Termite-hill: Performance optimized swarm intelligence based routing algorithm for wireless sensor networks

A wireless sensor network (WSN) is a large collection of sensor nodes with limited power supply, constrained memory capacity, processing capability, and available bandwidth. The main problem in event gathering in wireless sensor networks is the formation of energy-holes or hot spots near the sink. Due to the restricted communication range and high network density, events forwarding in sensor networks is very challenging, and require multi-hop data forwarding. Improving network lifetime and network reliability are the main factors to consider in the research associated with WSN. In static wireless sensor networks, sensors nodes close to the sink node run out of energy much faster than nodes in other parts of the monitored area. The nodes near the sink are more likely to use up their energy because they have to forward all the traffic generated by the nodes farther away to the sink. The uneven energy consumption results in network partitioning and limit the network lifetime. To this end, we propose an on-demand and multipath routing algorithm that utilizes the behavior of real termites on hill building termed Termite-hill which support sink mobility. The main objective of our proposed algorithm is to efficiently relay all the traffic destined for the sink, and also balance the network energy. The performance of our proposed algorithm was tested on static, dynamic and mobile sink scenarios with varying speed, and compared with other state-of-the-art routing algorithms in WSN. The results of our extensive experiments on Routing Modeling Application Simulation Environment (RMASE) demonstrated that our proposed routing algorithm was able to balance the network traffic load, and prolong the network lifetime.     

低功耗射频唤醒无线传感器网络设计

针对无线传感器网络采用睡眠/唤醒机制来实现低功耗时,不可避免地引起网络响应时延的问题.在波束供电技术的基础上提出了无线传感器网络低功耗射频唤醒机制,给出了低功耗射频唤醒无线传感器网络节点的硬件结构和详细设计.节点通过从电磁波中获取能量来及时地唤醒自己,以达到提高实时性的目的.性能分析表明低功耗射频唤醒无线传感器网络节点比采用传统睡眠/唤醒机制的节点具有更高的实时性和更低的功耗.     

一种新型唤醒机制的无线传感器网络节点设计

寿命过短一直困扰无线传感器网络(WSNs)与实际应用结合的难题。通过对WSNs工作效率低问题的研究,提出了一种新型射频唤醒机制的WSNs节点的设计方法,对降低节点的功耗和延长WSNs的寿命都有帮助。详细说明了节点设计的硬件结构和软件中的程序流程。可行性分析论证了节点的实用性和低功耗特性。     

Energy efficiency of femtocell deployment in combined wireless/optical access networks

Optical/wireless convergence has become of particular interest recently because a combined radio wireless and optical wired network has the potential to provide both mobility and high bandwidth in an efficient way. Recent developments of new radio access technologies such as the Long Term Evolution (LTE) and introduction of femtocell base stations open new perspectives in providing broadband services and applications to everyone and everywhere, but the instantaneous quality of radio channel varies in time, space and frequency and radio communication is inherently energy inefficient and susceptible to reflections and interference. On the other hand, optical fiber-based networks do not provide mobility, but they are robust, energy efficient, and able to provide both an almost unlimited bandwidth and high availability.In this paper, we analyze the energy efficiency of combined wireless/optical access networks, in which LTE technology provides ubiquitous broadband Internet access, while optical fiber-based technologies serve as wireless backhaul and offer high-bandwidth wired Internet access to business and residential customers. In this contest, we pay a particular attention to femtocell deployment for increasing both access data rates and area coverage. The paper presents a novel model for evaluating the energy efficiency of combined optical/wireless networks that takes into account the main architectural and implementational aspects of both RF wireless and optical parts of the access network. Several hypothetical network deployment scenarios are defined and used to study effects of femtocell deployment and power saving techniques on network’s energy efficiency in urban, suburban and rural areas and for different traffic conditions.     

Energy scavenging for mobile and wireless electronics

Energy harvesting has grown from long-established concepts into devices for powering ubiquitously deployed sensor networks and mobile electronics. Systems can scavenge power from human activity or derive limited energy from ambient heat, light, radio, or vibrations. Ongoing power management developments enable battery-powered electronics to live longer. Such advances include dynamic optimization of voltage and clock rate, hybrid analog-digital designs, and clever wake-up procedures that keep the electronics mostly inactive. Exploiting renewable energy resources in the device's environment, however, offers a power source limited by the device's physical survival rather than an adjunct energy store. Energy harvesting's true legacy dates to the water wheel and windmill, and credible approaches that scavenge energy from waste heat or vibration have been around for many decades. Nonetheless, the field has encountered renewed interest as low-power electronics, wireless standards, and miniaturization conspire to populate the world with sensor networks and mobile devices. This article presents a whirlwind survey through energy harvesting, spanning historic and current developments.     

