IEEE Journal on Selected Areas in Communications

This paper addresses the issues concerning the future of satellite communication, which will be influenced by the advancement of fiber optical cables, the proliferation ofC- andKu-band satellites, the standardization of ISDN, the requirements for new and low cost services, the economic disparity among countries, the extent of institutional policy changes, as well as technolog... View full abstract»

This paper reviews the demand for mobile satellite communications and radiodetermination services from the maritime, aviation, and land mobile communities. It briefly examines existing alternatives and the factors that are affecting the growth and development of mobile satellite communications, with particular reference to INMARSAT. Future mobile earth station standards and services are described ... View full abstract»

This paper describes a TV signal compression scheme which may become a common practice for analog video transmission and broadcast via satellite by the year 2000. The technique uses twodimensional interfield processing to reduce the video bandwidth with minimum degradation in subjective quality, and time multiplexed with analog multiplexing technique for transmission in component format. Computer ... View full abstract»

An appropriate sampling of devices and architectures for onboard TDMA (Time Division Multiple Access) equipment, burst modems, baseband switches, and SCPC (Single Channel per Carrier) multicarrier demodulators from the present to the year 2000 are selected and presented along with device technology development trends, in terms of minimizing onboard weight and power consumption. The results show th... View full abstract»

Towards the year 2000, maritime satellite communications using the INMARSAT system will employ a second and third generation of satellites and new ship earth stations (SES). The new SES standards will use very small antennas with gains between 0 and 15 dBi. At the lower end of SES there will be no antenna stabilization. The communication channel for such small stations is described by a model incl... View full abstract»

The paper discusses orbital diversity (OD) used as the common resource in a satellite communication adaptive system affected by rain attenuation. To give quantitative results, a simulation at 20/30 GHz is performed with a mathematical model; also, some experimental results are shown. OD performance for a single site is first discussed. Then the probabilistic theory for adaptive systems is built up... View full abstract»

The paper will review the conceptual development over the last decade of the use of very large spacecraft, i.e., "platforms," in geostationary orbit. Geostationary platforms were originally conceived as an efficient means of increasing the capacity at a point in the geostationary orbital arc. This geostationary platform was seen as a solution to the predicted crowding of the orbital arc since it c... View full abstract»

Europe has so far launched four experimental and six operational communications satellites successfully. Fifteen more spacecraft are scheduled to be launched before the end of 1990. As everywhere in the world, requirements for new telecommunications services are emerging very rapidly, and it is becoming increasingly apparent that the planned developments in terrestrial networks (ISDN, radio cellul... View full abstract»

A large geostationary communications platform can offer many attractive possibilities for providing lower cost communications. The platform payload concept described in this paper attempts to exploit these possibilities. The use of a combination of spot and wide-area coverage beams accommodates users in both high- and low-density population areas, and provides a good degree of frequency reuse. A s... View full abstract»

Japan now operates the communications satellite CS-2. A test communications satellite, CS-1, was launched in 1977, and CS-3 will be launched in 1988 as a successor to CS-2. On the other hand, in the area of mobile satellite communications development, Japan is proceeding with an experimental program; ETS-V/EMSS (Engineering Test Satellite-V/Experimental Mobile Satellite System), for which a satell... View full abstract»

An algorithm has been developed to evaluate the benefits of intersatellite links (ISL's) quantitatively in satellite communications networks. The developed algorithm derives the minimum satellite capacity, under the condition that the same type of satellites are located onto the geostationary orbit, by assigning traffic among earth stations to the satellites effectively. Some example calculations ... View full abstract»

This paper discusses a number of coding techniques for future satellite communication; they include Reed-Solomon error decoding for message blocks, probabilistic decoding techniques for punctured convolutional codes, and planar Euclidean geometry difference set codes for random multiple access applications. The provision of code concatenation, helical interleaving, and simulation results of new pu... View full abstract»

Commercial satellite communications continues to undergo changes arising not only from advancing technology but also from new service offerings and regulatory activities. As the communications industry grows more competitive, future directions in satellite communications will become more economically than technologically motivated. This paper addresses the future of satellite communications, empha... View full abstract»

An adaptive multiple beam system, which has flexibility to adapt beam power to varying beam traffic, is proposed. The multiple beam transmitter, which is called "hybrid transponder" in this paper, consists of a pair of multiport hybrids and a set of amplifying elements. Power combining, isolation, and intermodulation characteristics of this multiport network are analyzed. Also, a new interbeam exc... View full abstract»

This paper describes and analyzes a pipeline protocol for the data message communications of MSAT-X, a proposed experimental satellite-based mobile communications network. A demand-assigned multiple access protocol using pure ALOHA for making reservation requests has been developed for MSAT-X under error-free assumptions. Preliminary propagation studies indicate that the shortterm bit error rate o... View full abstract»

A PSK group modem which modulates and demodulates multiple PSK signals en bloc will play an important role in realizing a cost-effective satellite communications system based on the narrowband multicarrier PSK/FDMA technique. This paper briefly discusses its possible applications, and presents a developed PSK group modem including its algorithm, hardware design, and implementation. In the algorith... View full abstract»