A QoS-Based Multichannel MAC Protocol for Two-Tiered Wireless Multimedia Sensor Networks

Rapid penetration of small customized wireless devices and enormous growth of wireless communication technologies has already set the stage for large-scale deployment of wireless sensor networks. Offering precise quality of service (QoS) for multimedia transmission over sensor networks has not received significant attention. However offering some better QoS for wireless multimedia over sensor networks raises significant challenges. In this paper, we propose an adaptive Cross-Layer multi-channel QoS-MAC protocol to support energy-efficient, high throughput, and reliable data transmission in Wireless Multimedia Sensor Network (WMSNs). Our proposed protocol use benefit of TDMA and CSMA/CA to adaptively assign channels and timeslots to active multimedia sensor nodes in clusters. Simulations show that the proposed system achieves the performance objectives of WMSNs with increased network throughput at the cost of a small control and energy overhead.

ENERGY EFFICIENT DISTRIBUTED STEGANOGRAPHY FOR SECURE COMMUNICATION IN WIRELESS MULTIMEDIA SENSOR NETWORKS

A secure communication mechanism is necessary in the applications of Wireless Multimedia Sensor Networks (WMSNs), which is more vulnerable to security attacks due to the presence of multimedia data. Additionally, given the limited technological resources (in term of energy, computation, bandwidth, and storage) of sensor nodes, security and privacy policies have to be combined with energy-aware algorithms and distributed processing of multimedia contents in WMSNs. To solve these problems in this paper, an energy efficient distributed steganography scheme, which combines steganography technique with the concept of distributed computing, is proposed for secure communication in WMSNs. The simulation results show that the proposed method can achieve considerable energy efficiency while assuring the communication security simultaneously.

A time domain multiple-CFOs and CIRs estimation algorithm over wireless multimedia sensor networks

Channel parameters estimation in an orthogonal for the receiver station is a multi-dimensional （MD） frequency division multiple access （OFDMA） system optimization problem, because every user node has a separate local oscillator and every transmitter to receiver link has individual carrier frequency offset （CFO） and channel impulse response （CIR） parameters. In order to reduce the computational complexity for MD optimization, a time domain CFOs and CIRs estimation algorithm over the OFDMA based wireless multimedia sensor networks （WMSN） is proposed in this paper. In this algorithm, the receiver station can decouple the signal from every node by correlation based on specially designed training sequences, so that the MD optimization problem is simplified to an 1-D optimal problem. It is proved that the multiple CFOs can be identified from the correlation result using the phase shift of the consecutive training se- quences. Based on the CFOs estimation result, the CIRs can then he estimated according to the minimum mean square error （MMSE） criterion. The theoretic analysis and simulation results show that the proposed algorithm can effectively decouple the signal from different user nodes and the bit error rate （BER） per- formance curves are close to the ideal estimation when the user number is not large.

Enhanced Metaheuristics-Based Clustering Scheme for Wireless Multimedia Sensor Networks

Traditional Wireless Sensor Networks(WSNs)comprise of costeffective sensors that can send physical parameters of the target environment to an intended user.With the evolution of technology,multimedia sensor nodes have become the hot research topic since it can continue gathering multimedia content and scalar from the target domain.The existence of multimedia sensors,integrated with effective signal processing and multimedia source coding approaches,has led to the increased application of Wireless Multimedia Sensor Network(WMSN).This sort of network has the potential to capture,transmit,and receive multimedia content.Since energy is a major source in WMSN,novel clustering approaches are essential to deal with adaptive topologies of WMSN and prolonged network lifetime.With this motivation,the current study develops an Enhanced Spider Monkey Optimization-based Energy-Aware Clustering Scheme(ESMO-EACS)for WMSN.The proposed ESMO-EACS model derives ESMO algorithm by incorporating the concepts of SMO algorithm and quantum computing.The proposed ESMO-EACS model involves the design of fitness functions using distinct input parameters for effective construction of clusters.A comprehensive experimental analysis was conducted to validate the effectiveness of the proposed ESMO-EACS technique in terms of different performance measures.The simulation outcome established the superiority of the proposed ESMO-EACS technique to other methods under various measures.

A Sensor Awakening Algorithm for Wireless Multimedia Sensor Networks Three Dimensional Target Tracking

For node awakening in wireless multi-sensor networks, an algorithm is put forward for three dimensional tar- get tracking. To monitor target dynamically in three dimensional area by controlling nodes, we constract vir- tual force between moving target and the current sense node depending on the virtual potential method, then select the next sense node with information gain function, so that when target randomly move in the specific three dimensional area, the maximum sensing ratio of motion trajectory is get with few nodes. The proposed algorithm is verified from the simulations.

Clustering in Wireless Multimedia Sensor Networks

Wireless Multimedia Sensor Networks (WMSNs) are comprised of small embedded audio/video motes capable of extracting the surrounding environmental information, locally processing it and then wirelessly transmitting it to sink/base station. Multimedia data such as image, audio and video is larger in volume than scalar data such as temperature, pressure and humidity. Thus to transmit multimedia information, more energy is required which reduces the lifetime of the network. Limitation of battery energy is a crucial problem in WMSN that needs to be addressed to prolong the lifetime of the network. In this paper we present a clustering approach based on Spectral Graph Partitioning (SGP) for WMSN that increases the lifetime of the network. The efficient strategies for cluster head selection and rotation are also proposed as part of clustering approach. Simulation results show that our strategy is better than existing strategies.

