A Fiber-to-the-Curb System Based on Subcarrier Multiplexing and Asymmetric Digital Subscriber Lines

A fiber-to-the-curb (FTTC) system using subcarrier multiplexing on the optical fiber and asymmetric digital subscriber lines (ADSL) on the unshielded twisted-pair is proposed to deliver broadband services. In contrast to the current ADSL based FTTC approaches, the digital multiplexing/demultiplexing process is moved back to the central office by using subcarrier multiplexing in fiber transmission. The local node simply down-converts the subcarrier multiplexed ADSL transmission signal to a baseband signal, suitable to send directly into the twistedpair. In this hybrid-fiber/twisted-pair (HFTP) architecture, instead of installing in remote node, ADSL transceivers are installed at the central office to greatly reduce the remote node complexity. The reducing of complexity could result in lower initial installation cost, especially for a low service penetration rate. The maintenance and operation cost can also be reduced.