Power Allocation and Cooperative Diversity in Two-Way Non-Regenerative Cognitive Radio Networks

In this paper, we investigate the performance of a dual-hop block fading cognitive radio network with underlay spectrum sharing over independent but not necessarily identically distributed (i.n.i.d.) Nakagami-$m$ fading channels. The primary network consists of a source and a destination. Depending on whether the secondary network which consists of two source nodes have a single relay for cooperation or multiple relays thereby employs opportunistic relay selection for cooperation and whether the two source nodes suffer from the primary users' (PU) interference, two cases are considered in this paper, which are referred to as Scenario (a) and Scenario (b), respectively. For the considered underlay spectrum sharing, the transmit power constraint of the proposed system is adjusted by interference limit on the primary network and the interference imposed by primary user (PU). The developed new analysis obtains new analytical results for the outage capacity (OC) and average symbol error probability (ASEP). In particular, for Scenario (a), tight lower bounds on the OC and ASEP of the secondary network are derived in closed-form. In addition, a closed from expression for the end-to-end OC of Scenario (a) is achieved. With regards to Scenario (b), a tight lower bound on the OC of the secondary network is derived in closed-form. All analytical results are corroborated using Monte Carlo simulation method

Non-Orthogonal Multiple Access for FSO Backhauling

We consider a free space optical (FSO) backhauling system which consists of two base stations (BSs) and one central unit (CU). We propose to employ non-orthogonal multiple access (NOMA) for FSO backhauling where both BSs transmit at the same time and in the same frequency band to the same photodetector at the CU. We develop a dynamic NOMA scheme which determines the optimal decoding order as a function of the channel state information at the CU and the quality of service requirements of the BSs, such that the outage probabilities of both BSs are jointly minimized. Moreover, we analyze the performance of the proposed NOMA scheme in terms of the outage probability over Gamma-Gamma FSO turbulence channels. We further derive closed-form expressions for the outage probability for the high signal-to-noise ratio regime. Our simulation results confirm the analytical derivations and reveal that the proposed dynamic NOMA scheme significantly outperforms orthogonal transmission and existing NOMA schemes.Comment: This paper has been submitted to IEEE WCNC 201

The relationship of high-sensitivity C-reactive protein (Hs-CRP) serum level and peritonitis in patients on peritoneal dialysis

Background: C-reactive protein (CRP) is a predictor of cardiovascular diseases in both normal people and patients on hemodialysis. This study aimed to assess the relationship of high-sensitivity C-reactive protein (Hs-CRP) serum level and peritonitis in patients on peritoneal dialysis. Methods: 113 patients on peritoneal dialysis in Isfahan city, Iran, participated in our study in 2015. Serum albumin and Hs-CRP levels were measured in each patient at three times (baseline, and 6 and 12 month after that) and the patients were followed up for 1 year. All the patients were evaluated for peritonitis in every visit. At the end of the study, two groups of patients on peritoneal dialysis with and without peritonitis were compared. Findings: Among 113 patients, 24 were excluded from the study because of death or kidney transplantation and 89 patients were included in final analysis. The mean Hs-CRP levels in patients with peritonitis were 4.83, 5.79, and 7.42 mg/l at baseline, and 6 and 12 month after it, respectively; these levels were 4.47, 3.19, and 2.69 mg/l in patients without peritonitis, respectively. In addition, the mean albumin levels in patient with peritonitis were 3.38, 3.29 and 3.40 mg/l at baseline, and 6 and 12 month after it, respectively; these values were 3.56, 4.05, and 3.51 mg/l in patients without peritonitis, respectively. Conclusion: Results showed that with increase in Hs-CRP level, the risk of peritonitis increased. Besides, the albumin level decreased among patients with peritonitis in comparison with patients without peritonitis; there was no significant correlation between albumin level and peritonitis. © 2017, Isfahan University of Medical Sciences(IUMS). All rights reserved

Statistical Modeling of FSO Fronthaul Channel for Drone-based Networks

We consider a drone-based communication network, where several drones hover above an area and serve as mobile remote radio heads for a large number of mobile users. We assume that the drones employ free space optical (FSO) links for fronthauling of the users' data to a central unit. The main focus of this paper is to quantify the geometric loss of the FSO channel arising from random fluctuation of the position and orientation of the drones. In particular, we derive upper and lower bounds, corresponding approximate expressions, and a closed-form statistical model for the geometric loss. Simulation results validate our derivations and quantify the FSO channel quality as a function of the drone's instability, i.e., the variation of its position and orientation.Comment: This paper has been submitted to ICC 201