摘要
为提高数字电视地面广播(DTTB)系统的传输性能,在传统的串行级联编码结构中,引入Turbo码的思想,同时结合16QAM映射和多载波正交频分复用(OFDM)调制,构造了一种新的并行级联格型码(PCTC)作为内码方案。在接收端采用基于MAX-LOG-MAP准则的"滑动窗"迭代Turbo译码算法,以达到性能和复杂度的折衷并避免了归零处理。在加性高斯白噪声信道下的误码率性能仿真证明:在视觉门限下该方案所需的比特信噪比Eb/N0仅为3.4dB,比参考方案有约1.8dB的增益。在此场强水平下,该系统可提供净信息速率约为12.5Mb/s的可靠视频广播。
The transmission performance of digital television terrestrial broadcasting (DTTB) was improved using Turbo code based on the channel conditions and the DTTB transmission requirements in connection with 16QAM constellation and OFDM modulation. A new parallel concatenated trellis code was constructed as the kernel of the serially concatenated coding scheme. In the receiver the MAX-LOG-MAP iterative decoding algorithm with a sliding window was used as a compromise between system complexity and performance and to avoid trellis termination. Simulations for bit-error-rate on an additive white gaussian noise channel showed that at the threshold of visibility the required E _b/ N _0 was only 3.4 dB, which is 1.8 dB better than the reference schemes. At the field strength level, the system is able to support robust digital video transmission at a net information rate of about 12.5 Mb/s.
出处
《清华大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2004年第4期489-492,共4页
Journal of Tsinghua University(Science and Technology)
