Citation
Abstract
A strategy for data acquisition from a very distant spacecraft is presented, when the system performance can be severely degraded by the Earth’s weather due to the high microwave frequency being used. Two cases are considered, one in which there is a certain minimum data rate to be maintained and one in which there isn’t. The goal is to maximize expected data return, where we assume that there is always new data, ora backlog of old data, that can be sent if conditions are favorable. When there is no minimum rate to be maintained, the optimum strategy is the greedy strategy, which always transmits at that single rate which maximizes the expected data returned. If there is a minimum data rate that we strive to maintain even in adverse conditions, the optimum strategy transmits simultaneously at the minimum or base data rate and at a bonus data rate. We use a coding system designed for the bandwidth-constrained degraded broadcast channel. The optimum version of this system can, under realistic assumptions, save on the order of 5 dB over the conservative strategy of just transmitting at a single lower data rate.
Details
- Volume
- 42-65
- Published
- October 15, 1981
- Pages
- 34–46
- File Size
- 889.4 KB