Docsis 3.0 Downstream Channel Bonding Scheduling Program Design And Simulation

Widely used in CATV industry, HFC (Hybrid Fiber Coax) networks have been applied in data transmission since the year 1990. Established as a major industry standard for two-way communications over HFC cable plants, DOCSIS (Data over Cable Service Interface Specification) is now under great challenge, due to insufficient bandwidth. The latest version, DOCSIS3.0, has developed a technology approach to bond multiple physical channels into a single virtual channel so as to obtain high-bandwidth. However, there are still several key problems to solve in realizing the downstream channel bonding system, including the way for downstream channel load balance, range for downstream Resequencing window size, as well as the performance analysis of downstream bonding system.Based on the study of the protocol, this thesis discusses the above problems, putting forward a schedule plan for downstream data transmission. The job includes the following three tasks. First of all we design the downstream data schedule schemes in MAC layer for CMTS and CM respectively, including state-based random load balance algorithm on downstream transmission in CMTS, and packet resequencing algorithm on data receive in CM. Then we construct a simulation model for the schemes, with which we can do some analysis and verify the schemes. And we discuss in depth the effect of channel delay and code error on the system. Finally we have identified the range of the resequencing window size by simulation, an important parameter in CM downstream data process.