Modulo Signal Processing for OFDM Peak-to-Average Power Limitation
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Solution Overview
Problem
High peak-to-average power ratio (PAPR) in wireless communication systems, particularly in OFDM and CDMA, leads to inefficient power amplification due to the need for linear transmission circuits operating over a wide power range, resulting in high power consumption and complexity.
Innovation Solution
Implementing a modulo-based PAPR reduction method that limits the peak-to-average power ratio by applying a modulo operation to the amplitude of the digital time-domain signal, followed by digital-to-analog conversion and RF processing, reducing the dynamic range of the transmitter signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If linear transmission amplification circuits are used to handle high PAPR signals, then signal quality is maintained, but power consumption and device complexity increase
Solution Approach 1:
The patent applies preliminary action by performing PAPR reduction processing on the signal before transmission. The method reduces the peak-to-average power ratio of the signal in advance through signal processing techniques (such as clipping, filtering, or iterative optimization), so that the subsequent power amplifier can operate more efficiently without requiring linear operation over a wide power range, thereby reducing power consumption while maintaining signal quality
Solution Approach 2:
The patent changes the signal parameters by modifying the amplitude distribution of the signal. Through techniques like selective mapping, tone reservation, or iterative clipping and filtering, the signal's peak amplitude is reduced relative to its average amplitude, transforming the signal from high PAPR to low PAPR form, which enables more efficient power amplification
2Reliability
If linear transmission amplification circuits operate over a wide power range, then high PAPR signals are transmitted accurately, but device complexity increases
Solution Approach 1:
The patent performs preliminary PAPR reduction processing on the signal before it enters the power amplifier. By reducing the peak-to-average power ratio in advance through digital signal processing techniques, the signal is prepared in a form that can be amplified by simpler, non-linear power amplifiers without requiring complex linear operation circuits, thus reducing device complexity while maintaining transmission accuracy
Solution Approach 2:
The patent substitutes mechanical/circuit complexity with digital signal processing complexity. Instead of using complex linear power amplification circuits, the solution uses software-based PAPR reduction algorithms (such as iterative clipping and filtering or selective mapping) to preprocess the signal, replacing the need for complex hardware with more manageable digital processing
Data Source
AI summary
An embodiment provides a method comprising: generating a digital-form time-domain signal; carrying out a modulo-based operation to an amplitude of the generated digital-form time-domain signal or to in-phase and quadrature branches of the generated digital-form time-domain signal separately, wherein a divisor of the modulo-based operation has a pre-defined value smaller than a maximum of an amplitude of the digital-form time-domain signal for limiting a peak-to-average ratio of the digital-form time-domain signal, and carrying out digital-to-analogue conversion to the digital form time-domain signal for transmission.