NRZI and 17PP Decoder Selection for Noisy Optical Bit Streams

Solution Overview

Problem

Conventional data storage systems face inefficiencies in decoding optically stored data, particularly when using Non Return to Zero Inverted (NRZI) and 17 Parity Preserve/Prohibit (17PP) codes, which affects the reliability and speed of data retrieval.

Innovation Solution

A method and system that selectively employ NRZI and 17PP decoding techniques based on operating conditions, using combinations of decoding methods such as BCJR, Hypothesis Test, Analog XOR, and Naive methods to process coded bit streams, generating estimates of source bits with minimal errors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional decoding methods are used for NRZI and 17PP codes, then the decoding process is simpler, but the Bit Error Rate performance deteriorates in noisy conditions

Engineering Contradiction:

ImproveBit Error Rate performanceVSAvoiddecoding process complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The decoding process is divided into two separate stages: first decoding the NRZI code to recover the 17PP modulated bit stream, then decoding the 17PP code to retrieve the source information. This segmentation allows each decoder to be optimized for its specific code type, improving overall BER performance without requiring a single overly complex decoding system.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system dynamically selects between different decoding method combinations (Hypothesis Test, BCJR, Naive methods) based on operating conditions such as noise levels and data rates. This dynamic adaptation allows the system to optimize reliability for each specific operating scenario while managing complexity through selective method application.

Inventive Principle:

Principle #15Dynamics

2Reliability

If selective decoding methods are used to improve BER performance, then reliability improves, but processing time increases

Engineering Contradiction:

ImproveBER performanceVSAvoidprocessing time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The system dynamically selects between different decoding method combinations based on operating conditions such as noise levels and data rates. This dynamic adaptation allows the system to optimize reliability for each specific operating scenario while managing processing time through selective method application.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes operational parameters by selecting different decoding algorithms (Hypothesis Test, BCJR, Naive methods) and their combinations based on measured operating conditions. This parameter change enables the system to achieve optimal BER performance for each condition without always using the most computationally intensive methods.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If faster decoding is implemented to increase data transfer rates, then productivity improves, but decoding accuracy may deteriorate

Engineering Contradiction:

Improvedata transfer rateVSAvoiddecoding accuracy

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The decoding process is divided into two separate stages: first decoding the NRZI code to recover the 17PP modulated bit stream, then decoding the 17PP code to retrieve the source information. This segmentation allows each decoder to be optimized for its specific code type, improving overall BER performance without requiring a single overly complex decoding system.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system dynamically selects between different decoding method combinations (Hypothesis Test, BCJR, Naive methods) based on operating conditions such as noise levels and data rates. This dynamic adaptation allows the system to optimize reliability for each specific operating scenario while managing complexity through selective method application.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS8493246B2Methods and systems for decoding data

Publication Date: 2013.07.23 BLUE RIDGE INNOVATIONS LLC

AI summary

A method of decoding is presented. The method includes the steps of receiving a coded bit stream that is encoded using a Non Return to Zero Inverted (NRZI) code and a 17 Parity Preserve/Prohibit (17PP) code, determining a 17PP modulated bit stream based upon the coded bit stream using a first selected decoding method, and generating a plurality of decisions by processing the 17PP modulated bit stream using a second selected decoding method, wherein the received coded bit stream comprises a plurality of coded bits, and the plurality of decisions are estimates of a plurality of source bits in a source information.