Optical wireless communications (OWC) are emerging as cost-effective and practical solutions to the congested radio frequency-based wireless technologies. As part of OWC, optical camera communications (OCC) have become very attractive, considering recent developments in cameras and the use of fitted cameras in smart devices. OCC together with visible light communications (VLC) is considered within the framework of the IEEE 802.15.7m standardization. OCCs based on both organic and inorganic light sources as well as cameras are being considered for low-rate transmissions and localization in indoor as well as outdoor short-range applications and within the framework of the IEEE 802.15.7m standardization together with VLC. This paper introduces the underlying principles of OCC and gives a comprehensive overview of this emerging technology with recent standardization activities in OCC. It also outlines the key technical issues such as mobility, coverage, interference, performance enhancement, etc. Future research directions and open issues are also presented.

In this letter, we propose spatial diversity reception of non-line-of-sight (NLOS) ultraviolet (UV) communication in turbulent atmospheric channel. The turbulent atmospheric channel causes fluctuation in the received signal intensity of a UV system, resulting in power loss and subsequent performance degradation at the receiver. To mitigate this adverse effect, we present the spatial diversity reception in the form of dual-branch switch and stay combining (SSC) at the receiver. That is, one branch is only connected to the receiver at any instant using appropriate switching logic. The channels are assumed to be exponentially correlated in space, while irradiance fluctuation due to turbulence is modeled by a Gamma-Gamma distribution with parameters directly related to the attributes of the NLOS UV link. Analytic expressions for both the outage probability and the average symbol error probability are derived using the SSC diversity technique with the correlated receivers.

➤ Patients with type-1 or type-2 diabetes have an increased risk of fracture, which is secondary to early bone loss in type-1 diabetes whereas, in type 2, the development of abnormal osseous architecture results in paradoxically increased or normal bone mineral density. ➤ Diabetic patients diagnosed with osteoporosis should receive the same standard antiresorptive therapies as non-diabetic patients in conjunction with appropriate glycemic control. ➤ Medical management of type-2 diabetes can affect bone health and fracture risk. Thiazolidinediones have been correlated with an increased facture risk, whereas metformin can be protective of the bone health of diabetic patients. ➤ Diabetes increases the likelihood of nonunion and delayed union of fractures as well as other perioperative complications such as infection. ➤ Perioperative glycemic control may decrease the risk of perioperative complications, especially surgical site infection. Methods to directly improve diabetic fracture-healing such as the use of parathyroid hormone and sclerostin antibody are in the experimental phase. ➤ Prior to proceeding with operative intervention for fractures, it is necessary to consider the additional risk posed by diabetes, which must be taken into account when planning the approach, fixation, and postoperative management in this population.

Intelligent reflecting surface (IRS)-assisted wireless communication has recently become a promising technology to relax the line-of-sight requirement and also to provide a communication link in uncovered and remote areas. In this work, an alternate implementation of unmanned aerial vehicle (UAV)-based IRS-assisted hybrid free space optics/radio frequency wireless communications is presented. Phase shift errors occur due to the presence of reflecting elements in the IRS and affect the reflected beam. We consider the effect of phase shift error along with atmospheric turbulence, which is modeled as gamma-gamma distribution. Furthermore, a statistical model is considered for pointing errors due to the position and orientation fluctuation of the mounted IRS on the UAV. We derive closed-form expressions of the average symbol error rate and spectral efficiency of the considered system, under the combined effects of atmospheric turbulence, pointing error, and phase shift error. In addition, we present asymptotic analysis of the average symbol error rate of the system in a high SNR region and evaluate the diversity order and coding gain. The derived results are further validated using Monte Carlo simulation.

In this paper, we investigate the effects of jamming caused by a malicious unmanned aerial vehicle (UAV) on the performance of a free-space optical (FSO) communication system using a legitimate UAV as a relay and utilizing an intelligent reflecting surface (IRS) to improve the coverage. We statistically characterize the combined effects of the three impairments on the performance of the considered system: atmospheric turbulence (AT), pointing error (PE), and angle of arrival (AoA) fluctuation of both the UAVs. Incorporating the aforementioned effects, closed-form expressions of the overall average bit error rate (ABER) and outage probability (OP) for the considered system are derived. We also present a comprehensive study of the proposed system by considering different locations of the malicious UAV jammer and IRS and draw some interesting conclusions. Useful insights into the system performance are obtained through the asymptotic analysis. Furthermore, the analytically derived expressions are verified through Monte-Carlo simulations.