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- Nhan Vo, Van, et al.
(författare)
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On Security and Throughput for Energy Harvesting Untrusted Relays in IoT Systems Using NOMA
- 2019
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Ingår i: IEEE Access. - United States : IEEE. - 2169-3536. ; 2:1, s. 1-30
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we analyze the secrecy and throughput of multiple-input single-output (MISO) energy harvesting (EH) Internet of Things (IoT) systems, in which a multi-antenna base station (BS) transmits signals to IoT devices (IoTDs) with the help of relays. Specifically, the communication process is separated into two phases. In the first phase, the BS applies transmit antenna selection (TAS) to broadcast the signal to the relays and IoTDs by using non-orthogonal multiple access (NOMA). Here, the relays use power-splitting-based relaying (PSR) for EH and information processing. In the second phase, the selected relay employs the amplify-and-forward (AF) technique to forward the received signal to the IoTDs using NOMA. The information transmitted from the BS to the IoTD risks leakage by the relay, which is able to act as an eavesdropper (EAV) (i.e., an untrusted relay). To analyze the secrecy performance, we investigate three schemes: random-BS-best-relay (RBBR), best-BS-random-relay (BBRR), and best-BS-best-relay (BBBR). The physical layer secrecy (PLS) performance is characterized by deriving closed-form expressions of secrecy outage probability (SOP) for the IoTDs. A BS transmit power optimization algorithm is also proposed to achieve the best secrecy performance. Based on this, we then evaluate the system performance of the considered system, i.e., the outage probability and throughput. In addition, the impacts of the EH time, the power-splitting ratio, the numbers of BS antennas, and the numbers of untrusted relays on the SOP and throughput are investigated. The Monte Carlo approach is applied to verify our analytical results. Finally, the numerical examples indicate that the system performance of BBBR is greater than that of RBBR and BBRR.
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| 2. |
- Tran, Dien M., et al.
(författare)
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High prevalence of colonisation with carbapenem-resistant Enterobacteriaceae among patients admitted to Vietnamese hospitals : Risk factors and burden of disease
- 2019
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Ingår i: Journal of Infection. - : Saunders Elsevier. - 0163-4453 .- 1532-2742. ; 79:2, s. 115-122
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundCarbapenem-resistant Enterobacteriaceae (CRE) is an increasing problem worldwide, but particularly problematic in low- and middle-income countries (LMIC) due to limitations of resources for surveillance of CRE and infection prevention and control (IPC).MethodsA point prevalence survey (PPS) with screening for colonisation with CRE was conducted on 2233 patients admitted to neonatal, paediatric and adult care at 12 Vietnamese hospitals located in northern, central and southern Vietnam during 2017 and 2018. CRE colonisation was determined by culturing of faecal specimens on selective agar for CRE. Risk factors for CRE colonisation were evaluated. A CRE admission and discharge screening sub-study was conducted among one of the most vulnerable patient groups; infants treated at an 80-bed Neonatal ICU from March throughout June 2017 to assess CRE acquisition, hospital-acquired infection (HAI) and treatment outcome.ResultsA total of 1165 (52%) patients were colonised with CRE, most commonly Klebsiella pneumoniae (n=805), Escherichia coli (n=682) and Enterobacter spp. (n=61). Duration of hospital stay, HAI and treatment with a carbapenem were independent risk factors for CRE colonisation. The PPS showed that the prevalence of CRE colonisation increased on average 4.2 % per day and mean CRE colonisation rates increased from 13% on the day of admission to 89% at day 15 of hospital stay. At the NICU CRE colonisation increased from 32% at admission to 87% at discharge, mortality was significantly associated (OR 5•5, P < 0•01) with CRE colonisation and HAI on admission.ConclusionThese data indicate that there is an epidemic spread of CRE in Vietnamese hospitals with rapid transmission to hospitalised patients.
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| 3. |
- Huu, Tung Pham, et al.
(författare)
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Secrecy Performance Analysis of Cooperative NOMA Networks With Active Protection under alpha - mu Fading
- 2019
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Ingår i: 2019 12TH INTERNATIONAL CONFERENCE ON ADVANCED TECHNOLOGIES FOR COMMUNICATIONS (ATC 2019). - : IEEE. - 9781728123929 ; , s. 215-220
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Konferensbidrag (refereegranskat)abstract
- In this paper, we analyze the secrecy performance of a cooperative communication wireless system using non-orthogonal multiple access (NOMA) over alpha - mu fading channel. A new cooperative NOMA scheme is proposed to protect the confidential communication that is transmitted from a source to two users by the help of a relay under the monitoring of an eavesdropper (EAV). In particular, the legitimate user generates jamming signals to the EAV while the source transmits the signals to the relay and the source sends jamming signals to the EAV while the relay forwards the signals to the users. In order to evaluate the secrecy performance, the physical layer security (PLS) in term of the secrecy outage probability (SOP) for the active protection scheme (APS) is investigated and compared to that for a benchmark non-protection scheme (NPS). Simulation results show that the APS can effectively enhance the secrecy performance.
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| 4. |
- Vo, Van Nhan, et al.
(författare)
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Reliable Communication Performance for Energy Harvesting Wireless Sensor Networks
- 2019
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Ingår i: 2019 IEEE 89TH VEHICULAR TECHNOLOGY CONFERENCE (VTC2019-SPRING). - : IEEE. - 9781728112176
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Konferensbidrag (refereegranskat)abstract
- In this paper, we study the problem of how to provide reliable communications for energy harvesting (EH) wireless sensor network (WSN). Using the example of an autonomous quarry, where self-driving trucks autonomously collect and transport goods, there is a need for multiple wireless sensors collecting data about where and when goods can be collected, while guaranteeing reliable operation of the quarry. The vehicles transfer energy to the wireless sensors within range, forming a cluster. The sensors use this energy to transmit data to the vehicles. Finally, the vehicles relay information to an access point (AP). The AP processes the collected information and synchronize the operation of all vehicles. We propose an interference channel selection policy for the sensors-to-vehicles links and vehicles-to-AP links to improve the reliability of the communications, while enhancing the energy utilization. Accordingly, closed-form expression on how to achieve reliable communication within the considered system is derived and numerical results show that the proposed channel selection strategy not only improves the probability of achieving sufficiently reliable communication but also enhances the energy utilization.
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