Research And Performance Analysis Of Concatenated Code In Visible Light Channel

With the rapid development of LED industry and digital communication technology,visible light communication(VLC)is considered to be the most potential wireless communication technology for effectively developing wireless communication spectrum because of its characteristics of simultaneous data transmission and lighting,rich spectrum resources,fast speed,high security and low cost.Channel coding is the key technology to improve the performance of communication system.Concatenated code is a new coding scheme which combines two short member codes in series or parallel.In the selection of member codes,polar code is a major breakthrough in the field of wireless communication coding and decoding as the only kind of coding method to reach Shannon limited capacity.Therefore,the design of concatenated codes based on polar code has become the focus of the coding field.Based on National Natural Science Foundation of China(NSFC)and other projects,this paper focuses on the basic theoretical research and simulation experiment verification of VLC channel analysis modeling,coding and decoding construction principle,concatenated code scheme design and other issues,providing a feasible idea for the design of future coding and decoding schemes in VLC field.The main work and innovations are as follows:1.This paper describes the basic principle of indoor VLC system,discusses its general structure,analyzes the characteristics of VLC channel link mode.On this basis,a set of simulation indoor LED illuminance analysis scheme is designed,and the impulse response model of line-of sight(LOS)indoor VLC channel is established.2.The basic principles of polar code and low density parity check codes(LDPC)are studied and analyzed,including channel polarization,check matrix construction and common coding and decoding algorithms.The simulation results show that polar code and LDPC code can notably improve the BER performance of indoor LOS VLC channel,and the influence of key parameters on the performance of the polar code is analyzed.3.For the reason that the performance of the polar code is limited with medium and short code length and LDPC code inevitably appears the shortage of error flat layer,this thesis proposes a scheme of concatenation composed of polar code and LDPC code for VLC,analyzes the advantages and feasibility of the scheme,designs the structure of the concatenation system of polar code and LDPC code and the specific implementation process of encoding and decoding.The result of simulation proves that the scheme is suitable for VLC channel and it can improve the communication performance.