Research And Design Of Channel Coding And Modulation For China Digital Radio

Compared with traditional analog broadcasting system,digital audio broadcasting system enjoys superior reception quality,stronger anti-interference ability,wider coverage and higher spectrum efficiency.It is also more suitable for high-speed mobile reception.Currently,there are three main technical schemes,namely:Eureka-147 DAB,DRM/DRM+ and HD Radio IBOC system.These three techniques have their own advantages,disadvantages and applicabilities.In 2006,the State Administration of Radio Film and Television(SARFT)proposed our country's DAB System.However,it is not widely promoted and applied in our country due to its problems in policy,patent,compatibility issues and so on.In 2013,the SARFT officially promulgated the latest standard Digital Audio Broadcasting in FM Band-Part1:Framing Structure,Channel Coding and Modulation for Digital Broadcasting Channel(CDR)as our country's standard of the digital audio broadcasting.CDR implements digital-analog simulcast with more flexible spectrum mode and highly efficient coding algorithm.It will be extended and applied around the nation.Therefore,it is necessary and of practical significance to research and design CDR standard for our country.We firstly investigate the key technologies of CDR base-band transmission system,including scrambling,convolution coding,LDPC coding,bit interleaving and framing,OFDM modulation.We mainly discuss the impact of bit rate and decoding iterations on the performance of QC-LDPC code.Secondly,we design a CDR channel coding and modulation system,which are then compared with DAB to demonstrate the superiority of the CDR standard.Then,we design and implement every module of CDR on FPGA platform using a combination of Verilog HDL and VHDL jointly.Finally,cascading each module to complete the FGPA system design of the system and analyzing the results of ModelSim and MATLAB.The results show that the design system can achieve high accuracy rate encoding.The main performance metrics have reached the CDR standard.The main contributions of this paper are as follows:(1)since CDR provides the H matrix of with structural characteristics of QC-LDPC code,we design a QC-LDPC encoder based on SRAA circuit.By using ModelSim and MATLAB simulation software,the coding process is validated,and the results show that the encoder can encode information correctly,take up less storage and avoid delay.(2)We propose a flexible framing method to achieve flexible configuration of the digital signal using the filling patterns of the effective sub-carriers and virtual sub-carriers in the spectrum planning.The research results of this paper are important for the subsequent design and development of digital audio broadcasting system.Moreover,the result also provides some insight to build test environment of the whole system,and help realize the further ASIC chip.