Research On The MAC Layer New Technology Of Coaxial System

With the triple play to speed up the process, people will be more demanding on thenetwork’s complexity, diversity. The result of all this is that people require a higherbandwidth. Cable access technologies (EoC) is one of the key technology of the nextgeneration of broadcast networks (NGB), which is based on coaxial cable, through a varietyof digital modulation techniques to carry Ethernet services and other integrated services. Useof the technology for broadband cable television networks, two-way transformation, caneffectively play cable television frequency bandwidth, low cost, easy to spread the advantagesof cable TV network will help thousands of families into a multimedia information platformto meet the community and the general various needs of residents, promoting the triple play.In the new generation of coaxial cable access system, different from the existing two-wayaccess technology, combines the next generation of cable broadcasting (DVB-C2) andtwo-way access requirements, in-band solution, the transmission resources can be betweenbroadcasting and two-way business flexibility in the allocation; converged broadband dataaccess and transmission within the family needs. MAC protocol layer can be divided into twoparts, which are the MAC sublayer and the LLC sublayer. In the MAC sub-layer, the mainfunction is to complete the physical resource scheduling and registration access.In the context of the triple play, coaxial broadband access systems is hosting a variety ofdifferent business types, to provide voice, data, images, video and other means ofcommunication and connection of different means. Different according to each user’s business,for individual users using the FIR, CIR and PIR three forms of bandwidth assurance andcontrol. By this way the three-tier distribution business, to ensure that the bandwidth needs ofindividual users can be guaranteed to each user without allocating too much bandwidth, so thebandwidth waste of resources. Coaxial access system, is divided into two parts, the header and the terminal.After theheader completes the resource allocation process, it needs to construct time-frequencyresource allocation information to inform the terminal of the allocation result of resource,namely the need to construct MAP information. Unlike OFDMA system, coaxial accesssystem with a frequency selective channel characteristics, there will be a large number ofnon-contiguous allocation of resources to ensure that the frequency-selective diversity gain,and increase system capacity, so information on the original MAP format optimized to meetthe coaxial access system features.