Fixed Satellite Services

Fixed Satellite Systems (1) Objectives, Key Definitions and System Growth Dr. Joseph N. Pelton

Course Objectives 

The course explores the evolution of fixed satellite services over time and its relation to other ICT technologies – particularly fiber optic networks. This course explores such aspects as the development of new types of ground system, TTC&M operations, the ability of satellites to operate at higher power levels with increased frequency re-use, in higher frequency bands and in “noisy” urban environments. Many of these innovations are possible due to the evolution of digital services and technologies. Key trends in FSS field that are examined included the shift from C-band to Ku-band and now the Kabands frequencies, digital encryption, and the latest trends towards micro-terminals and Ultra-Small Aperture Terminals (USATs).

Course Objectives (Continued) 

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The course also address how various satellite systems are addressing orbital congestion, open trade, short-term on-demand access to satellite networks by broadcasters. It also briefly addresses defense systems and current business user needs provision of virtual private networks. Also explored are new MPEG standards, DVB and DOCSIS, the impact of the internet and broadband IP services on the satellite world, and the evolution of the new IPoS standard and “accelerators”. It also addresses how the communications satellite industry may evolve in the future to meet commercial, security and defense related needs. The course will include a series of lectures, readings in text materials, class assignments and final exam.

Traffic on Wireless Media

Age of Multimedia Transmission and Integrated Digital Services

Traffic on Fiber and Wire Technologies

The Relative Merits of Multiplexing Systems  FDMA:

Frequency Division Multiple Access  TDMA: Time Division Multiple Access  CDMA: Code Division Multiple Access  DWDM: Dense Wave Division Multiple Access (This is an approach that works for fiber optic networks but not for advanced satellite communications systems.)

FSS vs. MSS vs. BSS 

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Fixed Satellite Services (FSS) are offered essentially in C band (6/4 GHz), Ku bands (14/12 GHz) and Ka band (30/20 GHz) while defense fixed services are primarily in X band (8/7 GHz) and Ka band (30/20 GHz) and are between fixed antennas with a clear line of sight to the satellite and 3-6 dB of link margin. Mobile Satellite Services (MSS) are offered in the lower VHF, UHF bands (137 MHz, 400/432 MHz, 1.6 GHz, 2.0 GHz, 2.5/2.6 GHz bands because mobile terminals may be shadowed or partially blocked. They need to have frequencies that are more tolerant of not always having a clear line of sight to the satellite. They also need higher link margins (10-22 dB) because of blockage by foliage, power-line poles, buildings, hillsides, etc. They also need more power (power flux density) to be received especially by small portable or mobile user terminals (i.e. transceivers).

FSS vs. MSS vs. BSS 

Broadcast Satellite Services (BSS) are offered essentially 18/12 GHz bands allocated by the ITU but what is called direct-to-the-home (DTH) services are sometimes offered on FSS satellites that have higher power and thus can offer service to a small receiving terminal at the home even though it is technically not a BSS satellite operating in the BSS frequencies. Hughes Galaxy, SES Astra in Europe, and PanAmSat have operated DTH services in FSS frequency bands. They size of user terminals today are in the 0.8 meter to 0.35 meter range. BSS and FSS satellites are both used to provide Digital Video Broadcast (DVB) services.

History of Satellites  

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Newton showed how an artificial satellite could be launched. Everett Edward Hale wrote about The Brick Moon that would be launched into polar orbit to provide navigation and communications services. Tsiolokowsky, Willy Lev, Robert Goddard developed key ideas about rocket propulsion Arthur C. Clarke in 1945 wrote an article in Wireless World to explain how three satellites in Geosynchronous orbit could provide global coverage. In 1959 Sputnik was launched and in 1960 the first experimental communications satellites were launched These included SCORE, Courier 1B, Echo, Telstar, Relay, and Syncom.

Development of first GEO Satellite Systems Dr. Rosen and his crew at Hughes Satellite Systems

Other Growth Areas 

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Another major growth area has been broadcasting services as the number of satellite based channels world wide have grown to some 12,000. This growth has been aided by the emergence of effective capacity consolidators and value added contractors, the largest of which is Globecast. New digital compression standards has also increased the cost efficiency of these services. For the last five years Internet/IP related services and especially digital video broadcast with return channel service (DVB-RCS) and other similar standards, including the cable television based standard of DOCSIS (Data over Cable Service Interface Standard) have been a primary growth area for FSS satellites.

Assignment 

Assignment 7: – Explain the following:  Why DWDM can not work for Satellite communications systems?  What is meant by the term “The Brick Moon”  Define WGS, MUOS, HALE and DSCS