Comparison of coding strategies for a combined fiber/twisted-pair link

In this contribution we consider the concatenation of a passive optical network (PON) link with nonreturn-to-zero signaling, and a twisted pair (TP) link with discrete multitone modulation (DMT). Conventionally, the PON link is protected by a Reed-Solomon (RS) code, whereas the TP link is protected by trellis-coded modulation (TCM). We compare this conventional coding arrangement with an alternative coding arrangement, obtained by moving the RS decoder from the fiber output to the output of the TCM decoder; in this alternative arrangement, the RS code protects the concatenation of the uncoded PON and the TCM-encoded TP, rather than only the uncoded PON. Our numerical results indicate that the alternative coding arrangement allows to increase the information bitrate by about 20% compared to the conventional arrangement.