An LSI Controller for Satellite Switched TDMA

Abstract

Satellite-switched time division multiple access (SSTDMA) is a high efficiency technique likely to be exploited soon in communications satellites. Besides needing special equipment at the earth stations, two major units are required in the satellite to complete the system, namely, a microwave switching matrix (MSM) and a distribution control unit (DCU). The MSM connects any one uplink to any one downlink in a "telephone exchange" arrangement and the DCU, which can be programmed from the ground, controls the switching of the MSM connection patterns in real time. The DCU also provides the master clock for the complete SSTDMA system. This paper describes an implementation of a DCU using custom large scale integration (LSI), which employs only four chips (two each of two types) for the entire logic to control an 8 x 8 MSM. This offers considerable advantages in terms of mass, power consumption and reliability. Some of the benefits and problems of the LSI implementation are also discussed.