Power consumption analysis of access network in 5G mobile communication infrastructures — An analytical quantification model

Energy consumption growth of the fifth-generation (5G) mobile network infrastructure can be significant due to the increased traffic demand for a massive number of end-users with increasing traffic volume, user density, and data rate. The emerging technologies of radio access networks (RAN), e.g., millimeter-wave (mm-wave) communication and large-scale antennas, make a considerable contribution to such an increase in energy consumption. The multiband 2-tier heterogeneous network (HetNet), cloud radio access network (C-RAN), and heterogeneous cloud radio access network (H-CRAN) are considered the prospective RAN architectures of the 5G mobile communication. This paper explores these novel architectures from the energy consumption and network power efficiency perspective considering the varying high volume traffic load, the number of antennas, varying bandwidth, and varying density of low power nodes (LPNs), integrated with mm-wave communication and large-scale multiple antennas. The architectural differences of these networks are highlighted and power consumption analytical models that characterize the energy consumption of radio resource heads (RRHs), base band unit (BBU) pool, fronthaul, macro base station (MBS), and small cell base stations (SCBs) in HetNet, C-RAN, and H-CRAN are developed. The network power efficiency with the consideration of propagation environment and network constraints is investigated to identify the energy-efficient architecture for the 5G mobile network. The simulation results reveal that the power consumption of all these architectures increases in all considered scenarios due to an increase in power consumption of radio frequency components and computation power. Moreover, CRAN is the most energy-efficient RAN architecture due to its cooperative processing and decreased cooling and site support devices and H-CRAN consumes most of the energy compared to other 5G RAN architectures mainly due to a high level of heterogeneity.     

Network coding for unicast in a WiFi hotspot: Promises,challenges, and testbed implementation

In offices and residential buildings, WiFi networks have become a primary means for providing Internet access to wireless devices whose dominant traffic pattern is unicast. In the meantime, the emergence of network coding has brought about great promises for multicast in communication networks where intermediate nodes are allowed to process independent incoming information flows. Little is known about network coding for unicast, however. The objective of this paper is thus to depart from multicast scenarios and shed light on several possible unicast scenarios to which network coding may be applied in a WiFi hotspot in order to obtain communication benefits such as throughput gain, fairness, and reduced protocol complexity. We identify five representative scenarios in which network coding may be used to benefit unicasting in a WiFi hotspot. Several open research issues and practical challenges related to each scenario are discussed individually. To illustrate the benefits of network coding for unicast in a WiFi hotspot, we propose and implement iCORE: The interface COoperation Repeater-aided network coding Engine. iCORE is a practical system in which multi-channel multi-radio repeaters are used to relay unicast traffic for those terminals sitting far away from an access point and suffering from weak signals at a WiFi hotspot. It is based on our last scenario which illustrates the synergy among network coding, opportunistic routing, and interface management. Utilizing idle wireless interfaces and listening to traffic opportunistically, iCORE allows packets to move across the interfaces and to be coded across flows whenever it sees more transmission opportunities. We evaluate iCORE on a four-node chain-like topology testbed implemented using IEEE 802.11b/g radios and compare it to MORE – the state-of-art intra-flow network coding implementation based on opportunistic routing. Our experimental results reveal promising gains in terms of throughput over MORE.     

LPDQ: A self-scheduled TDMA MAC protocol for one-hop dynamic low-power wireless networks

Current Medium Access Control (MAC) protocols for data collection scenarios with a large number of nodes that generate bursty traffic are based on Low-Power Listening (LPL) for network synchronization and Frame Slotted ALOHA (FSA) as the channel access mechanism. However, FSA has an efficiency bounded to 36.8% due to contention effects, which reduces packet throughput and increases energy consumption. In this paper, we target such scenarios by presenting Low-Power Distributed Queuing (LPDQ), a highly efficient and low-power MAC protocol. LPDQ is able to self-schedule data transmissions, acting as a FSA MAC under light traffic and seamlessly converging to a Time Division Multiple Access (TDMA) MAC under congestion. The paper presents the design principles and the implementation details of LPDQ using low-power commercial radio transceivers. Experiments demonstrate an efficiency close to 99% that is independent of the number of nodes and is fair in terms of resource allocation.     

