Adaptive Moblile Spot Diffusing Transmiter for an Indoor Optical Wireless System

An adaptive approach is used to adjust the transmit power of each beam in a line strip multi-beam optical transmitter based on information about the quality of the received signal due to each spot. The system assumes a feedback link between the optical transceivers. Diversity detection is employed to combat the degrading effect of the background noise in the channel with a 7detectors angle diversity receiver. Both the optical transmitter and the multibranch receiver are fully mobile. The performance of the system is evaluated for two weakest links and compared against that of a non-adaptive spot diffusing transmitter. Our results show that the adaptive transmitter produces a considerable gain of 12.9 dB in signal-to-noise-ratio (SNR) when the distance separating the transceivers is largest in the case of a non mobile transmitter. Furthermore, a 6.8 dB increase in SNR is obtained for the mobile transmitter compared to the non-adaptive transmitter's scenario.