Satellite Communications - Introduction

This three-day introductory course reviews the essential elements of all satellite communications systems, with an emphasis on system design and performance. The objective is to inform new engineers and other professionals as well as those knowledgeable in specific technical and business areas by covering the technical characteristics of each aspect of the space and ground system, and show how they relate to each other. The fundamental connection is the radio link between satellite and earth station, which is covered in detail. Basic design of the satellite and earth station are covered to identify primary elements of each and to compare alternatives which have been and continue to be employed in real systems. These include geostationary satellites and non-geostationary constellations that are currently in development.

• How satellite communications relate to other forms of wireless systems that are used to provide one-way broadcasting and two-way interactive services, especially those delivered through the global Internet
• The framework that defines the properties of the satellite itself as part of the system and as governed by international rules and regulations, and as offered by commercial operators around the world
• The types of earth stations used to employ space resources, particularly very small aperture terminals (VSATs) to fixed and mobile users, and larger stations used as hubs and gateways
• The basic principles of radio-wave propagation and the link budget, which establish whether the connection between user and satellite will work as required
• The tradeoffs among the various orbits, frequency bands, and modulation and coding technologies needed to realize the required services via the satellite link
• The evolution of this technology in a changing world

1. Satellite Systems, Services, and Regulation. Introduction and historical background. The place of satellites in telecommunications. Satellite service definitions: broadcasting BSS, fixed-satellite FSS, and mobile satellite MSS. Major suppliers and operators of satellites. Satellite regulation: role of the ITU, FCC, and regulatory bodies of the various countries where services are provided. Satellite system design overview. Satellite real-world demands: security, control of accidental and intentional interference, resolving RFI.
2. Technical Fundamentals. Satellite orbit alternatives and their characteristics: geostationary and non-geostationary. Basic definitions: channels, circuits, transponders, decibels. Satellite frequency bands – L, S, C, X, Ku, Ka, etc.: properties of waves, free space loss, polarization, bandwidth. Propagation through the atmosphere: air and clouds, rain, the ionosphere. Carrying information on radio waves: coding, modulation, multiplexing, DVB-S2 standard and extensions. Digital communications demands: bit error rate and availability.
3. The Space Segment. The space environment: gravity, radiation and space debris. Orbits: geostationary orbits; non-geostationary orbits. Orbital slots, footprints, and coverage; satellite spacing; eclipses and sun interference. Basic design of a satellite: structure and spacecraft subsystems (bus), antennas and repeaters (payload).
4. The Ground Segment. Earth stations: types – VSATs and hubs, RF equipment (amplifiers and frequency converters), antenna configurations (reflector designs, phased arrays), mounting and pointing (fixed and mobile installations). Antenna properties: gain; directionality; sidelobes and legal limits on sidelobe gain. Electronics, EIRP, and G/T: LNA and LNB, SSPA; signal flow through an earth station.
5. The Satellite Earth Link. Atmospheric effects on signals: rain effects and rain climate models; rain fade margins. Link budgets, C/N and Eb/No. Multiple access techniques: FDMA, TDMA and ALOHA, CDMA; Paired Carrier Multiple Access, demand assignment; on-board processing. Signal security issues. Internet Protocol networks and adaptation to the satellite link.
6. Conclusion. Industry issues and trends: non-geostationary constellations for broadband, small sats, high altitude platforms, and challenges in the future.

Bruce R. Elbert MS (EE), MBA, Adjunct Professor (ret), College of Engineering, University of Wisconsin, Madison. Mr. Elbert is a recognized satellite communications expert and has been involved in the satellite and telecommunications industries for over 40 years. He founded Application Technology Strategy, LLC, to assist major private and public sector organizations that develop and operate cutting-edge networks using satellite and other wireless technologies During 25 years with Hughes Electronics, he directed the design of several major satellite projects, including Palapa A, Indonesia’s original satellite system; the Galaxy follow-on; and the development of the first GEO mobile satellite system capable of serving handheld user terminals. Mr. Elbert was also ground segment manager for the Hughes system, which included eight teleports and 3 VSAT hubs. He served in the US Army Signal Corps as a radio communications officer and instructor. By considering the technical, business, and operational aspects of satellite systems, Mr. Elbert has contributed to the operational and economic success of leading organizations in the field. He has written nine books on telecommunications and IT.