An integrated architecture for cooperative sensing networks

Distributed sensor networks (DSNs) consisting of many small, low-cost, spatially dispersed, communicating nodes have been proposed for many applications, such as area surveillance and environmental monitoring. Trends in integrated electronics, such as better performance-to-cost ratios, low-power radios, and microelectromechanical systems (MEMS) sensors, now allow the construction of sensor nodes with signal processing, wireless communications, power sources and synchronization, all packaged into inexpensive miniature devices. If these devices can be easily deployed and self-integrated into a system, they promise great benefits in providing real-time information about environmental conditions. Intelligent sensor nodes function much like individual ants that, when formed into a network, cooperatively accomplish complex tasks and provide capabilities greater than the sum of the individual parts. The paper discusses several technical challenges that must be overcome to fully realize the viability of the DSN concept in realistic application scenarios     

A social-aware routing protocol for opportunistic networks

Understanding nodes mobility is of fundamental importance for data delivery in opportunistic and intermittently connected networks referred to as Delay Tolerant Networks (DTNs). The analysis of such mobility patterns and the understanding of how mobile nodes interact play a critical role when designing new routing protocols for DTNs. The Cultural Greedy Ant (CGrAnt) protocol is a hybrid Swarm Intelligence-based approach designed to address the routing problem in such dynamic and complex environment. CGrAnt is based on: (1) Cultural Algorithms (CA) and Ant Colony Optimization (ACO) and (2) operational metrics that characterize the opportunistic social connectivity between wireless users. The most promising message forwarders are selected via a greedy transition rule based mainly on local information captured from the DTN environment. Whenever global information is available, it can also be used to support decisions. We compare the performance of CGrAnt with Epidemic, PROPHET, and dLife protocols in two different mobility scenarios under varying networking parameters. Results obtained by the ONE simulator show that CGrAnt achieves a higher message delivery and lower message redundancy than the three protocols in both scenarios. The only exception is in one of the scenarios, when messages have a time to live lower than 900 min, where CGrAnt delivers a bit less messages than dLife, although with a lower message redundancy.     

一种无线姿态传感节点的能耗优化研究

降低姿态监测传感节点能耗,延长其服务期限是工程应用中的关键点之一。设计缓冲采样方式,以增大传感节点处在休眠状态的时间比重;针对通信中空闲监听带来的能耗损失问题,采用低频唤醒芯片实现间接监听方式以减低连续监听的能耗。采用“缓冲采样+间接监听”的解决方案,本文设计了一种用于监测姿态信息的超低能耗无线传感节点。理论分析证明连续采样的能耗是缓冲采样的115.62倍。实验表明,参照三种采样方式和两种监听方式的六组对照组合,传感节点在最优组合下的能耗仅是最劣组合下的0.42%,节省99.58%的能量,延长238倍的预计工作寿命。一个配有一节2/3AA型1.65 Ah容量锂原电池的传感节点预测能够提供3.58年的连续监测服务,为畜牧业信息化提供应用实践借鉴。     

热电偶无线传感器节点低功耗优化设计

针对飞行器内部线缆复杂度高、布线困难的问题,提出采用无线通信模式来提高传感器部署的灵活性,减少线缆运输和安装成本;为了最大程度地延长无线传感器节点的使用寿命,对热电偶无线传感器进行了节点低功耗优化设计;硬件方面,基于DPM机制设计了能量分块管理模型,核心处理器采用国产低功耗芯片GD32E230C8T6;软件方面,提出了一种基于星型拓扑结构无线传感器网络的低功耗策略,并基于此策略给出节点剩余能量数学表达式;实验结果表明,此节点处于停机储运状态下的电流低于1μA,待机模式下的电流低于23 mA,证实了所设计的热电偶无线传感器具有低功耗、稳定的特点,能有效延长节点寿命。     

基于IPSec的移动AD-HOC安全体系结构

一直以来，认为在移动AD—HOC网络和无线节点之间运用IPSec来保证通信安全是困难的。文章描述了一个基于IPSec的体系结构，并把它用在AD—HOC网络上，无缝地实现了节点移动性和IP地址的转换。这种方法可以保证应用、移动管理与认证协议的安全通信，是一种基于认证的方法，它通过加入动态的密钥产生与分配节点之间的安全关联。     

无线传感器网络车流量统计的路由协议

提出了一种应用于交通管理中心统计道路车流量的路由协议,以便更好地进行交通管理。根据无线传感器网络能量有限的特点和具体应用的需求,在路由表中添加了车辆在检测区域内的有效时间,动态控制了中间节点是否转发信息,避免了基站接收无用信息,减少了节点的能量消耗。提出了一种节点唤醒策略,有效地提高了车流量统计应用中对目标追踪的质量。仿真实验表明:与AODV协议和TSR协议相比,延长了网络生存周期。     

节能无线传感网络系统设计

Wireless sensor networks have already enabled numerous embedded wireless applications such as military, environmental monitoring, intelligent building, etc. Because micro-sensor nodes are supposed to operate for months or even years with very limited battery power source, it is a challenge for researchers to obtain long operating hour without scarifying original system performances. In this paper, the energy consumption sources of the wireless sensor networks are firstly analyzed, with the digital processing and radio transceiver units being emphasized. Then, we introduce the design scheme of our energy-aware wireless sensor network (GAINS). In GAINS, techniques to conserve the energy are exploited including the energy optimization node, software and energy-efficient communication protocol. The design architecture of our ultra low power wireless sensor network (WO-LPP) is specially presented.     

