Radio Propagation and Wireless Coverage of LSAA-Based 5G Millimeter-Wave Mobile Communication Systems

Millimeter-wave(mm Wave) communications will be used in fifth-generation(5G) mobile communication systems, but they experience severe path loss and have high sensitivity to physical objects, leading to smaller cell radii and complicated network architectures. A coverage extension scheme using large-scale antenna arrays(LSAAs) has been suggested and theoretically proven to be cost-efficient in combination with ultradense small cell networks. To analyze and optimize the LSAA-based network deployments, a comprehensive survey of recent advances in statistical mmWave channel modeling is first presented in terms of channel parameter estimation, large-scale path loss models, and small-scale cluster models. Next, the measurement and modeling results at two 5G candidate mmWave bands(e.g., 28 GHz and 39 GHz) are reviewed and compared in several outdoor scenarios of interest, where the propagation characteristics make crucial contributions to wireless network designs. Finally, the coverage behaviors of systems employing a large number of antenna arrays are discussed, as well as some implications on future mmWave cellular network designs.

Modified Dwarf Mongoose Optimization Enabled Energy Aware Clustering Scheme for Cognitive Radio Wireless Sensor Networks

Cognitive radio wireless sensor networks(CRWSN)can be defined as a promising technology for developing bandwidth-limited applications.CRWSN is widely utilized by future Internet of Things(IoT)applications.Since a promising technology,Cognitive Radio(CR)can be modelled to alleviate the spectrum scarcity issue.Generally,CRWSN has cognitive radioenabled sensor nodes(SNs),which are energy limited.Hierarchical clusterrelated techniques for overall network management can be suitable for the scalability and stability of the network.This paper focuses on designing the Modified Dwarf Mongoose Optimization Enabled Energy Aware Clustering(MDMO-EAC)Scheme for CRWSN.The MDMO-EAC technique mainly intends to group the nodes into clusters in the CRWSN.Besides,theMDMOEAC algorithm is based on the dwarf mongoose optimization(DMO)algorithm design with oppositional-based learning(OBL)concept for the clustering process,showing the novelty of the work.In addition,the presented MDMO-EAC algorithm computed a multi-objective function for improved network efficiency.The presented model is validated using a comprehensive range of experiments,and the outcomes were scrutinized in varying measures.The comparison study stated the improvements of the MDMO-EAC method over other recent approaches.

Centralized Quasi-Static Channel Assignment for Multi-Radio Multi-Channel Wireless Mesh Networks

Employing multiple channels in wireless multihop networks is regarded as an effective approach to increas-ing network capacity. This paper presents a centralized quasi-static channel assignment for multi-radio multi-channel Wireless Mesh Networks (WMNs). The proposed channel assignment can efficiently utilize multiple channels with only 2 radios equipped on each mesh router. In the scheme, the network end-to-end traffics are first modeled by probing data at wireless access points, and then the traffic load between each pair of neighboring routers is further estimated using an interference-aware estimation algorithm. Having knowledge of the expected link load, the scheme assigns channels to each radio with the objective of mini-mizing network interference, which as a result greatly improves network capacity. The performance evalua-tion shows that the proposed scheme is highly responsive to varying traffic conditions, and the network per-formance under the channel assignment significantly outperforms the single-radio IEEE 802.11 network as well as the 2-radio WMN with static 2 channels.

Wireless Regional Area Networks and Cognitive Radio 2

IEEE has set up in October 2004 the IEEE802.22 Working Group-Wireless Regional Area Network (WRAN) Task Force to work out air interface standard based on Cognitive Radio (CR) technologies. The standard includes Physical Layer (PHY) and Media Access Control (MAC), utilizig the vacant spectrum bands already allocated to broadcast TV without interference.. The WRAN employs CR technologies to sense and estimate the television signals and use the technologies of dynamic spectrum management to find and then allocate vacant spectrums. The CR technologies are representing one of the major trends for future wireless communications. This article on WRANs and CR technologies will be divided into two issues. In this issue, WRANs and IEEE 802.22, CR technologies are introduced. And the second part in the next issue will analyze the applications of CR technologies.

