Software Design Of RFC Module In The Concentrator And Encapsulation Based On MPEG-2

With the expanding of network bandwidth and increasing of network services, the telecommunication network, CATV and Internet will infect and converge each other. Currently it's a certain direction to provide integrated services for users. HFC network, as a promising broadband solution with the particular advantage of bandwidth, suitable for providing integrated services and easier to modify the network are suitable for the family customers demand and more wide application foreground.The concentrator is the key equipment of the new HFC. It changes the network transmission mechanism, so some problems bothering HFC network including"funnel effect"are solved. As the changes of the network transmission mechanism, the concentrator should take on the demultiplexing function. Because the protocol is different with DOCSIS and the hardware and software are all different with the Set Top Box and Cable Modem, the equipment need to redesigned .The author of this thesis takes charge of the software design of the RFC module, demultiplexing the video signals and encapsulation based on MPEG-2.Firstly, in the thesis, the hardware of radio frequency interface module in the concentrator is introduced in detailed including demand analysis. The RF signals from CTS are dealed with frequency conversion, demodulation, synchronization, classify and transmission. The digital cable electronic tuner is mainly composed of the tune module TUA6020 and the demodulation module STV0297. Then the main body of software design of RFI part in the concentrator is given out. The main task design is introduced in detail. The main task is to initialize RFI module in the concentrator and synchronization. The initialization task is to initialize the registers to drive the RFC by analyzing the interior structure of RFC. The synchronization task is finished when the sign of start 0X47 is found three times continuously by analyzing the TS packages.The video signals which have been dealed with frequency conversion, demodulation and system demultiplexing need to be encapsulated before the signals are transmitted to the switch module. By analyzing the TCP and UDP protocol, a conclusion is made that the TCP isn't suitable to transmit the real-time multimedia data because of the speciality of real-time multimedia data, so a way to encapsulate based on RTP/UDP is given out. In order to reduce time delay and probability of error, one TS package is encapsulated to one IP package. The multicast address is added to IP package by communicate with the manager server. So all the work to encapsulate MPEG-2 are finished.The thesis tests the function of the designed software. The experiment results prove that the software is realized the expected function.