Selective Transform-precoding for PAPR Reduction in Wireless Networks
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Solution Overview
Problem
Wireless communication systems at higher frequency bands face challenges such as high Phase Noise, extreme propagation loss, high atmospheric absorption, and inefficient power amplifier utilization due to high Peak to Average Power Ratio (PAPR) in CP-OFDM waveforms, leading to increased costs and reduced performance.
Innovation Solution
A method involving transform-precoding of modulation symbols using techniques like Discrete Fourier Transformation (DFT), Symplectic Finite Fourier Transform (SFFT), and Inverse Discrete Fourier Transformation (IDFT) to reduce PAPR and interference, allowing for efficient power amplifier utilization and improved waveform performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If transform-precoding is applied to all modulation symbols, then PAPR is reduced and power amplifier efficiency is improved, but interference increases and performance deteriorates
Solution Approach 1:
The patent applies transform-precoding selectively to specific modulation symbols based on predefined criteria rather than uniformly to all symbols. This local application approach optimizes power amplifier efficiency for selected symbols while preserving signal performance for others, thereby resolving the contradiction between energy efficiency and reliability.
Solution Approach 2:
Instead of applying transform-precoding to all modulation symbols (excessive action), the patent applies it only to a selective subset of symbols (partial action) that meet specific criteria. This partial application reduces unnecessary interference while still achieving PAPR reduction and power amplifier efficiency improvement for the critical symbols.
2Loss of energy
If transform-precoding is used to convert multiple signals into single carrier waveform, then PAPR is reduced, but interference increases compared to CP-OFDM
Solution Approach 1:
The patent applies transform-precoding selectively to specific modulation symbols rather than uniformly to all symbols. This localized application reduces PAPR for selected symbols while minimizing the generation of interference, thereby resolving the contradiction between PAPR reduction and interference mitigation.
3Speed
If higher frequency bands are used for wireless communication, then data transmission capability is improved, but propagation loss and atmospheric absorption increase
Solution Approach 1:
The patent changes the waveform parameter (PAPR) by applying transform-precoding selectively to modulation symbols. This parameter change improves power amplifier efficiency, which compensates for the higher propagation loss and atmospheric absorption inherent in higher frequency bands, thereby maintaining effective data transmission capability.
4Power
If signal with high PAPR is transmitted, then power utilization is increased, but power amplifier cost increases exponentially
Solution Approach 1:
The patent changes the PAPR parameter of the signal by selectively applying transform-precoding to modulation symbols. This parameter change enables the power amplifier to operate closer to its saturation region, improving power utilization while reducing the exponential cost increase associated with high-PAPR signals.
Data Source
AI summary
A system (102) and method (200) of processing a bit stream for transmission over a wireless communication network (100) is described. The method comprises mapping, by a transmitting node (102), a bit stream to obtain at least one modulation symbol. A set of modulation symbols may be selected from the at least one modulation symbol based on one or more predefined precoding criteria, for enabling transform-precoding of the set of modulation symbols. The transform-precoding of the set of modulation symbols may be performed to obtain precoded symbols.