Multiple-Correlator Symbol Synchronization for Low-Power Wakeup Receivers
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Low power receivers face challenges in symbol synchronization due to clock shift and power consumption issues, leading to incorrect detection of incoming signals and increased power usage.
Innovation Solution
A receiver system utilizing a set of correlators that samples at a rate greater than the symbol rate, ensuring at least one correlator receives an interleaved subset of samples synchronously, reducing the likelihood of oversampling or under sampling, and generating a wakeup command when outputs satisfy a threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the receiver synchronizes the sample rate with the symbol rate, then symbol detection accuracy is improved, but power consumption increases
Solution Approach 1:
The invention divides the correlation process into multiple parallel correlators, each processing a different phase offset of the same symbol. This segmentation allows the system to capture the complete symbol information across multiple parallel paths without requiring precise timing synchronization, thereby maintaining detection accuracy while operating in low-power mode.
Solution Approach 2:
The invention uses more correlators than the minimum required (excessive action) to ensure that at least one correlator captures the symbol correctly even without precise synchronization. This partial redundancy approach guarantees detection accuracy while avoiding the need for power-consuming synchronization mechanisms.
2Device complexity
If the receiver uses a single correlator with synchronized sampling, then device complexity is reduced, but reliability of signal detection deteriorates due to clock shift
Solution Approach 1:
The invention segments the detection function across multiple correlators with different phase offsets. This segmentation provides redundancy against timing errors and clock shifts, ensuring that at least one correlator will correctly detect the symbol even without precise synchronization, thereby improving reliability without adding complex synchronization circuitry.
Solution Approach 2:
The invention changes the parameter being optimized from timing synchronization to parallel phase sampling. Instead of adjusting timing to achieve reliable detection, the system uses multiple correlators sampling at different phases, transforming the problem from a timing-critical single-path system to a phase-diverse parallel system that is inherently more reliable.
3Use of energy by moving object
If the receiver samples at exactly the symbol rate, then power consumption is minimized, but the likelihood of oversampling or under sampling increases due to timing offset
Solution Approach 1:
The invention segments the sampling process into multiple parallel correlators that sample at the same rate but with different phase offsets. This segmentation ensures that even if timing offset causes one correlator to miss the symbol, other correlators will capture it correctly, maintaining sampling accuracy without increasing the overall sample rate and thus avoiding additional power consumption.
Solution Approach 2:
The invention uses more sampling instances than strictly necessary by employing multiple correlators in parallel. This excessive sampling action across different phases ensures that at least one sample will be accurate even with timing offset, while the overall power consumption remains minimal because each correlator operates at the base symbol rate rather than requiring a higher unified sampling rate.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Methods, systems, and devices for a wakeup receiver operation is described. A receiver may include a conversion circuit that converts an RF signal to a baseband signal, where the baseband signal comprise a set of symbols received at a symbol rate. The receiver may include an analog-to-digital converter that converts the baseband signal to samples at a sample rate greater than the symbol rate. The receiver may include a set of correlators, each correlator of the set may receive a respective subset of the samples of the baseband signal and generate a respective output. The receiver may include a compare circuit that receives the respective outputs from the set of correlators and compares the respective outputs with a threshold, where the compare circuit also generates a wakeup command based at least in part on at least one output of the respective outputs satisfying the threshold.