Interference Topology Research Articles

Analisa Kinerja Protokol Routing Destination Sequenced Distance Vector Di Jaringan VANET

Vehicular network is a network where vehicles communicate via an ad-hoc network system that runs based on certain ad-hoc routing protocols. A vehicle ad-hoc network consists of two communication parts known as vehicle-to-vehicle communication and vehicle-to-infrastructure communication. Even though the roads have become very congested with many vehicles, controlling vehicle movement has become an urgent need. Automatic traffic control, critical moment notifications, post-accident notifications, correct route selection become very important and these can be implemented using vehicle ad-hoc network systems. For good communication between vehicles, vehicle ad-hoc networks use several protocols. One of the problems faced by VANET is routing. Routing in VANETs can perform challenging tasks due to high mobility, network topology interference, and path selection processes. DSDV is one of the routing used in VANET and simulations were carried out with NS2 to obtain DSDV routing performance in the VANET network based on quality of service with scenarios of 25 and 33 nodes. DSDV routing was chosen because it has the best performance in its class. From the simulation results, the end to end delay for 25 nodes is 22.22 and 33 nodes is 24.07, the packet drop obtained for 25 nodes is 0.85, and 33 nodes is 0.80. Furthermore, the throughput value obtained in the simulation for 25 nodes is 274.19 and 33 nodes 351.12, then the packet delivery ratio for 25 nodes is 2990, and 33 nodes is 4888

Retracted: Main Circuit Topology and Electromagnetic Interference of Electric Vehicle Bidirectional Charger

Retracted: Main Circuit Topology and Electromagnetic Interference of Electric Vehicle Bidirectional Charger

Main Circuit Topology and Electromagnetic Interference of Electric Vehicle Bidirectional Charger

In order to improve the electromagnetic compatibility performance of electric vehicle bidirectional chargers, the authors propose a main circuit topology and electromagnetic interference of the electric vehicle bidirectional charger. The design adopts the parallel connection of silicon carbide (SiC) MOSFETs and completes the bidirectional charging system based on the cascade connection of dual active bridge (DAB) and three-phase four-wire inverter. This paper mainly analyzes the influence of parasitic inductance on the drive and power loop of the T0-247 packaged switch in actual use, and according to the operating characteristics of the system, different gate resistors are used to reduce switching losses and improve system efficiency. And, we explore on how to reduce the overshoot voltage through the RC absorption circuit, thereby reducing the conducted interference. The result shows the following: the primary side absorption circuit resistance is 470 Ω and the capacitor is 47 nf, the secondary side absorption circuit resistance is 40 Ω and the capacitance is 4.7 nf, and the circuit power is 5000 W. Under the same conditions, without adding the RC absorption circuit, the conducted interference on the AC side does not meet the standard, and the amount of disturbance is large. After adding a suitable RC absorption circuit, the conducted interference on the AC side reaches the required value. Conclusion. This research provides a systematic design scheme and optimization method for designing power electronic devices using SiC.

A Tunable Caching Distribution Model for Unmanned Aerial Vehicle Networks

In existing works on performance analysis of cache-enabled unmanned aerial vehicle (UAV) networks, caching distribution is fixed, and the joint cache-level and transmission-level cooperation has not been analyzed in literature. Considering UAVs agility and line-of-sight (LOS)/ non-line-of-sight (NLOS) channel characteristics, this paper proposes a tunable caching distribution model, where content placement and transmission can be flexibly adjusted to match interference topology dynamics, and derives semi-closed expression of caching coverage probability via stochastic geometry. Specifically, UAVs will take the partition coefficient ρ to determine caching distribution, where the most popular content files are reserved in every UAV within the cooperation group and jointly transmit to the user, while other files are probabilistic stored in the remaining cache space to achieve content diversity. In addition, when requiring the less popular files, user will always connect to the UAV with the best signal-to-interference (SIR) ratio among cache hit UAVs within the cooperation group. The theoretical analysis investigates the effects of various system parameters such as UAVs height, cooperative radius, and content popularity on the caching coverage probability and optimal ρ for can be found. It can be seen that optimal ρ will be decreased firstly and then increased along with the increase of UAVs height, which reveals the tradeoff between cache hit probability and transmission reliability. Analytical results show that our proposed cache and transmission policy can achieve 34% gain of coverage probability compared to the policy of probabilistic cached.

