Deployment Strategy of Wireless Sensor Networks for Internet of Things

This paper proposes an open hierarchical network architecture for the Internet of Things (IoT), which can provide a unified network topology by using heterogeneous Wireless Sensor Networks (WSNs). With this proposed architecture, our research focuses on the optimal deployment strategy of the nodes on the convergence level. We aim at the maximization of the sub-network's lifetime while minimizing the deployment cost. Meanwhile, a novel metric named as the Ratio of Lifetime to Cost (RLC) is proposed to estimate the efficiency of convergence nodes deployment. Simulation results indicate that the proposed deployment algorithm can achieve the optimal number of convergence nodes. The proposed deployment strategy is able to achieve a balanced tradeoff between the network lifetime and the deployment cost.

Complex field network-coded cooperation based on multi-user detection in wireless networks

Cooperative communication can achieve spatial diversity gains,and consequently combats signal fading due to multipath propagation in wireless networks powerfully.A novel complex field network-coded cooperation（CFNCC） scheme based on multi-user detection for the multiple unicast transmission is proposed.Theoretic analysis and simulation results demonstrate that,compared with the conventional cooperation（CC） scheme and network-coded cooperation（NCC） scheme,CFNCC would obtain higher network throughput and consumes less time slots.Moreover,a further investigation is made for the symbol error probability（SEP） performance of CFNCC scheme,and SEPs of CFNCC scheme are compared with those of NCC scheme in various scenarios for different signal to noise ratio（SNR） values.

Optimization of an Underwater Wireless Sensor Network Architecture with Wave Glider as a Mobile Gateway

This paper presents an original probabilistic model of a hybrid underwater wireless sensor network(UWSN),which includes a network of stationary sensors placed on the seabed and a mobile gateway.The mobile gateway is a wave glider that collects data from the underwater network segment and retransmits it to the processing center.The authors consider the joint problem of optimal localization of stationary network nodes and the corresponding model for bypassing reference nodes by a wave glider.The optimality of the network is evaluated according to the criteria of energy efficiency and reliability.The influence of various physical and technical parameters of the network on its energy efficiency and on the lifespan of sensor nodes is analyzed.The analysis is carried out for networks of various scales,depending on the localization of stationary nodes and the model of bypassing the network with a wave glider.As a model example,the simulation of the functional characteristics of the network for a given size of the water area is carried out.It is shown that in the case of a medium-sized water area,the model of“bypassing the perimeter”by a wave glider is practically feasible,energy efficient and reliable for hourly data measurements.In the case of a large water area,the cluster bypass model becomes more efficient.

Investigation of Architecture and Essential Technologies of Wireless Sensor Network

This paper introduces the architecture of wireless sensor networks, presents a cross-layer network management and control mechanism. The key technologies, such as Medium Access Control (MAC) and wireless routing protocols are discussed and compared. A proposal of applying the simple IEEE 802 MAC protocol into the wireless sensor network is introduced. In addition, in order to improve the system capacity, a multi-channel strategy for the sensor nodes is presented for decreasing the blocking probability and suppressing the accessing time delay. It is concluded that there are still a number of problems to be solved, including decreasing power consumption, improving capacity and avoiding access collision, to promote the successful commercial application of wireless sensor network.

The Implementation of Electronic Intelligent Tag System Based on Wireless Sensor Network

Recently, Wireless Sensor Network (WSN) has been widely applied in many fields. In this paper, we design and implement a WSN-based Electronic Intelligent Tag System (EITS) to provide intelligent management of the modern supermarkets. As a main transceiver, nRF24L01+ wireless module is used in this system, which will make it possible to achieve low-power and low-cost for EITS. This system fully embodies the advantages and characteristics of WSN. This paper will introduce the system architecture, hardware structure and software design in details;and put forward a specific solution. Finally, we achieve the intelligent management of the mall based on wireless sensor network technology.

Management of Intelligent Campus Wireless Sensor Networks Based on Runtime Model

To quick customize and develop intelligent campus internet of things (ICIOT) system more efficiently, in this paper an approach based on runtime model to managing intelligent campus wireless sensor networks is proposed. Firstly, manageability of intelligent campus wireless sensors is abstracted as runtime models which automatically and immediately propagate any observable runtime changes of target resources to corresponding architecture models. Then, a composite model of intelligent campus wireless sensors is constructed through merging their runtime models in order to manage different kinds of devices in a unified way. Finally, a customized model is constructed according to the personalized management requirement and the synchronization between the customized model and the composite model is ensured through model transformation. Thus, all the management tasks can be carried through executing operating programs on the customized model. In the part of the teaching area schools conducted experiments and compared with the traditional method, this method can be more effective management of campus facilities, more energy efficient and orderly, which can reach a 16.7% energy saving.

