OFDM Subcarrier Phase Rotation for PAPR Reduction
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Solution Overview
Problem
The prior-art method for reducing Peak-to-Average Power Ratio (PAPR) in OFDM systems wastes resources and decreases throughput by requiring a dedicated data subcarrier to transmit phase rotation signals.
Innovation Solution
In the OFDM-based data transmission method, the original signals on subcarriers in each subblock are multiplied by a corresponding phase rotation signal, allowing the receiving device to obtain the phase rotation signal from pilot subcarriers, eliminating the need for a dedicated data subcarrier and ensuring each subblock includes a pilot subcarrier for phase rotation signal retrieval.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dedicated data subcarrier is used to transmit phase rotation signals, then the phase rotation information can be reliably transmitted, but resources are wasted and throughput decreases
Solution Approach 1:
The patent makes pilot subcarriers serve dual functions: both channel estimation and phase rotation signal transmission. By embedding phase rotation information in the phase of pilot subcarriers, the system eliminates dedicated phase rotation subcarriers while maintaining reliable phase information transmission, thus improving throughput without sacrificing reliability
Solution Approach 2:
The patent combines the channel estimation function and phase rotation signal transmission function into a single pilot subcarrier resource. Instead of using separate subcarriers for these functions, the invention merges them by modulating phase rotation information onto the existing pilot subcarriers, thereby reducing resource consumption and increasing throughput
2Stability of the object's composition
If multiple subcarriers with identical or similar phases overlap, then the OFDM symbol structure is maintained, but a large PAPR is generated
Solution Approach 1:
The patent divides the OFDM symbol's subcarriers into multiple subblocks and applies different phase rotation signals to each subblock. This segmentation prevents excessive phase alignment across all subcarriers, thereby reducing the peak power while maintaining the overall OFDM symbol structure and enabling better amplifier operation
Data Source
Figure 1
Figure 2~3
AI summary
Embodiments of the present invention provide an OFDM-based data transmission method and an apparatus. The method includes: generating, by a transmitting device, a data packet, and sending the data packet, where the data packet includes at least one OFDM symbol, where the OFDM symbol includes N sequentially numbered subcarriers, the N subcarriers are divided into L subblocks, each subblock includes └N/L┘ subcarriers, the N/L subcarriers in each subblock include M pilot subcarriers, and signals carried on all subcarriers in each subblock are signals obtained by multiplying original signals by a corresponding phase rotation signal. In this way, there is no need to carry the phase rotation signal on a dedicated data subcarrier, and resources are greatly saved. In addition, this division method ensures that each subblock includes a pilot subcarrier, and further ensures that a receiving device can obtain, according to signals carried on the pilot subcarrier in each subblock, the phase rotation signal corresponding to each subblock.