Research On Routing Algorithm And Transmission Mechanism For Low Earth Orbit Satellites

Satellite network has the advantages of wide coverage, high link bandwidth and multiplex in frequency; it provides global mobile access and alleviates transmission burden in terrestrial backbone network. To construct the future satellite network with the LEO satellites is our favorite choice due to the characteristics of low orbit, low delay, high link bandwidth and simple terminal realization. Routing and transmission protocol are very important components of the satellite network, but the existing ones failed to adapt to the characteristics of satellites, just as satellites'high-speed movement, changing topologies and poor on-board processing capability. To design a simple and effective routing and transmission protocol for LEO satellite network has an important theoretical and practical value.This dissertation makes efforts to solve the routing and transmission problem in LEO satellite network. The main contents of this dissertation are as follows:1. Several typical routing algorithms for satellite network were analyzed and compared in the packets transmitting efficiency, the system complexity and the algorithms'portability. The results indicated that the routing algorithm based on geographical position had a significant advantage. However, existing geographical position-based routing algorithms were researched on the base of ideal satellite system model, the forward processing over the cross-seam ISL and the polar link etc. were considered inadequately.2. This dissertation brought forward a new geographical position-based distributed routing algorithm (NPDA) and related models. The algorithm was based on a simplified topology model. It introduced a simple routing addresses update strategy, and realized highly effective transmitting mechanism with the maintenance of a link switching model for neighbors. In addition, this routing algorithm also had strong resistance to satellite destruction.3. This dissertation brought forward a point-to-point transmission acknowledge scheme. The experiment and theoretic analyse indicated that this scheme had advantages in reducing bare ACK packets and transmission efficiency compared with TCP protocol.