基于分布式中继选择的自适应协作传输方案

协作分集通过使网络用户共享彼此天线以形成虚拟多天线阵列,可以显著提高网络容量,然而针对网络拓扑的动态变化与无线传输的时变特性,仅靠协作分集并不能十分有效地解决这些问题,必须结合考虑相应的自适应传输策略.本文提出动态网络环境中协作中继的最佳选择准则,在此基础上给出最佳协作中继的分布式选择协议.根据协作中继与源节点间的无线信道质量,进一步提出一种自适应协作传输方案,以有效抵抗多用户网络环境中的无线衰落.此外,对自适应协作传输方案的误码性能,在瑞利衰落信道下进行相应的理论分析,得到了系统误比特率的解析表达式,据此给出数值仿真实验以进行性能比较.结果表明:相对于传统协作分集而言,本文提出的自适应协作传输方案获得了进一步的性能增益,误比特率显著下降.     

A Novel Adaptive and Cooperative Scheme to Save Energy for Wireless Sensor Network

In this paper, we evaluate the performance of a novel cooperative adaptive relaying scheme called ISDF (Incremental Selective Decode and Forward). We compare the energy efficiency of this underlying scheme with direct transmission (DT), Fixed and adaptive relaying schemes in Wireless Sensor Network (WSN). The system is constrained by a minimum value of Signal-to- Noise Ratio (SNR) and the end-to-end throughput. We consider a three-node cooperative system. The relay is equidistant to the source and destination, and then we study different positions of the latter. The destination receives two copies of the message: one from the source and the other from the relay. Then it combines them by using maximal ratio combining (MRC). The proposed scheme differs from other schemes by the combination of the selective decode and forward scheme with the incremental scheme which requires the presence of a feed-back from the destination. The analysis reveals that the proposed ISDF provides good energy efficiency compared to DT and other cooperative schemes. It also shows that DF cooperative scheme (decode and forward , either with feedback or no, is outperformed by AF (amplify and forward) scheme especially when the relay is placed near the destination.

     

基于协作通信系统的中继选择方案的研究

本文研究基于两跳的协作通信系统中的中继选择问题.为了降低中断概率,传统中继选择方案往往需要引入更多的中继节点参与协作传输,导致系统平均吞吐量下降.为解决上述问题,本文提出了一种新的自适应中继选择方案(ARSS),此方案可以结合两跳的链路信道状况,自适应地选择中继节点及其转发协议.仿真结果表明,与其他中继选择方案相比,本...     

基于自适应神经模糊推理系统的城市电力需求及预测模型

城市年度电能消耗数据具有较强的非线性特点。科学预测城市电力需求,是一项重要的基础性工作,需要有一种较为简易又有足够精度的预测方法。运用神经网络较强的非线性映射能力和模糊推理系统计算量小的特点构造了基于自适应神经模糊推理系统的城市电力需求及预测模型。经实证分析及与ARIMA方法的对比,结果表明,该方法适用于长中短各期预测并有很好的预测效果。     

一种基于随机密钥的无线传感器网络加密方案

密钥的建立与管理是无线传感器网络安全的重要且基础的组成部分,是影响大规模应用的一个关键问题。近来,密钥建立与管理成为无线传感器网络安全领域一个活跃的研究分支。提出一种基于随机密钥预分配的无线传感器网络加密方案。该方案通过密钥互斥机制解决传统随机密钥预分配方案中点到点数据源认证问题。     

Adaptive Buffering and Fuzzy Based Multilevel Clustering for Energy Efficient Wireless Sensor Network

Wireless Personal Communications - Wireless sensor network consists of a number of power constrained sensor nodes that sense data from the environment. The collected data is directed to the base...     

Cooperative Wireless Medium Access Exploiting Multi-Beam Adaptive Arrays and Relay Selection

Cooperative transmission among wireless network nodes can be exploited to resolve collisions and thereby enhance the network throughput. Incorporation of multi-beam adaptive array (MBAA) at a base station/access point (destination) receiver has been shown to improve the network performance. In this paper, we propose an efficient cooperative wireless medium access scheme that exploits novel relay selection methods in a network equipped with MBAA at the destination receiver. Unlike existing techniques that require the estimation of angles-of-arrival (AoAs), the proposed scheme uses the spatial correlation among users for simpler but more effective collision detection and resolution. We present two useful relay selection methods based on channel gain and spatial correlation. It is shown that the joint use of an effective relay selection method and an MBAA in a wireless network can significantly improve the uplink throughput. The throughput of the proposed scheme and its upper bound are analytically derived. Numerical and simulation results have demonstrated significant performance enhancement achieved by the proposed cooperative wireless medium access scheme.     

An Energy Efficient Cluster-Head Rotation and Relay Node Selection Scheme for Farmland Heterogeneous Wireless Sensor Networks

Wireless Personal Communications - A new routing protocol of wireless sensor network is proposed in this paper. Node residual energy, network topology density and the distance to the sink are all...     

一种无线传感器网络自适应协同通信路由协议

无线传感器网络的重要应用特性是具有感测信息的传感节点形成一个自适应本地网络,由中心节点执行不同的协作信息处理任务。该文基于互信息量分析了不同中心节点选择机制的开销性能,证明了基于扩散计算的选择机制的开销有效性;提出一种自适应协同通信路由协议(ACCRP)：节点以分布式的方式选择中心节点并建立传输路径;分析讨论了ACCRP的性能参数;并通过实验验证了ACCRP是能源有效的、可扩展的自适应路由协议。     

An Efficient Multi-constraint Relay Deployment Strategy for Wireless Sensor Network

Wireless Personal Communications - The relay node deployment for wireless sensor network has many application constraints, such as the energy efficiency, stable connectivity, survivability and low...     

