Novel Multiuser Indoor Ultraviolet Communications

This paper presents a novel ultraviolet (UV) based multiuser indoor wireless communication system. We consider a shot-noise limited photon-counting signal model for a multiple-input single-output (MISO) optical fading channel. The system model is described, considering practical constraints such as transmit power limitations and UV safety exposure limits. We characterize the minimum mean squared error (MMSE) filter to minimize the multiple access interference. The lower bound of the bit error rate (BER) of the proposed system is presented, assuming the channel state information (CSI) at the receiver. A maximum likelihood sequence detection (MLSD) is also developed to efficiently mitigate indoor channel impairments when no CSI is available. It is shown that the performance of the proposed system with MLSD approaches the CSI lower bound performance, even with very short sequences. Simulation results also indicate that the proposed system effectively realizes the diversity gain expected from the MISO configuration.