Evaluation of LDPC codes efficiency in channels with fading

Abstract

The article discusses the operation of communication systems using a low-density parity check codes in channels with multipath propagation. This class of codes has found wide application in modern communication and broadcasting systems and is one of the most effective in now. Some theoretical and practical issues of combating the effects arising from multipath propagation are presented. The description of the developed simulation model, channel codec, equalizer, and transmission channel is given. The channel encoder in the model is designed in accordance with the specifications for the 5G New Radio (5G NR) communication standard. The multipath parameters in the transmission channel correspond to the TDL models for 5G NR, with the exception of the Doppler shift, which is not taken into account in the simulation. In addition, there is additive interference in the channel. The decoding algorithm used was also described in detail. As a result of the study, the dependences of the bit error probability on the signal-to-noise ratio were obtained for the code rates 1/2 and 1/8, as well as for the system without coding. Based on the results obtained, it is possible to judge the correcting ability of this class of codes.