A channel encoding and decoding method and system for reducing bit error rate

Abstract

A channel encoding and decoding method and system for reducing the bit error rate, which relate to the field of optical communication applications, comprising the steps of: sending the terminal from 2 x Among the subcarriers, take 2 according to the frequency from low to high x -2 x‑p Subcarriers are divided into P layers, each layer of subcarriers is modulated separately, the data of each layer of subcarriers in the modulation is multiplied by the orthogonal cyclic transformation matrix of the corresponding length for encoding, the modulated subcarriers of each layer are summed, and then through parallel serial After conversion and digital-to-analog conversion, it is sent out through the light source; when the receiving end detects the optical signal, it first undergoes analog-to-digital conversion and serial-to-parallel conversion, and then performs layer-by-layer demodulation. The corresponding orthogonal cyclic transformation inverse matrix is ​​decoded during layer coding to obtain the data of each layer. The present invention balances the signal-to-noise ratio of each sub-carrier by using orthogonal cyclic transform precoding for each sub-carrier layer, reduces the bit error rate of each sub-carrier layer, and then reduces error transmission and reduces the total bit error Rate.

Description

technical field [0001] The invention relates to the field of optical communication applications, in particular to a channel encoding and decoding method and system for reducing bit error rates in LACO-OFDM systems. Background technique [0002] Low-cost intensity modulation / direct detection schemes are usually used in short-range optical communication systems. The intensity modulation / direct detection scheme requires the use of a modulation format whose signal is always positive, such as PAM (Pulse Amplitude Modulation, pulse amplitude modulation), DCO-OFDM (Direct-current-Biased Optical Orthogonal Frequency Division Multiplexing, DC biased optical orthogonal frequency Division Multiplexing), ACO-OFDM (Asymmetrically clipped Optical Orthogonal Frequency Division Multiplexing, Asymmetrically Clipped Optical Orthogonal Frequency Division Multiplexing), etc. DCO-OFDM adds a bias DC signal to the OFDM (Orthogonal Frequency Division Multiplexing, Orthogonal Frequency Division Mu...

AI Technical Summary

Problems solved by technology

This layer-by-layer decoding will cause the decoding error of the upper layer to affect the next layer, forming error transmission, especially for fading channels, the dense bit errors brought by subcarriers with lower SNR (Signal-Noise Ratio) will make After decoding, the bit error rate of each layer of subcarriers increases significantly

This additional bit error due to erroneous transmission reduces the usability of the LACO-OFDM system in fading channels and must be avoided

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