Wireless infrared communication links using multi-beam transmitters and imaging receivers

We discuss two modifications to the design of wireless infrared links that can yield dramatic performance improvements. In nondirected, non-line-of-sight (non-LOS) links, replacement of the diffuse transmitter by one that projects multiple narrow beams can reduce the path loss, typically increasing the link SNR by about 20 dB. In both non-directed, LOS and non-directed, non-LOS links, replacement of the non-imaging receiver by one employing an imaging light concentrator and a segmented photodetector can reduce the received ambient light noise and multipath distortion. This can yield SNR improvements of tens of decibels