Wireless Precoding Phase Shift Patterns for Lower PAPR
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Solution Overview
Problem
Precoding in wireless communication systems increases the peak to average power ratio (PAPR), leading to nonlinear distortion and communication errors due to the nonlinear characteristics of power amplifiers.
Innovation Solution
Implement phase shift processing on transmission data before precoding, using predefined phase shift patterns to minimize PAPR or maximize reception quality, and include an index signal to facilitate demodulation at the receiver.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If precoding is performed on transmission data, then channel equalization and stream separation are improved, but PAPR increases causing nonlinear distortion and communication errors
Solution Approach 1:
The patent applies preliminary action by performing phase shift processing on the transmission data before precoding. Specifically, phase shift patterns are applied to subcarriers in advance to control the PAPR of the signal that will subsequently undergo precoding. This preliminary phase adjustment prevents excessive PAPR from causing nonlinear distortion in the power amplifier, thereby maintaining communication reliability while enabling effective channel equalization and stream separation through precoding.
2Object-affected harmful factors
If phase shift processing is applied before precoding, then PAPR is reduced, but system complexity increases due to additional processing steps
Solution Approach 1:
The patent applies parameter changes by modifying the phase parameters of the transmission data before precoding. Instead of changing the fundamental structure or adding complex new components, the invention adjusts phase shift amounts for each subcarrier using predefined phase shift patterns. This parameter-based approach reduces PAPR effectively while keeping the additional processing complexity manageable, as it only involves phase rotation operations rather than fundamental system redesign.
Data Source
AI summary
A wireless communication method includes phase shift amount determination processing for determining a phase shift amount for each subcarrier of transmission data, modulation processing for modulating the transmission data and further shifting a phase according to the phase shift amount for each subcarrier, and precoding processing for performing precoding on the transmission data after the modulation processing. The transmission data after the precoding processing is transmitted from the transmission device to the reception device. A plurality of types of phase shift patterns prepared in advance define different phase shift amounts. The phase shift amount determination processing includes: selecting, from among the plurality of types of phase shift patterns, one that minimizes a PAPR of the transmission data after the precoding processing or one that maximizes a data reception quality in the reception device; and determining the phase shift amount for each subcarrier according to the selected phase shift pattern.