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Leonard E. Miller 《Journal of research of the National Institute of Standards and Technology》2001,106(2):401-412
The probability distribution is found for the link distance between two randomly positioned mobile radios in a wireless network for two representative deployment scenarios: (1) the mobile locations are uniformly distributed over a rectangular area and (2) the x and y coordinates of the mobile locations have Gaussian distributions. It is shown that the shapes of the link distance distributions for these scenarios are very similar when the width of the rectangular area in the first scenario is taken to be about three times the standard deviation of the location distribution in the second scenario. Thus the choice of mobile location distribution is not critical, but can be selected for the convenience of other aspects of the analysis or simulation of the mobile system. 相似文献
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Chaonan Wang Liudong Xing Amir Ehsani Zonouz Vinod M. Vokkarane Yan Sun 《Quality and Reliability Engineering International》2017,33(4):823-837
Communication reliability of wireless sensor networks (WSNs) is essential to ensure the correct and reliable operation of the network. Two distinct communication paradigms exist in WSNs: infrastructure communication and application communication, and a practical communication task typically involves both types of communications. To the best of our knowledge, no reliability studies on WSNs have been dedicated to combining the two communication paradigms. In this paper, we advance the state‐of‐the‐art by proposing a phased‐mission framework to analyze the communication reliability of WSNs considering both infrastructure communication and application communication, as well as K‐coverage requirements. WSNs containing two types of sensor nodes (energy harvesting sensor nodes and battery‐powered sensor nodes) are modeled. Corresponding to the two types of sensor nodes, two different link reliability models are first presented. Binary decision diagram (BDD) based algorithms are then developed for the phased‐mission communication reliability analysis of WSNs. Case studies are given to illustrate the application of the proposed algorithms. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
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卫星移动通信系统星间链路几何参数分析 总被引：4，自引：0，他引：4
对现有卫星移动通信系统星间链路的分析发现，随着卫星通信系统轨道高度的增加，卫星通信系统星间链路指向的动态调节范围不断扩大，星间链路的相对距离也不能增大，据此进行了对最优化极轨道卫星通信系统星间链路与主要参数的模拟与分析，并得到了一些规律性的结论，为星间链路的设计与建立闰定了理论基础，同时，卫星通信系统星间链路指向性能的周期性规律变化也为星间链路连接过程中最优化搜索算法的建立提供了探索方向和理论依据 相似文献
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Abdul Kadir Hamid Fahd N. Al-Wesabi Nadhem Nemri Ammar Zahary Imran Khan 《计算机、材料和连续体（英文）》2022,70(2):2923-2941
With the emergence of 5G mobile multimedia services, end users’ demand for high-speed, low-latency mobile communication network access is increasing. Among them, the device-to-device (D2D) communication is one of the considerable technology. In D2D communication, the data does not need to be relayed and forwarded by the base station, but under the control of the base station, a direct local link is allowed between two adjacent mobile devices. This flexible communication mode reduces the processing bottlenecks and coverage blind spots of the base station, and can be widely used in dense user communication scenarios such as heterogeneous ultra-dense wireless networks. One of the important factors which affects the quality-of-service (QoS) of D2D communications is co-channel interference. In order to solve this problem of co-channel interference, this paper proposes a graph coloring based algorithm. The main idea is to utilize the weighted priority of spectrum resources and enables multiple D2D users to reuse the single cellular user resource. The proposed algorithm also provides simpler power control. The heterogeneous pattern of interference is determined using different types of interferences and UE and the priority of color is acquired. Simulation results show that the proposed algorithm effectively reduced the co-channel interference, power consumption and improved the system throughput as compared with existing algorithms. 相似文献
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Yang Yang Zhang Wuxiong Hu Honglin Zhang Sihai Wang Xin Zhao Haitao Zhou Wuyang Wei Jibo 《中国工程科学》2011,13(1):24-29
