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In this paper, we present an ambient light backscatter communication design that enables Internet of Things (IoT) devices to communicate through the backscattering ambient light emitted from lighting infrastructure or sunlight. The device can selectively modulate ambient light by switching a liquid crystal display (LCD) shutter located on its surface, so that a nearby smart device, which includes a photodiode or a camera, can demodulate this backscattered light information. To verify the practicality of the proposed concept, we design an IoT device equipped with a commercial LCD shutter and a microcontroller. Our device produces ambient light backscattered data at a speed of 100 bps, and these data are successfully decoded by a commercial photodiode module 10 cm away from the IoT device. We believe that our ambient light backscatter communication design is appropriate for implementation in various IoT applications.

In this paper, we suggested a real-time frequency interference test-bed considering both interferer's frequency and time domain characteristics. Due to the versatile programming capability of universal software radio peripheral (USRP) and LabVIEW, actual frequency interference environments can be easily modeled. Therefore, performance degradation effects at a victim receiver due to actual multiple interferers, such as bit error rate (BER) and packet error rate (PER), can be analyzed intuitively. As an example, we demonstrated an interference scenario consisting of Zigbee node as a victim and Wi-Fi nodes as interferers. From the measured results, it was verified that our test-bed can model various real-time interference scenarios easily.