Experimental Demonstration of High-Speed 4 × 4 Imaging Multi-CAP MIMO Visible Light Communications

• Published in: Journal of lightwave technology 2018-05, Vol.36 (10), p.1944-1951
• Main Authors: Werfli, Khald, Chvojka, Petr, Ghassemlooy, Zabih, Hassan, Navid Bani, Zvanovec, Stanislav, Burton, Andrew, Haigh, Paul Anthony, Bhatnagar, Manav R.
• Format: Article
• Language: English
• Subjects: Bandwidth; Bandwidths; Bit error rate; Imaging; Lenses; Light emitting diodes; MIMO communication; Modulation bandwidth; multi-band carrier-less amplitude and phase modulation; multiple-input multiple-output; Multiplexing; OFDM; Optical communication; Organic light emitting diodes; Subcarriers; Visible light communication; visible light communications; White light
• ISSN: 0733-8724; 1558-2213
• DOI: 10.1109/JLT.2018.2796503

In general, visible light communication (VLC) systems, which utilise white light-emitting diodes (LEDs), only offer a bandwidth limited to the lower MHz region. Therefore, providing VLC-based high data rate communications systems using VLC becomes a challenging task. To address this challenge, we propose a solution based on multiplexing in both the frequency and space domains. We experimentally demonstrate a 4 × 4 imaging multiple-input multiple-output (MIMO) VLC system (i.e., space multiplexing) utilising multiband carrierless amplitude and phase (m-CAP) modulation (i.e., frequency multiplexing). Independently, both MIMO and m-CAP have separately shown the remarkable ability to improve the transmission speeds in VLC systems, and hence, here we combine them to further improve the net data rate. We investigate the link performance by varying the number of subcarriers m, link distance L, and signal bandwidth B sig . From all the values tested, we show that a data rate of ~249 Mb/s can be maximally achieved for m = 20, B sig = 20 MHz, and L = 1 m, at a bit error rate of 3.2 × 10 -3 using LEDs with ~4 MHz bandwidth.