Improving routing protocol performance in delay tolerant networks using extended information

Delay tolerant networks (DTNs) are wireless mobile networks that do not guarantee the existence of a path between a source and a destination at any time. When two nodes move within each other’s transmission range during a period of time, they can contact each other. The contact of nodes can be periodical, predictable and nonpredictable. In this paper, we assume the contact of nodes is nonpredictable so that it can reflect the most flexible way of nodes movement. Due to the uncertainty and time-varying nature of DTNs, routing poses special challenges. Some existing schemes use utility functions to steer the routing in the right direction. We find that these schemes do not capture enough information of the network. Thus, we develop an extended information model that can capture more mobility information and use regression functions for data processing. Experimental results from both our own simulator and real wireless trace data show that our routing algorithms based on the extended information model can increase the delivery ratio and reduce the delivery latency of routing compared with existing ones.     

Optimizing communication in mobile ad hoc network clustering

Mobile ad hoc networks (MANETs) are gaining popularity in recent years due to their flexibility, the proliferation of smart computing devices, and developments in wireless communications. Clustering is an important research problem for MANETs because it enables efficient utilization of resources, and must strike a delicate balance between battery energy, mobility, node degree, etc. In this paper, we consider the typical communication workload of every mobile node as well as the additional communication workload of clusterheads in MANET clustering. We propose an algorithm that optimizes communication workload, power consumption, clusterhead lifetime, and node degree. Experiment results show that our clustering approach produces effectively balanced clusters over a diverse set of random scenarios.     

Hybrid wireless sensor network for building energy management systems based on the 2.4 GHz and 400 MHz bands

In this paper, a hybrid wireless sensor network (WSN) system is considered and implemented for the building energy management systems. Characteristics of the radios, which are based on the 2.4 GHz and 400 MHz bands, respectively, are analyzed for the building environments. For battery-operated portable sensors, narrow-bandwidth radios of the 400 MHz band are employed in a star connection between their parent nodes. Between the parent nodes, a mesh network is constructed for an efficient and fast data transmission based on the wide-bandwidth radios of the 2.4 GHz band. The hybrid WSN system is implemented and tested for a building environment and provides a reliable wireless communication link for gathering sensing data.     

New distributed positioning algorithm based on centroid of circular belt for wireless sensor networks

This paper presents a new distributed positioning algorithm for unknown nodes in a wireless sensor network.The algorithm is based exclusively on connectivity.First,assuming that the positions of the anchor nodes are already known,a circular belt containing an unknown node is obtained using information about the anchor nodes that are in radio range of the unknown node,based on the geometric relationships and communication constraints among the unknown node and the anchor nodes.Then,the centroid of the circular belt is taken to be the estimated position of the unknown node.Since the algorithm is very simple and since the only communication needed is between the anchor nodes and the unknown node,the communication and computational loads are very small.Furthermore,the algorithm is robust because neither the failure of old unknown nodes nor the addition of new unknown nodes influences the positioning of unknown nodes to be located.A theoretical analysis and simulation results show that the algorithm does not produce any cumulative error and is insensitive to range error,and that a change in the number of sensor nodes does not affect the communication or computational load.These features make this algorithm suitable for all sizes of low-power wireless sensor networks.     

基于无线唤醒方式的车间人员活动信息监测系统

针对现代化生产监管需求,为便于对车间工作人员活动信息的统计和管理,结合低频唤醒、有源射频识别(Radio Frequency Identification,RFID)、WiFi无线网络及嵌入式系统,设计一种新型的人员活动信息监测系统。系统硬件由触发器、移动终端和无线网关组成,将人员活动信息经无线网络送云服务端,完成对人员信息数据的存储。通过PC机或手机终端的管理平台可以从服务器的数据库获取数据,对人员进行实时考勤及动态监测。系统采用无接触式低频唤醒及有源射频通信相结合的打卡方式,具备终端功耗低、监测稳定性高、自动化程度高的特点,能够有效地促进生产管理水平,提升企业整体形象。