Wireless Mesh Network Latency Control via Pre-calculated Routes

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Solution Overview

Problem

Existing wireless mesh networks lack the ability to effectively specify and ensure quality of service constraints, particularly in ensuring timely packet transmission from a source node to a destination node, as node-to-node selection is arbitrary and does not account for latency or stability.

Innovation Solution

The implementation of a process that determines routes and frame lengths in a wireless mesh network to achieve low average latency, incorporating retry mechanisms based on stability between nodes, allowing for fault tolerance and efficient packet transmission by optimizing frame construction and node-to-node communication within the frame.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If arbitrary node-to-node selection is used in wireless mesh networks, then device complexity is reduced, but quality of service constraints cannot be ensured and latency increases

Engineering Contradiction:

Improvenode-to-node selection complexityVSAvoidquality of service constraint satisfaction

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent pre-calculates and stores optimal routes between node pairs before communication occurs. When a transmission is needed, the system retrieves the pre-determined route and frame structure, eliminating the need for complex real-time routing decisions while ensuring QoS constraints are met through advance planning of transmission sequences and timing.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If frame length is extended to accommodate retry mechanisms, then reliability improves, but communication latency increases

Engineering Contradiction:

Improvefault toleranceVSAvoidcommunication latency

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent divides the communication frame into multiple segments or time slots, each dedicated to specific transmission attempts. By structuring the frame with designated retry slots rather than extending it uniformly, the system accommodates reliability requirements through segmented retry opportunities while minimizing overall latency by precisely allocating time resources only where needed for potential retransmissions.

Inventive Principle:

Principle #1Segmentation

3Reliability

If multiple transmission attempts are allowed within a frame, then reliability improves, but power consumption increases

Engineering Contradiction:

Improvetransmission success rateVSAvoidnode power consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent implements a selective retry mechanism where not all node pairs receive the same number of transmission attempts. Instead, the system applies retry logic only to transmissions that fail or are at risk of failing, based on channel conditions and historical performance. This partial application of retry mechanisms maintains reliability for critical transmissions while avoiding unnecessary power consumption from redundant retry attempts in stable channels.

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS7787427B1Providing low average latency communication in wireless mesh networks

Publication Date: 2010.08.31 ANALOG DEVICES INT UNLTD CO

AI summary

Communicating using a wireless mesh network is disclosed. A route is determined from a first node to each other node in the wireless mesh network including one or more intermediate nodes that receive and transmit the packet. A frame length used for communicating a packet is selected based on the routes from the first node to each other node in the wireless mesh network. Node to node communications are selected within the frame along the route such that a predetermined average communication latency time is achieved.