Polar Code Length Matching for Low-Latency Channel Encoding

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Solution Overview

Problem

Current channel encoding methods, such as Turbo codes and LDPC codes, face challenges in supporting a wide range of bit rates with low complexity, particularly in 5G communications, especially for medium and short packet transmissions, and struggle to achieve ideal performance due to high complexity in encoding and decoding processes.

Innovation Solution

The proposed solution involves using polar codes, which are designed to reach the Shannon limit with low encoding/decoding complexity, by determining the length of a mother code based on the load size of a control channel, allowing for polar encoding without the need for rate matching, thereby reducing information transmission complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If Turbo code or LDPC code is used for channel encoding in 5G communications, then data transmission reliability is improved, but encoding and decoding complexity increases

Engineering Contradiction:
Improvedata transmission reliabilityVSAvoidencoding and decoding complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent changes the fundamental parameter of the encoding scheme from Turbo code or LDPC code to polar code. This parameter change enables the system to achieve comparable or superior transmission reliability while significantly reducing encoding and decoding complexity, as polar code utilizes a simpler recursive structure that can be efficiently implemented with lower computational resources

Inventive Principle:
Principle #35Parameter changes

2Area of stationary object

If Turbo code or LDPC code is used for medium and short packet transmission, then communication coverage is improved, but performance deteriorates due to limited code length

Engineering Contradiction:
Improvecommunication coverageVSAvoidtransmission performance
Core Design Contradiction:
Area of stationary objectVSReliability

Solution Approach 1:

The patent applies dynamic code length adaptation by configuring polar code with flexible code lengths that can be dynamically adjusted according to the actual transmission requirements. This enables the system to optimize performance for medium and short packets by selecting appropriate code lengths, thereby maintaining both communication coverage and transmission performance without the limitations of fixed code length structures

Inventive Principle:
Principle #15Dynamics

3Adaptability or versatility

If rate matching is performed after polar encoding to match channel load size, then transmission adaptability is improved, but encoding overhead and complexity increase

Engineering Contradiction:
Improvechannel load adaptabilityVSAvoidencoding overhead
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent performs preliminary configuration by pre-configuring the polar code length to match the channel load size before encoding begins. This preliminary action eliminates the need for subsequent rate matching operations, as the code is already sized appropriately for the transmission channel, thereby reducing encoding overhead and simplifying the overall encoding process while maintaining transmission adaptability

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3487097B1Information transmission method and sending end device
Publication Date: 2020.12.02 HUAWEI TECH CO LTD
  • EP3487097B1 patent drawingFigure 1
  • EP3487097B1 patent drawingFigure 2~3
  • EP3487097B1 patent drawingFigure 4

AI summary

Embodiments of this application provide an information transmission method, a transmit-end device, and a receive-end device. The method includes: determining a length N of a mother code of a polar code based on a load size of a first channel, where the load size of the first channel is N bits, N is 2n, and n is a positive integer; performing polar encoding on target information that needs to be transmitted, to obtain N coded bits; and transmitting the N coded bits by using the first channel. In the embodiments of this application, because a quantity of coded bits obtained after polar encoding is equal to a load size of a channel, no rate matching process is required when the N coded bits are transmitted by using the first channel. This reduces encoding overheads of a channel. In addition, because no rate matching is required, complexity and a latency of channel encoding are greatly reduced, and a performance loss brought by a rate matching operation is avoided.