Polynomial Phase Frequency Rotation Mask for OFDM PAPR Control
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Solution Overview
Problem
Existing OFDM systems face challenges with high Peak to Average Power Ratio (PAPR) and sub-carrier attenuation due to windowing functions, leading to significant attenuation of OFDM sub-carriers and increased complexity in transmitter components.
Innovation Solution
The implementation of a frequency rotation mask based on a polynomial phase, combined with a time domain window, to mitigate out-of-band radiation and control PAPR, ensuring maximum sub-carrier to sub-carrier power deviation is within +/â5 dB for any arbitrary data pattern.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If windowing functions are applied to mitigate out-of-band radiation, then spectral containment is improved, but sub-carrier attenuation increases and PAPR control becomes more difficult
Solution Approach 1:
The frequency rotation mask is applied to the OFDM signal before windowing in the time domain. This preliminary action modifies the signal characteristics in advance, ensuring that when windowing is subsequently applied for spectral containment, the sub-carrier attenuation is minimized and PAPR is controlled within acceptable limits.
2Object-generated harmful factors
If windowing functions are applied to improve spectral containment, then out-of-band radiation is reduced, but transmitter component complexity increases
Solution Approach 1:
The frequency rotation mask applies phase rotation to sub-carriers based on polynomial phase parameters. By adjusting these parameters, the system achieves effective PAPR control and mitigates sub-carrier attenuation while maintaining spectral containment through subsequent windowing, thereby managing transmitter complexity through parameter optimization rather than structural complexity.
3Reliability
If frequency rotation mask based on polynomial phase is applied, then PAPR is controlled and sub-carrier attenuation is reduced, but computational complexity increases
Solution Approach 1:
The patent replaces complex iterative PAPR reduction algorithms with a direct frequency rotation mask application based on polynomial phase. This substitution transforms a computationally intensive iterative process into a simpler, closed-form solution that achieves comparable PAPR control with reduced computational complexity.
Data Source
AI summary
In one aspect, a method includes performing a mapping on bits to form a complex data symbol, applying a frequency rotation mask to the complex data symbol based on a polynomial phase, performing an inverse discrete Fourier transform (IDFT) after applying the frequency rotation mask, applying a time domain window after performing the IDFT, converting digital data to analog data after applying the time window and transmitting the analog data as an analog signal.