Double-Direction Hybrid Fiber Cable Networds Return Channel Design

HFC(Hybrid Fiber Cable) Network is most popular used in video and broadcasting area. Advantage of HFC is its wide bandwidth , which down link bitrate can reach 1000Mbps and up link bitrate can reach 40MBps. There are a lot of customers who watch TV programs based on HFC transmitting. HFC is one of the network which cover most area in china and HFC has very bright application future.After Author looked up a lot of thesis and document about returning channel design in worldwide area, this thesis elaborates the performance of returning channel and its related noisy source. It discusses a series of optical system technology, BER(bitrate error ration) and NPR( noise power ratio). Author has very rich practice experience about Dual-direction HFC change. Based on theory and practice, author put forward four rules when design HFC returning channel: Reliability, Compatibility, Expendability and Practicability.HFC reliability design should focus on reliability of network equipment, redundancy backup, self error recovery of main network, network management standardization, device and system security and network construction standardization; Compatibility design should focus on network management software complying with international standard(SNMP), interface and middle ware parameters should standardize; Expendability design should focus on network smoothly upgrading, the technical parameters and interface of selected devices should be expendable in future. Practicability design should focus on making relatively high profit with low investment, with following international standard.At the end, the thesis describes key technology when design returning channel. Incorporate with his returning channel debug experience, Author propose a feasible way to design HFC returning channel. It gives a reliable and usable solution to design HFC returning channel.