Clustering in Wireless Multimedia Sensor Networks Using Spectral Graph Partitioning

Wireless multimedia sensor network (WMSN) consists of sensors that can monitor multimedia data from its surrounding, such as capturing image, video and audio. To transmit multimedia information, large energy is required which decreases the lifetime of the network. In this paper we present a clustering approach based on spectral graph partitioning (SGP) for WMSN that increases the lifetime of the network. The efficient strategies for cluster head selection and rotation are also proposed.

Queuing Management in Wireless Sensor Networks for QoS Measurement

Data transmission in multimedia WSNs are required high bandwidth and reliable transfer because of large amount of data size. However, some applications of WSNs are required high quality. In this context, main factor in quality of services (QoS) metrics in WSNs becomes longevity of the network and high quality. In sensor nodes, choosing relevant transceiver and microcontroller components plays important role in assembling sensor devices, in which data controls should be designed so that packet loss is minimized. Available QoS metrics based on queuing/buffer management in wired and other wireless networks don’t applicable in WSNs because of its unique characteristics. In this paper the simplest model of QoS model-bufferless system were proposed. In the proposed model, measurement of the probability of blocking of the arrival packets was suggested by using queuing theory in order to increase QoS. Given probability of blocking (PB) illustrates clear picture how system specification should be chosen so that blocking state would be minimized.

基于蝗虫算法的配电通信WMSNs多路径QoS路由优化模型研究

为提高配电通信网络的生命周期,降低网络能耗和均衡化WMSNs多路径QoS路由网络负荷,提出一种基于配电通信网的蝗虫算法优化WMSNs多路径QoS路由算法研究。选择WMSNs多路径QoS路由路径最短和能量最低为目标函数。研究结果表明,与改进算法和经典算法相比,基于GOA的WMSNs多路径QoS路由算法网络能耗最低、死亡节点数最少,效果很好,可以延长死亡节点产生的时间,有效提高整个WMSNs多路径QoS路由网络的生存寿命。

Energy Efficient and QoS Aware Framework for Video Transmission over Wireless Sensor Networks

Wireless Multimedia Sensor Networks (WMSNs), is a network of sensors, which are limited in terms of memory, computing, bandwidth, and battery lifetime. Multimedia transmission over WSN requires certain QoS guarantees such as huge amount of bandwidth, strict delay and lower loss ratio that makes transmitting multimedia is a complicated task. However, adopting cross-layer approach in WMSNs improves quality of service of WSN under different environmental conditions. In this work, an energy efficient and QoS aware framework for transmitting multimedia content over WSN (EQWSN) is presented, where packet, queue and path scheduling were introduced. It adapts the application layer parameter of video encoder to current wireless channel state, and drops less important packets in case of network congestion according to packet type. Finally, the path scheduling differentiates packets types/priority and route them through different paths with different QoS considering network lifetime. Simulation results show that the new scheme EQWSN transmits video quality with QoS guarantees in addition to prolonging network lifetime.

基于方差的WMSN图像非均匀分块自适应压缩算法

针对无线多媒体传感器网络数据量较大和储存能力有限等问题,提出了基于方差的图像非均匀分块自适应压缩算法。在传统的压缩方法中,均匀分块的稀疏变换对图像信号进行压缩,会带来图像重构的块状效应,而且无法有效地分离出重要区域或者背景区域。给出一种基于方差的图像非均匀分块自适应压缩算法,以图像方差值作为块大小分割依据,利用四叉树算法进行图像块大小的划分。并将分块大小结果分成快速变化块、过度块和缓慢变化块3类,适时做不同程度的压缩。实验结果表明:本文所提出的算法在图像重构质量方面优于传统的均匀分块压缩方法。

一种适用于WMSNs的多信道快速数据收集算法

为了提高WMSNs中多个源节点到sink节点的数据收集效率,文章提出了一种基于树型拓扑结构的多信道快速数据收集算法。该算法有三个主要特点:基于接收方的信道分配算法有效地消除了信道间的干扰;TDMA机制消除了节点间的竞争和冲突;节点度受限的平衡路由树的构建,消除了由于单个节点度太深所造成的调度瓶颈。通过在不同节点配置密度下的深入仿真,验证了文中提出的多信道调度算法与同样基于树的多信道调度协议TMCP相比,具有更快的调度收集性能,同时,采用平衡路由树进一步缩短了收集调度长度。

