Research And Design Of Digital Audio Broadcasting Channel Coding

Compared with traditional analog broadcasting system, digital audio broadcasting system is with superior reception quality, stronger anti-interference ability, wider coverage and higher spectrum efficiency. It’s also more suitable for high-speed mobile reception. Digital audio broadcasting technology is the inevitable trend of the development of broadcasting technology, which will bring enormous industrial benefits and social utility to China.Currently, there are three main technical schemes, namely:Eureka-147 DAB digital audio broadcasting system, DRM/DRM+ digital amplitude modulation system, HD Radio IBOC system. These three techniques have their own advantages, disadvantages and applicabilities. In 2006, the State Administration of Radio Film and Television officially introduced the 30 MHz～3000 MHz Terrestrial Digital Audio Broadcasting System Technical Specification as the digital audio broadcasting industry standard in China. However, it is no widely promoted and applied in our country due to problems such as policy, patent, compatibility and other issues. Therefore, it is necessary and important to design a digital audio broadcasting scheme which has independent intellectual property rights and is suitable for the application and development of our country.Channel coding and modulation technology is one of the core technologies of digital audio broadcasting. Firstly, after deep study of the key technologies of DAB baseband transmission system, this paper designs a DAB channel coding and modulation system based on MATLAB simulation platform. Secondly, specific to COFDM technology used in DAB system, this paper discusses the principles of several efficient channel coding schemes such as convolution code, RS code, concatenated code, Turbo code and LDPC code and their applicabilities in the digital audio broadcasting system, and also compares the decoding performance of different channel coding schemes combined with computer simulation. The results show that the QC-LDPC code can provide stronger anti-interference ability and is more suitable for application in the digital audio broadcasting system. On this basis, this paper proposes a new digital audio broadcasting system based on QC-LDPC code, and discusses the impact of code length, bit rate and decoding iterations on the performance of QC-LDPC code.Recently, CDR, the new generation of Chinese digital audio broadcasting system, has achieved initial results. The system adopts the QC-LDPC code as channel coding method, which is in conformity with the previous research results of this paper. According to the structure characteristics of QC-LDPC code provided by CDR, this paper designs a QC-LDPC encoder based on SRAA circuit. By using ModelSim and MATLAB simulation software, the coding process is validated, the results show that the encoder can encode information correctly.QC-LDPC code is the core module of CDR channel coding. The research results of this paper have vital significance for the subsequent design and development of digital audio broadcasting system.