Optical Camera Communications for IoT-Rolling-Shutter Based MIMO Scheme with Grouped LED Array Transmitter

Area of Science:

• Optical Camera Communications (OCC)
• Wireless Sensor Networks
• Internet of Things (IoT)

Background:

• Optical Camera Communications (OCC) faces challenges in providing flicker-free illumination and high data rates simultaneously.
• The rolling-shutter (RS) property of image sensors offers a potential solution for OCC receivers (Rx).

Purpose of the Study:

• To propose and experimentally validate an RS-based multiple-input multiple-output (MIMO) OCC scheme tailored for Internet of Things (IoT) applications.
• To demonstrate flicker-free transmission using a simplified multi-channel transmitter (Tx) design with a compact LED array.

Main Methods:

• Implementation of a multi-channel transmitter (Tx) with a 7.2 × 7.2 cm^2, 8 × 8 distributed Light Emitting Diode (LED) array, utilizing LED grouping.
• Experimental setup of an indoor OCC system employing a Raspberry Pi camera in RS capturing mode as the receiver (Rx).
• Investigation of different multi-channel Tx configurations to extend communication range and data throughput.

Main Results:

• Established flicker-free communication links ranging from 20-100 cm with data throughputs of 120-960 bps, suitable for IoT.
• Extended communication link spans up to 1.8 m and achieved data throughputs of 13.44 kbps with optimized Tx configurations.
• Measured peak signal-to-noise ratios of ~14-16 dB and successfully received bit rates of 81-99.4% at a 1 m link span for different shutter speeds (200-800 µs).

Conclusions:

• The proposed RS-based MIMO OCC scheme effectively addresses the challenges of flicker-free illumination and data rate provision for IoT.
• The system demonstrates feasibility for practical indoor IoT applications, offering adjustable performance through Tx configuration and camera settings.