一种适用于多跳WMSNs的分布式图像压缩算法

在节点资源严重受限的无线多媒体传感器网络(WMSNs)中处理和传输大数据量的图像信息具有很大的挑战性。文章在研究基于小波变换的图像压缩算法SPIHT的基础上,提出了一种基于SPIHT算法的分布式并行图像压缩算法D-SPIHT,该算法具有复杂度低、设计简单、执行速度快、完全分布式并行执行的特点。仿真结果表明,文中提出的D-SPIHT算法,能够有效地平衡网络中各节点的能耗,从而延长网络的生命期,还能大大缩短图像压缩处理的时延,非常适合于对实时性要求较高的WMSNs中的图像压缩和传输。

面向配电通信网的WMSNs多路径QoS路由算法

为建立满足配电网通信Qo S需求的路由机制,建立合理的配电通信网WMSNs结构方式,对配电通信网业务需求进行了分析,提出一种保障Qo S面向配电通信网的WMSNs多路径路由算法(MRFD)。根据多步前向区域建立多路径树,使用距离、角度的综合条件来反向选取下一跳,并进行精简,建立了多路径。在传输路径的选取时,使用结合节点个数、单包传输能耗、剩余能量的多因素路径函数。实验表明MRFD满足配电网通信的Qo S需求,并有效优化延迟、延长生命周期,实现了能量的均衡使用。

使用蚁群优化的WMSNs负载均衡路由方案

由于无线多媒体传感器网络(WMSNs)具有资源受限、信道容量可变、数据冗余度高等特点,研究WMSNs的QoS路由具有极大的挑战性。针对上述问题,提出了一种使用蚁群优化的WMSNs负载均衡路由方案——ACOLBR。ACOLBR采用分簇技术进行区域划分,簇间利用ACO找到一条簇首到基站的最优路径,簇内利用以簇首为根节点的最小生成树算法组织路由。仿真结果表明,与AGRA和M-IAR算法相比,ACOLBR在负载均衡、传输时延、传输成功率、可扩展性和自适应性等方面均有较大改进,实现了全网的负载均衡,有效地延长了网络生命期,保证了网络传输的QoS。

一种WMSNs能量感知QoS路由机制设计

随着对监测数据的要求越来越高,多媒体传感器网络具有广泛的应用前景。由于多媒体信息对QoS的要求比较高和网络对能量的依赖较大,使得无线多媒体网络中QoS问题的研究极具挑战性。从网络层角度提出一种基于能量感知的可靠路由机制,通过充分考虑节点的剩余能量和路径的可靠性,选择相应的路由,从而提高了对网络资源的利用和网络的可靠性。仿真实验显示该机制能有效提高传输的可靠性,降低网络通信开销。

基于遗传算法的WMSNs多路径多目标优化路由算法

针对WMSNs路由算法设计的需求,依据遗传算法的基本原理和Pareto多目标优化方法,提出WMSNs多路径多目标优化路由算法MMOR-GA。该算法充分利用基站的存储空间充裕、能量充足和计算能力强的优势,在全局范围内搜索WMSNs多路径多目标优化路由。同时构建了基于前向邻居概念的网络模型和多目标优化函数,设计特定的编码方案及选择、交叉、变异算子。将MMOR-GA和TPGF进行模拟仿真实验,结果表明MMOR-GA算法能均衡有效地提高WMSNs路由的多QoS参数。

DTFMM:一种适应于WMSNs的多信道MAC协议

基于分簇网络拓扑,提出了一种无冲突的分布式时分/频分多信道MAC协议,简称为DTFMM(Distributed time andfrequency division multi-channel MAC)。该协议主要由三部分组成:信道分配、簇内通信和簇间通信。首先,各簇首运行分布式信道分配算法选择簇内通信的信道,然后各簇内节点采用基于TDMA的信道访问方式与簇首通信,最后各簇首通过最小生成树路由将收集到的数据转发到基站。该协议最大的优点在于充分复用了可用的多信道频率资源,提高了网络吞吐量,更好地提供了对带宽要求很高的多媒体应用的支持。仿真结果表明,该协议具有良好的可分级性,而且在吞吐量、数据包传输延迟等方面均优于基于冲突的多信道协议MMSN。

基于三维感知模型的WMSNs最优空间覆盖研究

无线多媒体传感器网络(WMSNs)的覆盖问题的研究成果大多基于二维感知模型.对于视频节点而言,二维感知模型无法准确地描述其感知范围,监测平面上方的空间通常会被遗漏.因此,提出了空间覆盖的概念,并重新定义了三维感知模型.通过分离两个影响空间覆盖的因素——视频传感器俯仰角和偏向角,采用粒子群优化算法对一重空间覆盖率进行优化.并结合实际应用需求,提出了有效空间覆盖率的概念,保证了对监测目标的有效视频信息收集.最后,通过仿真实验优化,网络的空间覆盖程度得到了明显提高,证明了优化算法的有效性.

一种适用于WMSNs的分布式图像压缩算法

为了克服无线多媒体传感器网络(WMSNs)中单个节点存储、处理能力和能量严重受限的问题,在研究双正交叠式变换(LBT)的基础上,提出了一种适用于无线多媒体传感器网络的基于LBT变换的分布式图像压缩算法。仿真结果表明,该算法具有低存储、低处理需求和极低能耗的特点,在传感器节点部署较为密集的情况下能成倍地提高网络生命周期。