Variable NCP CRC-FEC Coding for Reliable OFDM Codeword Pointers

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Solution Overview

Problem

Current communication systems face challenges in achieving low bit error rates (BER) and symbol error rates (SER) at given signal-to-noise ratios (SNR), with existing forward error correction (FEC) and error correction code (ECC) technologies not fully optimized for specific applications, limiting their performance and efficiency.

Innovation Solution

The implementation of a communication system that encodes next codeword pointers (NCPs) using a combination of FEC and cyclic redundancy check (CRC) codes, with the number of NCPs varying to adapt to different transmission conditions, and incorporates orthogonal frequency division multiplexing (OFDM) and orthogonal frequency division multiple access (OFDMA) symbols to indicate codeword beginnings, allowing for flexible encoding and decoding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional FEC or ECC coding is used, then error correction capability is provided, but performance is not optimized for specific applications and cannot achieve low BER/SER at given SNR

Engineering Contradiction:

ImproveBER/SER performanceVSAvoidapplication-specific optimization

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent implements dynamic selection of the number of NCPs (Next Codeword Pointers) based on transmission conditions and channel state. The system can adaptively adjust between 1 to 11 NCPs per OFDM symbol, allowing the error correction mechanism to dynamically optimize performance for specific applications and channel conditions rather than using a fixed coding scheme

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of NCP count from a fixed value to a variable parameter that can be adjusted between 1-11 instances. This parameter change enables the system to optimize BER/SER performance for different applications by selecting appropriate NCP counts based on channel quality, signal-to-noise ratio, and error correction requirements

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If a fixed number of NCPs is used, then encoding and decoding is simplified, but the system cannot adapt to varying transmission conditions and channel states

Engineering Contradiction:

Improveadaptation to transmission conditionsVSAvoidencoding and decoding complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The system employs dynamic NCP selection where the number of NCPs (1-11) is adjusted based on transmission conditions, channel state information, and error correction needs. This dynamic approach allows the system to adapt to varying SNR and channel quality while maintaining manageable complexity through structured encoding procedures

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent segments the error correction function into multiple NCP instances that can be independently configured. Each NCP points to a codeword and can be individually encoded/decoded, allowing the system to divide the overall error correction task into manageable segments that can be processed separately, thus controlling complexity while providing adaptability

Inventive Principle:

Principle #1Segmentation

3Reliability

If CRC and FEC are combined on variable NCPs, then error correction performance is improved, but encoding and decoding processing complexity increases

Engineering Contradiction:

Improveerror correction capabilityVSAvoidencoding and decoding processing

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges CRC (Cyclic Redundancy Check) and FEC (Forward Error Correction) coding operations into a unified encoding process applied to variable numbers of NCPs. This combination allows the system to achieve enhanced error correction capability by integrating two complementary error protection mechanisms, where CRC provides error detection and FEC provides error correction

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The combined CRC-FEC encoding is segmented and applied independently to each NCP instance (1-11 NCPs per OFDM symbol). This segmentation allows the complex combined coding operation to be broken down into manageable per-NCP processing tasks, reducing the overall processing complexity while maintaining enhanced error correction performance across multiple codewords

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS9432143B2Combining CRC and FEC on a variable number of NCPs

Publication Date: 2016.08.30 AVAGO TECHNOLOGIES INTERNATIONAL SALES PTE LTD

AI summary

A communication device is configured to communicate coded information to other communication device(s). The communication device uses NCPs to indicate locations of codewords within signal(s) transmitted to the other communication device(s). The communication device is configured to encode NCP(s) using an FEC code to generate coded NCP(s) and also to encode the NCP(s) using a cyclic redundancy check (CRC) code to generate NCP CRC bits. The communication device is also configured to encode the NCP CRC bits using the FEC code to generate coded NCP CRC bits. The communication device is then configured to generate OFDM or OFDMA symbol(s) include the coded NCP(s) and the coded NCP CRC bits to indicate beginnings of codeword(s) within at least one of the OFDM symbol(s) and/or additional OFDM symbol(s). The communication device is also configured to transmit the OFDM or OFDMA symbols to another communication device via a communication interface of the communication device.