Optical Receiver Noise Cancellation for Management Data
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Solution Overview
Problem
Existing optical transmission systems face challenges in transmitting management data with improved performance due to increased latency and bandwidth requirements when management data frames are inserted in the data channel, and limitations in data speed when management data is sent over a separate channel, particularly due to noise interference from NRZ encoded data.
Innovation Solution
A method where the noise introduced by the NRZ data signal is filtered out by subtracting the recovered NRZ bit sequence from the received bit sequence, allowing for a higher data rate on the management data channel by reducing noise interference, and implementing low-pass filtering and amplification to facilitate this process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If management data frames are inserted in the data channel, then management data can be transmitted, but latency is introduced and data on the data channel is delayed
Solution Approach 1:
The patent combines the management data channel and traffic data channel into a single optical fiber channel. Management data is superimposed on the traffic data signal using pulse width modulation, allowing both types of data to be transmitted simultaneously over the same physical medium without requiring separate channels, thereby eliminating the latency associated with frame insertion while avoiding the cost of additional separate channels.
Solution Approach 2:
The management data signal is nested within the traffic data signal by superimposing it using pulse width modulation. The management data modulates the pulse width of the traffic data signal, effectively hiding the management channel within the traffic channel structure, allowing concurrent transmission without additional bandwidth or significant latency.
2Reliability
If management channel is sent over a separate channel, then management data can be transmitted, but there is a cost for that separate channel
Solution Approach 1:
The patent merges the management data channel and traffic data channel into a single optical fiber channel. By superimposing the management data on the traffic data signal using pulse width modulation, the system transmits both types of data simultaneously over the same physical medium, eliminating the need for separate channels and reducing bandwidth consumption.
Solution Approach 2:
The single optical fiber channel serves dual purposes: transmitting both traffic data and management data simultaneously. The pulse width modulation technique allows the same physical channel to carry multiple types of information, making the channel universal and eliminating the need for dedicated separate channels for management data.
3Productivity
If information data is superimposed on the data channel by pulse width modulation, then management data can be transmitted on the same channel, but the noise introduced by the traffic on the data channel limits the data speed to only a few kbit/s
Solution Approach 1:
The patent extracts the NRZ-encoded traffic data signal from the superimposed composite signal and removes it before detecting the management data. By recovering and subtracting the traffic data component, the system eliminates the dominant noise source, allowing the management data to be detected with much higher accuracy and at significantly higher data rates than would be possible with the noise present.
Solution Approach 2:
The patent converts the harmful noise effect of the NRZ traffic data into a beneficial process. By deliberately recovering the NRZ signal and using it for cancellation, the system transforms the noise source into a tool for noise reduction. The same traffic data signal that creates noise when superimposed is used to cancel that noise, enabling high-rate management data transmission.
4Productivity
If the bandwidth of the low pass filter in the receiver is increased to allow higher data rate, then more noise from NRZ data passes through
Solution Approach 1:
The patent extracts and removes the NRZ traffic data signal from the composite signal before low-pass filtering and management data detection. By eliminating the NRZ component beforehand, the system can use a wider bandwidth filter without allowing excessive noise to pass through, since the dominant noise source has already been removed. This enables higher management data rates with controlled noise levels.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables simultaneous transmission of management data with traffic data without additional bandwidth, achieving a high enough data rate to meet transmission needs while maintaining low Bit Error Rates, ensuring reliable data recovery.
Implementation Method 1
The recovered NRZ bit sequence is added in anti-phase to the received bit sequence. Stated differently the recovered NRZ bit sequence is subtracted from the received bit sequence. This operation will to a large extent cancel the noise introduced by the transmitted data signal.
Implementation Method 2
To facilitate the subtraction of the recovered NRZ bit sequence from the received bit sequence, the received bit sequence and the recovered NRZ bit sequence can in an advantageous implementation be low-pass filtered before the sequences are added.
Data Source
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AI summary
Described are, among other things, a method and a receiver for receiving a management data signal in an optical transmission system where a traffic data signal is transmitted as a NRZ modulated signal. The traffic data signal has a management data signal superimposed thereon as a pulse width modulation of the symbols of the NRZ modulated signal. The NRZ modulated signal is received with the data signal superimposed thereon and the traffic data signal is recovered. The recovered traffic data signal in anti-phase is added to the received signal. The management data signal is detected from the added signals.