Abstract: 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.

Abstract: Optical wireless links automatically re-acquire alignment after detecting the loss of an incoming signal bearing light beam. The loss of the signal may be due to a temporary blockage of the light path, so the devices will await a programmable period of time before attempt to re-align themselves. If re-alignment is required, the devices will first position their light beams to the last known aligned position and will from that point sweep through a pattern seeking to re-align with the remote device. The devices transmit their beam position information during the sweep, which information will be echoed back or fed back to the device once its beam impinges upon the remote devices photodetectors. If the devices cannot re-align, then a second, longer sweep pattern may be performed, starting at some predefined default location.

Abstract: Optical wireless links communicate beam alignment information between them over a collimated, modulated light beam, without the requirement of a secondary channel. The alignment feedback signal can be formatted as control packets that are inserted between data packets traveling over the optical wireless channel, as control packets that are combined with the data packets, as a low frequency modulation of the light beam, or similar approaches. Alignment feedback signals are used by the device receiving the signal to align its light beam using a beam steering device, such as a micro-mirror device. Control signals preferably include x and y coordinate information relating to the position of both devices that are communicating, as well as time stamp, sample number, and similar synchronization information. Control packets are extracted from the data stream by a switch based upon the destination address of the control packets.

Abstract: 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 links 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.