LiDAR Integrated High-Capacity IR OWC System with Abilities of Localization and Link Alignment

By using narrow infrared (IR) beams, optical wireless communication (OWC) system can realize ultra-high capacity and high-privacy transmission. However, due to the point-to-point connection approach, a high-accuracy localization system and beam-steering antenna (BSA) are required to steer the signal beam to user terminals. In addition, to achieve link alignment in the receiver, the BSA needs to be within the limited receiver field of view (FoV). This problem greatly limits the practical application of high-capacity IR optical wireless communication and has not been well solved yet. In this paper, we proposed an indoor beam-steering IR OWC system with high-accuracy and calibration-free localization ability by employing a coaxial frequency modulated continuous wave (FMCW) light detection and ranging (LiDAR) system. In the meantime, benefit from the mm-level ranging accuracy of the LiDAR system, a feasible approach to deal with the link alignment issue for practical applications is firstly demonstrated. With the assistance of the LiDAR system, we experimentally achieved the localization of user terminals with a 0.038-degree localization accuracy, link alignment at the receiver and an error-free on-off keying (OOK) downlink transmission of 20 Gb/s in free space at 3-m distance is demonstrated.

LiDAR Integrated High-Capacity IR OWC System with Abilities of Localization and Link Alignment

By using narrow infrared (IR) beams, optical wireless communication (OWC) system can realize ultra-high capacity and high-privacy transmission. However, due to the point-to-point connection approach, a high-accuracy localization system and beam-steering antenna (BSA) are required to steer the signal beam to user terminals. In addition, to achieve link alignment in the receiver, the BSA needs to be within the limited receiver field of view (FoV). This problem greatly limits the practical application of high-capacity IR optical wireless communication and has not been well solved yet. In this paper, we proposed an indoor beam-steering IR OWC system with high-accuracy and calibration-free localization ability by employing a coaxial frequency modulated continuous wave (FMCW) light detection and ranging (LiDAR) system. In the meantime, benefit from the mm-level ranging accuracy of the LiDAR system, a feasible approach to deal with the link alignment issue for practical applications is firstly demonstrated. With the assistance of the LiDAR system, we experimentally achieved the localization of user terminals with a 0.038-degree localization accuracy, link alignment at the receiver and an error-free on-off keying (OOK) downlink transmission of 20 Gb/s in free space at 3-m distance is demonstrated.

Creation of Hollow-Gaussian Beam for Optical Trap by Dual-beam Nonliear Fabry-perot Interferometer

In this paper, a model of dual-beam nonlinear Fabry-Perot interferometer (DBNFPI) for creation laser hollow-Gaussian beam (HGB) is investigated. It includes a thin film of organic dye sandwiched between two optical mirrors, and irradiated by two signal and pump laser Gaussian beams. Based on the equation describing the output-input relation of intensities concerning pump intensity and the expression of the spatial intensity distribution of output signal beam (OSB), the range of pump intensity and collection of designed parameters are numerically calculated and discussed for HGB creation. These results give us the opportunity to use DBNFPI for optical trap of low-index dielectric particles.

Observation of Nonlinear Optical Phenomenon in Vacuum by Four Waves Mixing

In the present paper, we studied possibility of observation and detection of nonlinear optical effects in free space. We studied four wave mixing process in which signal is generated opposite to the direction of probe beam. We observed that large number of photons are generated in signal beam, which should be detectable.

High-fidelity spatial mode transmission through a 1-km-long multimode fiber via vectorial time reversal

The large number of spatial modes supported by standard multimode fibers is a promising platform for boosting the channel capacity of quantum and classical communications by orders of magnitude. However, the practical use of long multimode fibers is severely hampered by modal crosstalk and polarization mixing. To overcome these challenges, we develop and experimentally demonstrate a vectorial time reversal technique, which is accomplished by digitally pre-shaping the wavefront and polarization of the forward-propagating signal beam to be the phase conjugate of an auxiliary, backward-propagating probe beam. Here, we report an average modal fidelity above 80% for 210 Laguerre-Gauss and Hermite-Gauss modes by using vectorial time reversal over an unstabilized 1-km-long fiber. We also propose a practical and scalable spatial-mode-multiplexed quantum communication protocol over long multimode fibers to illustrate potential applications that can be enabled by our technique.

