Network Coding for Wireless Ad Hoc Throughput

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Solution Overview

Problem

Wireless ad hoc networks face inefficiencies due to bottlenecks in data transmission, particularly when using traditional routing methods in mesh networks, which limit the average packet delivery rate due to constraints on communication links.

Innovation Solution

The implementation of network coding techniques, specifically linear network codes, where intermediate nodes mix incoming packets using Galois Fields to transmit fewer combined packets, allowing multiple packets to be received by destination nodes in a single time slot, thereby overcoming bottlenecks and improving network throughput.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If traditional routing methods are used in mesh networks, then network structure is simple and easy to implement, but communication links become bottlenecks limiting packet delivery rate

Engineering Contradiction:
Improvepacket delivery rateVSAvoidnetwork coding complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by transforming the network transmission model from traditional routing (one packet per link per time slot) to network coding (multiple packets combined into one coded packet). This changes the fundamental parameter of transmission efficiency, allowing intermediate nodes to transmit linear combinations of multiple packets simultaneously, thereby increasing packet delivery rate without proportionally increasing network complexity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces network coding as an intermediary mechanism at intermediate nodes. These nodes act as mediators that receive multiple packets, perform linear coding operations, and transmit coded packets to multiple destinations. This intermediary function resolves the bottleneck problem by allowing a single transmission to serve multiple destinations, improving productivity while managing complexity through standardized coding operations

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If network coding is implemented to overcome bottlenecks, then throughput is improved, but computational complexity increases

Engineering Contradiction:
Improvenetwork throughputVSAvoidcoding computation complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the network into source nodes, intermediate nodes, and destination nodes with clearly defined functions. Source nodes generate packets, intermediate nodes perform coding operations on received packets, and destination nodes decode received coded packets. This segmentation allows each node type to be optimized independently, improving overall throughput while managing computational complexity through specialized node functions

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements partial action by having intermediate nodes perform coding operations only on packets they have received and stored, rather than coding all possible packets. Nodes selectively code packets based on their reception status and destination requirements, improving throughput for active flows while avoiding unnecessary computational overhead for inactive or already-delivered packets

Inventive Principle:
Principle #16Partial or excessive action

3Productivity

If packets are forwarded through intermediate nodes, then network coverage is extended, but transmission time increases due to multiple hops

Engineering Contradiction:
Improvedata transmission efficiencyVSAvoidtransmission delay
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The patent applies merging by combining multiple packet transmissions into a single coded packet transmission at intermediate nodes. Instead of forwarding packets sequentially through multiple hops to different destinations, intermediate nodes merge multiple packets into one coded packet that can be simultaneously delivered to multiple destinations, improving transmission efficiency and reducing the time loss associated with multiple sequential transmissions

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3342111B1Wireless ad hoc network assembly using network coding
Publication Date: 2020.12.09 MOTOROLA MOBILITY LLC
  • EP3342111B1 patent drawingFigure 1(a)~1(b)
  • EP3342111B1 patent drawingFigure 2
  • EP3342111B1 patent drawingFigure 3

AI summary

A method of setting up a wireless ad hoc network includes constructing an initial network graph by a source device (401). The network graph represents the source device (401), at least one intermediate device (407, 408, 409), and at least one communication path (402) between the source device (401) and the intermediate device. The initial network graph is sent from the source device (401) to the intermediate device (407, 408, 409) along with an update request. The source device (401) receives a second network graph from the intermediate device (407, 408, 409) in response to sending the initial network graph, and determines an updated network graph by performing a union of the initial network graph and the second network graph. The process is performed by each intermediate device (407, 408, 409) required to reach a destination device (411, 412, 413).