Proposal Number: ECS-9632829 Principal Investigator: Joseph Kahn/University of California Berkeley Title: Wireless Infrared LANs Using Multi-Beam Transmitters and Image Diversity Receivers Abstract This research will focus on the development of wireless Infrared Local area networks, as an economical high performance alternative to radio for many applications of short range wireless communications. Two new components in wireless infrared links form the main focus of the research (1) multibeam transmitters and (2) imaging diversity receivers. The transmitter, used in non-directed non-line of sight links, replaces the single wide beam of the diffuse transmitter by a collection of much narrower beams that are oriented different directions. By changing the path loss law from the fourth power of distance to the square of distance, the multibeam transmitter can dramatically reduce the transmitter power required in non-directed non-line of sight links. The imaging diversity receiver will use a single optical concentrator such as a liens with a photodetector segmented into multiple pixels, each of which is connected to a separate preamplifier. The imaging receiver will provide several key advantages over the non-imaging receiver: spatial discrimination of signal from noise, high optical gain over a wide field of view, and reduction of multipath delay spread and mitigation of co-channel interference.
