Signal Processing
Modulation/Demodulation
As with fiber optics, ASK modulation are envisaged for in space. In connection with a coherent receiver, phase shift keying (and possibly frequency shift keying) is an attractive alternative to on-off keying, as it makes better use of the carrier power. Because of recent developments in demodulation of phase shifted laser signals in free space, Walter R. Leeb, a researcher at the Technische Universität in Austria suggests that BPSK will probably be the standard modulation method, because of it's relatively lower signal loss through the atmosphere. When it comes to Earth to Satellite communication, this is very important.
Encoding/Decoding Schemes
Recent studies show that a simple Return-to-Zero encoding scheme would work well for laser communication in free space and may actually be more efficient than using the traditional NRZ protocol in other optical systems.
Data Rates
Typical Data rates for retrofitting existing systems with optical laser communications technology could speed up the current data rates of about 6 Mbps to between 60 and 600 Mbps!