Communication Receiver Group Delay Compensation
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Solution Overview
Problem
Current group delay compensation techniques in communication systems, such as optical communication systems, face high computational complexity and low compensation performance, often introducing artefacts during chromatic dispersion compensation.
Innovation Solution
The method involves transforming a communication signal into frequency sub-band signals, where each sub-band is separately compensated using a first delayer for group delay and a second delayer for excess group delay, employing finite impulse response (FIR) filters and interpolation filters to efficiently address phase responses, with the group delay values and excess group delay values derived from a smoothing function.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If common compensation techniques are used to compensate for chromatic dispersion, then compensation can be achieved, but computational complexity increases and compensation performance decreases with artefacts introduced
Solution Approach 1:
The communication signal is transformed into multiple frequency sub-band signals, and each sub-band is compensated separately using dedicated delayers. This segmentation allows parallel processing of different frequency components, reducing overall computational complexity while improving compensation accuracy by addressing specific group delay characteristics of each sub-band independently
Solution Approach 2:
The patent changes the approach from applying a single global compensation parameter to using multiple sub-band specific parameters (group delay values and excess group delay values). By deriving these parameters from a smoothing function and applying them selectively to different frequency sub-bands, the system achieves better compensation performance without proportionally increasing computational complexity
2Reliability
If group delay compensation is applied to compensate for chromatic dispersion, then compensation performance improves, but artefacts are introduced during compensation
Solution Approach 1:
Different compensation parameters are applied to different frequency sub-bands based on their local group delay characteristics. The group delay values and excess group delay values are derived specifically for each sub-band using a smoothing function, ensuring that compensation is tailored to local signal characteristics rather than applying a uniform approach that introduces artefacts
Solution Approach 2:
A smoothing function is introduced as an intermediary to derive the group delay values and excess group delay values from the phase response. This smoothing operation prevents abrupt changes in compensation parameters that would otherwise introduce artefacts, while still maintaining accurate compensation of the underlying group delay variations
Data Source
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AI summary
The invention relates to a communication receiver (100) for compensating a group delay of a communication signal, the group delay being indicated by a plurality of group delay values being associated to different frequency sub-bands of the communication signal, the plurality of group delay values forming a group delay function, the communication receiver (100) comprising a transformer (101) being configured to transform the communication signal into a plurality of frequency sub-band communication signals, a processor (103) being configured to convolute the group delay function by a smoothing function to obtain a plurality of excess group delay values, a plurality of first delayers (105) for delaying the plurality of frequency sub-band communication signals upon the basis of the plurality of group delay values to obtain a first plurality of delayed frequency sub-band communication signals, wherein a first delayer (107) of the plurality of first delayers (105) is configured to delay a frequency sub- band communication signal upon the basis of a group delay value associated with the frequency sub-band communication signal, a plurality of second delayers (109) for delaying the first plurality of delayed frequency sub-band communication signals upon the basis of the plurality of excess group delay values to obtain a second plurality of delayed frequency sub- band communication signals, wherein a second delayer (111) of the plurality of second delayers (109) is configured to delay a delayed frequency sub-band communication signal of the first plurality of delayed frequency sub-band communication signals upon the basis of an excess group delay value associated with the delayed frequency sub-band communication signal of the first plurality of delayed frequency sub-band communication signals, and an inverse transformer (113) being configured to inversely transform the second plurality of delayed frequency sub-band communication signals for compensating the group delay of the communication signal.