Optimized SOD Sequences for PON Synchronization
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Solution Overview
Problem
Conventional data synchronization techniques in Passive Optical Networks (PONs) are inadequate due to high bit error probabilities in Start of Data (SOD) delimiters, leading to false locking and synchronization issues, which are not effectively addressed by existing methods.
Innovation Solution
The implementation of optimized SOD sequences with a Hamming distance of 32 between the SOD delimiter and False Synchronization Candidates, reducing the false locking probability and improving synchronization reliability by using a SOD correlation circuit with a Hamming distance module and synchronization decision module.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional SOD delimiters are used in PON systems, then the system structure remains simple, but the bit error probability increases leading to false locking and synchronization failures
Solution Approach 1:
The patent changes the parameter of the SOD delimiter sequence by introducing optimized sequences with specific Hamming distances (32, 48, or 64) between the SOD delimiter and false synchronization candidates. This parameter change increases the minimum Hamming distance, thereby reducing the bit error probability and preventing false locking while maintaining synchronization reliability.
Solution Approach 2:
The patent introduces a Hamming distance module as an intermediary component in the synchronization circuit. This module calculates the Hamming distance between the received SOD delimiter and the stored optimized sequence, and uses this distance information to make synchronization decisions. The intermediary helps distinguish between valid and false synchronization candidates, reducing false locking without requiring complete redesign of the synchronization architecture.
2Reliability
If the Hamming distance between SOD delimiter and false synchronization candidates is increased, then false locking probability decreases, but the synchronization decision process becomes more complex
Solution Approach 1:
The patent optimizes the Hamming distance parameter to specific values (32, 48, or 64) which provide sufficient separation between valid and false synchronization candidates. By carefully selecting these parameter values, the system achieves strong false locking resistance while keeping the synchronization decision process manageable through standardized comparison procedures.
Solution Approach 2:
The patent implements a feedback mechanism where the Hamming distance calculation result is fed back to the synchronization decision module. Based on the calculated Hamming distance, the system can confirm valid synchronization or reject false locking attempts, allowing for adaptive and reliable synchronization decisions without requiring overly complex processing.
3Measurement precision
If optimized SOD sequences with higher Hamming distance are implemented, then synchronization accuracy improves, but the implementation cost increases
Solution Approach 1:
The patent provides multiple optimized SOD delimiter sequences with different Hamming distances (32, 48, or 64), allowing system implementers to select the appropriate sequence based on their specific requirements and constraints. This flexibility enables achieving high synchronization accuracy while controlling implementation costs by choosing the minimum necessary Hamming distance for the given application scenario.
Solution Approach 2:
The patent uses standardized optimized SOD delimiter sequences that can be copied and implemented across different PON systems. The sequences are designed to be easily stored and processed by standard synchronization circuits, reducing the complexity and cost of implementation while maintaining high synchronization accuracy through the use of pre-optimized patterns.
Data Source
AI summary
System and method for data synchronization in Passive Optical Networks. According to an embodiment, the present invention provides a method for providing upstream data synchronization in an optical communication network. The method includes sending data from an Optical Network Unit. The data includes a first data frame, which includes a header sequence, a synchronization segment, and a data segment. The synchronization segment includes 66 bits, which includes a first number of bits having nonzero values and a second number of bits having a value of zero. The first number is different from the second number. The method further includes receiving at least the first data frame by an Optical Line Terminal. The method also includes processing the first data frame. The method additionally includes selecting a first segment of the first data frame, the first segment including 66 bits.