ONU Activation Rate Switching for Accurate 50G PON Setup
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Solution Overview
Problem
The activation process for optical network units (ONUs) in high bit rate PONs is challenged by significant errors in decoding burst-mode upstream messages due to the need for receiver equalization at the 50 G upstream rate, which is exacerbated by the lack of a priori knowledge of the required equalization parameters.
Innovation Solution
Perform the ONU activation process at a lower line rate, such as 25 G or 12.5 G, to avoid the need for receiver equalization, and then switch to the higher 50 G rate once the activation is complete.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the ONU activation process is performed at the 50 G upstream line rate, then the communication speed is high, but significant errors occur in decoding burst-mode upstream messages due to the need for receiver equalization without a priori knowledge of equalization parameters
Solution Approach 1:
The patent applies preliminary action by performing the ONU activation process at a lower line rate (12.5 G or 25 G) before switching to the higher 50 G rate. This preliminary activation at reduced speed allows the OLT to decode upstream messages accurately without requiring complex receiver equalization, thereby establishing reliable communication parameters before high-speed operation begins.
Solution Approach 2:
The patent utilizes parameter changes by dynamically adjusting the line rate during the activation process. The system transitions from a lower line rate (12.5 G or 25 G) during activation to the higher 50 G rate for normal operation. This parameter change allows the system to optimize between decoding accuracy during setup and communication speed during data transmission.
2Productivity
If receiver equalization techniques are used at the OLT's receiver to recover information from 50 G upstream messages, then the communication capacity is maximized, but the complexity of the receiver increases and significant errors may still occur without proper equalization parameters
Solution Approach 1:
The patent applies preliminary action by performing receiver training and equalization parameter acquisition at a lower line rate before high-speed communication begins. This preliminary step allows the receiver to be properly configured with the necessary equalization parameters without requiring complex real-time adaptation during the activation phase, thereby reducing receiver complexity during setup while maintaining high communication capacity during operation.
3Measurement precision
If the ONU activation is performed at a lower line rate (12.5 G or 25 G), then the accuracy of message recovery at the OLT is improved, but the activation process takes longer
Solution Approach 1:
The patent applies parameter changes by using a lower line rate (12.5 G or 25 G) specifically during the activation phase when accuracy is critical, then switching to the higher 50 G rate for normal communication. This temporary parameter change accepts increased activation time as a trade-off for ensuring accurate message recovery and proper system setup, after which the full speed capability is utilized.
Data Source
AI summary
A method and apparatus is proposed for performing the ONU activation process in a PON having a standard line rate of 50G or higher. The method and apparatus are based upon having the OLT instruct any activating ONUs to transmit at a line rate that is less than 50G, which allows for an OLT receiver without any particular equalization configuration to accurately recover the upstream burst-mode transmissions from the activating ONUs. Once the activation process is completed, the OLT may instruct the new ONUs to reset their transmitters to operate at the higher line rate of the PON. Alternatively, at the end of the activation process, the new ONUs may be configured to automatically reset their transmitters to higher line rate.