Research of the noise characteristic on the upstream channel for HFC network

Currently there is a growing demand towards interactive multi-media services using high capacity Hybrid Fiber Coaxial (HFC) networks. With regards to the realization of upstream traffic, many problems occur with the accumulation of noise due to the tree and branch architecture of the coaxial access network. We have figured out the typical network topology for the two-way HFC network, and pointed out where the DS1610s were set. From this figure, we can clear know the reason of noise accumulation and know where and how we´ve got the characteristic of the damage signal. Several types of typical noise and interference for the upstream channel in actual HFC network are given in this paper, with the help of a special equipment called DS1610. Several parameters of the noise, such as the types, causes, effect to the upstream, and the frequency of appearance and so on, which are given in form of spectrum or constellation, can be easily found in this paper. And it also gives the main characteristics of some typical noise and interference, which can be very useful for further study of the noise and interference for the upstream channel in HFC network.