Underwater Acoustic Fountain Coding With Limited Feedback

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Solution Overview

Problem

Underwater acoustic networks face challenges with high bit error rates, long propagation delays, narrow bandwidth, and limited energy, leading to inefficient data transmission due to the transmission of useless coding packets and excessive feedback, which reduces channel utilization and shortens network lifetime.

Innovation Solution

The implementation of a sequential recursive online fountain code with limited feedback (SROFC-LF) that minimizes connected components, reduces the number of required encoded and feedback packets, and optimizes encoding and decoding processes to ensure each packet is useful for decoding, thereby improving channel utilization and energy efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If online fountain codes are used for reliable transmission, then transmission reliability is improved, but the number of feedback packets increases causing packet collision and propagation delay

Engineering Contradiction:

Improvetransmission reliabilityVSAvoidpropagation delay

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent implements a feedback mechanism where the receiver sends feedback packets to the sender about which original packets have been successfully decoded. The sender uses this feedback information to determine which coding packets to transmit next, enabling adaptive encoding that reduces unnecessary transmissions and feedback overhead while maintaining reliable delivery

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The encoding process dynamically adapts based on feedback received from the receiver. The sender adjusts the selection of coding packets to encode based on the current decoding state, making the transmission process dynamic rather than static, which reduces redundant transmissions and optimizes resource usage

Inventive Principle:

Principle #15Dynamics

2Reliability

If coding packets are transmitted to ensure reliable delivery, then transmission reliability is improved, but energy consumption increases

Engineering Contradiction:

Improvetransmission reliabilityVSAvoidenergy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The feedback mechanism enables the sender to avoid transmitting redundant coding packets by knowing which original packets have already been decoded. This reduces the total number of transmissions required, thereby reducing energy consumption while maintaining reliable delivery

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent changes the encoding parameters dynamically based on feedback information. Instead of using fixed-degree encoding, the system adapts the encoding degree and packet selection based on the current state of decoding progress, optimizing energy efficiency

Inventive Principle:

Principle #35Parameter changes

3Reliability

If coding packets are transmitted to ensure reliable delivery, then transmission reliability is improved, but channel bandwidth utilization decreases

Engineering Contradiction:

Improvetransmission reliabilityVSAvoidchannel bandwidth utilization

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

Feedback packets provide real-time information about decoding progress, allowing the sender to optimize the selection and degree of coding packets. This reduces the total number of coding packets needed and improves channel bandwidth utilization while maintaining reliable transmission

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system dynamically adjusts encoding parameters based on feedback, optimizing channel usage. The encoding degree and packet selection are adapted in real-time to minimize redundant transmissions and maximize effective bandwidth utilization

Inventive Principle:

Principle #15Dynamics

4Measurement precision

If excessive feedback packets are sent, then decoding accuracy is improved, but packet collision increases and propagation delay worsens

Engineering Contradiction:

Improvedecoding accuracyVSAvoidpropagation delay

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

Instead of sending feedback for every possible decoding state, the system sends feedback selectively based on what is necessary to maintain accurate decoding state information. This partial feedback approach maintains decoding accuracy while reducing feedback overhead and propagation delay

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS11722245B2Data encoding and decoding method for underwater acoustic networks (UANs) based on improved online fountain code

Publication Date: 2023.08.08 QINGHAI NORMAL UNIV

AI summary

A data encoding and decoding method for underwater acoustic networks (UANs) based on an improved online fountain code, including: in a build-up phase, subjecting all original packets to sequential encoding according to their serial numbers to generate and send encoded packets with degree 2; merging k original packets to k/8 connected components with a size of 8; performing random encoding until a largest connected component is successfully decoded; in a completion phase, sending, by a receiver, a feedback packet according to a current decoding graph; according to a feedback packet containing decoding states of all the original packets, sending, by a sender, encoded packets with degree m; and randomly selecting original packets for recursive encoding to generate and send encoded packets with degree 1 or 2; and setting, by the receiver, a threshold to restrict the number of feedback packets.