Untrusted NOMA with Imperfect SIC: Outage Performance Analysis and Optimization

Non-orthogonal multiple access (NOMA) has come to the fore as a spectral-efficient technique for fifth-generation and beyond communication networks. We consider the downlink of a NOMA system with untrusted users. In order to consider a more realistic scenario, imperfect successive interference cancellation is assumed at the receivers during the decoding process. Since pair outage probability (POP) ensures a minimum rate guarantee to each user, it behaves as a measure of the quality of service for the pair of users. With the objective of designing a reliable communication protocol, we derive the closed-form expression of POP. Further, we find the optimal power allocation that minimizes the POP. Lastly, numerical results have been presented which validate the exactness of the analysis, and reveal the effect of various key parameters on achieved pair outage performance. In addition, we benchmark optimal power allocation against equal and fixed power allocations with respect to POP. The results indicate that optimal power allocation results in improved communication reliability.Comment: 6 pages, 5 figures, WCNC 202

Secure Transmission in NOMA-enabled Industrial IoT with Resource-Constrained Untrusted Devices

The security of confidential information associated with devices in the industrial Internet of Things (IIoT) network is a serious concern. This article focuses on achieving a nonorthogonal multiple access (NOMA)-enabled secure IIoT network in the presence of untrusted devices by jointly optimizing the resources, such as decoding order and power allocated to devices. Assuming that the devices are resource-constrained for performing perfect successive interference cancellation (SIC), we characterize the residual interference at receivers with the linear model. Firstly, considering all possible decoding orders in an untrusted scenario, we obtain secure decoding orders that are feasible to obtain a positive secrecy rate for each device. Then, under the secrecy fairness criterion, we formulate a joint optimization problem of maximizing the minimum secrecy rate among devices. Since the formulated problem is non-convex and combinatorial, we first obtain the optimal secure decoding order and then solve it for power allocation by analyzing Karush-Kuhn-Tucker points. Thus, we provide the closed-form global-optimal solution of the formulated optimization problem. Numerical results validate the analytical claims and demonstrate an interesting observation that the conventional decoding order and assigning more power allocation to the weak device, as presumed in many works on NOMA, is not an optimal strategy from the secrecy fairness viewpoint. Also, the average percentage gain of about 22.75%, 50.58%, 94.59%, and 98.16%, respectively, is achieved by jointly optimized solution over benchmarks ODEP (optimal decoding order, equal power allocation), ODFP (optimal decoding order, fixed power allocation), FDEP (fixed decoding order, equal power allocation), and FDFP (fixed decoding order, fixed power allocation).Comment: 10 pages and 6 figure

Surgical stump site pregnancy-an unusual case report

Ectopic pregnancy is an obstetrics emergency which we all encounter in our day-to-day practice. Though maternal mortality rate is decreasing worldwide, still ectopic pregnancy is an important contributor towards maternal morbidity and mortality. Ectopic pregnancy at surgical stump site after salpingectomy is extremely rare with reported prevalence of 0.4-1.2%. We report one of such unusual case of 30 years old female, who had history of left salpingectomy 5 years back and presented to our hospital with abdominal pain. On evaluation, ectopic pregnancy at ipsilateral tubal stump was confirmed and she was successfully managed with surgical intervention. As early diagnosis of tubal stump pregnancy holds the key in successful management, we should keep high suspicion and carefully examine the patients with history of salpingectomy for ectopic pregnancy.

Genetic Polymorphism and Alcohol Metabolism

Throughout the world, human population experiment with alcohol, result into short- and long-term consequences including increased risk of accidental injuries, risky sexual behavior and lower education attainment. Due to polymorphism in the gene whose product enzymes are responsible for alcohol metabolism, serious health consequences including liver cirrhosis and hepatocarcinoma can occur. Enzyme alcohol dehydrogenase, CYP450 and catalase are alcohol metabolizing enzymes. Polymorphism in any one or all of the enzymes will result in defective alcohol metabolism and acetaldehyde accumulation cause serious health problems. This article mainly focuses on the consequences of alcohol consumption at genetic level that ultimately affect alcohol metabolism resulting in various health disorders

The interaction surface of a bacterial transcription elongation factor required for complex formation with an antiterminator during transcription antitermination

The bacterial transcription elongation factor, NusA, functions as an antiterminator when it is bound to the lambdoid phage derived antiterminator protein, N. The mode of N-NusA interaction is unknown, knowledge of which is essential to understand the antitermination process. It was reported earlier that in the absence of the transcription Elongation Complex (EC), N interacts with the C-terminal AR1 domain of NusA. However, the functional significance of this interaction is obscure. Here we identified mutations in NusA N terminus (NTD) specifically defective for N-mediated antitermination. These are located at a convex surface of the NusA-NTD, situated opposite its concave RNA polymerase (RNAP) binding surface. These NusA mutants disrupt the N-nut site interactions on the nascent RNA emerging out of a stalled EC. In the N/NusA-modified EC, a Cys-53 (S53C) from the convex surface of the NusA-NTD forms a specific disulfide (S-S) bridge with a Cys-39 (S39C) of the NusA binding region of the N protein. We conclude that when bound to the EC, the N interaction surface of NusA shifts from the AR1 domain to its NTD domain. This occurred due to a massive away-movement of the adjacent AR2 domain of NusA upon binding to the EC. We propose that the close proximity of this altered N-interaction site of NusA to its RNAP binding surface, enables N to influence the NusA-RNAP interaction during transcription antitermination that in turn facilitates the conversion of NusA into an antiterminator

