Domestic Satellite Communication System Research Articles

Telesat Canada's Anik E spacecraft

Starting in 1990, Telesat Canada, the owner and operator of Canada's domestic satellite communications system, will need to replenish its C-band and Ku-band space segments because of service life considerations. The need to replace both C-band and Ku-band satellites within a short timeframe, and the availability of new large capacity spacecraft service modules has enabled Telesat to specify dual-band satellites for its fifth generation Anik E space segment. Two Anik E satellites will be launched in 1990 and will provide enhanced performance in both frequency bands when compared to the existing space segment. The satellites promise significant cost savings over single-band satellites of comparable performance. Spar Aerospace has been selected as the Prime Contractor and RCA will provide the RCA 5000 service modules. This paper reviews the main performance requirements and the key spacecraft design features of Anik E. The dual-band communications subsystem is discussed in some detail, and the main features of the service module are also addressed.

The Palapa Project and Rural Development in Indonesia

abstractThe Palapa domestic satellite communications system is an indispensable part of Indonesia’s plan to achieve national integration and economic stability.The use of rural “satellite” television is vital in terms of rural development and in promoting the use of the national language Bahasa Indonesia among Indonesia’s 170 different ethnic groups scattered over an area of more than five million sq kilometers

Minors and the Satellite

The Australian Satellite Users Association (AUSSAT, later SATUsers)1 was formed in 1981 by a number of concerned individuals who believed that planning for a domestic satellite communications system was proceeding with scant regard for the interests of minor, non-profit, users. While much had been said about the potential benefits of the proposed system for the isolated and disadvantaged, there was every indication that its technical specifications, tariff schedules and operating conventions would be heavily influenced by the demands of television networks and by Telecom Australia's determination to protect existing terrestrial markets.

30/20-GHz domestic satellite communication system in the public communication network of Japan: Design and operation

Nippon Telegraph and Telephone Public Corporation (NTT) initiated the world's first 30/20-GHz domestic satellite communication system for commercial use, using CS-2s launched from Japan in 1983. This system utilizes TDMA digital communication in the trunk transmission route of the public communication network, which includes interregional-center routes and main-island-to-remoteisland routes. Small transportable earth stations enable easy access to the public communication network from any place in Japan. The adoption of the 30/20-GHz band enables use of a compact on-board antenna that has a shaped beam that effectively covers the main islands of Japan. It also enables the use of high-performance, compact antennas at the earth stations. These antennas can easily be installed on the roof of telephone offices or set on motor vehicles. One apparent disadvantage of using the 30/20-GHz band is rain attenuation. However, NTT has realized a commercial system that is affected very little by rain attenuation. This was accomplished by utilizing high-performance radio equipment and by concentrating on appropriate system design. Adoption of the 30/20-GHz band is quite significant because the wide bandwidth available enables construction of high-capacity economical transmission systems. It also enables use of small antennas, which allow construction of high-speed digital direct-to-user transmission systems using small earth stations. These expand the application of the domestic satellite communication system to even small service areas. Therefore, NTT considers satellite communication to be of primary importance for its proposed digital communication network, and has begun research on a high-capacity, economical, multibeam communication satellite system using the 30/20-GHz band. This paper describes the 30/20-GHz band radio technology, digital communication technology utilizing high-speed TDMA, and operational technology in the public communication network.

RCA satellite networks: High technology and low user cost

Channel demands on the RCA Americom domestic satellite communications system have continued to increase rapidly since the first launch in 1975. After deploying four of the first-generation 24-channel spacecraft, Americom introduced an advanced, all-solid-state design in 1982 which has more than twice the traffic capacity of the original series. To supplement the operational network of six C-band satellites, K-band satellites will be introduced in 1985 to serve the "small master-antenna TV market and digital satellite networks. Accompanying the continuous incorporation of state-of-the-art technology into successive satellites to achieve increased traffic capacity and longer life, new terrestrial equipment and efficient signal processing/modulation techniques are being exploited to continue the competitive reduction of cost per satellite Circuit per year.

Satellite Communication System Using TDM and SSMA

An outline and the multiple access techniques used in a domestic satellite communications system accommodating numerous small Earth stations are presented. Two kinds of Earth stations are employed in this system, a small Earth terminal (SET) and a master Earth station (MES). Forty-eight two-way satellite channels were achieved in the 6/4 GHz bands with a transponder eirp of about 62 dBm. Time division multiplex is employed in the MES to SET link and spread spectrum multiple access in the SET to MES link.

30/20 GHz Band SCPC Satellite Communication Using Small Earth Stations

This paper presents a domestic satellite communication system accommodating numerous 30/20 GHz band small earth stations emphasizing the system outline, the use of multiple-access (MA) techniques. It also describes associated earth station configurations, equipment performance, and experimental results using the Japanese CS (medium capacity communications satellite for experimental purposes). Two kinds of earth stations are employed in this system, a small earth terminal (SET) and a master earth station (MES). The SET, which has an antenna about 2 m in diameter, is placed near a subscriber. The MES, which has an 11.5 m diameter antenna, is connected to the terrestrial telephone network through a satellite telephone switching center (STC). There are about 50 two-way channels with bit rates of 32 kbits/s which are achieved through the use of a 30/20 GHz band transponder whose EIRP is about 71.5 dBm, a <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">G/T</tex> of about 2.7 dB/K and an SET's antenna diameter of 1.8 m. This results in a system availability of 99.5 percent under typical Japanese statistical rain attenuation data. To enable a demand-assigned MA technique to be employed in this system, a single channel per carrier (SCPC) is selected, taking into consideration power efficiency of the SET, flexibility of system configurations, and the adaptability of the adaptive power control during rainy periods.