Parallel-Transmission: A New Usage of Multi-Radio Diversity in Wireless Mesh Network

To fully utilize the diversity of multi-radio, a new parallel transmission method for wireless mesh network is proposed. Compared with conventional packet transmission which follows “one flow on one radio”, it uses the radio diversity to transmit the packets on different radios simultaneously. Three components are presented to achieve parallel-transmission, which are control module, selection module and schedule module. A localized selecting algorithm selects the right radios based on the quality of wireless links. Two kinds of distributed scheduling algorithms are implemented to transmit packets on the selected radios. Finally, a parallel-adaptive routing metric is presented. Simulation results by NS2 show that this parallel-transmission scheme could enhance the average throughput of network by more than 10%.

Wireless Regional Area Networks and Cognitive Radio(1)

IEEE has set up in October 2004 the IEEE802.22 Working Group—Wireless Regional Area Network (WRAN) Task Force to work out air interface standard based on Cognitive Radio (CR) technologies. The standard includes Physical Layer (PHY) and Media Access Control (MAC),to use the already allocated fallow spectrums to broadcast TV in a non-interference way. The WRAN employs CR technologies to sense and estimate the television frequencies and use the technologies of dynamic spectrum management to find and then allocate idle spectrums. The CR technologies are representing one of the major trends for future wireless communications. This article on WRANs and CR technologies will be divided into two issues. In this issue,WRANs and IEEE 802.22,CR technologies are introduced. And the second part in the next issue will analyze the applications of CR technologies.

Radio Coverage Mapping in Wireless Sensor Networks

Radio coverage directly affects the network connectivity, which is the foundational issue to ensure the normal operation of the network. Many efforts have been made to estimate the radio coverage of sensor nodes. The existing approaches (often RSSI measurement-based), however, suffer from heavy measurement cost and are not well suitable for the large-scale densely deployed WSNs. NRC-Map, a novel algorithm is put forward for sensor nodes radio coverage mapping. The algorithm is based on the RSSI values collected by the neighbor nodes. According to the spatial relationship, neighbor nodes are mapping to several overlapped sectors. By use of the least squares fitting method, a log-distance path loss model is established for each sector. Then, the max radius of each sector is computed according to the path loss model and the given signal attenuation threshold. Finally, all the sectors are overlapped to estimate the node radio coverage. Experimental results show that the method is simple and effectively improve the prediction accuracy of the sensor node radio coverage.

Universal Band Pass Sampling Algorithm for Integration of Multiple Wireless Technologies Using Software Defined Radio Platform

Software Defined Radio (SDR) architecture allows us to integrate different mobile technologies using common hardware but with different software modules. To achieve this, we need to keep the signal in digital form for as much portion of the circuitry as possible, so that the implementation could be carried out by programmable digital processors. For this purpose, the incoming radio frequency (RF) signal is down converted to baseband spectrum using band pass sampling method. Research works carried out so far in this field have developed a few algorithms for band pass sampling. But, these algorithms are not much useful for most of the mobile communication systems and they use complex methodology for computing the sampling frequency values. In order to use the SDR platform to integrate all current wireless technologies, an efficient, cost effective and less complex algorithm that can be labelled as universal band pass sampling algorithm is developed in this paper for multiple mobile systems. This algorithm is based on a novel idea of inserting guard bands between the signals which reduces the design complexities of perfect ADC and sharp cut off filters. Using this algorithm, valid sampling frequency ranges and corresponding IF values are calculated for down converting RF signals. The algorithm is tested for six RF signals of different wireless technologies which are integrated and simultaneously down converted using SDR based front end receiver and thus the system multiplies the base station capacity by a factor of six. The simulation results are obtained and shown in this paper which proves that the algorithm developed works well for most of the wireless technologies.

Cooperative Spectrum Sensing for Cognitive Radio-Wireless Sensors Network Based on OR Rule Decision to Enhance Energy Consumption in Greenhouses

Wireless sensors networks (WSNs) combined with cognitive radio have developed and solved the limited space of the frequency spectrum. In this paper, we propose different types of spectrums sensing and their own decisions depend on the probabilities that applied into fusion center, and how these probabilities’ techniques help to enhance the energy consumption of WSNs. In the same way, the importance of designing balanced distribution between the wireless sensors networks and their own sinks. This research also provides an overview of security issues in CR-WSN, especially in Spectrum Sensing Data Falsification (SSDF) attacks that enforces harmful effects on spectrum sensing and spectrum sharing. We adopt OR rule as four types of CRSN sensing protocolin greenhouses application by using Matlab and Netsim simulators. Our results show that the designing balanced wireless sensors and their sinks in greenhouses are very significant to decrease the energy, which is due to the traffic congestion in the sink range area. Furthermore, by applying OR rule has enhanced the energy consumption, and improved the sensors network lifetime compared to cognitive radio network.

