Extending the digital transport capabilities of fiber-to-the-curb networks

Digital transport capabilities to a home served by a fiber-to-the-curb (FTTC) network are limited by the transmission characteristics of the twisted-pair drop cable. Advanced digital signal processing techniques can substantially extend the data transmission capability over the relatively short lengths of metallic drop cables. Results of a numerical simulation of adaptive equalizers and drop lengths (up to 1000 ft) of twisted-pair cable indicate that rates in excess of 10 Mb/s should be attainable, limited primarily by the speed of the signal processing electronics. An eight-level bipolar coding scheme appears to be best suited to the low-crosstalk, short-length environment characteristic of the FTTC drop. Assuming the limitation set by the speed of the electronics could be removed, drop lengths of 100 and 300 ft could transport over 40 Mb/s and 25 Mb/s, respectively