基于协作通信的最佳中继选择方案

协作通信中的机会中继是一种基于即时信道状态选择的中继选择算法,可以获得与传统协作分集技术相同的分集增益,而不需要使用复杂的空时编码技术。但是多个节点同时竞争最佳中继时,可能出现冲突而导致选择失败。提出一种新的方案,通过引入候选节点限制策略以及控制信道对算法进行改进,仿真表明,该算法特别适用于候选中继较多的情况,可以在实现快速选择节点的同时降低选择失败概率。     

分布式环境中协作分集的移动中继动态选择和切换策略研究

在协作无线通信系统中,中继节点的移动会大大降低系统的性能,目前该方面的结果很少。本文探讨分布式环境中协作分集的移动中继选择算法,在放大转发（AF）协作通信模式下,给出了基于信道统计状态信息的功率分配和中继的动态选择策略。针对单中继情况提出了中继切换方案,针对多中继情况提出了动态剔除、补充中继的方案,并导出了分集增益及系统容量的计算公式。通过模拟仿真分析,该方案能有效的降低中断概率,提高系统分集增益,扩大系统容量,实现良好的整体性能。      

WSN中一种能量有效的自适应协同节点选择方案

该文针对能量有限的无线传感器网络,提出了一种能量有效的自适应协同节点选择方案,该方案先根据预设的能量阈值来确定协同节点的可选集,再综合考虑可选节点的剩余能量和信道状况,选出最佳节点作为簇头节点的协同节点。通过对总能耗的最小化,获得不同传输距离对应的最优能量阈值;根据簇头节点与数据融合中心间的距离自适应地预设最优能量阈值,使总能耗最小。理论分析和仿真结果证明,该文方案能在传输能耗和电路能耗间找到最佳平衡点,有效地减小总能耗,使总能耗达到最小。     

一种无线传感器网络的协作时间同步方法

传统的基于分组消息交换的无线传感器网络(WSN)同步方式很难做到同时兼顾同步精度和能耗.本文提出了一种基于分组消息交换的协作时间同步方法(CTS):对同步分组信息交互过程进行分析得出,协作中继的引入不会改变同步精度.通过协作中继对收发两端的同步分组信息进行接收转发来降低发射功率、降低能耗.理论分析和计算机仿真都表明在不降低同步精度的前提下,通过引入协作中继能达到降低能耗的目的,在视距信道模型中最大可达到4倍能耗效率.     

一种基于无线传感网的图像传输系统

实现了在多障碍物环境下的无线传感器网络中的图像传输。传统的图像传输均采用有线的方式。随着无线通信技术的发展,它也被用来传输图像。但是这些最初的无线传输技术只能够点对点传输、对硬件要求高、成本昂贵。在无线传感器发展成熟后,我们考虑到无线传感器网络具有自组网、对硬件要求低、成本低廉等特点,采用了无线传感器网络来传输图像。在文中所描述的图像传输系统中,首先用摄像头对图像进行采集,再用无线传感器网络来对采集到的图像进行传输,最后通过网关及计算机终端对传输的图像进行接收。实验结果表明：该系统具有组网简单,不需要特殊的设备就能够在环境恶劣的场合（如矿井下）实现图像传输。     

An Improved Fuzzy Unequal Clustering Algorithm for Wireless Sensor Network

This paper introduces IFUC, which is an Improved Fuzzy Unequal Clustering scheme for large scale wireless sensor networks (WSNs).It aims to balance the energy consumption and prolong the network lifetime. Our approach focuses on energy efficient clustering scheme and inter-cluster routing protocol. On the one hand, considering each node’s local information such as energy level, distance to base station and local density, we use fuzzy logic system to determine each node’s chance of becoming cluster head and estimate the cluster head competence radius. On the other hand, we use Ant Colony Optimization (ACO) method to construct the energy-aware routing between cluster heads and base station. It reduces and balances the energy consumption of cluster heads and solves the hot spots problem that occurs in multi-hop WSN routing protocol to a large extent. The validation experiment results have indicated that the proposed clustering scheme performs much better than many other methods such as LEACH, CHEF and EEUC.     

Energy Harvesting Based Efficient Routing Scheme for Wireless Sensor Network

Wireless Sensor Network were deployed in a complex environment where the wide range of complex application is mandatory for the services. Such application includes military, agriculture, healthcare, defense, monitoring, surveillance etc. In general sensor nodes were spatially distributed and deployed in remote fashion, usually they are powered up by batteries. These battery powered sensor nodes are pruned to failure due to its power constrained nature. This led many researchers to explore energy efficient context aware routing for Wireless Sensor Networks. Hence a novel energy harvesting based efficient routing scheme is desirable to address the above stated problem. The key idea is to harvest the energy source from the deployed environment. The proposed routing scheme is tested and validated in MATLAB based simulation test bed. The experimental results shows that the proposed routing scheme is robust and meet all the requirements of routing and promising results for energy usage.     

DF协作中继网络基于买者/卖者博弈的中继选择和功率分配策略

该文针对采用解码-转发(DF)协议的协作中继网络,提出了一种基于买者-卖者博弈的中继选择和功率分配策略,通过将用户建模为买者,可以以最大效用为标准选择最优中继和确定最佳的购买功率;将中继建模为卖者,可通过先市场后利润的功率价格调整策略获得最大的利润。分析了两者博弈达到平衡的条件并进行了仿真,结果验证了纳什均衡点的存在并表明,该策略计算量少,收敛速度快,实用性强,在兼顾用户和中继节点的利益的同时可以有效提高用户的传输速率,扩大基站的覆盖范围,提高功率利用效率。