Hierarchical Deep Channel Coding for Short-Block 6G Reliability

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Solution Overview

Problem

Current channel coding techniques, such as LDPC and turbo codes, face challenges in supporting low-latency requirements for 6G cellular data networks, especially for augmented reality (AR)/virtual reality (VR) applications and ultra-reliable low-latency communication (URLLC), as they exhibit poor performance with short block lengths and are not optimal for non-AWGN channel models, leading to increased latency and suboptimal feedback mechanisms.

Innovation Solution

A hierarchical channel coding approach using a concatenation of two autoencoders (AEs) with feedback from layer-0 to layer-1, incorporating learned recurrent neural network (RNN) codes and conditional feedback for iterative error refinement, which reduces redundant feedback and improves spectral efficiency by conditioning the layer-1 encoder and decoder with log-likelihood ratios (LLRs) for joint error correction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional channel coding techniques (LDPC, turbo codes) are used, then reliability is maintained for long block lengths, but performance deteriorates for short block lengths required in 6G low-latency applications

Engineering Contradiction:
Improveblock error rate performanceVSAvoidlatency
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent segments the channel coding task into multiple hierarchical layers (layer-0, layer-1, layer-2 autoencoders), where each layer processes a portion of the data with different code rates. This segmentation allows the system to achieve reliable error correction for short block lengths by distributing the coding burden across multiple specialized layers, with layer-0 handling basic protection and higher layers providing enhanced correction for critical data.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a hierarchical dimension to traditional channel coding by stacking multiple autoencoder layers with progressively different code rates. Instead of using a single code rate, the system operates in a multi-dimensional coding space where each layer contributes differently to error correction, enabling optimal performance for short block lengths while maintaining scalability.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Reliability

If feedback mechanisms are implemented for error correction, then reliability improves, but spectral efficiency deteriorates due to redundant feedback

Engineering Contradiction:
Improveerror correction capabilityVSAvoidspectral efficiency
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent applies local quality by assigning different code rates to different hierarchical layers, with layer-0 using a lower code rate for robust basic protection and layer-1/2 using higher code rates for enhanced correction. This localized optimization allows feedback to be more targeted and efficient, reducing redundant transmissions by matching the feedback intensity to the specific error correction needs of each data portion.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The hierarchical structure enables partial action where layer-0 provides baseline error correction that handles many errors without requiring feedback, while layer-1 and layer-2 provide additional correction only when needed. This partial approach reduces the overall feedback burden compared to applying full-strength error correction uniformly across all data.

Inventive Principle:
Principle #16Partial or excessive action

3Loss of energy

If hierarchical deep channel coding is implemented, then spectral efficiency improves through reduced redundant feedback, but device complexity increases due to multiple autoencoder layers

Engineering Contradiction:
Improvespectral efficiencyVSAvoidcoding structure complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent implements nested doll by embedding multiple autoencoder layers within a hierarchical structure, where layer-1 and layer-2 autoencoders are nested within the overall communication system that already contains layer-0. Each nested layer processes data that has already been partially processed by outer layers, creating a compact hierarchical architecture that achieves high spectral efficiency while organizing complexity in a manageable nested fashion.

Inventive Principle:
Principle #7Nested doll (Nesting)

4Loss of time

If short block lengths are used for low-latency communication, then latency is reduced, but error correction performance deteriorates

Engineering Contradiction:
ImprovelatencyVSAvoiderror correction performance
Core Design Contradiction:
Loss of timeVSReliability

Solution Approach 1:

The patent changes the parameter of code rate across hierarchical layers, with layer-0 using code rate 1/2, layer-1 using 2/3, and layer-2 using 3/4. This parameter variation allows the system to achieve high error correction performance for short block lengths by distributing the correction burden across layers with progressively higher code rates, optimizing the balance between latency and reliability.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS12155482B2Hierarchical deep channel coding
Publication Date: 2024.11.26 NOKIA SOLUTIONS & NETWORKS OY
  • US12155482B2 patent drawing
  • US12155482B2 patent drawing
  • US12155482B2 patent drawing

AI summary

Systems, methods, apparatuses, and computer program products for hierarchical coding. One method may include encoding, by a layer-0 autoencoder, bit sequence x into a layer-0 codeword. The method may further include transmitting, by the layer-0 autoencoder, the layer-0 codeword over a channel, and decoding, by the layer-0 decoder, a received layer-0 codeword.