Wireless Transmitter DFT Precoder PAPR Reduction
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Solution Overview
Problem
Existing wireless transmission technologies face challenges in achieving low peak-to-average-power ratio (PAPR) for efficient power consumption, especially in uplink transmissions, which often require expensive power amplifiers due to large power amplifier backoff, and struggle with wider bandwidth and higher spectral efficiency.
Innovation Solution
A wireless transmitter is designed with multiple coding and modulation modules applying corresponding algorithms, utilizing a single discrete Fourier transform (DFT) precoder and inverse fast Fourier transform (IFFT) module to process information blocks, mapping DFT outputs as clusters of contiguous subcarriers for improved PAPR and cubic metric, enabling efficient power amplification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional wireless transmission processing is used, then device complexity is reduced, but peak-to-average-power ratio increases causing power amplifier inefficiency
Solution Approach 1:
The transmitter divides the information block into multiple segments and applies different coding and modulation algorithms to each segment. This segmentation allows for lower peak power requirements in each segment, reducing the peak-to-average-power ratio and improving power amplifier efficiency, while the modular structure manages complexity systematically
Solution Approach 2:
The system changes coding and modulation parameters dynamically across different segments of the information block. By varying these parameters, the transmission can operate at lower peak power levels while maintaining data integrity, thereby improving power amplifier efficiency without excessive complexity increase
2Power
If power amplifier backoff is increased to reduce peak power, then peak-to-average-power ratio decreases, but power amplifier efficiency worsens
Solution Approach 1:
By segmenting the information block and applying different coding/modulation schemes to each segment, the peak power requirement is reduced. This allows the power amplifier to operate closer to its peak capability without excessive backoff, improving efficiency by reducing the gap between peak and average operating points
Solution Approach 2:
The system employs periodic variations in coding and modulation across segments, creating a more uniform power distribution over time. This periodic structure reduces peak power demands while maintaining average power efficiency, minimizing energy loss in the power amplifier
3Productivity
If wider bandwidth and higher-order MIMO are implemented, then spectral efficiency improves, but device complexity and processing requirements increase
Solution Approach 1:
The information block is divided into multiple segments that can be processed independently through different coding and modulation paths. This segmentation enables efficient handling of wider bandwidth and MIMO requirements by breaking down complex processing into manageable segments, improving spectral efficiency without proportionally increasing overall system complexity
Solution Approach 2:
The system dynamically adjusts coding and modulation parameters across different segments and antenna paths. This dynamic adaptation allows the transmitter to efficiently utilize wider bandwidth and MIMO capabilities while managing complexity through flexible, adaptive processing rather than rigid fixed-structure approaches
Data Source
AI summary
In general, according to an embodiment, a wireless transmitter includes a plurality of coding and modulation modules to apply corresponding coding and modulation algorithms to input information blocks. A discrete Fourier transform (DFT) precoder applies DFT processing to outputs of the coding and modulation modules, and an inverse fast Fourier transform (IFFT) module receives a DFT output of the DFT precoder, which is mapped to different subcarriers according to the resource allocation indicated by the base station, and applies IFFT processing to the DFT output. An output processing stage produces output signals based on the output of the IFFT module to transmit wirelessly to a wireless receiver. In a different implementation, the outputs of the coding and modulation modules can be provided to an IFFT module to produce IFFT-processed output information.