Uplink LDPC FEC Coding for Variable-Grant High-Speed PON
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Solution Overview
Problem
Existing passive optical network (PON) technologies lack a method for uplink FEC encoding, leading to inefficiencies and bandwidth waste due to incomplete FEC codewords and varying grant granularities, particularly in high-speed PONs like the 50 G PON.
Innovation Solution
Implement an LDPC coding scheme for uplink FEC encoding where the FEC codeword data and parity bits are divisible by the grant granularity, ensuring complete codewords and high code rates, and utilize a mother code matrix for encoding and decoding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If downlink FEC encoding method is used for uplink transmission, then coding continuity is maintained, but uplink transmission efficiency deteriorates due to incomplete FEC codewords and varying grant granularities
Solution Approach 1:
The patent segments the uplink transmission into complete FEC codeword units based on grant granularity. By dividing the uplink data into segments that align with the grant granularity (16 bytes, 32 bytes, or 64 bytes), the system ensures that each segment forms a complete FEC codeword, eliminating the inefficiency of incomplete codewords while maintaining coding continuity through standardized segmentation rules.
Solution Approach 2:
The patent changes the parameter of codeword alignment by adjusting the FEC codeword structure to match the grant granularity. Instead of using fixed downlink-oriented codeword lengths, the system adapts the codeword parameters (data bit length, parity bit length) to be divisible by the grant granularity, thereby optimizing uplink transmission efficiency while maintaining coding stability.
2Adaptability or versatility
If grant granularity varies with uplink rate, then bandwidth allocation flexibility is improved, but FEC codeword completeness deteriorates leading to bandwidth waste
Solution Approach 1:
The patent applies local quality by tailoring the FEC codeword parameters to match the specific grant granularity of each uplink transmission. For each grant type (16-byte, 32-byte, or 64-byte granularity), the system configures the corresponding codeword data bit length and parity bit length to ensure completeness. This localized adaptation eliminates bandwidth waste while preserving flexibility across different uplink rates.
Solution Approach 2:
The system dynamically adjusts the FEC codeword structure based on the grant granularity assigned to each uplink transmission. The codeword parameters (data bit length, parity bit length) are dynamically configured to be divisible by the current grant granularity, ensuring that the coding scheme adapts to varying bandwidth allocations without causing incomplete codewords or bandwidth waste.
3Reliability
If LDPC coding scheme is used for uplink, then error correction performance is improved, but code rate optimization is challenging due to grant granularity constraints
Solution Approach 1:
The patent optimizes the code rate by changing the LDPC codeword parameters (data bit length, parity bit length) to be divisible by the grant granularity. For each grant type, the system selects appropriate codeword parameters that maximize the code rate while ensuring completeness. This parameter optimization allows the system to achieve high code rates (e.g., 9/10 code rate) across different uplink rates without sacrificing error correction performance.
Data Source
AI summary
This application provides a method for uplink FEC encoding. On example method includes: receiving, by an optical network unit (ONU), a grant length from an optical line terminal (OLT), wherein a granularity of the grant length is 16 bytes, or 32 bytes, or 64 bytes, wherein the ONU is in a high speed passive optical network (HSP), and an uplink rate of the HSP is greater than 10 Gbit/s.