A Study on Power Assignment of Hierarchical Modulation Schemes for Digital Broadcasting

Masakazu MORIMOTO  Hiroshi HARADA  Minoru OKADA  Shozo KOMAKI  

IEICE TRANSACTIONS on Communications   Vol.E77-B   No.12   pp.1495-1500
Publication Date: 1994/12/25
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on Digital Broadcasting Technology)
digital broadcasting,  HDTV,  hierarchical modulation,  graceful degradation,  

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In the future satellite broadcasting system in 21GHz band, the rainfall attenuation is a most significant problem. To solve this problem, the hierarchical transmission systems have been studied. This paper analyzes the performance of the hierarchical modulation scheme from the view point of power assignment in the presence of the rainfall attenuation. This paper shows an optimum power assignment ratio to maximize the spectral efficiency and the signal-to-noise ratio of received image, and these optimum ratio is varied with the measure of system performance.