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We propose a scheme of ultraviolet (UV) communication system, with polar channel coding method. The bit error rate (BER) performance of the UV polar code scheme is analyzed by simulations and offline experiments, in contrast with low-density parity-check (LDPC) scheme. Results suggest that the polar code scheme has a better BER performance than LDPC scheme in the UV communication system.
We experimentally demonstrate an indoor visible light positioning system based on optical camera communications, in which the transmitted coordinate data are spatially separated and demodulated by a camera. The receiver's position is calculated based on the coordinates of light-emitting diodes in the real word and in the image.
We propose a MIMO ultraviolet (UV) communication system which can increase the data rate effectively. The bit error rate (BER) performance of a 2×2 MIMO scheme is measured and analyzed by offline experiments.
We propose a dual-function scheme which supports both failure protection of the fiber links and P2P communication between RSOA-based colorless ONUs. Equivalent experiments are performed to evaluate the feasibility of the proposed scheme.
In this paper, a real-time seven-direct-sequence spread-spectrum (7-DSSS) visible light communications (VLC) system based on field-programmable-gate-array (FPGA) is implemented and experimentally demonstrated. We add interference light in our field experiments to build the multipath environment. And then, we measure the bit error rate performance of both on and off keying (OOK) and 7-DSSS VLC systems...
An Field Programmable Gate Array (FPGA)-Based online visible light communication system with RGB LEDs and ordinary PIN is implemented and demonstrated. The system uses simple OOK modulation. With the help of over-sampling technique at the receiver, the synchronization problem is solved. A bitrate of 120Mbps across 1m with the bit error rate less than 10−3 can be theoretically achieved without using...
In this letter, we experimentally demonstrate a 1024-quadrature-amplitude-modulation (QAM) optical camera communications (OCC) system using a dual light-emitting diode (LED) and a commercial digital single-lens reflex camera. An undersampled QAM subcarrier modulation (UQAMSM) is proposed to support a high-efficiency and non-flickering OCC system. Owing to the built-in gamma correction function of...
A machine learning-based classifier, namely SVM, is introduced to create the nonlinear decision boundary in M-ary PSK-based coherent optical system to mitigate NLPN. The maximum transmission distance and LPRD tolerance are improved by 480 km and 3.3 dBm for 8PSK.
Inter-symbol interference (ISI) may become detrimental when the data rate rises in the atmospheric scattering UV channel. In this paper, we model the ISI effect due to delay spread in the UV channel and evaluate the approach of direct sequence spread spectrum (DSSS) in eliminating ISI and improve the system performance. Both the measured noise and newly reported experimental results of impulse response...
We firstly applied diversity reception technology to a real-time none-light-of-sight (NLOS) ultraviolet (UV) communication system based on a 9.3mW LED array. Field experiment with 4 receivers (Rxs) achieves bit error rate (BER) improvement, and related conclusions on single-input-multiple-output (SIMO) UV system design are given. Innovatively, the correlation characteristics in UV channel are studied...
In this paper, the influence of the mobility feature of a ultraviolet (UV) communication system is explored via experiments, the performance at four different relative speeds within different valid working distance ranges are tested. In order to get the maximum communication distance of our UV communication system, a large number of repeated tests are made at 5 meter intervals. Meanwhile, Selective...
We propose a non-imaging MIMO-OFDM based VLC, and analyzed its bit-error-rate (BER) performance for different LED arrangements. Rectangular LED arrangement offers improved BER compared to the linear arrangement for a range of higher-order modulation schemes.
To reduce the computational complexity and latency of Turbo decoding, a new decoding scheme is proposed. Firstly, the Max-Log-MAP algorithm is modified to improve performance while guarantee the calculation simplicity at the same time. Then, the parallel decoding scheme was introduced, and an improvement is made so that the two SISO decoders can work at the same time. The simulation results show that...
The enhanced visible light communications (VLC) system with transmission distance of 7m is demonstrated using transmission path design and forward error correction code in this paper. Moreover, RS (160, 128) and LDPC (960, 480) code are implemented and experimented via VLC test-bed. The results suggest that based on the given power, 5Mbps transmission bit rate and 10−3 bit error rate (BER), in comparison...
Under the background of blind demodulation of Continuous Phase Modulation (CPM) signals, this paper extends the multiple-symbols differential demodulation, and makes an analysis of its principle, performance, and its tolerance to frequency offset, timing offset and modulation index offset. Its complexity of computation is also analyzed. The numeric computer simulation is presented. The results show...
In this paper, a method to improve the performance of Ultraviolet (UV) communication system without hardware enhancement in the optical link is presented and tested. Three kinds of noises are modeled and their impacts on the UV communication system are measured and analyzed. An FPGA-based moving average filter is utilized to reduce noise. In order to validate the designed filter, we implement a BER...
Presented in this paper is an experimental research on the mobile sensor and communication system based on transmitting with ultraviolet in either line-of-sight or non-line-of-sight conditions. The performance of this type of communication system is shown on the experimental platform which is set up. It proves the feasibility of ultraviolet communication system.
One major disadvantage of OFDM is that the time domain OFDM signal which is a sum of several sinusoids leads to high peak to average power ratio (PAPR). The precoding scheme based on pulse shaping is an effective and flexible way for reducing the peak-to-average power ratio (PAPR) of OFDM signals. Clipping technique is the most simple reduction PAPR method. However, clipping degrades the bit-error-rate...
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