PAPR Reduction via Signal Segmentation in Mobile Fronthaul
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Solution Overview
Problem
Current mobile fronthaul systems suffer from high Peak-to-Average Power Ratio (PAPR) and Error Vector Magnitude (EVM) due to noise and errors in peak signals, which negatively impact signal-to-noise ratio (SNR) and overall efficiency.
Innovation Solution
The system separates input signals into peak and non-peak signals, transmitting peak information on a high-quality control word channel and clipped signals on an in-phase and quadrature (IQ) channel, reducing PAPR and EVM by processing the signals using specific algorithms to clip peaks and transmit only time indices of peaks, thereby reducing data transmission and assuming all data are non-peaks unless indicated otherwise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If peak signals are transmitted on the IQ channel along with clipped signals, then complete signal information is transmitted, but the PAPR increases and EVM deteriorates due to noise and errors in peak signals
Solution Approach 1:
The patent segments the signal transmission into two separate channels: the IQ channel carries clipped signals, while a dedicated control word channel carries peak signal information. This segmentation isolates the vulnerable peak signals from the noisy IQ channel, preventing error propagation while maintaining complete signal reconstruction capability at the receiver.
Solution Approach 2:
The control word channel acts as an intermediary carrier for peak signal information. Instead of transmitting peak signals directly through the noisy IQ channel, the system uses this separate high-reliability control channel as a mediator to convey critical peak information, thereby protecting against noise and errors in the primary transmission path.
2Productivity
If all signal data are transmitted through the IQ channel, then transmission simplicity is maintained, but bandwidth efficiency decreases due to high PAPR requiring higher power margins
Solution Approach 1:
The patent extracts peak signal information from the main signal stream and transmits it separately through the control word channel. By taking out only the essential peak information rather than transmitting complete peak signals, the system reduces the power margin requirements and improves bandwidth efficiency while maintaining signal fidelity.
Solution Approach 2:
The system changes the transmission parameters by using a separate control word channel with different characteristics from the IQ channel. This parameter change allows peak information to be transmitted with higher reliability and different power constraints, optimizing overall system bandwidth efficiency and power utilization.
3Use of energy by moving object
If peak signals are clipped to reduce PAPR, then power amplifier efficiency improves, but signal fidelity deteriorates due to clipping distortion
Solution Approach 1:
The patent applies beforehand cushioning by transmitting peak signal information through a separate high-reliability control channel before the receiver needs to reconstruct the original signal. This pre-transmission of peak information cushions against the clipping distortion that occurs in the IQ channel, allowing the receiver to accurately recover the original signal by combining clipped IQ data with the preserved peak information.
Data Source
AI summary
An apparatus comprises: a receiver port configured to receive an input signal comprising in-phase and quadrature (IQ) data and control words (CWs); a peak-to-average power (PAPR) reducer coupled to the receiver port and configured to: receive the IQ data, process the IQ data, separate the IQ data into a clipped signal and a peak signal, and determine peak information associated with the peak signal; and a transmitter port coupled to the PAPR reducer and configured to separately transmit the clipped signal and the peak information. A method comprises: receiving an input signal comprising first data and second data; processing the first data; separating the first data into a clipped signal and a peak signal; determining peak information associated with the peak signal; and transmitting the clipped signal and the peak information.