数字电视地面接收机的解映射改进算法及实现

Improved De-mapping Algorithm for Receivers in DTTB Systems

针对《数字电视地面传输系统帧结构、信道编码和调制技术规范》国家标准(以下称国标),提出一种用于国标全模式接收机的解映射改进算法。利用国标中的QAM星座图中符号与信息比特间的规律,简化解映射电路,同时实现多QAM模式的解映射模块复用。算法已在基于FPGA的国标全模式接收机中得到了验证,与传统解映射算法相比,算法既节省了硬件资源,同时还提高了系统速度。

Based on the national standards,'Framing structure,channel coding and modulation for digital television terrestrial broadcasting system',an improved algorithm for QAM de-mapping is proposed in this paper.After finding the relation between QAM constellation and the output of de-mapping,a simplified circuit with less logic gates and registers is introduced,instead of the look-up-table circuit.Meanwhile,module reusing is taken into account among 4QAM,4QAM-NR,16QAM and 64QAM.After verifying the prototype on FPGA,the hardware resource occupied in the improved circuit is 50% less than in the conventional look-up-table circuit.