Citation
Abstract
We show the capacity of a pulse-position-modulated (PPM) direct-detected optical communications link goes as 1/R2 at high signal-to-noise ratio (SNR) and 1/R4 at low SNR, where R is the range, and illustrate some consequences of this change in slope. First, we show the capacity is unaffected when the receive diameter is increased and the effective isotropic radiated power (EIRP) decreased in equal proportions, only up to a critical diameter, and that when the receive diameter is larger than this threshold, the receive diameter– EIRP trade-off is unequal (2:1, in dB). Second, we show that this transition in slope implies a crossover in optical and RF capacities as a function of the range, demonstrating the transition for sample deep-space communications links.
Details
- Volume
- 42-199
- Published
- November 15, 2014
- Pages
- 1–10
- File Size
- 587.3 KB