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

2. 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 Ka-bands frequencies, digital encryption, and the latest trends towards micro-terminals and Ultra-Small Aperture Terminals (USATs).
TTC&M = Tracking, Telemetry Command and Monitoring

3. Course Objectives (Continued)
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.

4. Nicholas Negroponte – Director of MIT Media Lab says all the services that are wireless today will become wired and all wired services will become wireless based services. His prediction is based on the fact that we are running out of available RF spectrum. It says that OTA broadcast TV service will go on fiber optic cables because of its broadband nature and limitation of frequency spectrum. In 1980s this flip flop has more or less occurred.
Dr. Pelton disagrees from this prediction saying that market trend are not governed by technological constraints. This prediction that since we have spectrum limitation, the market will be forced to shift is not valid. So he proposed his own prediction in mid 1980s. Moreover the analysis is very much based on stats of USA and not valid worldwide.

5. Traffic on Wireless Media
Age of Multimedia Transmission and Integrated Digital Services
Traffic on Wireless Media
Traffic on Fiber and Wire Technologies
There are many services that work on Wireless and many services that work on fiber optic, so the future will be to provide services by merging both wired and wireless technologies. Moreover spectrum re-use techniques and new efficiencies on communication technology will drive the future of communication. A type of open interface will be required between fiber and satellite based technologies
HALE (High Altitude, Long Endurance) = High Altitude Platforms systems powered blimp flying at 21Km (14 miles) high to provide mobile telephony and telecommunication services. Japanese obtained a reverse band utilization with lower uplink and higher downlink frequencies with maximum interference of about 5% as submitted to ITU by them.

6. 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.)
FDMA is still used in some parts of the world and is mostly used for Analog transmission but phasing out due to its limitation of carrier assignments etc
Most new satellites use TDMA or CDMA
The terrestrial cable network over fiber has moved to DWDM which works well for fiber (point to point connectivity) but not for satellites where we have processing time (specially in satellites where satellites have onboard processing where the received signal of radio wave is broken down to intermediate frequencies down to base band, re-process, re-generate and send it back to intermediate frequency and then to an RF frequency for re- transmission back to earth. All of this takes time and unless you have Time division type of operation e.g. TDMA or CDMA, because there is no way that we can do all of this processing in the middle of our transmission)

7. FSS vs. MSS vs. BSS
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).
3 dB margin means double the power for transmission
6 dB means 4 folds power for transmission
Due to rain attenuation we have move attenuation at higher frequencies, so uplink can be done by the earth station having no power limitations while downlink from satellites is mostly on solar power hence lower frequencies are utilized to send lower frequency signals to get lesser attenuation and interference.
VHF and UHF around 137, 400/432 MHz are used for data mobile or store and forward type of services while 1.6, 200, 2.5/2.6 GHz are used for mobile voice and data services. We require 10 to 12 dB link margin to allow small portable transceivers to work under foliage and other land based interferences.

8. 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.
DVB RCS = Digital Video Broadcast with Reverse Channel Service used for DTH and Voice services

9. History of Satellites
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.
Newton showed how a cannon fired at the correct elevation angle with the right speed can launch things in the orbit
Arthur C. Clark envisioned the idea of satellites but he thought that due to unreliability of radio tubes will be required to replace the tubes by manned crew But people at Bell Labs invented the transistors that replaced the tubes.
Today people still call Geostationary Orbits after Arthur Clarke as Clarke’s belt
In 1965 we had the first MONLIA Russian satellite systems and IntelSat Early bird Commercial Satellites

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

11. Evolution of different types of satellite services focussing of Big 3 FSS, MSS and DBS services
Blue represents FSS is fueled by DVB and IPoS
MSS is clearly the weak third sister in the industry
The Direct Broadcast Satellite systems Echostart V in USA and SES Global in Europe are predominant
Total revenue in entire satellite services is around $100Billion .

12. Ground equipment is growing from $9.7B to $24B
Launch industry is showing least growth with very few launches from 2001 to 2003 and is consolidated in recent year
Satellite Manufacturing is consolidated also with 16 to 20 satellites per year
Satellite Services have grown very significantly

13. WTO has made agreements with International Telecom companies to develop markets in Asia, Africa and Middle east

17. There are 17000 Channels on Satellites today
VSATs provide Corporate applications such as Credit card verification, inventory control etc.
Dual means some commercial satellites providing military services like video services for soldiers etc.

18. DoD’s share is 25% of FSS utilization is 20~25% satellite services
WGS: The Wideband Global SATCOM system (sometimes called the Wideband Gap-filler Satellite system) is a satellite communications system planned for use in partnership by the United States Department of Defense (DoD) and the Australian Department of Defense. A single WGS spacecraft has as much bandwidth as the entire existing Defense Satellite Communications System (DSCS) constellation.
MUOS: The Mobile User Objective System is an array of geosynchronous satellites being developed for the United States Department of Defense (DoD) to provide global satellite communications (SATCOM).

20. Other Growth Areas
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.
12000 is number of channels Atlantic and pacific regions
While Indian ocean region has the rest of channels
DOCSIS: Data Over Cable Service Interface Specification

21. 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
mailto: