An introduction of up-link access method for cable modem which provides better robustness to actual ingress noise, and the result of test in an actual CATV network

Abstract

Ingress noise is generally known to degrade up-link signals in CATV network. In particular, ingress noise in the frequency band lower than 20MHz disturbs seriously the data communication. In this paper, at first, we analyze the ingress noises in the actual CATV networks. Based on the measurement result above, we introduce the up-link access method, which uses multi-carrier frequency hopping mechanism. Then we show a potential of communication in low frequency bandwidth by means of the test result in an actual CATV network with the cable modem system that uses the access method.