Comparisons of fiber-to-the-curb upgrade alternatives for multichannel digital video

Key technical and economic factors involved in transporting voice and video services over hybrid fiber/coax distribution networks are examined. Two upgrade architectures for providing multichannel digital video services as an overlay in a narrowband fiber-to-the-curb (FTTC) system with eight living units (LUs) per optical network unit (ONU) are investigated. The upgrade provides video subscribers with access to switched channels and to a menu of 140 multicast or broadcast channels, all digitally compressed to 4 Mb/s per channel. One of the upgrade architectures transports video channels in asynchronous transfer mode (ATM) cells using a wavelength division multiplexing (WDM) overlay from the host digital terminal (HDT) to upgraded ONUs, with coaxial drops to set-top converters at the customer premises. The alternative architecture uses subcarrier multiplexing (SCM) technqiues to transport video channels in 16-quadrature AM (QAM) format to video ONUs (V-ONUs) each serving 64 LUs through a coax-bus distribution.