【正文】 uting algorithm is very important for LEO satellite works. LEO work routing algorithm should not only consider characteristics of satellite work, but also take its own characteristic into account. This dissertation first introduces the status of LEO satellite works, and several typical LEO systems, summarizes the research status of the satellite work routing algorithm, discusses the problems and difficulties of routing algorithms for LEO works, according to their characteristics. And then the dissertation discusses how to design a simulation scenario using OPNET and STK in order to provide an effective research platform to verify data transmission and routing on both transport layer and work layer. Finally, considering the routing loop problem cased by switching routing table between each time slices, the dissertation analysis a LEO work routing algorithm without loop based on timeshare model. Through the simulation scenario set up before, the simulation results prove that the algorithm can eliminate loop and improve endtoend delay. At the same time, the simplified routing table can save satellite resources and reduce occupation of the limited satellite limited storage space on board. Key words: LEO work。delay III 目 錄 第 1 章 緒論 ..................................................................................................................... 1 課題來源及背景 ................................................................................................. 1 研究目的及意義 ................................................................................................. 5 國內(nèi)外發(fā)展現(xiàn)狀 ................................................................................................. 6 國外衛(wèi)星路由算法研究現(xiàn)狀 ................................................................... 6 國內(nèi)衛(wèi)星路由算法研究現(xiàn)狀 ................................................................... 6 國內(nèi)外發(fā)展綜述 ....................................................................................... 7 本文研究主要研究內(nèi)容 ..................................................................................... 7 第 2 章 LEO 衛(wèi)星網(wǎng)絡(luò)典型路由算法分析 .................................................................... 9 LEO 衛(wèi)星通信系統(tǒng)概述 ..................................................................................... 9 幾種典型的低軌衛(wèi)星系統(tǒng) ............................................................................... 10 Iridium 系統(tǒng) ............................................................................................. 10 Teledesic 系統(tǒng) .......................................................................................... 11 Globalstar 系統(tǒng) ........................................................................................ 13 現(xiàn)有的典型 LEO 衛(wèi)星路由算法分析 ............................................................. 14 本章小結(jié) ........................................................................................................... 15 第 3 章 LEO 衛(wèi)星移動通信網(wǎng)絡(luò)仿真場景設(shè)計 .......................................................... 17 LEO 衛(wèi)星星座覆蓋特性分析 ........................................................................... 17 OPNET 網(wǎng)絡(luò)仿真原理分析 .............................................................................. 19 OPNET 的功能組成 ................................................................................ 19 OPNET 的優(yōu)缺點 .................................................................................... 19 OPNET 仿真步驟 ................................................................................... 20 仿真機(jī)制 ................................................................................................. 21 通信機(jī)制 ................................................................................................. 21 基于 OPNET 結(jié)合 STK 的 LEO 衛(wèi)星系統(tǒng)仿真場景 .................................... 21 協(xié)議結(jié)構(gòu)及仿真場景 ............................................................................. 21 層次化建模 ............................................................................................. 22 網(wǎng)絡(luò)場景模型 ......................................................................................... 23 節(jié)點場景模型 ......................................................................................... 24 進(jìn)程場景模型 ......................................................................................... 25 本章小結(jié) ........................................................................................................... 27 第 4 章 基于分時模型的 LEO 衛(wèi)星網(wǎng)絡(luò)無環(huán)路由算法 ............................................. 28 IV 路由算法設(shè)計 ................................................................................................... 28 衛(wèi)星路由算法設(shè)計原則 ......................................................................... 28 LEO 衛(wèi)星網(wǎng)絡(luò)路由設(shè)計考慮因素 ......................................................... 29 基于分時的無環(huán)路由算法設(shè)計 ....................................................................... 30 無環(huán)充分條件 ......................................................................................... 30 算法中的設(shè)計參數(shù) ................................................................................. 31 基于分時的無環(huán)路由算法 ..................................................................... 33 基于分時的無環(huán)路由算法仿真驗證 ............................................................... 38 本章小結(jié) ........................................................................................................... 41 結(jié) 論 ............................................................................................................................... 42 參 考 文 獻(xiàn) ................................................................................................................... 43 致 謝 ......................................................................................................................... 45 基于分時的 LEO 衛(wèi)星網(wǎng)絡(luò)無環(huán)路由算法 1 基于分時的 LEO 衛(wèi)星網(wǎng)絡(luò)無環(huán)路由算法 第 1 章 緒論 課題來源及背景 目前，移動通信系統(tǒng)已經(jīng)進(jìn)入 3G/4G 時代，在日常生活中扮演著越來越重要的角色，時刻影響著人們的生活習(xí)慣和交流方式。 如圖 所示為