A Four-Element 5–6-GHz CMOS Quadrature Balanced Full-Duplex MIMO Transmitter With Wideband Digital Interference Cancellation

This work presents a 5-6 GHz full-duplex (FD) multiple-input and multiple-output (MIMO) transmitter front-end based on a quadrature balanced power amplifier (QBPA) topology and wideband digital interference cancellation. The proposed architecture benefits from low implementation complexity and is compatible with MIMO scaling with no additional hardware and power consumption penalties. The QBPA chip was fabricated in 180 nm CMOS and assembled on a four-element PCB MIMO array. The system was measured using a 320 MHz OFDM signal with 11 dB PAPR at 4 dBm TX power per element. 44 dB of combined self and cross-interference (XI) cancellation in the RF domain is demonstrated while requiring only -17 dBm of canceling signal power, along with -32 dB of TX EVM and 0.7 and 1.8 dB of TX and RX insertion losses (ILs), respectively. The standalone QBPA chip delivers P $_{sat}$ and peak PAE of >19.3 dBm and >31%, respectively, between 5 and 6 GHz.

Automatic Pixel-Level Pavement Crack Recognition Using a Deep Feature Aggregation Segmentation Network with a scSE Attention Mechanism Module.

Pavement crack detection is essential for safe driving. The traditional manual crack detection method is highly subjective and time-consuming. Hence, an automatic pavement crack detection system is needed to facilitate this progress. However, this is still a challenging task due to the complex topology and large noise interference of crack images. Recently, although deep learning-based technologies have achieved breakthrough progress in crack detection, there are still some challenges, such as large parameters and low detection efficiency. Besides, most deep learning-based crack detection algorithms find it difficult to establish good balance between detection accuracy and detection speed. Inspired by the latest deep learning technology in the field of image processing, this paper proposes a novel crack detection algorithm based on the deep feature aggregation network with the spatial-channel squeeze & excitation (scSE) attention mechanism module, which calls CrackDFANet. Firstly, we cut the collected crack images into 512 × 512 pixel image blocks to establish a crack dataset. Then through iterative optimization on the training and validation sets, we obtained a crack detection model with good robustness. Finally, the CrackDFANet model verified on a total of 3516 images in five datasets with different sizes and containing different noise interferences. Experimental results show that the trained CrackDFANet has strong anti-interference ability, and has better robustness and generalization ability under the interference of light interference, parking line, water stains, plant disturbance, oil stains, and shadow conditions. Furthermore, the CrackDFANet is found to be better than other state-of-the-art algorithms with more accurate detection effect and faster detection speed. Meanwhile, our algorithm model parameters and error rates are significantly reduced.

Temporal Correlation and Long-Term Average Performance Analysis of Multiple UAV-Aided Networks

In multiple unmanned aerial vehicles (UAVs)-aided networks, the time-varying channel caused by the impact of the line of sight (LOS) and nonline of sight (NLOS) leads to signal fluctuations; moreover, the UAV's agility and the constraint of the spatial distribution of blind areas on the UAV's deployment result in interference topology fluctuations. Accordingly, the instantaneous signal-to-interference ratio is fluctuant and cannot accurately reflect network performance. Considering a multi-UAV-aided network with UAV spatial dependence, this article derives the semiclosed expression of long-term average throughput considering the fluctuations of the channel and topology, which are measured by calculating correlation coefficients of the signal and interference. Specifically, the time-varying channel is characterized by incorporating the link-state conversions and randomness of small-scale fading into channel gains, the time-varying network topology is quantified by considering the effect of distance variation caused by mobility on interference topology. In addition, considering multiple UAVs are clustered in corresponding blind areas, UAV networks are modeled as matern cluster processes (MCP), and time-averaged performances at intracluster and extracluster are analyzed, respectively. The numerical results show the effects of clustering parameters and deployment parameters on temporal correlation and long-term average network performance.