A survey of free space optical networks

Free Space Optical （FSO） networks, also known as optical wireless networks, have emerged as viable candidates for broadband wireless communications in the near future. The range of the potential application of FSO networks is extensive, from home to satellite. However, FSO networks have not been popularized because of insufficient availability and reliability. Researchers have focused on the problems in the physical layer in order to exploit the properties of wireless optical channels. However, recent technological developments with successful results make it practical to explore the advantages of the high bandwidth. Some researchers have begun to focus on the problems of network and upper layers in FSO networks. In this survey, we classify prospective global FSO networks into three subnetworks and give an account of them. We also present state-of- the-art research and discuss what kinds of challenges exist.

Study of Smart Grid Communication Network Architectures and Technologies

Smart Grid (SG) is an emerging paradigm of the modern world to upgrade and enhance the existing conventional electrical power infrastructure from generation to distribution to the consumers in a two-way communication fashion to automate the electrical power demand and supply and make this a cyber-physical system. SG infrastructure key elements, such as smart meters, circuit breakers, transformers, feeders, substations, control centers, grid stations, are required well-formed communication network architectures. SG infrastructure is divided into three main communication networks architectures, such as HAH, NAN, and WAN. Each of these communication network architectures requires reliable, stable, secure, high data rate at real-time with the help of different wireline and wireless communication technologies from HAN to WAN networks. To understand the complete concepts about SG, a concise review is presented and it will help the readers to get foundations of communication network architectures and technologies of SG.

A Real-Time-Enabled, Blackboard-Based, Publish/Subscribe Architecture for Wireless Sensor Nodes

Wireless sensor network nodes have only limited resources concerning memory and battery life-time. Mem- ory can be efficiently used by sharing data, and the life-time of a battery can be extended, when the node has long power saving sleep-phases. We propose a publish/subscribe architecture that achieves these two aims. The results of our work are of great interest for sensor application developers, giving them now the opportu- nity to use our architecture for sharing data among different applications on the node as well as the different layers of the operating system. We introduce a blackboard which is used for centrally storing published val- ues, like measured data from a monitored sensor. This makes it possible to share stored data without monitoring the sensors once again, which is advantageously concerning power consumption, memory space, and reaction time. Beside the proposed publish/subscribe method for sensor nodes with its notification possibili- ties, our architecture fulfills also real-time requirements. We show how the well-known sensor operating system MANTIS OS can be extended by a real-time enabled, blackboard-based publish/subscribe architect- ture. This architecture and first of all its implementation is of special interest for cross layer optimization of sensor applications. Cross-layer approaches benefit from our architecture because the available implementa- tion can be used as an efficient framework for central storing and managing of shared values.

Energy Conservation Challenges in Wireless Sensor Networks: A Comprehensive Study

A Wireless Sensor Network (WSN) consists of a large number of randomly deployed sensor nodes. These sensor nodes organize themselves into a cooperative network and perform the three basic functions of sensing, computations and communications. Research in WSNs has become an extensive explorative area during the last few years, especially due to the challenges offered, energy constraints of the sensors being one of them. In this paper, a thorough comprehensive study of the energy conservation challenges in wireless sensor networks is carried out. The need for effective utilization of limited power resources is also emphasized, which becomes pre-eminent to the Wireless Sensor Networks.

5G High Mobility Wireless Communications: Challenges and Solutions

The fifth generation(5G) network is expected to support significantly large amount of mobile data traffic and huge number of wireless connections,to achieve better spectrum- and energy-efficiency,as well as quality of service(QoS) in terms of delay,reliability and security.Furthermore,the 5G network shall also incorporate high mobility requirements as an integral part,providing satisfactory service to users travelling at a speed up to 500 km/h.This paper provides a survey of potential high mobility wireless communication(HMWC) techniques for 5G network.After discussing the typical requirements and challenges of HMWC,key techniques to cope with the challenges are reviewed,including transmission techniques under the fast timevarying channels,network architecture with mobility support,and mobility management.Finally,future research directions on 5G high mobility communications are given.