Advanced high capacity domestic satellite communications system

This paper describes a concept of multibeam high capacity transmission possible with a 30/20 GHz and 50/40 GHz domestic satellite communication system. The relationship between satellite antenna pointing accuracy and multi-beam antenna interference, as well as the relationship between satellite antenna pointing accuracy and multi-satellite interference are looked at. The ultra high capacity domestic satellite communication system will have multi-beam antennas with a 76.0 dB at both 20 GHz and 40 GHz. These antennas will provide 4950 beams that approximately correspond to the number of end office of the Japanese telephone network, and have a pointing accuracy of 0.005 degrees. This system will be equipped with 9900 30/20 GHz and 50/40 GHz transponder channels with bit rates of 800 Mbps. Its capacity will be 119 Tbps through use of 15 large communication satellite platforms.

30–20 GHz domestic satellite communication system experiments

Experiments have been carried out on a 30–20 GHz domestic satellite communication system. This system employs both a fixed earth station having an 11.5 m-effective-aperture antenna and a small transportable earth station with a 2.7 m-aperture antenna. It was verified that a fixed earth station installed in a major-city telephone office can provide a transmission capacity of 480 two-way voice channels per transponder using a 65 Mbit/s TDMA system. For the implementation of temporary circuits, it was found that a small transportable earth station can provide 132 FDM muliplexed telephone signals per transponder.

NTT's domestic satellite communication system

The author presents a survey of Japanese satellite technology on the brink of the "second generation."

Offset Cassegrain Earth Station Antenna for the Japanese Domestic Satellite Communication System

Offset reflector antennas have advantages for communication systems because they are not severely subject to blocking. Difficulties mainly arising from structual asymmetries have inhibited the realization of an offset reflector antenna with a large aperture for commercial use. This paper describes the design of an offset Cassegrain earth station antenna for the Japanese domestic satellite communication system. Antenna measurements showed 76 and 69 percent aperture efficiencies at 20 and 30 GHz, respectively, less than -20 dBi wide angle directivity and an 18 K noise temperature in operating conditions. Performances are far superior to conventional axisymmetrical earth station antennas. The antenna was reassembled on a telephone office building after the measurements. The antenna gain was reconfirmed there, using the sun as a radio frequency source. Experiments show that the earth station antenna and a terrestrial antenna can be placed on the same building without serious interference.

K-Band Mobile Earth Station for Domestic Satellite Communications System

Design considerations of a K -band (30/20 GHz) mobile earth station for a domestic satellite communications system are described. A Japanese Medium Capacity Communication Satellite which utilizes K and C satellite communication bands was considered for the system design. Transmitting power control method, statistical link quality estimation, and equipment description are given.

20, 30 GHz Band Cassegrain Earth Station Antenna for the Japanese Domestic Satellite Communication System

An 11.5 m 30/20 GHz band Cassegrain antenna has been developed for a Japanese domestic satellite communication system earth station. In order to form an economical satellite communication network, the earth station antenna is required to be installed on the top of a telephone office building in a large city. Therefore, interference with terrestrial radio relay systems and antenna load on a building become the most important problems to be investigated. Considering the satellite position in geostationary orbit, a limited steerable system combined with a two-jackscrew drive mechanism is employed to lighten and simplify the antenna structure. Measured antenna aperture efficiencies are 72% in 20 GHz band and 68% in 30 GHz band. Measured wide angle radiation patterns satisfy the CCIR recommendation level. The G/T of the antenna at the feed horn port is measured to be 53.9 dB/K at El = 45\deg at 18.75 GHz. Interference with the 20 GHz band terrestrial radio relay system in extremely near field was experimentally studied. Results show that the terrestrial system's antennas can be installed closely up to about 20 m without serious interference.

Pan-African Telecommunication Network: A Case for Telecommunications in the Development of Africa

Some of the special problems and constraints associated with African Continental Telecommunications axe reviewed. A description of plans to establish a continental terrestrial telecommunication network-now called the Pan-African Telecommunication (PANAFTEL)network is given together with traffic predictions. Future development of such a network in a rapidly expanding traffic environment is surveyed taking into account the complementary role which a domestic satellite communication system would play.

Effect of Trees on Direct Broadcast Television Service by Satellites

Attenuation due to the presence of trees and woods in the vicinity of transmitting and receiving antennas for terrestrial television service have been summarized and used for predicting and theoretically calculating the same in case of a domestic Satellite Communication System. Suggestions have been made for modifying the design of receiving system.

A Model of a Domestic Satellite Communication System

A preliminary study of a domestic satellite system is reported. Since the objective was to determine what might ultimately be possible, no attempt is made to relate system capacity to estimated needs; rather an effort has been made to conceive a system to carry the greatest possible amount of traffic. By making full use of modern rocket technology including the Saturn V class propulsion systems, highly directive multibeam antennas operating in the range from 15 to 40 GHz, interference resistant modulation methods, highly stabilized synchronous repeater platforms, and integrated solid state microwave repeater electronics, a very large communication capacity is obtained. For example, using 50 ground stations and 50 satellites operating in bands at 20 and 30 GHz, each 4 GHz wide, a total of 100 million voice circuits, or equivalent, can be provided.