An Energy-Efficient Duty-Cycled Wake-Up Radio Protocol for Avoiding Overhearing in Wireless Sensor Networks

Wake-up radio (WuR) system is often presented as the best candidate for replacing traditional duty cycled Medium Access Control (MAC) protocols in Wireless Sensor Networks (WSNs). The Double Radio (DoRa) protocol is a new MAC protocol for in-band WuR system with addressing capabilities. While the DoRa protocol improves the WSNs energy efficiency, it still suffers from an overhearing problem when the WuR system is very often requested. The WuR wastes a noticeable amount of energy when overhearing to wake-up demand intended to other nodes, but it is neither measured nor solved in other works. In this paper, an adaptive duty-cycled DoRa (DC-DoRa) is then proposed to solve the overhearing problem. The primary concept of the work is to enable the WuR functionality before the node is addressed and to disable the WuR after the node sent data. Extensive simulations under OMNeT++ using real input parameters are then performed to show the significant energy-savings through the two protocols and the nearly suppression of overhearing with DC-DoRa. In fact, the mean power consumption is three-order below using the DoRa protocol compared to traditional MAC protocols. While overhearing can represent up to 93% of the WuR energy consumption with the DoRa protocol, it is reduced to only 1% with the DC-DoRa protocol.

A Fault-Tolerant Cooperative Spectrum Sensing Algorithm over Cognitive Radio Network Based on Wireless Sensor Network

A serious threat to cognitive radio networks that sense the spectrum in a cooperative manner is the transmission of false spectrum sensing data by malicious sensor nodes. SNR fluctuations due to wireless channel effects complicate handling such attackers even further. This enforces the system to acquire authentication. Actually, the decision maker needs to determine the reliability or trustworthiness of the shared data. In this paper, the evaluation process is considered as an estimation dilemma on a set of evidences obtained through sensor nodes that are coordinated in an underlying wireless sensor network. Then, a likelihood-based computational trust evaluation algorithm is proposed to determine the trustworthiness of each sensor node's data. The proposed procedure just uses the information which is obtained from the sensor nodes without any presumptions about node’s reliability. Numerical results confirm the effectiveness of the algorithm in eliminating malicious nodes or faulty nodes which are not necessarily conscious attackers.

基于GNU Radio的230MHz多通道主站电台的设计

采用GNU Radio技术及与其配套的硬件前端USRP设计和实现了230 MHz软件无线电多通道主站电台。该主站电台在调制方式上与现有无线电台设备全面兼容,覆盖了整个电力系统230 MHz全双工频段,可以同时在多个频点以不同的速率和调制方式与不同制式的从站电台进行双工通信。所提出的方案可以充分利用230 MHz无线频率资源,增加终端接入数量,提高通信系统组网的灵活性和可靠性,同时有效降低维护和升级的成本。

基于动态Radio Map的粒子滤波室内无线定位算法

针对目前大多数基于射频信号强度匹配定位算法在定位精度及鲁棒性方面不足,提出了一种基于动态Radio Map的粒子滤波室内无线定位算法.该算法利用参考节点构建基于空间关联性的动态Radio Map模型,以反映信号环境的实时变化,并将移动目标定位由分类问题转化为回归问题,打破了传统网格式Radio Map模型的限制,降低了算法的时空复杂度.实验结果表明,相对于静态Radio Map模型,动态Radio Map模型将定位精度平均提高了约20%,表现出良好的环境动态自适应能力.

基于GNU Radio和USRP的无线通信系统建模仿真

针对无线通信环境的复杂特性,为了实现无线通信系统快速准确的建模仿真,应用GNU Radio和USRP组成的软件无线电系统作为新的建模仿真方法。介绍并分析该方法的软件特性和硬件架构,进行MPSK调制系统在仿真信道和实际信道下链路模型的误码率对比实验,并在包含实际无线信道的链路模型基础上,设计并实现了一套无线视频流传输原型系统。分析和实验结果表明,新方法能够快速实现无线通信系统原型,将实际无线信道纳入系统模型中,从而获得更准确的仿真和分析结果。该方法适用于对通信协议标准及系统有定制化需求、针对传输环境复杂的无线通信系统研究开发。

