Wavelet-artificial neural network receiver for indoor optical wireless communications

The multipath-induced intersymbol interference (ISI) and fluorescent light interference (FLI) are the two most important system impairments that affect the performance of indoor optical wireless communication systems. The presence of either incurs a high optical power penalty and hence the interferences should be mitigated with suitable techniques to ensure optimum system performance. The discrete wavelet transform (DWT) and the artificial neural network (ANN)-based receiver to mitigate the effect of FLI and ISI has been proposed in the previous study for the ON-OFF keying (OOK) modulation scheme. It offers performance improvement compared to the traditional methods of employing a high-pass filter and a finite impulse response equalizer. In this paper, the investigation of the DWT-ANN-based receiver for baseband modulation techniques including OOK, pulse position modulation, and digital pulse interval modulation is reported. The proposed system is implemented using digital signal processing board and results are verified by comparison with simulation data.