During the last two decades, mobile communication systems (such as GSM, GPRS and 3G networks), wireless broadcasting networks, wireless local area networks (WLAN or WiFi), and wireless sensor networks have been successfully developed and widely deployed through different technological routes for providing a variety of communication services in different application scenarios. While making tremendous contributions to social progress and economic growth, these heterogeneous wireless networks consume a lot of energy in achieving overlapped service coverage, and at the same time, generate strong electromagnetic interference (EMI) and radiation pollution, especially in big cities with high building density and user population. In order to guarantee the overall return on investment (ROI), improve user experience and quality of service (QoS), save energy, reduce EMI and radiation pollution, and enable the sustainable deployment of new profitable applications and services, this paper proposes a cross-network cooperation mechanism to effectively share network resources and infrastructures, and then adaptively control and match multi-network energy distribution characteristics according to actual user/service requirements in different geographic areas. Some idle or lightly-loaded Base Stations (BS or BSs) will be temporally turned off for saving energy and reducing EMI. Initial simulation results show the proposed approach can significantly improve the overall energy efficiency and QoS performance across multiple cooperative wireless networks. 相似文献
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提出了利用无线长波对水下潜艇自航模进行长波遥控的通信技术，阐述了长波遥控的发射、接收及天线系统的硬件组成和系统设计。对发射天线的现场测试结果进行了分析，提出了实际电路的阻抗匹配实现方法；对接收信号的噪声和灵敏度等有关问题进行了分析，采用天线的方向性自适应控制技术解决了潜艇水下接收，在实际应用中取得较好的效果。 相似文献
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Fahd N. Al-Wesabi Imran Khan Mohammad Alamgeer Ali M. Al-Sharafi Bong Jun Choi Abdallah Aldosary Ehab Mahmoud Mohamed 《计算机、材料和连续体（英文）》2021,69(1):301-317
With the rapid development of Internet technology, users have an increasing demand for data. The continuous popularization of traffic-intensive applications such as high-definition video, 3D visualization, and cloud computing has promoted the rapid evolution of the communications industry. In order to cope with the huge traffic demand of today’s users, 5G networks must be fast, flexible, reliable and sustainable. Based on these research backgrounds, the academic community has proposed D2D communication. The main feature of D2D communication is that it enables direct communication between devices, thereby effectively improve resource utilization and reduce the dependence on base stations, so it can effectively improve the throughput of multimedia data. One of the most considerable factor which affects the performance of D2D communication is the co-channel interference which results due to the multiplexing of multiple D2D user using the same channel resource of the cellular user. To solve this problem, this paper proposes a joint algorithm time scheduling and power control. The main idea is to effectively maximize the number of allocated resources in each scheduling period with satisfied quality of service requirements. The constraint problem is decomposed into time scheduling and power control subproblems. The power control subproblem has the characteristics of mixed-integer linear programming of NP-hard. Therefore, we proposed a gradual power control method. The time scheduling subproblem belongs to the NP-hard problem having convex-cordinality, therefore, we proposed a heuristic scheme to optimize resource allocation. Simulation results show that the proposed algorithm effectively improved the resource allocation and overcome the co-channel interference as compared with existing algorithms. 相似文献
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研究了协作通信与认知无线电的结合,针对TD-SCDMA系统和WiMAX系统组成的异构无线网络,提出了一种基于多用户分集的协作频谱感知机制.根据该算法,WiMAX用户被分成若干个簇,选择每个簇内瞬时信道条件最好的WiMAX用户协作检测频谱,并利用软硬结合的判决手段,既保证检测性能,又不增加复杂度.分析和仿真表明,该算法一方面保证了频谱检测的可靠性,降低了虚警概率,另一方面减少了通信开销,提高了判决消息传输的可靠性,达到了提升频谱利用率的目的. 相似文献
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Hanan Abdullah Mengash Radwa Marzouk Siwar Ben Haj Hassine Anwer Mustafa Hilal Ishfaq Yaseen Abdelwahed Motwakel 《计算机、材料和连续体（英文）》2022,73(1):327-342
Artificial intelligence (AI) techniques have received significant attention among research communities in the field of networking, image processing, natural language processing, robotics, etc. At the same time, a major problem in wireless sensor networks (WSN) is node localization, which aims to identify the exact position of the sensor nodes (SN) using the known position of several anchor nodes. WSN comprises a massive number of SNs and records the position of the nodes, which becomes a tedious process. Besides, the SNs might be subjected to node mobility and the position alters with time. So, a precise node localization (NL) manner is required for determining the location of the SNs. In this view, this paper presents a new quantum bird migration optimizer-based NL (QBMA-NL) technique for WSN. The goal of the QBMA-NL approach is for determining the position of unknown nodes in the network by the use of anchor nodes. The QBMA-NL technique is mainly based on the mating behavior of bird species at the time of mating season. In addition, an objective function is derived based on the received signal strength indicator (RSSI) and Euclidean distance from the known to unknown SNs. For demonstrating the improved performance of the QBMA-NL technique, a wide range of simulations take place and the results reported the supreme performance over the recent NL techniques. 相似文献
