UE Synchronization Signal Acquisition Using Cumulative Correlation
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Solution Overview
Problem
Wireless user equipment (UE) experiences excessive power consumption and computational delays due to highly overlapped and complex correlations during system timing detection, which is inefficient in multiple access wireless communication systems.
Innovation Solution
The UE employs a multi-step process with reduced computational complexity by using synchronization signals composed of short, repeated sequences, performing cumulative correlations over non-overlapping intervals, and shifting phase offsets to determine timing structure boundaries, thereby reducing the need for sample-level alignments and simplifying the correlation process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the UE performs correlation at each possible sample period to detect synchronization signals, then the detection accuracy is improved, but the power consumption and computational complexity increase excessively
Solution Approach 1:
The patent segments the continuous correlation process into discrete steps: first performing correlation only at candidate timing positions identified from sequence repetitions, then refining the search around these candidates. This segmentation avoids exhaustive correlation at every sample period while maintaining detection accuracy, thereby reducing power consumption.
Solution Approach 2:
The patent performs preliminary correlation on the repeated sequences within the synchronization signal to identify candidate timing positions before performing the final correlation. This preliminary action narrows down the search space, allowing the UE to avoid exhaustive correlation at all possible sample periods while ensuring accurate synchronization detection.
2Measurement precision
If the UE performs correlation at each possible sample period to detect synchronization signals, then the detection accuracy is improved, but the computational delay increases
Solution Approach 1:
The patent segments the correlation process into two phases: initial correlation at candidate positions derived from sequence repetitions, followed by refined correlation only around promising candidates. This segmentation dramatically reduces the number of correlation operations required, thereby reducing computational delay while preserving detection accuracy.
Solution Approach 2:
The patent performs preliminary identification of candidate timing positions by exploiting the periodic structure of repeated sequences before performing the computationally intensive correlation. This preliminary action eliminates the need for exhaustive correlation at every sample period, significantly reducing computational delay while maintaining accurate synchronization detection.
3Loss of information
If the synchronization signal uses long non-repeated sequences, then the correlation provides comprehensive timing information, but the computational complexity and power consumption increase
Solution Approach 1:
The patent segments the synchronization signal into multiple repeated shorter sequences rather than using a single long non-repeated sequence. This segmentation allows the UE to perform correlation on individual repetitions to identify candidate timing positions, then refine the search around these candidates, reducing overall computational complexity while maintaining complete timing information.
Solution Approach 2:
The patent exploits the periodic structure of repeated sequences in the synchronization signal. By performing correlation on these periodic repetitions, the UE can identify candidate timing positions and then refine the search around these candidates, reducing computational complexity while preserving complete timing information that would otherwise require a long non-repeated sequence.
Data Source
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AI summary
Methods, systems, and devices for wireless communication are described. A user equipment (UE) may identify a set of non-overlapping periodic intervals for monitoring a synchronization signal, which may be composed of or may include a repeated sequence; and the UE may identify possible timing structure (e.g., subframe, slot, etc.) boundaries using the intervals. The UE may then determine that one of the possible boundaries is a boundary using a second synchronization signal. For instance, the UE may perform a cumulative correlation during each of a series of correlation periods corresponding to the periodic intervals. Each of the cumulative correlations may contain multiple coherent correlations associated with the sequence repetitions. From the cumulative correlations, the UE may identify possible boundaries. The UE may perform a secondary correlation based on a second synchronization signal for each possible boundary in order to determine the system timing.