Linear Network Coding for Wireless Ad Hoc Network Throughput

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Solution Overview

Problem

Wireless ad hoc networks face inefficiencies due to bottlenecks in data transmission, particularly in mesh networks where intermediate nodes can become bottlenecks, limiting the average number of packets received by destination nodes per time slot.

Innovation Solution

The implementation of network coding, where intermediate nodes mix incoming packets using linear combinations, allowing them to transmit fewer mixed packets instead of multiple original packets, enabling destination nodes to decode the original packets, thereby increasing throughput.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If data is forwarded through intermediate nodes in a mesh network, then network coverage and connectivity are improved, but network bottlenecks occur at intermediate nodes limiting throughput

Engineering Contradiction:
Improvenetwork coverageVSAvoidthroughput
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent combines multiple incoming packets into a single mixed packet using network coding at intermediate nodes. Instead of forwarding each original packet separately through bottleneck links, intermediate nodes create linear combinations of packets, reducing the number of transmissions required and eliminating throughput limitations imposed by bottleneck edges.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent changes the parameter of packet transmission by transforming individual packets into mixed packets through linear network coding. This parameter change allows the system to overcome bottleneck constraints by transmitting information in a compressed, combined form that can be decoded at destination nodes.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If routing algorithms are used to manage data flow in mesh networks, then packet delivery is achieved, but maintenance and exchange of routing tables increases system complexity

Engineering Contradiction:
Improvepacket deliveryVSAvoidrouting table maintenance
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent extracts the complexity of routing table maintenance and packet forwarding decisions from intermediate nodes by implementing network coding. Instead of requiring intermediate nodes to make complex routing decisions and maintain routing tables, the system uses a simpler approach where intermediate nodes apply pre-determined linear combinations to incoming packets.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If multiple original packets are transmitted through bottleneck links, then all packets can reach destinations, but the number of transmissions per time slot is limited by link capacity

Engineering Contradiction:
Improvepacket deliveryVSAvoidpackets per time slot
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent merges multiple original packets into mixed packets at intermediate nodes using linear network coding. This allows multiple packets to be transmitted through bottleneck links in fewer time slots while maintaining reliable delivery, as destination nodes can decode the original packets from the mixed packets received.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3342063B1Wireless ad hoc network communications using linear network coding
Publication Date: 2021.12.01 MOTOROLA MOBILITY LLC
  • EP3342063B1 patent drawingFigure 1(a)~1(b)
  • EP3342063B1 patent drawingFigure 2
  • EP3342063B1 patent drawingFigure 3

AI summary

A method of operating a wireless ad hoc network includes determining a group of intermediate devices (c1, c2, c3) on communication paths from a first source device (S1) and a second source device (S2) to a set of destination devices (T1, T2). Each intermediate device (c1, c2, c3) of the group has a communication path to a corresponding subset of destination devices (T'1, T'2, T'3) such that a communication path exists from both the first source device (S1) and the second source device (S2) to each destination device (t1-t8) of the set of destination devices. Each intermediate device (c1, c2, c3) of the group of intermediate devices is configured with a first linear network code (1501) corresponding to the first source device (S1), and with a second linear network code (1502) corresponding to the second source device (S2). The intermediate devices (c1, c2, c3) are also configured with an additional linear network code (1503, 1504, 1505) between itself and its corresponding subset of destination devices (T'1, T'2, T'3).