Core Module Optimization Of Chinese Digital Television Standard And Key Technology Research On Next Generation Standard

Chinese terrestrial digital television (DTV) standard:Digital Television/Terrestrial Multimedia Broadcasting (DTMB), with its key technology Time-Domain Synchronous Orthogonal Frequency Division Multiplexing (TDS-OFDM) have been carried into effect in China. The DTMB system begins to enter the global market with optimized equipments. However, the Europe and American first generation DTV standards has been fully developed and exported to many countries all over the world. What is more, their second generation DTV standards, with advanced communication technology, are carried out. To face this challenge, we prepare to further optimize the DTMB key equipment and research transmitter diversity technology in the second generation standards. This paper launch the key technology research in the Fast Fourier Transform (FFT) of the TDS-OFDM,3780-point FFT processor optimization, space time block codes (STBC).Firstly, TDS-OFDM is the key technology in DTMB standard. TDS-OFDM has unique advantage comparing with other OFDM system. The3780-point FFT architecture in TDS-OFDM is designed for DTMB standard and Chinese DTV frequency band.3780is not an integer’s power, so the common radix-2and radix-4FFT processor module can not be used in the3780-point FFT. A special algorithm should be designed for the3780-point FFT. This paper presents a novel3780-point FFT processor scheme to reduce the computational complexity. Comparing with the typical3780-point FFT scheme, our proposed3780-point FFT processor scheme reduces45%of the multiplications in the price of1%increase of the additions. The analysis results show that our proposed scheme has the best performance among all the existing optimize algorithms.Secondly, the3780-point FFT should be decomposed into small points DFT modules, so the3780-point FFT structure is always cascade connected. The reordering cache and twiddle factor multipliers consume a great amount of hardware resources. This paper designs a mapping method suitable for the iterative Winograd Fourier Transform Algorithm (WFTA) architecture. The small point FDT module’s input and output data are designed to be natural number order. An optimized Coordinate Rotation Digital Computer (CORDIC) module is designed to do the twiddle factor multiplication to further reduce the resource consumption. The simulation results show that, the resource consumption of our proposed3780-point FFT processor is53%and81%of two similar existing designs. The proposed scheme also performs the best in system delay and DSPs consumption. It is an efficient design for the Chinese DTMB standard.Thirdly, the transmitter diversity technology is essential part of the advanced communication technology in the second generation DVB standard. The differential space-time block codes (DSTBC) is designed for complicated channel situation. DSTBC has great prospect in the next generation Chinese DVB standard. However, the DSTBC dose not rely on CSI but the differential method causes constellation expansion. This paper presents a double mapping method DSTBC, which can avoid constellation expansion and achieve full code rate. The proposed double mapping method is the simplest structure among all similar codes. The simulation results show that the proposed DSTBC performs best among all the existing codes without constellation expansion. Comparing with the typical DSTBC with constellation expansion, our proposed DSTBC has1dB loss in low SNR situation but can achieve the same performance in high SNR situation.