DM-RS Initialization Mapping Across CDM Groups to Lower PAPR
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Solution Overview
Problem
High Peak-to-Average Power Ratio (PAPR) in wireless communication signals leads to clipping and out-of-band spurious emissions, degrading system performance and increasing the cost and complexity of power amplifiers.
Innovation Solution
The method involves generating DM-RS sequences with different initialization values for each Code Division Multiplexing (CDM) group based on cell IDs and scrambling code IDs, toggling these values using the nSCID parameter in DCI, to reduce PAPR and maintain signal quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If signal waveforms with high PAPR are used, then the dynamic range of the signal is increased, but severe clipping occurs at the power amplifier output and in-band signal distortion increases
Solution Approach 1:
The patent applies parameter changes by modifying the initialization values used to generate DM-RS sequences. By using different initialization values for different CDM groups based on the nSCID parameter, the signal waveform characteristics are changed to achieve lower PAPR while maintaining signal quality and dynamic range requirements.
2Power
If power amplifiers are designed to handle high PAPR signals, then the maximum output transmit power can be maintained, but the cost and complexity of the power amplifier increases
Solution Approach 1:
The patent converts the harmful effect of high PAPR by using different initialization values for DM-RS sequences. This transforms the signal characteristics to have lower PAPR, thereby eliminating the need for complex high-linearity power amplifiers while maintaining the ability to transmit at maximum output power.
3Ease of operation
If the same initialization value is used for all CDM groups, then the implementation is simplified, but the PAPR reduction effectiveness is compromised
Solution Approach 1:
The patent applies segmentation by dividing the CDM groups into different categories based on the nSCID parameter. Different initialization values are assigned to different CDM groups (e.g., CDM groups 0 and 1 use one initialization value, while CDM groups 2 and 3 use another), which enables PAPR reduction while keeping the implementation structure relatively simple through systematic assignment.
Data Source
AI summary
A user equipment (UE) is configured to enhance Demodulation Reference Signals (DM-RS) in order to reduce the Peak-to-Average Power Ratio (PAPR) to the same level as for data symbols. To accomplish this function, the UE obtains a first initialization value that is calculated based on one of a first parameter (e.g., cell ID) and a second parameter and a scrambling code ID. The UE then maps the first initialization value to either a first Code Division Multiplexing (CDM) group or a second CDM group based on the scrambling code ID. The mapping associates the first initialization value with the first or second CDM group such that the initialization value is used when generating a demodulation sequence for that CDM group.