Cyclic Prefix Length Detection via Reference Signal Scrambling
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Solution Overview
Problem
In wireless communication systems, particularly in E-UTRAN, cyclic prefix length detection is prone to errors due to timing issues with neighboring cells, leading to incorrect detection of cyclic prefix lengths, which affects the reliability of reference signal correlation and verification.
Innovation Solution
The solution involves explicit or implicit signaling of cyclic prefix length through DL RS sequences and mappings, dependent on the CP length, using modifications such as CP length indicators, scrambling initialization, and frequency shifts to differentiate between normal and extended CP lengths, thereby simplifying and enhancing the accuracy of CP length verification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If cyclic prefix length detection is performed using reference signal correlation in E-UTRAN, then the system can support both normal and extended CP lengths, but timing issues with neighboring cells cause detection errors and reduce reliability
Solution Approach 1:
The patent uses cell-specific reference signals as an intermediary to convey cyclic prefix length information. The CRS are scrambled with a sequence that depends on the CP length, allowing the UE to detect CP length by correlating with hypothesized CRS sequences. This intermediary approach resolves the contradiction by enabling reliable CP length detection despite timing issues with neighboring cells.
Solution Approach 2:
The patent changes the scrambling parameter of the reference signal based on the cyclic prefix length. By modifying the scrambling sequence initialization to include CP length information, the system can differentiate between normal and extended CP lengths. This parameter change allows reliable detection while maintaining support for different CP configurations.
2Measurement precision
If explicit signaling of cyclic prefix length is implemented through reference signal sequences, then detection accuracy is improved, but system complexity increases due to additional signaling requirements
Solution Approach 1:
The patent merges the cyclic prefix length indication with the existing reference signal transmission. Instead of adding separate signaling channels, the CP length information is embedded in the scrambling of the CRS that are already being transmitted for channel estimation and other purposes. This merging approach improves detection accuracy without significantly increasing system complexity.
Solution Approach 2:
The reference signal serves multiple functions: channel estimation, channel quality indication, and cyclic prefix length detection. By making the CRS universal and using them for multiple purposes including CP length indication, the system avoids adding dedicated signaling structures while improving measurement precision.
Data Source
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AI summary
In one exemplary embodiment, a method includes: inserting an indication of a cyclic prefix length into a transmission; and sending the transmission. In another exemplary embodiment, a method includes: receiving a transmission; and processing the received transmission to obtain an indication of a cyclic prefix length.