Study On Error Control Technology For Reliable Multicast Of Satellite

In the global communications satellite network plays an important role, which not only can support global coverage, and can support broadband services, in addition to support for flexible network configurations. As technology advances, more and more satellite networks to support IP services, and IP multicast is one of the important part. Aspects of satellite communications in support multicast itself has a unique advantage, now, with the expansion of IP services and satellite capacity strengthening, through the satellite network supports IP Multicast has gradually started to become the future direction of development of network communications.However, compared with terrestrial networks via satellite for reliable multicast is also facing some problems. First, the delay problem : For satellite communication, the link transmission delay causes long IGMP group management protocols and multicast routing protocols use greatly reduced. Second, a high packet error probability : satellite networks are exposed to the space among the radio channel there are lots of unstable factors( weather conditions in complex, multi-path interference), which leads to a higher bit error rate, which also produced a relatively high packet error probability of the ground.Therefore, how to overcome the impact of the channel large delay, how to improve the harsh climatic conditions satellite multicast transmission performance, especially how to eliminate the impact of rain attenuation multicast technology can successfully applied in the satellite communications is one of the key factors. This article is based on reliability considerations, for satellite multicast error control technology has been studied and implemented, the main research contents are as follows.Describes multicast communications satellite concept packet error rate and packet error rate for satellite multicast impact and describes three commonly used satellite multicast error control techniques, including the physical layer FEC techniques, ARQ techniques and packet level FEC technologies.Multicast communication satellite packet level FEC technique for a specific analysis and presentation. Shows the two level FEC packets used for introduction-using RSE code packet level FEC technology and the use of a convolutional code packet level FEC technology, including methods of their realization, advantages and disadvantages, and so. It also describes the combination of the ARQ packet level FEC(HEC) concept.The simulation code on the use of RSE packet level FEC techniques in-depth study. Occupancy rate of bandwidth and latency is measured through a lot of simulation, analysis and discussion of the receiver group size, FEC parameters, including the size and influence of rainfall, and the performance of the two network models were compared. On this basis, then there is a feedback channel for satellite multicast network model proposes an improved scheme and simulation analysis. Many of the conclusions of the actual multicast system applications with better guidance.