Multicarrier Signal Clipping for WCDMA IPDL Compliance
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Solution Overview
Problem
Existing multicarrier clipping technologies fail to meet the power demands of the Idle Period in DownLink (IPDL) time template in WCDMA systems, leading to subcarrier signal leakage and impaired location functionality in base stations.
Innovation Solution
A device and method for detecting the start of IPDL in each subcarrier and dynamically selecting appropriate clipping filter coefficients to manage power levels, ensuring compliance with the IPDL time template without compromising multicarrier clipping performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If multicarrier clipping technology is applied to reduce peak-to-average ratio, then power amplifier efficiency is improved and cost is reduced, but the IPDL power requirements cannot be met causing subcarrier signal leakage
Solution Approach 1:
The patent implements dynamic filter coefficient selection that adapts to different signal conditions. The system switches between different clipping filter coefficients based on whether IPDL is detected in each subcarrier, enabling the clipping function to dynamically adjust its behavior to meet both power efficiency and IPDL compliance requirements
Solution Approach 2:
The patent applies different clipping filter coefficients to different subcarriers based on their individual IPDL status. Each subcarrier can have its own optimized clipping parameters, allowing aggressive clipping where IPDL is not present (for power efficiency) while maintaining strict control where IPDL is detected (for compliance)
2Loss of energy
If clipping filter coefficients are optimized for multicarrier clipping performance, then peak-to-average ratio reduction is improved, but IPDL power limits are exceeded
Solution Approach 1:
The patent changes the filter coefficient parameters based on IPDL detection results. When IPDL is detected in a subcarrier, different (more restrictive) coefficients are applied compared to when IPDL is not present, allowing the system to optimize peak-to-average ratio reduction while preventing subcarrier signal leakage
3Loss of energy
If aggressive clipping is applied to reduce peak power, then power amplifier efficiency increases, but location functionality is impaired due to signal leakage
Solution Approach 1:
The patent applies different clipping strategies to different subcarriers based on their IPDL status. Subcarriers with IPDL use conservative clipping to prevent leakage that would impair location functionality, while subcarriers without IPDL use aggressive clipping for power efficiency, thus preserving location accuracy where needed
Data Source
AI summary
A device and a method for clipping multicarrier signal are provided. The method for clipping multicarrier signal includes: detecting whether an Idle Period in DownLink (IPDL) starts in each subcarrier forming a multicarrier joint signal and generating an IPDL flag just when the IPDL starts in a subcarrier; detecting power of each subcarrier to get a detection result; selecting a clipping filter coefficient according to the IPDL flag and the detection result; performing a clipping processing of the received multicarrier joint signal according to the clipping filter coefficient and outputting the multicarrier joint signal after the clipping processing. Embodiments of the present invention meet demands of an IPDL time template and effectively support an IPDL mechanism in a Wideband Code Division Multiple Access (WCDMA) system on the premise of no multicarrier signal clipping performance is affected.