Ultra-Low Power 1 Volt Small Size 2.4 GHz CMOS RF Transceiver Design for Wireless Sensor Node

Ultra-low power transceiver design is proposed for wireless sensor node used in the wireless sensor network（WSN）.Typically,each sensor node contains a transceiver so it is required that both hardware and software designs of WSN node must take care of energy consumption during all modes of operation including active/sleep modes so that the operational life of each node can be increased in order to increase the lifetime of network.The current declared size of the wireless sensor node is of millimeter order,excluding the power source and crystal oscillator.We have proposed a new 2.4 GHz transceiver that has five blocks namely XO,PLL,PA,LNA and IF.The proposed transceiver incorporates less number of low-drop outs（LDOs）regulators.The size of the transceiver is reduced by decreasing the area of beneficiary components up to 0.41 mm;of core area in such a way that some functions are optimally distributed among other components.The proposed design is smaller in size and consumes less power,<1 mW,compared to other transceivers.The operating voltage has also been reduced to 1 V.This transceiver is most efficient and will be fruitful for the wireless networks as it has been designed by considering modern requirements.

Application Study of Greenhouse Environment Monitoring System Based on ZigBee Technology

Against the demand of intelligent greenhouse construction of facility agriculture,greenhouse environment monitoring system is developed.The system contains three-layer architecture: sensor network layer at the bottom,data transmission convergence layer in the middle and monitoring application layer on the top,which is different from design idea of the existing system architecture.The bottom layer uses ZigBee wireless communication technology to construct wireless sensor network,and node type contains coordinator,router and acquisition terminal.Acquisition terminal is distributed in each greenhouse to collect data and play the role of wireless transmission,and router plays the function of data forwarding as the bridge of acquisition terminal and coordinator.Middle layer is composed of monitoring software developed by Lab VIEW software of NI Company and coordinator,which is used to gather data from the bottom layer.The top layer is comprehensive monitoring platform developed by Java language,which is used to gather greenhouse data of all plantation bases in one region,thereby providing comprehensive information service for government,enterprise and farmer.Greenhouse environment monitoring system realizes data collection and sharing of greenhouse environment information(air temperature,air humidity,light intensity and carbon dioxide concentration).Via test verification,the system's operation is stable,with certain application value.

BigEar: Ubiquitous Wireless Low-Budget Speech Capturing Interface

This article presents BigEar, a wireless low-cost speech capturing interface that aims to realize unobtrusive and transparent context-aware vocal interaction for home automation. The speech recognition process implemented in BigEar system considers noise sources including possible holes in the reconstructed audio stream and tries to overcome them by means of inexactness toleration mechanisms to improve intelligibility of the reconstructed signal. Key contribution of this work is the use of extremely low cost devices to realize a modular flexible and real-time wireless sensor network. On-field implementation and experiments show that the proposed solution can perform real-time speech reconstruction, while listening tests confirm the intelligibility of the reconstructed signal.

基于频率切换实现恒流/恒压输出的电场耦合无线电能传输系统

电场耦合无线电能传输(electric-field coupled wireless power transfer,EC-WPT)技术的实际应用中,有些用电设备需要系统具有不同的恒定输出特性(恒流/恒压),即系统输出电压或输出电流与负载解耦,此外,系统还需具备在恒流、恒压模式间按需切换的功能。针对该需求,基于LC-CLC谐振网络提出1种具有恒流/恒压输出特性的EC-WPT系统,分析LC-CLC谐振网络特性,推导恒流/恒压输出特性的实现条件以及恒流频率和恒压频率的计算方法,并给出系统参数设计方法,分析系统对工作频率的敏感性。最后通过仿真和实验验证所提出的EC-WPT系统恒流/恒压输出特性及其参数设计方法的正确性和有效性。实验结果表明所提出的系统在输入电压恒定的不同负载工况下分别实现2 A的恒流输出以及96 V的恒压输出,其最大传输效率分别为87.83%及88.17%。

