PON Equalizer ISI Compensation via ONU Training Sequence
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Solution Overview
Problem
As the line rate of passive optical networks (PON) increases, the bandwidth supported by optical components becomes insufficient, leading to intersymbol interference (ISI) and performance degradation of the optical line terminal (OLT).
Innovation Solution
A training sequence determining method where an optical network unit (ONU) determines a target training sequence based on an indication from the OLT and sends it to the OLT. The OLT then uses this training sequence to determine the working parameter of an equalizer, which compensates for channel impairment and eliminates ISI.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the line rate of PON is increased to meet bandwidth requirements, then the transmission speed is improved, but intersymbol interference occurs and performance deteriorates
Solution Approach 1:
The patent applies preliminary action by introducing a training sequence before the actual data transmission. This training sequence allows the equalizer to be pre-configured with the appropriate working parameters based on channel characteristics, enabling the system to achieve high line rates without intersymbol interference. The training sequence is sent separately to allow the OLT to determine equalizer parameters before normal communication begins.
2Productivity
If the line rate is increased from 2.5 Gbit/s to 10 Gbit/s or 50 Gbit/s, then the transmission capacity is improved, but mutual interference between adjacent code types occurs
Solution Approach 1:
The patent converts the harmful effect of intersymbol interference into a beneficial process by using the training sequence to characterize the channel and configure the equalizer. The interference problem at high line rates is addressed by having the OLT measure channel characteristics during the training phase and adjust equalizer parameters accordingly, transforming the potential harmful interference into useful channel information for performance optimization.
3Reliability
If a training sequence is introduced to eliminate ISI, then the performance is improved, but the device complexity increases
Solution Approach 1:
The patent extracts the training sequence as a separate, dedicated component from the normal data transmission process. By separating the training function from data communication, the system can implement equalization without significantly increasing overall device complexity. The training sequence is handled through existing protocol mechanisms (PLOAM messages), avoiding the need for completely new hardware architectures.
Data Source
AI summary
This application provides a training sequence determining method and a related device. The method in embodiments of this application includes: An ONU receives a first message sent by an OLT. Then, the ONU determines a target training sequence based on the first message, where the target training sequence is used to determine a working parameter of an equalizer in the OLT. Further, the ONU generates a first data frame including the target training sequence. In this application, the OLT may perform training based on the received target training sequence to determine the working parameter of the equalizer in the OLT.