Link Reliability Metric Computation in Mesh Networks
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In frequency hopping mesh networks, especially in low-power and lossy networks, determining the cause of packet drops is challenging due to the limitations of narrow-band transceivers, which are half-duplex and can only operate on a single channel, leading to confusion between link reliability and congestion issues.
Innovation Solution
A transmitter computes a link reliability metric by excluding transmissions that coincide with the receiver's active transmission times, using past and future transmission information to accurately assess link reliability and schedule transmissions to avoid interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a narrow-band transceiver is used to reduce cost and energy consumption, then device complexity and energy use are reduced, but the ability to accurately determine transmission failure causes deteriorates due to single-channel limitation
Solution Approach 1:
The patent segments the transmission timing information into distinct intervals (receiver busy periods vs. non-busy periods) to separately analyze packet loss causes. By dividing the timing data and comparing it against the channel hopping schedule, the system can identify whether losses occurred during receiver transmission periods, thereby distinguishing congestion from link failures while using energy-efficient narrow-band transceivers.
2Measurement precision
If transmission timing information is collected and analyzed to improve link reliability measurement, then measurement precision is improved, but device complexity increases due to additional processing requirements
Solution Approach 1:
The patent implements self-service by having each device independently generate and maintain its own transmission timing information and channel hopping schedule. Each node compares its stored timing data with its own schedule to determine busy periods, eliminating the need for complex centralized processing or additional hardware while achieving accurate link reliability measurement.
3Ease of operation
If all transmissions are included in link reliability metric to simplify calculation, then ease of operation is improved, but measurement precision deteriorates by conflating link reliability with congestion
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing the receiver's busy periods based on its transmission timing information and channel hopping schedule before evaluating packet losses. This advance preparation allows the system to efficiently filter out losses occurring during busy periods, maintaining measurement precision while keeping the actual reliability calculation simple and straightforward.
Data Source
AI summary
In one embodiment, a transmitter in a communication network receives an indication of active transmission times of a receiver to which the transmitter attempts to reach with first transmissions, the active transmission times indicating respective times of second transmissions initiated by the receiver. Based on determining when the first transmissions occur, the transmitter may then compute a link reliability metric for a link from the transmitter to the receiver by excluding one or more of the first transmissions from the indicated active transmission times of the second transmissions. In one embodiment, the active transmission times are in the past and the reliability metric excludes any first transmissions in the past during those times, while in another embodiment the active transmission times are scheduled in the future and the reliability metric does not include any first transmissions since the first transmissions may be scheduled to avoid the active transmission times.