A Novel QoS Routing Protocol For Satellite Networks And Its Optimization

A novel Time-slot Division QoS Routing Protocol (TDRP) is introduced in this paper, based on a three layered satellite network architecture (TLSN) which consists of low Earth orbit (LEO), medium Earth orbit (MEO), and geostationary Earth orbit (GEO) satellites, and the idea of time-slot division. The method of time-slot optimization and that of time-slot division are illustrated in detail. The QoS routing model gains emphatically research. In addition, the implementation principle of the routing protocol and an algorithm (Bandwidth-constrained Minimum-Delay Algorithm, BDA) are also discussed. The performance of the proposed satellite network architecture and QoS routing protocol are evaluated efficiently through simulations and analysis. The series of topics related to analysis of satellite networks architecture and onboard routing protocol are discussed.(1) Research on satellite network architecture. Typical satellite constellations are systematically discussed. The topological dynamicness of the one-layered satellite network is systematically investigated and its relation with the constellation types and constellation parameters is also presented. For the Multi-Layered Satellite Networks (MLSN), the topological dynamics of typical satellite constellations is quantified via simulation based on the simulation platform. The method of time-slot divisions and its optimization are expatiated in detail. Time-slot division optimization can decrease handovers and provide more efficient routing convergence time.(2) A QoS model based on DiffServ for satellite networks. The multi-constraint QoS routing is modeled based on hop-by-hop routing and premium service (PS). The feasibility of QoS routing is analyzed and proved. The end-to-end delay, one of QoS parameters, is systematically studied by building priority-based queuing model. The result of end-to-end delays is solved. (3) QoS routing protocol design and its optimization. The framework of TDRP and its optimal method are introduced. An optimal isolated method of collection and process of QoS information can reduce communication overheads of routing protocols efficiently. The BDA that uses distributed and centralized routing calculation is designed, and it is valid for routing protocols to decrease computational overhead and guarantee routing convergence within a time-slot. A heuristic path search algorithm is presented to provide PS for rerouting packets in strict left-isotonic networks.(4) Development for Simulation platform and performance evaluation of routing protocols. Based on the OPNET network simulation environment, we proposed the simulation platform architecture, and studied the issues from perspectives of network topology, access policy, neighboring satellite discovery, autonomic orbit maintenance, and satellite link simulation. The developed simulation platform provides the basis for our following protocol analysis. The performance of the proposed satellite network architecture and routing protocol is evaluated efficiently. The feasibility of TDRP and QoS guaranteed capabilities of BDA are proved by simulations.