Effects of Transceiver Jitter on the Performance of Optical Scattering Communication Systems

In ultraviolet communications, the transceiver jitter effects have been ignored in previous studies, which can result in non-negligible performance degradation especially in vibration states or in mobile scenes. To address this issue, we model the relationship between the received power and transceiver jitter by making use of a moment-based density function approximation method. Based on this relationship, we incorporate the transceiver jitter effects in combination with Poisson distribution. The error rate results are obtained assuming on-off key modulation with optimal threshold based detection. We validate the error rate expressions by comparing the analytical results with Monte-Carlo simulation results. The results show that the transceiver jitter effects cause performance degradation especially in smaller transceiver elevation angles or in shorter distances, which are often adopted in short-range ultraviolet communications. The results also show that larger elevation angle cases have a better performance with respect to anti-jitter and may perform better compared to smaller elevation angle situations in the case of larger standard deviation of jitter. This work studies for the first time the transceiver jitter effects in ultraviolet communications and provides guidelines for experimental system design.Comment: 5 pages, 2 figures, comments are welcome

Gigabit per second UV-C LEDs for communications

We explore the modulation bandwidth, data communication capabilities and nanosecond pulsed performance of Ultraviolet-C (UV-C) AlGaN LEDs with peak emission wavelengths ranging from 235-275 nm. Data rates from 0.5 to 2 Gbps were achieved with -3dB modulation bandwidths up to ~100MHz

The design and optimization of synchronization sequence for Ultraviolet communication

In the ultraviolet (UV) scattering communication, the received signals exhibit the characteristics of discrete photoelectrons due to path loss. The synchronization is based on maximum Pulse Number-Sequence correlation problem. First of all, the accuracy of synchronization is vital to channel estimation and decoding. This article focuses on improving synchronization accuracy by designing and optimizing synchronization sequences. As for the maximum Pulse Number-Sequence correlation problem, it is assumed that the correlation values satisfy the Gaussian distribution and their mathematical expectation, variance and covariance are derived to express the upper bound of synchronization offset. The synchronization sequence we designed has two equilong RANDOM parts (Symbols meet Bernoulli distribution with equal probability.) and a $\{1,0,1,0,1,0,...,1,0,1,0\}$ part between them with $\alpha$ as its proportion of entire sequence. On the premise of ensuring the synchronization reliability, the synchronization deviation can be reduced by optimizing $\alpha$. There are simulation experiments to verify correctness of the derivation, reasonableness of the hypothesis and reliability of optimization. Compared with equilong random sequence, the synchronization accuracy of the optimized synchronization sequence is significantly improved

A Survey on Ultraviolet C-Band (UV-C) Communications

Recent advances in semiconductor laser and light emitting diode devices, able to efficiently operate in the solar blind regime, have brought the oblivious ultraviolet C-Band (UV-C) communications to the fore again. The non-light-of-sight transmission ability as well as the negligible background noise effect are a few of the intriguing benefits offered by this alternative broadband wireless solution. Motivated by such inherent characteristics, the current survey presents a quick and clear entry point to the topic, useful to the researchers who first get confronted with UV-C communications. To better understand the UV-C systems, a brief classification in the introductory section and a trace back to the historical evolution of this technology from its very beginnings to the current trends are provided. Then, several aspects related to the transceiver device characteristics are addressed, whereas particular emphasis is given on channel modeling including the major degrading effects, such as absorption and scattering. Modulation and multiple access schemes as well as other ways for performance enhancement as diversity and encoding techniques are also summarized. Since networking is necessary to overcome the short UV-C range, interference, connectivity, and coverage issues are thoroughly investigated. Finally, the study is concluded with a discussion regarding the challenges needed to make UV-C systems able to meet the high demands of the next generation wireless networks. © 1998-2012 IEEE