Design and simulation of an adaptive beam smart antenna using MATLAB

<span id="docs-internal-guid-ad3b6b0d-7fff-2d92-685e-3d423ac2713f"><span>Signals transmitted over a long range of distance may pass through several obstacles and scatter, taking multiple paths to reach the receiver. Beamforming antennas are controlled electronically to adjust the radiation pattern following the first received signal. This allows the antenna to maximize the received signal and consequently, suppress the interfering signals received. A smart antenna should be able to diminish noise, increase the signal to noise ratio, and have better system competence. The adaptive beam makes use of the spacing of the several antennas and the phase of the signal of each antenna array to control the shape and direction of the signal beam. This paper focuses on the use of smart antennas using an adaptive beam method as a better system for the transmission of signals. A simulation between the existing Omnidirectional antenna system and the smart antenna system will be made and compared. The paper will discuss the corresponding advantages that a smart antenna system has compared to the Omnidirectional antenna system.</span></span>

Indoor Omnidirectional Antenna Network Planning using Capacity and Coverage Planning in Gandaria 8 Office Tower Building in PT Artisan Wahyu

Planning to improve the signal condition of cellular telephone networks in a company is very important. PT. Artisan Wahyu is a company engaged in property and real estate. The purpose of this study was to determine the quality and strength of the signal beam at the Gandaria 8 Office Tower using the G-net Track Lite application, to determine the number of indoor omnidirectional antennas based on capacity planning method, and for determining the number of omnidirectional indoor antennas based on coverage planning method. The research method used is quantitative method with a descriptive type of research. By using the analysis method of Capacity Planning and Coverage Planning. Therefore, it is necessary to plan an omnidirectional indoor antenna analysis so that activities in communication can be enjoyed properly. From the results of the research conducted, there were four plans for omnidirectional indoor antenna networks for the 2nd floor based on capacity and coverage of 6 antennas. Whereas for the 22nd floor based on capacity as much as 3 and for coverage as many as five antennas so that the Coverage Planning method is recommended to be applied to the Gandaria Building 8 Office Tower. (FF, FA, RM).

Penerima Sinyal Emergency Locator Transmitter dengan Metode Direct Receiver pada Frekuensi 121,5 MHz

To find out the location of an aircraft accident from an ELT signal beam of 121.5 MHz, search and rescue (SAR) officers or civil aviation authorities need an ELT signal receiver device that works at the same frequency, which is 121.5 MHz. The purpose of this research is to produce an ELT signal receiver with direct receiver method at a frequency of 121.5 MHz which is simpler, requires fewer RF devices, and is according to specifications for civil aviation. In this research, the design and realization of ELT signal receivers are carried out using the direct receiver method, including: a BPF and a RF amplifier as a direct receiver circuit, an AM demodulator, and an audio amplifier. Based on the results of measurements and tests that have been done, the direct receiver circuit can receive an ELT signal at a frequency of 121.5 MHz in the range of 121.330 to 121.617 MHz with -40.35 dB sensitivity, the AM demodulator can demodulate the audio signal at a frequency of 346.6 Hz, and the audio signal at a frequency of 337.6 Hz as a pointer to an ELT signal can be heard through the loudspeaker. The results of this study are ELT signal receivers with direct receiver method at a frequency of 121.5 MHz which are according to specifications for civil aviation.

On the Performance of Random Cognitive mmWave Sensor Networks

This paper investigates the secrecy performance of a cognitive millimeter wave (mmWave) wiretap sensor network, where the secondary transmitter (SU-Tx) intends to communicate with a secondary sensor node under the interference temperature constraint of the primary sensor node. We consider that the random-location eavesdroppers may reside in the signal beam of the secondary network, so that confidential information can still be intercepted. Also, the interference to the primary network is one of the critical issues when the signal beam of the secondary network is aligned with the primary sensor node. Key features of mmWave networks, such as large number of antennas, variable propagation law and sensitivity to blockages, are taken into consideration. Moreover, an eavesdropper-exclusion sector guard zone around SU-Tx is introduced to improve the secrecy performance of the secondary network. By using stochastic geometry, closed-form expression for secrecy throughput (ST) achieved by the secondary sensor node is obtained to investigate secrecy performance. We also carry out the asymptotic analysis to facilitate the performance evaluation in the high transmit power region. Numerical results demonstrate that the interference temperature constraint of the primary sensor node enables us to balance secrecy performance of the secondary network, and provides interesting insights into how the system performance of the secondary network that is influenced by various system parameters: eavesdropper density, antenna gain and sector guard zone radius. Furthermore, blockages are beneficial to improve ST of the secondary sensor node under certain conditions.