Neural network-based comprehensive papr suppression method and system for aco-ofdm system

Abstract

The invention provides an ACO-OFDM system integrated PAPR inhibition method and system based on a neural network. A self-encoder network is used to realize Q-I mapping and demapping of a transmissionsignal, and an extended SLM method and a Clipping method are added into the network structure. The method comprises the following steps: carrying out serial-parallel conversion of an input signal andtransmitting the input signal to an encoder part of a self-encoder network to obtain I-Q constellation mapping output; transmitting a PAPR signal to a phase rotator to generate an alternative low PAPRoutput sequence; carrying out Hermitian symmetry of the replaced output sequence and carrying out fast Fourier inverse transformation to obtain a time domain OFDM signal; carrying out the parallel-serial conversion and cyclic prefix addition of the time domain OFDM signal, and then enabling the OFDM signal to be suitable for the limited emission range of an LED through amplitude limiting; and enabling the receiving end to recover the distorted signal through an opposite process. In network training, two factors of bit error rate and PAPR are considered at the same time, and the automatic encoder is trained by adopting a combined loss function. According to the comprehensive scheme based on the neural network, the PAPR is effectively reduced by more than 12dB.

Description

technical field [0001] The present disclosure relates to the technical field of optical wireless communication, in particular to a neural network-based ACO-OFDM system comprehensive PAPR suppression method and system. Background technique [0002] Optical wireless communication (OWC) has been an effective complementary method to radio frequency (RF) wireless communication due to its very large number of unlicensed bands and strong robustness against electromagnetic interference. Visible light communication (VLC) based on light-emitting diodes is a promising indoor wireless access technology. In order to overcome the multipath distortion caused by the reflection of different indoor light sources and improve the communication efficiency, the VLC system widely adopts Optical Orthogonal Frequency Division Multiplexing (OFDM) technology. However, the peak-to-average power ratio (PAPR) is one of the main limiting factors of the VLC system due to the limitation of the average radi...

AI Technical Summary

Problems solved by technology

However, the peak-to-average power ratio (PAPR) is one of the main limiting factors for VLC systems due to the limitation of the average radiated optical power and the dynamic range of the front-end equipment

The high peak power ratio makes VLC systems, especially Asymmetrically Cleaved Optical OFDM (ACO-OFDM) systems more susceptible to nonlinear distortion, which greatly degrades the system performance

[0003] In recent years, the peak-to-average ratio suppression methods of ACO-OFDM systems include schemes based on recoverable upper half clipping, subcarrier grouping schemes, pilot-aided methods, and semi-definite relaxation methods to reduce the peak-to-average ratio of ACO-OFDM, but These methods lead to problems such as increased system complexity, loss of data rate and degradation of bit error rate (BER) performance, etc.

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