Heat-Diffusion: Pareto Optimal Dynamic Routing for Time-Varying Wireless Networks

A dynamic routing policy, referred to as Heat-Diffusion (HD), is developed for multihop uniclass wireless networks subject to random traffic, time-varying topology and inter-channel interference. The policy uses only current condition of queue occupancies and channel states, with requiring no knowledge of traffic and topology. Besides throughput optimality, HD minimizes an average quadratic routing cost defined by endowing each channel with a time-varying cost factor. Further, HD minimizes average network delay in the class of routing policies that base decisions only on current condition of traffic congestion and channel states. Further, in this class of routing policies, HD provides a Pareto optimal tradeoff between average routing cost and average network delay, meaning that no policy can improve either one without detriment to the other. Finally, HD fluid limit follows graph combinatorial heat equation, which can open a new way to study wireless networks using heat calculus, a very active area of pure mathematics.

Microwave bandpass filter by feedback interference topology

This paper proposes a signal feedback interference topology to control the characteristics of a coupled line bandpass filter. Control is carried out by varying the ratio of the transmission line parameters of the forward and the feedback couplers. The topology produces a compact filter that does not require a complicated design or fabrication. The results of the insertion and return losses show that the feedback-controlled design has desirable features in terms of the design frequency, fractional bandwidth, stopband rejection level, roll-off rate and insertion loss. The test results of the fabricated prototype achieved good agreement with the simulation results of the ideal transmission line design model. Several microwave, modern wireless and mobile/satellite communication systems may benefit from such a filter design due to its compactness and flexibility.

When and how much to neutralize interference? Balancing the benefits and cost of interference management

Interference management (IM) is essential to wireless communication systems, but it is also known to consume transmission resource such as power and degree of freedom, hence degrading users’ achievable spectral efficiency (SE). Therefore, it is important to select an appropriate IM method with optimal operating parameters so as to balance the benefits brought by and the cost of IM. Interference neutralization (IN) has recently been receiving considerable attention, with which a duplicate of interference of the same strength and opposite phase with respect to the original interfering signal is generated to neutralize the disturbance at the intended receiver. However, to the best of our knowledge, all existing IN schemes assume that interference is completely neutralized without accounting for their power consumption. To remedy this deficiency, we propose a novel scheme, called dynamic interference neutralization (DIN). By intelligently determining the appropriate portion of interference to be neutralized, we balance the transmitter’s power used for IN and the desired signal’s transmission. We then extend the proposed DIN to general cases where the numbers of interferences, desired data streams, as well as pico base stations and pico user equipments, are variables. Moreover, in addition to the design under asymmetric interference topology, the application of DIN in symmetric interference situation is also presented. Our in-depth analysis and simulation have shown that the proposed strategy can make better use of the transmit power than existing IM methods, hence enhancing users’ SE.

Distributed self-optimizing interference management in ultra-dense networks with non-orthogonal multiple access

Both non-orthogonal multiple access (NOMA) and ultra-dense network (UDN) are promising technologies in future wireless networks. However, considering the overlapped coverage of small base stations (SBSs) and the spectrum sharing with NOMA, interference management (IM) becomes a more complex and fundamental problem. Moreover, considering the massive SBSs and dynamic network conditions in UDN, more efficient mechanisms need to be designed to deal with the IM issue. Thus, we propose a distributed self-optimizing interference management approach to address both the intra-cell interference caused by NOMA and the inter-cell interference among dense deployed SBSs. Aiming to minimize the interference and guarantee the users’ requirements, we mathematically formulate the joint resource allocation and user selection problem with consideration of the diverse user requirements, complicated interference topology, and limited resources. Furthermore, we consider the imperfections of successive interference cancellation at receivers for separating and decoding superimposed signals and analyze the impacts of residual interference and outage probability in NOMA-based UDNs. For tractability purpose, we introduce interference graph and satisfaction game theory and propose distributed algorithms to solve the problem. Simulation results show that interference can be reduced significantly in UDNs with NOMA compared with the traditional IM approaches.

