Adaptive Sample Timing for Bursty Wireless Signal Reception
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Solution Overview
Problem
Wireless receivers face challenges in accurately synchronizing with bursty signals, particularly in beam-hopping satellite systems where illumination is intermittent, leading to issues with timing re-synchronization and data demodulation errors due to uncertainty in framing grid alignment and power level detection.
Innovation Solution
A wireless receiver system that includes an adjustable sample provider, a feedback path with a loop filter, and a replacement value provider to adaptively adjust sample timing based on power level detection and known sequence analysis, allowing for accurate synchronization even during non-illumination periods by using a replacement sample timing information calculated over a longer time period.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If feedback-based sample timing adaptation is used for continuous signals, then synchronization accuracy is maintained, but timing re-synchronization fails for bursty signals during non-illumination periods
Solution Approach 1:
The system dynamically switches between two operational modes: feedback-based adaptation mode for continuous signals and replacement value mode for bursty signals. The mode selection is triggered by detecting signal presence/absence, allowing the timing adaptation mechanism to adapt its behavior according to signal characteristics, thereby resolving the contradiction between maintaining accuracy for continuous signals and handling bursty signals effectively
Solution Approach 2:
A replacement value provider acts as an intermediary mechanism that supplies pre-calculated timing information during non-illumination periods. This replacement value is computed during illumination periods when signal is present and stored for use during non-illumination periods, bridging the gap between feedback-based adaptation and bursty signal requirements
2Use of energy by moving object
If timing loop is frozen during non-illumination periods for bursty signals, then power consumption is reduced, but timing accuracy drifts over time
Solution Approach 1:
The system performs preliminary calculation of replacement timing values during illumination periods when the signal is present and the timing loop is active. These pre-calculated replacement values are stored and used during non-illumination periods, eliminating the need to keep the timing loop active and frozen, thus reducing power consumption while maintaining timing accuracy through the use of pre-computed values
3Speed
If loop filter processes timing error over short time period, then response speed is fast, but accuracy is insufficient for bursty signals
Solution Approach 1:
The timing adaptation process is segmented into two distinct phases: a fast response phase using loop filter for continuous signals with short time periods, and an accurate measurement phase using replacement value provider for bursty signals with longer time periods. Each segment is optimized for its specific requirement, resolving the contradiction between response speed and measurement precision
Data Source
AI summary
Receivers, controller units for receivers and related methods are provided. One receiver includes an adjustable sample provider providing samples of an input signal using an adjustable sample timing and a feedback path providing a feedback signal to the adjustable sample provider based on a timing error. The feedback path includes a loop filter providing sample timing information to the adjustable sample provider and a replacement value provider providing a replacement sample timing information replacing the sample timing information when an input signal does not fulfil a predetermined requirement for a feedback-based sample timing adaptation. The replacement value provider provides the replacement sample timing information considering a timing error information over a longer time period when compared to a time period considered by the loop filter for a provision of the sample timing information.