Trial application of spread spectrum technologies to hierarchical digital broadcasting

This paper describes two advanced hierarchical digital transmission systems using SS (spread spectrum) technology in order to improve the breakdown characteristics of digital transmission. One is AW-CDM (adaptively weighted code division multiplexing) hierarchical digital transmission system for terrestrial digital broadcasting, which enables one to use mobile/portable receiver as well as fixed receiver. The other is TDM-SS (time division multiplexing using spread spectrum) hierarchical digital transmission system for Ka-band satellite broadcasting, which enables one to receive limited but continuous service even in heavy rain attenuation. Through simulations and experiments using prototype models, some of their features have been verified.