Orthogonal code division multiplexed DSL for interferencesuppression in cable networks

摘要

A new scheme termed orthogonal code division multiplexing (OCDM)is proposed for digital subscriber line (DSL) applications. Through theuse of serial to parallel conversion and orthogonal codes, a“spreading gain” is achieved against narrowband interferencewithout expanding the required transmission bandwidth of the informationsignal. Groups of orthogonal codes with different spreading gains andbandlimited (chip) filtering are used together with M-PAM datamodulation. Spectral matching (to input power density that achieves thecapacity of the copper cable channel) is performed followed bythroughput optimization under a symbol error rate (SER) constraint inorder to select the system parameters. The OCDM/DSL system performanceis evaluated for several scenarios of interest