Adaptive Clipping Ratio for OFDM Energy Efficiency
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Solution Overview
Problem
Current communication devices using OFDM technology face reduced power efficiency due to high peak to average power ratio (PAPR) and increased pilot overhead, especially with high dimensional modulation schemes like 16 QAM or 64 QAM, leading to inter symbol interference and decreased link performance.
Innovation Solution
Adaptive determination of a clipping ratio (CR) based on the modulation method, power of the input signal, and signal to interference plus noise ratio (SINR), with inverse fast Fourier transform (IFFT) and clipping of the input signal to optimize energy efficiency, and optionally applying single carrier-frequency division multiple access (SC-FDMA) or skipping clipping in certain conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If OFDM scheme is used for high speed transmission, then data transmission rate is improved, but peak to average power ratio increases reducing power amplifier efficiency
Solution Approach 1:
The patent applies dynamic clipping ratio adjustment based on signal conditions. The clipping ratio is adaptively determined according to the instantaneous peak to average power ratio and modulation scheme, allowing the system to dynamically optimize the balance between PAPR reduction and signal quality, thereby improving power amplifier efficiency while maintaining high data transmission rates
Solution Approach 2:
The patent changes the clipping ratio parameter adaptively based on signal characteristics and modulation schemes. By adjusting this parameter dynamically, the system optimizes the trade-off between PAPR reduction (for power amplifier efficiency) and signal distortion (for transmission quality), resolving the contradiction between high-speed transmission and energy efficiency
2Loss of energy
If DFT-S-OFDM or SC-FDMA is used to reduce PAPR, then power amplifier efficiency is improved, but pilot overhead increases and link performance deteriorates
Solution Approach 1:
The patent applies local quality by selectively applying clipping only to specific signal portions or subcarriers based on their individual characteristics. Instead of uniformly processing all signals, the system identifies and clips only those signal components that exceed the clipping threshold, thereby reducing pilot overhead and maintaining link performance while still improving power amplifier efficiency
Solution Approach 2:
The patent applies partial action by using selective clipping rather than complete signal processing. The clipping operation is applied only when and where necessary (when signal peaks exceed thresholds), avoiding unnecessary processing of normal signal portions, thus reducing overhead while maintaining reliability
3Productivity
If higher dimensional modulation such as 16 QAM or 64 QAM is used, then data transmission capacity is improved, but pilot overhead increases and link performance is reduced
Solution Approach 1:
The patent dynamically adjusts the clipping ratio based on the modulation scheme being used. For higher dimensional modulations like 16 QAM and 64 QAM, the system adapts the clipping threshold and ratio to preserve the finer signal distinctions required by these schemes, thereby maintaining link performance and reliability while still achieving PAPR reduction and high data transmission capacity
Data Source
AI summary
Provided is a method and device for increasing energy efficiency by adaptively performing clipping with respect to an input signal. The method may adaptively determine a clipping ratio (CR) based on a modulation method of the communication device and perform clipping based on the determined CR.