Research And FPGA Implementation Of LDPC Codes Decoder For CMMB&T-MMB

In many application fields,mobile television is a widely concerned industry in a stage of rapid development.Mobile television is bound to access to people's recogonition of favor due to it's small size,portability and rich media content.All of mobile television standards,CMMB and T-MMB are relatively mature. CMMB launched by SARFT has become the industry standard and T-MMB has become GB in 2008.CMMB and T-MMB have LDPC codes included in channel coding progam.LDPC forward error correction codes encoding technology they applied will greatly promote the development of mobile video.LDPC(Low Density Parity Check) codes is one of the key technologies of the fourth-generation mobile communications.LDPC codes is excellent error-correcting codes with performance close to the Shannon limit.It is adapted for hardware's high speed implementation because of its low decoding complexity.It also has better flexibility and lower error floor.In this paper,based on the two mobile television standards,CMMB and T-MMB,a deep research about channel coding of LDPC codes was finished,and two rates of LDPC codes decoders of CMMB are implemented in FPGA.Analysis of channel coding of CMMB and T-MMB television standards were done and the characteristics of LDPC codes were researched.Take CMMB standard as an example,respectively in BPSK,QPSK,16 QAM mapping mode,simulation of channel coding and decoding was done;I simulated some parameters used in the implementation of FPAG.Such as,the maximum iteration,quantization bits,normalized factor.By studying the cycle characteristics of LDPC structure of CMMB and T-MMB,coding method is designed. And I also designed timing programs and various Sub-modules;Two rates of LDPC codes decoders were implemented with VHDL language in QuartusⅡplatform.The compiled results proved that LDPC codes decoder has great advantage in Occupation of the hardware resources,processing speed and decoding performance;By using the test platform established by predecessors,two rates of LDPC codes decoders of CMMB were tested and the test results are similar to theoretical values.It proved the design of this paper is excellent and the great performance of LDPC codes.