Performance of diffused indoor optical wireless links employing neural and adaptive linear equalizers

This paper presents a comparative study of two equalizers, the adaptive linear and the neural equalizer for indoor optical wireless (OW) links. Three modulation schemes representative of a range of modulation techniques widely adopted in indoor OW systems are chosen to investigate the effectiveness of the proposed equalizers. It is shown that on-off keying (OOK) modulation technique is least affected by the multipath induced intersymbol interference (ISI), while the pulse position modulation (PPM) scheme is the most severely affected. In case of highly diffused channel, the equalized digital pulse interval modulation (DPIM) outperforms the equalized PPM and there is little or no gain in using PPM compared to OOK.