A New Routing Algorithm of Two-tier LEO/MEO Mobile Satellite Communication Systems

The performance of a two-tier LEO/MEO satellite network including inter-satellite links (ISL´s) is analyzed. Specific emphasis is laid on the design of an ATM-based routing scheme for the ISL part of the system (MEO layer). The approach is to prepare a virtual topology by means of virtual path connections (VPC´s) connecting all pairs of end nodes in the ISL sub-network for a complete period in advance, similar to implementing a set of (time dependent) routing tables. The search for available end-to-end routes within the ISL network is based on a new routing Algorithm (S-DRA) integrates the advantages of static routing and dynamic routing. Additionally, a new quick clustering scheme is introduced to monitor the faults to guarantee the usability of VPC. The new algorithm guarantees that: 1) the survey of VPC route is not carried on blindly no longer because of the application of the clustering scheme, 2) the flow of control information is reduced, 3) whereas the channel of link is allowable, it can reduce handover frequency as much as possible. Finally, a simulation on MEO layer analyzes the performance of the new routing algorithm