用户为中心的网络:体系架构与关键技术

随着全球通信技术的飞速进展,5G向6G的转变已成为通信领域的关键焦点。以用户为中心的网络(User-Centric Network,UCN)架构代表了通信技术的革命性创新,通过将用户需求和体验置于设计的核心,为6G环境下的多样化应用提供了全方位服务。深入探讨了6G时代UCN的发展轨迹、架构特性及核心技术,涵盖分布式与去中心化网络架构、集中化控制与资源优化网络架构,以及诸如资源分配、无缝漫游和隐私保护等关键技术。介绍了一种创新的F5G下服务于UCN架构的无感漫游方案,仿真结果表明了该方案的优越性。通过系统综述与技术梳理,旨在阐明UCN在塑造未来移动通信领域中的重要作用,为6G网络技术的进一步发展提供理论支撑和实践方向。

用于MIMO检测的基于NoC的多核动态可重构架构

随着无线通信技术的发展,实现多输入多输出(MIMO)系统检测性能与复杂度之间的最优权衡日益困难,深度学习DL为此提供了新方向。文中提出基于片上网络(NoC)的多核动态可重构架构MCDBP,以提高基于DL的MIMO检测算法的性能,并增强架构的可编程性和扩展性。MCDBP通过集成轻量级计算内核及片上网络互连,并行处理矢量-矩阵乘法、常数-矢量乘法、矢量点积、矢量加法等大多数深度展开网络的基本运算,有效提高复杂MIMO检测性能。架构的创新在于可重构的处理元件PE设计,可以依据DL驱动的MIMO检测需求动态调整。该设计对基于DL的MIMO检测算法共性进行深入分析,支持多种基本运算模式,展现极高灵活性。实验结果显示,MCDBP在执行基于DL的MIMO检测算法时,与通用CPU相比,可以实现12.66~22.98的加速比,算法性能有所提高,可以适应不同应用场景。

6G智能内生无线通信网络:现状、挑战、系统设计和架构

移动通信系统已经成为支持各领域信息传输需求的基础设施,而6G的功能预计将超越简单的数据传输。6G智能内生无线通信网络具有提供智能包容性的潜在能力,可以让任何终端用户随时随地获得人工智能服务。现有的分布式人工智能架构中,执行算法的终端间相对独立,无法为整个无线通信提供内生智能系统性功能。针对这一问题提出了一个能够为6G提供智能内生功能的基本系统框架,使6G网络可以更好地实现高性能安全计算和通信,构建一个智能体可相互合作的生态架构。首先简述了无线通信网络的发展背景和现状,然后从数据、智能和网络的维度讨论了实现6G智能内生架构的挑战,最后提出了一个基本的6G智能网络的系统架,包括了网络层、数据层、智能层和应用层四层结构。

基于智能超表面的6G近场网络构建

近年来,近场传播特性的研究备受关注,尤其是基于RIS的近场技术成为研究的热点。目前尚缺乏对基于RIS的近场技术进行全面梳理的文献。首先简要概述了近场技术的基本概念,然后分别从三个方面系统地梳理了基于RIS的近场技术研究进展及挑战,包括RIS构建泛在的近场无线传播环境、使能6G网络的近场新范式以及基于RIS的近场技术面临的挑战等。通过技术梳理,期望对RIS和近场技术研究工作起到推进作用。

面向应急环境的无线传感网生存性问题研究

【背景】当前,无线传感网在各种应急场合中发挥的应急保障和抢险救援等作用日益凸显,同时应急环境下无线传感网的生存能力也面临诸多问题和挑战。【目的】为了能够延长网络生存时间和增强信息服务水平,需根据应急环境动态变化高效利用有限的系统资源,以充分发挥无线传感网的功效。基于网络生存性的目标需求,分析无线传感网在应急场景下的生存态势、服务要求和性能瓶颈,进而探讨应急环境下增强无线传感网生存性的若干关键技术及有效措施。【方法】首先,总结归纳应急环境下无线传感网的生存性特征和服务需求,全面分析应急环境下无线传感网生存性面临的诸多开放问题和技术挑战;然后,系统调研国内外无线传感网生存性相关研究工作。在此基础上,从网络体系架构、生存性增强技术和生存性评估方法三个方面出发,探讨应急环境下无线传感网进行高效组织、运行和维护涉及的一系列技术难题并给出可行的解决方案。【结论】网络生存性技术已成为无线传感网大规模部署应用的研究热点之一,本研究的工作重点关注复杂多变应急环境下通过高效利用网络资源和节点的自适应协调来确保无线传感网关键服务的按需提供,希望为应急场合下构建灵活、健壮的高生存性异构无线传感网提供有参考借鉴价值的解决思路。