User-Pair Selection for QoS-Aware Secrecy Rate Maximization in Untrusted NOMA

Non-orthogonal multiple access (NOMA) has been recognized as one of the key enabling technologies for future generation wireless networks. Sharing the same time-frequency resource among users imposes secrecy challenges in NOMA in the presence of untrusted users. This paper characterizes the impact of user-pair selection on the secrecy performance of an untrusted NOMA system. In this regard, an optimization problem is formulated to maximize the secrecy rate of the strong user while satisfying the quality of service (QoS) demands of the user with poorer channel conditions. To solve this problem, we first obtain optimal power allocation in a two-user NOMA system, and then investigate the user-pair selection problem in a more generalized four user NOMA system. Extensive performance evaluations are conducted to validate the accuracy of the proposed results and present valuable insights on the impact of various system parameters on the secrecy performance of the NOMA communication system

Secrecy Outage Probability Analysis for Downlink NOMA with Imperfect SIC at Untrusted Users

Non-orthogonal multiple access (NOMA) has come to the fore as a spectrally efficient technique for fifth-generation networks and beyond. At the same time, NOMA faces severe security issues in the presence of untrusted users due to successive interference cancellation (SIC)-based decoding at receivers. In this paper, to make the system model more realistic, we consider the impact of imperfect SIC during the decoding process. Assuming the downlink mode, we focus on designing a secure NOMA communication protocol for the considered system model with two untrusted users. In this regard, we obtain the power allocation bounds to achieve a positive secrecy rate for both near and far users. Analytical expressions of secrecy outage probability (SOP) for both users are derived to analyze secrecy performance. Closed-form approximations of SOPs are also provided to gain analytical insights. Lastly, numerical results have been presented, which validate the exactness of the analysis and reveal the effect of various key parameters on achieved secrecy performance.Comment: 5 pages, 5 figures, and EUSIPCO 202

Application of Natural Dyes for Herbal Textiles

Clothing, the second skin of our body, is of immense importance in human life and has been evolved continuously. Textile products having special properties are used for umpteen purposes, and one such product is herbal textiles. Changing trends in clothing, cosmetics, and aesthetics necessitates the development of newer technologies that can benefit end users by enhancing their health and aesthetics and provide a sense of relief and satisfaction. Herbal textiles are prepared by imparting essential oils and herbal extract finishes to textiles. These treatments provide medicinal value and aroma to the garment, which enhance its value. Herbal extracts and oils can be incorporated in textiles by microencapsulation, sensory perception technology, liposomes, dyes, and coated textile technology. The temperatures of the finish, the duration and concentration of plant extract, the blend of herbs, and the equipment used need to be carefully controlled. Herbal textiles are revitalizing and help in keeping the body fresh and healthy. These fabrics also shown to have therapeutic value in ailments like skin allergies, breathing problems, sleeping disorders, and blood pressure. In this chapter, emphasis is given on the significance of herbal clothing and the use of natural herbal extracts to produce them

Evaluation of the effect of piperine per se and its interaction with ondansetron on haloperidol induced catalepsy in Albino mice

Background: This study aims to evaluate the per se effect of piperine and its interaction with ondansetron on haloperidol induced catalepsy in swiss albino mice.Methods: The piperine crystals were separated from crude extract of Piper nigrum. Catalepsy was induced by haloperidol (1mg/kg, i.p.). Control group received 2% gum acacia (10ml/kg), standard group ondansetron (0.5mg/kg), test group piperine (10mg/kg) and combination group ondansetron plus piperine (0.5mg/kg + 10mg/kg), per oral, respectively. In acute study, drugs were administered only once, one hour prior to the haloperidol administration. Whereas in chronic study, catalepsy was determined on the seventh day of treatment.Results: In acute study, from 60 min onwards after haloperidol administration, ondansetron and ondansetron plus piperine group resulted in significantly lower cataleptic scores than the control treated group. On the other hand, 120 min onwards ondansetron group showed significantly lower cataleptic scores (24.62) as compared to the ondansetron plus piperine group (31.50). In the chronic study, from 60 min onwards, ondansetron and the ondansetron plus piperine resulted in significantly lower cataleptic scores than the control treated group. Also the combination of ondansetron plus piperine was more significantly protective compared to ondansetron alone (P <0.05).Conclusions: Piperine has the potential to be used as a bioenhancer when combined with other drugs which would reduce the dose of drugs and thereby adverse effects. It may act probably by enhancing the bioavailability as well as by inhibiting the metabolic pathways of other drugs