Optical beam propagation through the turbulent media such as the vehicle exhaust plumes need to be studied in order to estimate the communication performance degradations on vehicular visible light communication (V2LC) networks. When the optical transceiver is close to the exhaust plumes, the optical waves may be distorted in both phase and amplitude, by perturbations on the air's refractive index spatially and temporally. In this paper, the authors present the measurements performed on V2LC communication link using two different vehicles. In particular, several different transceiver configurations with respect to the position of exhaust nozzle have been tested and compared, and the turbulence strength is evaluated by scintillation index (SI). Since the V2LC applications are mainly based on intensity modulated, direct detection method, only the receiving optical power fluctuation (scintillation) will be discussed. Finally, the error rate performance under different log intensity variances is analyzed, demonstrating that scintillation effects introduced by the vehicle exhaust can be negligible in V2LC applications.
Short range non-line-of-sight (NLOS) ultraviolet (UV) communication, with its solar blind and Non-Line-of- Sight characteristic, received grant interest. However as the communication range increases, the communication performance deteriotes due to NLOS UV turbulence, even with special UV turbulence mitigation. In this work, we conducted a series of outdoor experiments to investigate the received signal energy distribution, which is the product of the complex interaction of transmitted UV radiation, by utlizing both a UV LED array and a UV laser, with the atmosphere. Separation distance, pointing angles and UV light source were taken into considerate as key parameters to affect the distribution. These experimental results will be valuable for studying NLOS UV communication performance.
Proc. SPIE. 8874, Laser Communication and Propagation through the Atmosphere and Oceans II
KEYWORDS: Signal to noise ratio, Photon counting, Scattering, Signal attenuation, Ultraviolet radiation, Interference (communication), Receivers, Telecommunications, Mie scattering, Global Positioning System
Recently, Ultraviolet communication is paid more and more attention, with its solar blind and Non-Line-of-Sight characteristic. However, it is hard to capture and recover the transmitted signal outdoor without synchronized signal. In this work, we integrate Universal Software Radio Peripheral (USRP) into UV communication system and employ GPS as synchronized signal. At receive side, photon counting and adaptive threshold method are used to recover original signal. Through experiments, we test path loss and BER of the system under di erent con guration geometries. Some results are compared to the previous proposed path loss and BER models.