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Non-orthogonal multiple access (NOMA) has emerged as an integral component for the future cellular networks. The purpose to install more small cells in the vicinity of a macrocell is to provide seamless and ubiquitous coverage to a huge density of users. Hence, security becomes an important aspect, which needs to resolve for users under critically acclaimed applications. The conventional encryption techniques and physical layer security measures may not be feasible always in Ultra Dense Network due to limited resources. Thus, the NOMA-based multiple access (MA) technique is emphasized to ensure reliability and confidentiality to users under dense picocells deployment. This paper sheds light on the security challenges of vehicular users and examines the impact of the NOMA-based MA technique on overall performance in comparison to the conventional approach. We design a training model to determine the density of vehicular users in a given picocell, before assigning power and resources. However, the proposed approach takes care of low mobile vehicular users as the eavesdropper tends to impact them more. The operation of NOMA-enabled users under the influence of intracellular and intercellular interference is also discussed. The results demonstrate that NOMA is successful in achieving a high sum rate for vehicular users by efficiently exploiting the resources in the power domain. To end this, we also compare the NOMA-based solution for the same scenario with the conventional approaches. [ABSTRACT FROM AUTHOR]

This paper proposes a zone-based approach referred to as zone-based GrEEn (ZBGrEEn) algorithm, for energy-efficient spectrum sharing (SS) networks. The SS network is considered to encompass device-to-device (D2D) transmissions between a single primary transmitter (PT) and multiple primary receivers (PRs), placed in distinctive zones around the PT. Power allocation is performed optimally so that the target rate of each application demanded by the PRs are adequately met. When the PT fails to meet the target rates over ${\rm{PT}} \to {\rm{PR}}$ D2D links, it transmits cooperatively through an appropriate secondary transmitter (ST) in the SS network, which acts as an amplify-and-forward (AF) relay. The ST's basis for selection is the ${\rm{PT}} \to {\rm{ST}}$ channel state and power level at the ST. Use of game theory for solving the energy efficiency (EE) maximization problem has also been quantified. ZBGrEEn introduces zone factor for determining the transmission time for each zone in the SS network. This time determines the energy consumption at the user terminals, thereby impacting its battery lifetime. The efficiency of the proposed scheme has been validated through simulation results, with the enhancement in battery lifetime of up to 46.28% achievable for the PT. Game theory is also observed to be rewarding in battery lifetime augmentation, especially for ultradense networks (UDNs). Performance of other user terminals in the network can be similarly evaluated. [ABSTRACT FROM AUTHOR]

A fully coupled finite element analysis (FEA) technique was proposed for solving the ion-flow field due to corona discharge under a high-voltage direct-current (HVDC) bipolar transmission line employing a field enhancement factor. To cover the shape and roughness effects for the stranded wire conductor, the field enhancement factor was introduced in the charge generation mechanism. The employed fully coupled FEA can solve the corona electric field with space charge propagation without the Deutsch assumption and is stable and fully convergent regardless of the possible higher values of wind speed. First, we simulated a dc ±500 kV transmission line tower consisting of six subconductor bundles in a bipolar configuration. Furthermore, the accuracy and the reliability of the simulated results were validated using the experimental results from the literature for a dc ±800 kV one-bipolar transmission line with six subconductor bundles. Moreover, the electric fields were assessed with and without consideration of the space charge, including the wind effect. Overall, the simulated results agree with the experimental results from the literature. [ABSTRACT FROM AUTHOR]

This paper considers a novel non-orthogonal multiple access (NOMA) enabled device-to-device (D2D) communication fifth generation cellular network, practicing sectorization. Though successive interference cancellation (SIC) is the key aspect of NOMA in the current wireless communication systems, the proposed NOMA-based approach introduces the concept of multiple interference cancellation (MIC), which stimulates the phenomenon of cancellation of interference levels in the network, involving optimal resource allocation. The interference reduction achieved with MIC is way below SIC. Such a framework improves the receiver’s signal-to-interference-plus-noise ratio (SINR), as shall be examined. Promising gains are provided by the proposed scheme, in terms of sum rate of the network, total energy-efficiency (EE), and fairness factor (FF). MIC reduces the power levels at the regenerators, achieving considerable circuit power saving. Another important redressal of the proposed scheme is the reduced level of complexity achieved with MIC. The implications of proposing MIC in the NOMA-D2D networks are evaluated through simulation results. [ABSTRACT FROM AUTHOR]

The mounting content sharing among users has resulted in a considerable rise in wireless data traffic, pressurizing the cellular networks to undergo a suitable upheaval. A competent technology of the fifth-generation (5G) networks for efficiently supporting proximity-based applications is device-to-device (D2D) communication, underlaying cellular networks. Significant advances have been made till date, for allocating resources to D2D users in cellular networks, such that sharing of spectral resources between cellular and D2D users is carried out in a coordinated manner. In this paper, a sector-based radio resource allocation (SBRRA) algorithm for resource block (RB) allocation to D2D pairs has been proposed, where the number of resource blocks (RBs) is allocated to each D2D pair in an adaptive manner, based on the demanded application by each pair. Different applications demand a varying number of RBs, in accordance with their priority. This algorithm focuses on the use of sectored antennas at the base station, for a better performance and low complexity. Extensive simulations are carried out, considering real-time scenario, for ensuring satisfactory quality of service (QoS) and quality of experience (QoE) by the users. The efficiency of the proposed scheme is proved by comparing it with the RB allocation using hidden Markov model. [ABSTRACT FROM AUTHOR]

The next generation of mobile communication has progressed toward the deployment of small cells to meet the growing demands of increased capacity and QoS as compared to the conventional method, where all the computations were performed by the base station (BS)'s only. To reduce burden at the BS side, small cells deployment has been stressed upon, thus resulting in the formation of ultradense networks (UDN) having high concentration of small cells (e.g., picocell, femtocell, hotspots) and as a counter effect of which distance between two small cells is reduced to a greater extent. With such a close association of cells in UDN, the probability of frequent handovers also increases abruptly. As a result, the chances for attacker to spoof the bandwidth also increases many folds. In this paper, we have analyzed SNR, signal-to-interference-plus-noise ratio, and channel quality information channel parameters, such that the position of moving users at which handover is initiated in picocell deployment of UDN can be traced out successfully or region where the probability of attackers presence is high. Through this paper, we have tried to introduce the attacking scenario for the high mobility conditions in UDN. [ABSTRACT FROM AUTHOR]

All over the world, there is a gigantic stir in the number of subscribers which gave rise to numerous challenges, like interference management and capacity enhancement. The enabling candidates to deal with this plight are the enabling technologies of the 5G wireless communication networks. Though the 5G technologies meet the mounting demands, yet, security remains a vital concern. In this paper, the security issues of 5G wireless communication networks have been emphasized upon, with the game theoretic analysis of bandwidth spoofing attack on the multistage 5G wireless communication network. The intrusion on the relay, small cell access point and base station, which are forming a multistage 5G wireless communication network, is detected using a proposed Adaptive Intrusion Detection System. [ABSTRACT FROM PUBLISHER]