基于Wireless USB的数据采集系统设计

针对工业生产过程中大批量高速数据采集和实时传输处理的要求。采用Cypress公司的无线USB系统作为无线数据的射频收发模块,结合Cypress公司的EZ-USB系列芯片和Altera公司的ACEX1K系列FPGA芯片设计了一套数据信号采集和无线传输系统。主要阐述了整个系统的原理、硬件构建方法和软件部分的开发过程。

多radio无线mesh网络跨层路由协议

与传统的无线多跳网络不同,多radio无线mesh网络的路由器是固定的,节点具有异构性。提出一种协作的异构多radio无线mesh系统路由设计模型,该路由协议模型按路由发现过程,分4个子模块,分别为半同步式邻居发现机制r、adio异构刻画的路由metric、分层的信息发布模型、满足业务需求的路由算法。该路由协议模型对多radio的异构性进行了刻画,采用分层协作方式共享网络拓扑信息。实验证明这种适应异构无线环境的跨层路由设计方案比传统方案更符合用户需求。

EasiTest:多Radio异构无线传感器网络测试平台

设计并实现了一种多Radio的异构无线传感器网络综合测试平台系统EasiTest,该平台采用了两种不同性能、功能的测试节点,可以支持大规模、异构传感器网络综合性能测试以及应用性研究.平台内采用了结构复杂、功能完备的多Radio的EZ271作为中高速测试节点,以及以 WiFi作为测试通道的EZ521作为中低速测试节点;系统提供传感/测试数据收集、数据管理、资源分配、服务器状态检查、节点状态检查与参数配置以及资源注册共享等功能模块,保障用户能够方便快捷地实现功能实验;通过友好的 Web访问页面,用户能够模拟真实的网络环境对多种类,如802.15.4,802.11协议等,以及多层次,如 MAC层、路由层、应用层等的网络协议研究成果进行灵活的综合实验验证,从而能够有效地提高无线传感器网络技术的研究效率.

基于GNU Radio的ADS-B信号收发系统设计

针对高集成度ADS-B系统不易开展创新性研究的问题,基于软件无线电设计了一套ADS-B信号收发系统;首先以可修改形式实现ADS-B报文编码、基带信号生成、前导脉冲检测、信号解调以及ADS-B信息解码等自定义GNU Radio模块的编写;然后创建ADS-B发射机和接收机流图,驱动硬件外设HackRF实现ADS-B信号的发射与接收;最后通过实验对各模块功能及数据接口进行测试;实验结果表明,该系统设计方案可行,ADS-B信号格式及报文广播速率符合Do-260B标准,且ADS-B接收机接收灵敏度为-68 dBm,信号检测率达89%。

基于双流融合网络的非接触式IR-UWB人体动作识别方法

随着智能感知技术的飞速发展,人机交互(Human Computer Interaction, HCI)领域迎来了全新的发展态势。传统的人机交互方法主要依赖可穿戴设备或者摄像头采集用户的行为数据,虽然识别精准,却存在不小的局限性。具体而言,可穿戴设备会给用户带来额外的使用负担,而基于摄像头的方案不仅会受到环境光线的影响,还会涉及用户隐私的泄露,这些因素均限制了其在日常生活中的广泛应用。为了突破这些限制,实现精确的、非接触式人机交互应用,利用无线射频(Radio Frequency, RF)领域中脉冲超宽带(Impulse Radio Ultra-Wideband, IR-UWB)所具有的高灵敏度和精细空间分辨率等优势,提出了一种基于双流融合网络的非接触式人体动作识别方法。该方法捕获目标运动所导致的时域信号变化,并通过对时域特征进行多普勒频移变化,提取到对应的频域特征。在此基础上,构建了一个融合多维卷积神经网络(Convolutional Neural Networks, CNNs)和GoogLeNet模块的双流网络模型,以实现高精度的动作识别。通过广泛的实验测试,结果表明所提方法对8种常见人体动作的平均识别准确率达到94.89%,并且在不同的测试条件下均能保持超过90%的识别准确率,进一步验证了所提方法的鲁棒性。

Multi-Radio传感器网络MAC协议可靠性的研究

研究了Multi-Radio传感器网络MAC协议的可靠性问题,建立Multi-Radio传感器网络MAC协议可靠性的概率模型,并分了协议的可靠性,同时比较了Multi-Radio传感器网络与现有传感器网络的差别。实验结果表明,对MAC协议可靠性的分析与实验结果相一致,从而验证了本理论分析的正确性。