BER Reduction for mQAM High-Speed Tranmission in Optical Fiber Networks Using Convalutional BCH, RS and LDPC Error Correcting Codes
A comparative study of digital m-ary Quadrature Amplitude Modulation (mQAM) channel coding signals for optical high-speed transmission is presented in this article. The needs to transmit information at high speed are topical and relevant to the images, the sounds, and data of any kind, etc. The photonic networks are the subject of much research on the application in optical domain of techniques already used in wireless networks such as mQAM digital modulations and error correcting codes. The mQAM digital modulations interest lies in the fact that they are now being used as subchannel modulation techniques in other advanced modulations such as Othogonal Frenquency Division Multiplexing (OFDM). Indeed, OFDM using mQAM modulation seems to be a good candidate in high speed networks. This allows considering transmission systems at very high speeds in optical transmission networks. The performance of channel coding is based on the estimation of the Bit Error Rate (BER) implementing techniques of Convolutional codes, Bose Chaudhuri Hocquenghem (BCH) codes, Reed-Solomon (RS) codes and Low Density Parity Check (LDPC) codes in a 10Gbps transmission. The BER is estimated as a function of the OSNR and also as a function of the transmission distance.
The study was conducted in a software cosimulation environment with VPITransmissionMaker and Matlab software. The simulation results showed that error correcting codes and particularly LDPC codes are effective and provide satisfactory solutions to reduce the BER by fighting against optical transmission channel disturbances such as chromatic dispersion and nonlinearities.
Keywords: mQAM, broadband, BER, optical fiber, error correcting codes.