SERDES Receiver Power Reduction via Selective AEQ DFE Adaptation
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Solution Overview
Problem
SERDES receivers face significant power consumption due to continuous adaptation of analog equalizer (AEQ) and decision-feedback equalizer (DFE) processes, which can be unnecessary and degrade performance from temperature and voltage variations, necessitating a method to selectively enable and disable these processes based on parameter stability.
Innovation Solution
Implementing a process that monitors and adapts coefficients to determine if changes warrant re-enabling the AEQ and DFE adaptation loops, allowing for selective suspension during stability and power savings, with a control processor managing the adaptation and monitoring of metrics derived from coefficients to assess the need for re-adaptation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If continuous adaptation of AEQ and DFE processes is performed, then receiver performance is maintained under temperature and voltage variations, but power consumption increases significantly
Solution Approach 1:
The patent implements dynamic control of the adaptation process by continuously monitoring coefficient stability metrics and adaptively adjusting whether the AEQ and DFE adaptation loops remain active or are suspended. This dynamic approach allows the system to transition between full adaptation mode and suspended mode based on real-time channel conditions, resolving the contradiction between maintaining performance and reducing power consumption.
Solution Approach 2:
The patent employs feedback mechanisms by monitoring the stability of equalizer coefficients and using this information to control the adaptation process. The system calculates metrics based on coefficient changes and uses this feedback to determine when to suspend or resume adaptation, thereby optimizing the balance between performance maintenance and power consumption reduction.
2Use of energy by moving object
If AEQ and DFE adaptation processes are suspended to reduce power consumption, then energy efficiency improves, but receiver performance degrades due to temperature and voltage variations
Solution Approach 1:
The system dynamically adjusts the adaptation state based on monitored coefficient stability. When coefficients remain stable within threshold limits, the adaptation process is suspended to save power. When variations exceed thresholds indicating performance degradation, the system dynamically reactivates adaptation to restore performance, thus resolving the contradiction between power savings and performance maintenance.
Solution Approach 2:
The system performs self-monitoring of coefficient stability and self-regulation of the adaptation process. By automatically detecting when adaptation is unnecessary (stable coefficients) and when it is needed (unstable coefficients), the system serves itself to optimize both power consumption and performance without external intervention.
3Reliability
If full-range adaptive equalization is implemented to handle unknown and varying channel characteristics, then communication quality improves, but device complexity increases
Solution Approach 1:
The patent segments the equalization function into two distinct components: an analog equalizer (AEQ) for continuous-time frequency-dependent equalization and a decision-feedback equalizer (DFE) for discrete-time intersymbol interference cancellation. This segmentation allows each component to specialize in specific aspects of signal degradation, improving overall communication quality while managing complexity through functional division.
Solution Approach 2:
The system adapts parameters of both the AEQ (gain and coefficient) and DFE (tap values) based on monitored channel conditions. By dynamically changing these parameters in response to coefficient stability metrics, the system handles unknown and varying channel characteristics effectively, improving communication quality while avoiding unnecessary parameter adjustments that would increase complexity.
Data Source
AI summary
Described embodiments include a process and apparatus that takes into account the operating voltage and temperature (VT) variations of a SERDES receiver implemented in an integrated circuit (IC) or system-on-chip (SoC). An analog equalizer (AEQ) adaptation loop and a decision feedback equalizer (DFE) adaptation loop are disabled after the loops have converged or stabilized the parameters of the AEQ and DFE. While the AFE and DFE adaptation loops are disabled, certain monitor coefficients related to signals corrected by the AFE and DFE are adapted and metrics derived therefrom are generated. The metrics are compared to threshold values to check if they have sufficiently changed over time to warrant re-enabling of the AFE and DFE adaptation loops.