Optical wireless links automatically align themselves using feedback information
that is transmitted over the light beams being aligned. Each link performs an acquisition
routine in which its light beam is swept through a pre-defined pattern while transmitting
its beam alignment information. When a link receives beam alignment information
from a remote link, it updates its transmission to include the alignment information
received from the remote link. At some point during the acquisition routine, the
remote link will receive its own alignment information "echoed back" from the first
link and will re-align its beam accordingly. At some point, each link will have
received its own alignment information echoed back from the other link and will
have aligned itself to that position. Data communication can begin at that point,
or a more refined alignment step can then be performed. The alignment information
can be based upon position, sample number, or time transmitted.
