多载波与单载波频域均衡系统的仿真与测量

摘要

Chinese national standard of digital terrestrial Television broadcasting (DTTB) was a block transmission sys-tem in which the orthogonal frequency-division multiplexing (OFDM) and single-carrier frequency domain equalization (SC-FDE) transmission technologies were compatible. In order to compare the performance of these two technologies over frequency selective fading channel, OFDM and SC-FDE systems using low density parity check code (LDPC) were simulated. Moreover, laboratory tests were carried out to measure the performance of the actual DTTB system. Both the simulation and measurement results show that for the LDPe coded system, OFDM outperforms SC-FDE over fre-quency-selective fading channels, and the advantage of OFDM becomes more obvious with the deterioration of the fad-hag channel and/or increase of the modulation level. The results are expected to be helpful for the design and optimization of the Chinese DTTB system.%我国数字电视地面广播传输标准GB20600-2006(以下简称国标)兼容多载波正交频分复用(OFDM)和单载波频域均衡(SC-FDE)2种块传输技术.为了在国标框架下对2种传输技术的抗频率选择性衰落性能进行比较,根据国标的系统参数对采用低密度奇偶校验码(LDPC)的OFDM和SC-FDE传输系统进行了仿真,并对国标实际系统进行了测量.仿真和实测结果均表明:在LDPC编码系统中,OFDM的抗频率选择性衰落性能好于SC-FDE系统,且随着信道频率选择性衰落的恶化和调制级别的提高,这种优势会更加明显.此仿真和实测结果可以为国标系统的实现与优化提供参考.