Interference Aware, Topology, Power and Flow Control Channel Assignment Algorithm for Multi-Radio Multi-Channel Wireless Mesh Networks

Interference Aware, Topology, Power and Flow Control Channel Assignment Algorithm for Multi-Radio Multi-Channel Wireless Mesh Networks

Aharonov-Bohm effect in graphene Möbius strips: an analytical treatment

In this work, the influence of an Aharonov-Bohm flux on the low energy physical properties of graphene nanorings exhibiting Mobius topology is examined. Our approach lies in the continuum description of graphene, providing an analytical treatment for Aharonov-Bohm problem in the context of general relativistic confined systems, whose main goal is to understand the role of boundary conditions and their effects in such a background. We study a class of quantum rings described by a particular set of boundary conditions which combines infinite mass confinement along the transverse direction with a Mobius-type periodicity longitudinally, in order to sketch out insights into the electronic behavior of typical hard wall nanoribbons within a relativistic domain in response to the interplay between non-trivial topology and quantum interference effects. Boundary conditions are found to be only partially compatible, leading to spatial constraints on the solution, which also manifests itself in the nature of energy spectrum and persistent currents. Expressions for flux-dependent energy eigenvalues and persistent currents are explicitly calculated, as well as comparative graphs are plotted and analyzed. Both quantities are shown to alternate their expressions not only in dependence on the transverse modes, but also showing sensitivity to the allowed positions of the domain.

PHY-caching in 5G wireless networks: design and analysis

In this article, we propose a PHY-caching scheme for 5G wireless networks to achieve spectral efficiency gain over conventional caching schemes, which do not induce physical layer cooperation. By properly caching some popular contents at the BSs, the proposed PHY-caching can opportunistically transform the topology of the RAN from an unfavorable topology (e.g., relay or interference topology) into a more favorable MIMO broadcast topology and enjoy spectral efficiency gain. Specifically, we first introduce a generic cache model and cache-assisted PHY transmission, and show that PHY-caching can significantly enhance the spectral efficiency of the wireless network by inducing dynamic side information at the BSs. Then we discuss the design challenges and solutions of PHY-caching. We introduce maximum-distance-separable-coded caching and online cache content placement design as a potential solution. As a case study, we analyze the performance trade-off between PHY-caching at the BS and CN-caching at the gateway under capacity-limited CN-fronthaul. We show that even though PHY-caching covers fewer users than CN-caching and results in a lower cache hit rate, it is still efficient to do PHY-caching at the BS.

Optimality of Treating Interference as Noise: A Combinatorial Perspective

For single-antenna Gaussian interference channels, we reformulate the problem of determining the generalized degrees of freedom (GDoF) region achievable by treating interference as Gaussian noise (TIN) derived by Geng et al. from a combinatorial optimization perspective. We show that the TIN power control problem can be cast into an assignment problem, such that the globally optimal power allocation variables can be obtained by well-known polynomial time algorithms (e.g., centralized Hungarian method or distributed Auction algorithm). Furthermore, the expression of the TIN-achievable GDoF region (TINA region) can be substantially simplified with the aid of maximum weighted matchings. We also provide conditions under which the TINA region is a convex polytope that relax those by Geng et al. For these new conditions, together with a channel connectivity (i.e., interference topology) condition, we show TIN optimality for a new class of interference networks that is not included, nor includes, the class found by Geng et al. Building on the above insights, we consider the problem of joint link scheduling and power control in wireless networks, which has been widely studied as a basic physical layer mechanism for device-to-device communications. Inspired by the relaxed TIN channel strength condition as well as the assignment-based power allocation, we propose a low-complexity GDoF-based distributed link scheduling and power control mechanism (ITLinQ+) that improves upon the ITLinQ scheme proposed by Naderializadeh and Avestimehr and further improves over the heuristic approach known as FlashLinQ. It is demonstrated by simulation that ITLinQ+ without power control provides significant average network throughput gains over both ITLinQ and FlashLinQ, and yet still maintains the same level of implementation complexity. Furthermore, when ITLinQ+ is augmented by power control, it provides an energy efficiency substantially larger than that of ITLinQ and FlashLinQ, at the cost of additional complexity and some signaling overhead.

