I found some articles in this direction: - http://arxiv.org/pdf/0810.3966 http://arxiv.org/pdf/0810.3966, Searching for Cost-Optimized Interstellar Beacons and

I found some articles in this direction: - http://arxiv.org/pdf/0810.3966 http://arxiv.org/pdf/0810.3966, Searching for Cost-Optimized Interstellar Beacons and Messaging with Cost-Optimized Interstellar Beacons, by James Benford (short pulses rather than a continuous signal). - http://escholarship.org/uc/item/4w59f2wk.pdf http://escholarship.org/uc/item/4w59f2wk.pdf, Design of interstellar digital communication links: Some insights from communication engineering, by David Messerschmitt (optimization as a coordination tool with aliens).