Spectrally and power efficient non-DC MIMO super-Nyquist m-CAP with linear pre- and DFE post-equalizer

Abstract

This paper investigates a multiple-input multiple-output (MIMO) super-Nyquist multi-band carrier-less amplitude and phase (Sm-CAP) visible light communication system to improve spectral efficiency (SE). In Sm-CAP, SE is improved by violating the frequency-domain orthogonality between sub-bands (SBs) at the cost of introducing a pre-determined inter-band interference. Pre- and post-equalizers are also utilized to ameliorate the inter-symbol, inter-band, and inter-channel interference exhibited by the limited modulation bandwidth of light emitting diodes (LEDs), overlapping SBs, and MIMO channel, respectively. Here, we transmit positive and absolute values of negative data over independent LEDs with no DC-biasing to improve the power efficiency. Results show that, by adopting bit-loading in conjunction with the pre- and post-equalizers, a maximum SE of 10.1 b/s/Hz (or equivalently, a bit rate of ∼151 Mb/s) can be achieved for a bandwidth compression level and a roll-off factor of 10% and 0.1, respectively, at the target forward error correction bit error rate limit of 7%.