Dynamic spectrum access enabled home area networks for smart grid communications

In this paper, we investigate the dynamic spectrum access for home area network in smart grid communications where home appliances access RF spectrum opportunistically. We evaluate the proposed approach through simulations and the numerical results show that the proposed dynamic spectrum access-based smart grid communication outperforms the static spectrum access-based smart grid communications. Smart grid is the transformation of current power grid system through the integration of advanced information technology and communication technology with power system grid. The choice of communication technology for smart grid is highly critical to provide secure, reliable and efficient information transfer between the smart grid components. However, because of dynamic topology changes, connectivity problems, interference and fading issues, and delay requirements, current information and communication infrastructures and standards are incapable of meeting the strict requirements of smart grid technology. The dynamic spectrum access capability of cognitive radio networks is a promising technology that can be used to reduce the communication expenses and improve reliability by improving spectrum utilisation in smart grids.

SSMAB: A Slotted Sense Multiple Access Broadcasting Protocol for Dynamic Wireless Sensor Networks

Abstract In industrial monitoring and control sensor networks, a control server or a sink needs to send a message or command to a group of nodes, or all nodes in a reliable manner to control their operations. This is done by means of a repeated rebroadcasting. This suffers from message collision and high energy consumption due to all nodes that have to remain active. In the tree-based TDMA approach, every node is assigned a unique broadcast slot within which it rebroadcasts a message toward its children in order to prevent collision. This limits the active time of a node to its sending and receiving slot. However, this approach does not respond effectively to the dynamic change of topology and signal interference, requiring frequent tree reconstruction and slot rescheduling. The worse thing is that the failure of a node to receive a message affects all its descendants. To overcome this problem, one sharable slot is assigned to the nodes in each tree level so that the nodes at the same level compete for broadcasting. This approach allows a node to move to another level without causing a global slot rescheduling. Simulation results prove that this approach not only improves the reliability of message broadcasting, but also allows energy saving significantly.

Quality-of-service differentiation in single-path and multi-path routing for wireless sensor network-based smart grid applications

Electrical grid is one of the most important infrastructure of the modern nation. However, power grid has been aged over 100years and prone to major failures. The imbalance between power demand and supply, the equipment failures and the lack of comprehensive monitoring and control capabilities are other important signs to take incremental steps for switching to a smarter power grid with effective communication, automation and monitoring skills. This new concept is named as smart grid, which is a modern power grid system with advanced communication, monitoring, sensing and control capabilities. Wireless sensor network (WSN) concept places an important role in this modernization process of the power grid with its efficient and low-cost deployment characteristics. However, harsh and complex smart grid environmental conditions, dynamic topology changes, connectivity problems, interference and fading may pose some challenges for the communication performance of WSN technology. For this objective, in this paper, the use of multi-path and single-path QoS-aware routing algorithms under harsh SG environmental conditions is investigated in order to evaluate their service differentiation capabilities in reliability and timeliness domains. In this regard, this study is an important step towards developing novel routing protocols specifically designed for smart grid environments.

Algorithms for Enhanced Inter-Cell Interference Coordination (eICIC) in LTE HetNets

The success of LTE Heterogeneous Networks (HetNets) with macro cells and pico cells critically depends on efficient spectrum sharing between high-power macros and low-power picos. Two important challenges in this context are, {(i)} determining the amount of radio resources that macro cells should {\em offer} to pico cells, and {(ii)} determining the association rules that decide which UEs should associate with picos. In this paper, we develop a novel algorithm to solve these two coupled problems in a joint manner. Our algorithm has provable guarantee, and furthermore, it accounts for network topology, traffic load, and macro-pico interference map. Our solution is standard compliant and can be implemented using the notion of Almost Blank Subframes (ABS) and Cell Selection Bias (CSB) proposed by LTE standards. We also show extensive evaluations using RF plan from a real network and discuss SON based eICIC implementation.

A New Distributed and Power-Efficient Topology Control Algorithm for Wireless Ad-Hoc Networks

To guarantee the performance of ad hoc networks, utilizing a hierarchical architecture model is necessary. An instance of this structure is clustering. In this paper a cluster-based topology control algorithm is proposed which builds an energy-efficient and a low interference topology. It uses low-quality information, exchanges a few messages, and does not need for extra hardware equipment as well. It is also suitable for practical use, because in the implementation of this algorithm is not needed to know the location or the direction information of the network nodes. So it is possible to classify this algorithm as a neighbor-based topology control algorithm. In addition, for the transmitting and the maintained power levels of each node, a modification is applied according to the real hardware platforms. It improves the energy consumption in the ideal conditions.