Research On Differential Chaotic Bit-Interleaved Coded Modulation System Over Power Line Channels

When signal is transmitted over Power Line Communication(PLC)channel,it is affected by a variety of interferences,including inter-symbol interference(ISI)caused by multipath propagation,signal attenuation due to cable loss,various types of impulse noise and so on.Differential chaotic modulation technology has attracted people's attention because of its inherent spread spectrum,strong anti-multipath interference capability and no need for carrier synchronization.It is expected to be a transmission scheme over PLC in the future.In view of the serious interference of PLC,the paper introduces the iterative receiver(IR)into the constellation-based differential chaotic bit-interleaved coded modulation(DC-BICM)system.The DC-BICM-IR system is proposed and codes are designed.The system inherits the excellent features of DC-BICM,such as bandwidth validity,strong anti-multipath and anti-jamming characteristics,strong robustness,low complexity of the device,etc.And due to the introduction of IR and codes optimization,the system performance has been greatly improved.It is a chaotic digital communication transmission scheme suitable for working over complex and variable channels with limited bandwidth.The main innovative work of the paper can be summarized as follows:(1)The capacity of constellation-based M-ary Differential Chaos Shift Keying(M-DCSK)system is calculated by Gaussian approximation over multipath Rayleigh fading channel.The difference of capacity bounds between M-DCSK system and traditional coherent modulation system indicates that the optimal LDPC code over the traditional standard coding channel does not necessarily continue to provide optimal performance for the differential chaotic system.This inspired us to redesign the codes used by the DC-BICM system.(2)The DC-BICM-IR system is proposed over PLC.We introduce the nonlinear myriad filter(MyF)and IR structure into the DC-BICM system to mitigate the effects of ISI and impulse noise.The proposed protograph Extrinsic Information Transfer(P-EXIT)algorithm and simulation experiments verify the structural necessity and performance superiority of the system.(3)The P-LDPC used in the DC-BICM-IR system is optimized.Considering the characteristics of differential chaotic modulation and its capacity bound,we redesigned the P-LDPC code.Both P-EXIT analysis and simulation results show the superiority of the new code for the system.