Title :
Analysis of Demmapping for Hierarchical 16QAM
Author :
Choi, Seung Hyun ; Oh, Cheon In ; Oh, Doeck Gil ; Chang, Dae Ig
Author_Institution :
Mobile Comm & Digital Broadcasting Eng. Dept., Univ. of Sci. & Technol., Daejeon
fDate :
Oct. 18 2006-Sept. 20 2006
Abstract :
A hierarchical modulation scheme is presented to upgrade an existing digital broadcast system by adding more data stream in its transmissions. The hierarchical modulation is composed of a basic constellation, which is the same as in the original system, and a secondary constellation, which carries the additional data for the upgraded system. The upgraded system with the hierarchical modulation is backward compatible (BC mode) in the sense that receivers that have been deployed in the original system can continue receiving data in the basic constellation. Hierarchical receivers can be designed to receive data carried in the secondary constellation, as well as those in the basic constellation. Two independent streams can be detected by applying to LLR (log likelihood ratio) but in this paper we propose the robust demapping algorithm with same performance of LLR
Keywords :
broadcasting; data communication; quadrature amplitude modulation; receivers; backward compatible; basic constellation; data stream; demmapping; digital broadcast system; hierarchical 16QAM; hierarchical modulation scheme; log likelihood ratio; secondary constellation; Bit rate; Digital communication; Digital modulation; Multimedia communication; Multimedia systems; Quadrature phase shift keying; Radio broadcasting; Satellite broadcasting; Streaming media; TV broadcasting;
Conference_Titel :
Communications and Information Technologies, 2006. ISCIT '06. International Symposium on
Conference_Location :
Bangkok
Print_ISBN :
0-7803-9741-X
Electronic_ISBN :
0-7803-9741-X
DOI :
10.1109/ISCIT.2006.339828
