Hfc-catv Network Upstream Channel And Data Transmission Technology

This thesis studies the properties and data transmission technologies of the upstream channel of HFC-CATV networks. First, the upstream channel model of HFC networks is established through theoretic analyses and simulation experiments. And the specific noise of the upstream channel as well as its influence on the modulation techniques are studied in details. Secondly, two-stage synchronization techniques required for multiple access channel, i.e., network synchronization and burst synchronization, are researched. The recovery of carrier and symbol timing is the key points of burst synchronization. With the model of 16QAM signals as an example, the specific framework preamble and the fast synchronization recovery algorithm of a all-digital burst transmission based on the preamble is presented. Simulation results show that good acquisition performances can be achieved when the symbol number of the preamble is lager than sixteen. Finally, the all-digital receiver techniques are studied, the FIR filter is designed with FPGA devices. Experimental results indicate that the filter is suitable for the burst mode transmission of the upstream channel of the HFC networks.