OFDM Partial Transmission Sequences for Lower PAPR and Distortion
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Solution Overview
Problem
Existing OFDM communication systems suffer from high peak-to-average power ratio (PAPR), leading to signal distortion and reduced efficiency due to the limitations of linear amplifiers.
Innovation Solution
The method involves decomposing the OFDM signal into multiple component sub-signals, applying phase rotations, and adding canceling signals to the reference sub-signal to reduce peak power, while ensuring the signal's recoverability at the receiver through a novel coding mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If OFDM signal is transmitted through power amplifier, then communication data rate is achieved, but signal distortion occurs due to high PAPR exceeding amplifier threshold
Solution Approach 1:
The OFDM signal is segmented into multiple component sub-signals (first component signal, second component signal, third component signal). Each sub-signal is processed separately with different phase rotations, and then combined to form the transmitted signal. This segmentation allows the peak power to be reduced while maintaining the overall signal structure and data transmission capability.
Solution Approach 2:
The invention changes the phase parameters of the component sub-signals by applying different phase rotations (first phase rotation, second phase rotation, third phase rotation). By optimizing these phase parameters, the peak power of the combined OFDM signal is reduced, allowing the power amplifier to operate within its linear region and avoid signal distortion.
2Loss of energy
If peak power of OFDM signal is reduced, then linear amplifier efficiency is improved, but average signal power delivered to receiver is reduced
Solution Approach 1:
The invention dynamically adjusts the phase rotations of the component sub-signals to optimize the peak-to-average power ratio. By making the phase parameters variable rather than fixed, the system can reduce peak power while maintaining acceptable average power levels, thereby improving amplifier efficiency without excessive loss of transmitted power.
3Object-affected harmful factors
If multiple component sub-signals are combined to reduce peak power, then PAPR is reduced, but signal complexity and processing requirements increase
Solution Approach 1:
The OFDM signal is divided into a specific number of component sub-signals (three in the embodiment), which limits the complexity of the segmentation process. Each sub-signal undergoes relatively simple phase rotation processing, and the combination is straightforward addition. This controlled segmentation reduces PAPR while keeping the processing complexity manageable.
Solution Approach 2:
The phase rotation parameters are optimized to achieve effective PAPR reduction with minimal processing overhead. By carefully selecting the phase rotation values for each component sub-signal, the invention achieves good PAPR reduction performance without requiring complex optimization algorithms or extensive computational resources.
Data Source
AI summary
A method for reducing peak-to-average signal power in a transmitted orthogonal frequency division multiplexing (OFDM) signal is described.