📄 node197.html
字号:
<html><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN"><!--Converted with jLaTeX2HTML 2002 (1.62) JA patch-1.4patched version by: Kenshi Muto, Debian Project.LaTeX2HTML 2002 (1.62),original version by: Nikos Drakos, CBLU, University of Leeds* revised and updated by: Marcus Hennecke, Ross Moore, Herb Swan* with significant contributions from: Jens Lippmann, Marek Rouchal, Martin Wilck and others --><HTML><HEAD><TITLE>17.1.1 Geostationary satellites</TITLE><META NAME="description" CONTENT="17.1.1 Geostationary satellites"><META NAME="keywords" CONTENT="everything"><META NAME="resource-type" CONTENT="document"><META NAME="distribution" CONTENT="global"><META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1"><META NAME="Generator" CONTENT="jLaTeX2HTML v2002 JA patch-1.4"><META HTTP-EQUIV="Content-Style-Type" CONTENT="text/css"><LINK REL="STYLESHEET" HREF="everything.css" tppabs="http://www.isi.edu/nsnam/ns/doc/everything.css"><LINK REL="next" HREF="node198.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node198.html"><LINK REL="previous" HREF="node196.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node196.html"><LINK REL="up" HREF="node196.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node196.html"><LINK REL="next" HREF="node198.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node198.html"></HEAD><BODY ><!--Navigation Panel--><A NAME="tex2html4312" HREF="node198.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node198.html"><IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="file:/usr/share/latex2html/icons/next.png"></A> <A NAME="tex2html4306" HREF="node196.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node196.html"><IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="file:/usr/share/latex2html/icons/up.png"></A> <A NAME="tex2html4300" HREF="node196.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node196.html"><IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous" SRC="file:/usr/share/latex2html/icons/prev.png"></A> <A NAME="tex2html4308" HREF="node1.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node1.html"><IMG WIDTH="65" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="contents" SRC="file:/usr/share/latex2html/icons/contents.png"></A> <A NAME="tex2html4310" HREF="node590.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node590.html"><IMG WIDTH="43" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="index" SRC="file:/usr/share/latex2html/icons/index.png"></A> <BR><B> Next:</B> <A NAME="tex2html4313" HREF="node198.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node198.html">17.1.2 Low-earth-orbiting satellites</A><B> Up:</B> <A NAME="tex2html4307" HREF="node196.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node196.html">17.1 Overview of satellite</A><B> Previous:</B> <A NAME="tex2html4301" HREF="node196.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node196.html">17.1 Overview of satellite</A>   <B> <A NAME="tex2html4309" HREF="node1.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node1.html">Contents</A></B>   <B> <A NAME="tex2html4311" HREF="node590.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node590.html">Index</A></B> <BR><BR><!--End of Navigation Panel--><H2><A NAME="SECTION031411000000000000000"></A><A NAME="sec:satellite_overview_geo"></A><BR>17.1.1 Geostationary satellites</H2><P>Geostationary satellites orbit the Earth at an altitude of 22,300 miles above the equator. The position of the satellites is specified in termsof the longitude of the nadir point (subsatellite point on the Earth'ssurface). In practice, geostationary satellites can drift from theirdesignated location due to gravitational perturbations- these effectsare not modelled in . <P>Two kinds of geostationary satellites can be modelled. Traditional``bent-pipe'' geostationary satellites are merely repeaters in orbit-all packets received by such satellites on an uplink channel are pipedthrough at RF frequencies to a corresponding downlink, and the satellite nodeis not visible to routing protocols. Newer satellites willincreasingly use baseband processing, both to regenerate the digital signal andto perform fast packet switching on-boardthe spacecraft. In the simulations, these satellites can be modelled more like traditional nodes with classifiers and routing agents. <P>Previously, users could simulate geostationary satellite links by simplysimulating a long delay link using traditional links and nodes. Thekey enhancement of these satellite extensions with respect to geostationarysatellites is the capability to simulate MAC protocols. Users can nowdefine many terminals at different locations on the Earth's surface andconnect them to the same satellite uplink and downlink channels, and thepropagation delays in the system (which are slightly different for eachuser) are accurately modelled. In addition, the uplink and downlink channelscan be defined differently (perhaps with different bandwidths or error models).<P><HR><!--Navigation Panel--><A NAME="tex2html4312" HREF="node198.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node198.html"><IMG WIDTH="37" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="next" SRC="file:/usr/share/latex2html/icons/next.png"></A> <A NAME="tex2html4306" HREF="node196.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node196.html"><IMG WIDTH="26" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="up" SRC="file:/usr/share/latex2html/icons/up.png"></A> <A NAME="tex2html4300" HREF="node196.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node196.html"><IMG WIDTH="63" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="previous" SRC="file:/usr/share/latex2html/icons/prev.png"></A> <A NAME="tex2html4308" HREF="node1.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node1.html"><IMG WIDTH="65" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="contents" SRC="file:/usr/share/latex2html/icons/contents.png"></A> <A NAME="tex2html4310" HREF="node590.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node590.html"><IMG WIDTH="43" HEIGHT="24" ALIGN="BOTTOM" BORDER="0" ALT="index" SRC="file:/usr/share/latex2html/icons/index.png"></A> <BR><B> Next:</B> <A NAME="tex2html4313" HREF="node198.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node198.html">17.1.2 Low-earth-orbiting satellites</A><B> Up:</B> <A NAME="tex2html4307" HREF="node196.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node196.html">17.1 Overview of satellite</A><B> Previous:</B> <A NAME="tex2html4301" HREF="node196.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node196.html">17.1 Overview of satellite</A>   <B> <A NAME="tex2html4309" HREF="node1.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node1.html">Contents</A></B>   <B> <A NAME="tex2html4311" HREF="node590.html" tppabs="http://www.isi.edu/nsnam/ns/doc/node590.html">Index</A></B> <!--End of Navigation Panel--><ADDRESS>2003-09-23</ADDRESS></BODY></HTML>⌨️ 快捷键说明
复制代码
Ctrl + C
搜索代码
Ctrl + F
全屏模式
F11
切换主题
Ctrl + Shift + D
显示快捷键
?
增大字号
Ctrl + =
减小字号
Ctrl + -