This document discusses satellite communications and provides details on various topics: 1) It explains how satellites relay communications between two earth stations, with signals sent to the satellite (uplink) and received from the satellite (downlink). 2) Satellites provide advantages like wide coverage area and independence from transmission distance, but also disadvantages like high launch costs and limited bandwidth. 3) It describes different types of satellite orbits - geostationary (GEO), low earth orbit (LEO), medium earth orbit (MEO), and Molniya orbit - and their characteristics. 4) The document outlines capacity allocation methods for satellites, specifically frequency division multiple access (FDMA) and time division multiple access (