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Nemanja Zdravković Aleksandra Cvetkovic Dejan Milic Goran T. Djordjevic 《Journal of Modern Optics》2017,64(16):1657-1668
This paper analyses end-to-end packet error rate (PER) of a free-space optical decode-and-forward cooperative network over a gamma–gamma atmospheric turbulence channel in the presence of temporary random link blockage. Closed-form analytical expressions for PER are derived for the cases with and without transmission links being prone to blockage. Two cooperation protocols (denoted as ‘selfish’ and ‘pilot-adaptive’) are presented and compared, where the latter accounts for the presence of blockage and adapts transmission power. The influence of scintillation, link distance, average transmitted signal power, network topology and probability of an uplink and/or internode link being blocked are discussed when the destination applies equal gain combining. The results show that link blockage caused by obstacles can degrade system performance, causing an unavoidable PER floor. The implementation of the pilot-adaptive protocol improves performance when compared to the selfish protocol, diminishing internode link blockage and lowering the PER floor, especially for larger networks. 相似文献
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多出口网络链路负载均衡系统的研究 总被引：1，自引：2，他引：1
苏开宇 《中国计量学院学报》2009,20(1):65-70
针对当前广泛使用的多链路技术,研究了多链路网络的运行机制,对多链路的流量特性、负载分配策略进行了分析.将企业网日常的Internet流量分为Outbound流量和Inbound流量,并结合FreeBSD下的PF包过滤和动态DNS解析技术,分别给出了Inbound和Outbound流量的负载均衡策略和模型.基于该模型研制的系统,能成功地依照事先定义的负载均衡策略实现Inbound和Outbound流量的负载均衡,多个Internet链路的合理分配利用而使得总访问带宽扩大,能够很好地消除几大ISP间互访的瓶颈,还为内部网上SERVER提供更高的可靠性和性能. 相似文献
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舰船高传递损失基座振动波传递特性 总被引：2，自引：0，他引：2
基于波动理论,根据阻抗失配和波形转换原理,分析了不同基座连接结构中振动波传递特性,给出了隔振性能随基座板架厚度比及频率变化规律.接着讨论了阻振质量偏心布置对其隔振性能的影响,给出了偏心阻振质量对基座振动波传递的阻抑公式.在理论分析基础上,将高传递损失的基座连接结构延拓到基座面板、腹板和安装板架中,综合运用阻振质量以及贴... 相似文献
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本文讨论了分别在运动和静止镜面上反射的相干电磁波包的干涉现象,运动镜面反射所导致的多普勒效应会出现在这种干涉现象之中。本文按照经典电动力学边值问题,特别是运动界面边值问题的观念和方法,为这种干涉现象提供了一个理论描述,分析和讨论了这种干涉现象的特点,并给出了一个确定运动镜面速度的解析表达式.文章最后指出,还有许多与本文内容紧密相联的重要而有趣的问题有待进一步研究和讨论. 相似文献
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The Internet of Things (IoT) technology has been developed for directing and maintaining the atmosphere in smart buildings in real time. In order to optimise the power generation sector and schedule routine maintenance, it is crucial to predict future energy demand. Electricity demand forecasting is difficult because of the complexity of the available demand patterns. Establishing a perfect prediction of energy consumption at the building’s level is vital and significant to efficiently managing the consumed energy by utilising a strong predictive model. Low forecast accuracy is just one of the reasons why energy consumption and prediction models have failed to advance. Therefore, the purpose of this study is to create an IoT-based energy prediction (IoT-EP) model that can reliably estimate the energy consumption of smart buildings. A real-world test case on power predictions is conducted on a local electricity grid to test the practicality of the approach. The proposed (IoT-EP) model selects the significant features as input neurons, the predictable data is selected as output nodes, and a multi-layer perceptron is constructed along with the features of the Convolution Neural Network (CNN) algorithm. The analysis of the proposed IoT-EP model has higher accuracy of 90%, correlation of 89%, and variance of 16% in less training time of 29.2 s, and with a higher prediction speed of 396 (observation/sec). When compared to existing models, the results showed that the proposed (IoT-EP) model outperforms with a satisfactory level of accuracy in predicting energy consumption in smart buildings. 相似文献
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H. G. Aksoy 《先进材料力学与结构力学》2018,25(5):375-385
Mechanics of nanoporous metallic materials have been an interest due to their applications in a wide range of areas such as sensors, energy conversion, and smart materials design. In this study, the effects of morphological parameters, such as ligament diameter and length, on wave propagation in bicontinuous porous nanostructures is studied by using the discontinuous Galerkin method. Computational results show that energy is localized on the surface independent of the morphological parameters. It is observed that localization length increases with the increase in frequency. In addition, surface roughness parameter and ligament diameter do not have a significant influence on localization length. 相似文献