a common ancestor device selection method and reverse packet removal to ensure reliable downlink traffic, even when one path becomes invalid due to parent changes in mobile devices, thereby minimizing network life shortening and energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If RPL protocol uses single path routing for mobile devices, then network simplicity is maintained, but downlink traffic reliability deteriorates due to packet loss when parent device changes
Solution Approach 1:
The patent segments the routing path into multiple independent paths (first path through prefer parent and second path through alternate parent) for downlink traffic to mobile devices. This segmentation allows packets to be transmitted through alternative routes when one path becomes invalid due to mobile device movement, thereby improving downlink traffic reliability without requiring complete protocol redesign.
Solution Approach 2:
The patent establishes multiple parent devices (prefer parent and alternate parent) and pre-configures backup routing paths before mobile device movement occurs. The sync device maintains routing information for both paths in advance, so when the mobile device moves and the primary path becomes invalid, packets can immediately be transmitted through the pre-configured alternate path without delay.
2Reliability
If RPL protocol performs redundant packet retransmission for mobile devices, then downlink traffic reliability improves, but energy consumption increases
Solution Approach 1:
The patent introduces the sync device as an intermediary that maintains routing information for both the first path (through prefer parent) and second path (through alternate parent). The sync device intelligently selects which path to use for packet transmission based on current network conditions and mobile device location, eliminating the need for the mobile device to perform energy-consuming redundant retransmissions. The intermediary manages the complexity of path selection while the mobile device simply receives packets.
3Measurement precision
If RPL protocol updates routing information frequently for mobile devices, then routing accuracy improves, but network overhead increases
Solution Approach 1:
The patent makes the sync device a universal routing information maintenance point that serves multiple functions: it maintains routing information for both first and second paths, performs path selection, and manages updates. This multi-functionality allows the system to maintain accurate routing information for mobile devices without requiring frequent updates from multiple sources, as the sync device consolidates routing management and can efficiently update both paths when needed.
Data Source
AI summary
Disclosed is a device for increasing reliability of downlink traffic to mobility devices in an RPL environment that can increase reliability of downlink traffic by dual path generation and redundant packet retransmission for the mobile device in an environment where mobility exists. The moving device includes a directed acyclic graph (DAG) rank value acquisition unit for receiving a destination oriented directed acyclic graph information object (DIO) of parent devices to obtain a DAG rank value of each parent device; a parent device selection unit for selecting prefer parents and alternate parents based on a DAG rank of the parent device; and a destination advertisement object (DAO) signal processing unit for transmitting a DAO to a sync device when the prefer parents and the alternate parents are determined.