T ELECOMMUNICATIONS traffic studies on communications satellites indicate a saturation of current C-band and Ku-band spectrums in the early 1990’s. Satellite switched time division multiple access (SS/TDMA) is a developing technology that will enhance the efficient utilization of frequency spectrum allocations and the geosynchronous orbital arc.  This  paper describes basic SS/TDMA concepts and esign considerations, and provides an overview of selected planned SS/TDMA systems.

Orbital efficiency through satellite digital switching

http://ieeexplore.ieee.org/iel7/7261566/7261567/07261581.pdf

Network Distribution of Digital Television Signals

Domestic communication satellite (domsat) systems in the United States have a history of 14 years. Currently, several systems are in operation and another will be in early 1981. In recent years, many papers have been published, each describing certain details of a specific system. In contrast, this paper presents an overview and comparison of all the systems. As a background to this survey, the U. S. domsat history is briefly reviewed. The system overview then begins with a look at the satellites. Their basic designs are compared pictorially and through tabular data. Communication subsystems are also compared. The survey then goes on to the terminals, the terrestrial parts of the systems. Representative terminal characteristics are discussed. Finally, the various communication services offered by these systems are described.

U. S. Domestic Communication Satellite Systems

An analysis of SS/TDMA steady-state synchronization is presented, in which the need for reliable sync maintenance during periods of deep signal fades, beyond the point of communications outage, is considered. The time required for sync-maintenance measurements, together with impact on guard time requirements, will lead to degradation of SS/TDMA transmission efficiency. The need to ensure a sufficiently low rate of occurence of errors in the syncmaintenance measurements also impacts transmission efficiency. A generalized formulation relating the degree of immunity to signal fading, degradation in transmission efficiency, and rate of occurrence of measurement errors is developed. Numerical results are obtained for a typical satellite communications system of current interest. It is shown that sync-maintenance systems can be designed to operate reliably during severe signal fades, orders of magnitude beyond the point of communication outage, at the expense of minimal degradation of transmission efficiency. For this level of performance it is shown that, with proper choice of parameters, virtually error-free syncmaintenance operation can be achieved. Numerical values of typical design parameters are presented.

W. Callanan

Papers

Advanced Westar SS/TDMA system