Performance Analysis of Decision Feedback and Linear Equalization schemes for Non-Directed Indoor Optical Wireless Systems

Abstract — Indoor optical wireless systems provide an attractive alternative for realizing next generation Wireless Local Area Networks (WLANs). In this paper, the potential of non-directed, equalized optical wireless systems is theoretically investigated, taking into account the indoor channel impulse response and the characteristics of ambient light noise and thermal noise at the receiver. Three modulation schemes, Pulse-Position-Modulation, On-Off Keying and Pulse Amplitude Modulation, are combined with appropriate equalization methods in order to mitigate the effect of intersymbol interference induced by the infrared chanel. It is shown that the various non-directed configurations can provide data rates of the order of 100Mb/s and beyond, over a medium sized room. Index Terms—wireless infrared communications, decision feedback equalization, linear equalization, pulse position modulation (PPM), on-off keying (OOK), pulse amplitude modulation (PAM) I