卫星物联网场景下基于节点选择的协作波束成形技术研究

针对卫星物联网(IoT)场景下信号长距离传输衰减大以及单个终端节点传输性能受限的问题，该文提出一种基于节点选择的协作波束成形算法，增强终端节点的传输能力。在实际终端位置信息存在误差的条件下，推导出了协作波束成形平均方向图函数，分析了不同系统参数对于协作波束成形平均方向图和瞬时方向图差异的影响。在此基础上，根据卫星物联网链路传输性能需求，提出一种区域分组优化的协作节点选择算法。仿真结果表明，相比于传统的分布式协作波束成形节点选择算法，该文提出的算法在实际的误差模型中旁瓣抑制和零陷生成方面具有更好的性能。     

基于抽样估计的能量异构无线传感器网络分簇算法

提出一种基于抽样估计的能量异构无线传感器网络分簇算法.采取对网络中节点抽样的办法估计出网络中的平均剩余能量,节点根据剩余能量与网络平均能量的比例来进行簇首竞争,使簇首选择更加合理.仿真实验表明:该算法可以更好地实现负载均衡,延长的网络生存时间.     

一种新的无线可充电传感器网络分簇算法

为了弥补现有无线可充电传感器网络充电效率低下和节点能量冗余并存的问题,提出了一种基于节点信息的分簇算法。首先,根据传感器节点的剩余能量状态,选择候选簇首。其次,计算候选簇首集合中节点之间的距离,并与基于节点密度的距离阈值比较,最终筛选出合适的簇首。其他节点根据就近原则选择簇首,形成对应的簇。该算法由于同时考虑节点剩余能量和簇首之间的距离,可以使得具有较多剩余能量的节点成为簇首,且簇首均匀分布整个网络中。仿真结果表明,提出的算法可以提高充电效率,减少节点的能量冗余或节点能量消耗过快而死亡的现象,从而有效延长整个网络的寿命。     

无线传感器网络的分布式能量有效非均匀成簇算法

研究了现有成簇路由算法,提出了分布式能量有效成簇路由算法,该算法主要包括3部分内容:一是选择候选簇头时通过引入平均能量因子来平衡全网节点的剩余能量情况;二是构造了基于能量和距离的能量消耗率函数以平衡节点的能量效率;三是首次提出了基于同构单跳网络的分布式能量有效非均匀成簇路由算法.理论和仿真结果均说明该算法优于EECS,生命周期比EECS延长达到约30%.     

混合传感器网络中基于向量代数的覆盖补偿算法

针对混合传感器网络中,能量耗尽造成的覆盖空洞与休眠冗余节点能量剩余可能并存的矛盾现象,提出一种基于向量代数的移动节点覆盖补偿方法.算法包含所有可能参与补偿的冗余节点对各自位移量的计算方法,空洞边缘节点在平衡节点剩余能量的基础上,对最佳冗余节点的选择启用策略,保证网络能充分利用遗留能量资源的同时实现完全覆盖补偿.实验分析表明,本算法在平均移动距离、能量开销等方面均优于COA算法.     

基于能效优化的WSNs多径流量分配路由算法

该文针对传感器节点能量受限的特点建立能效优化模型,该模型兼顾网络传输能耗和能耗均衡特性,以最大化网络节点总剩余能量和最小化剩余能量的方差为目标,通过合理分配多条路径的流量来优化网络能效。利用权衡评价函数实现了模型的求解,进而提出一种多径流量分配路由(MFAR)算法。仿真实验表明,该算法能够合理配置各路径流量,显著提高网络能量效率,达到在降低网络能耗的同时保证能耗分布均衡的目标。     

认知无线传感器网络中基于GSC的协作传输机制

针对无线传感器网络中单个节点能量和发射功率均受限的特点,在发送端已知信道状态信息(CSI)的条件下提出了一种基于广义选择合并算法(GSC)的协作传输机制。根据GSC算法和节点的功率受限条件来决定具体参与协作传输的节点个数,并结合信道状态和节点的剩余能量来对节点进行调度。理论分析和仿真结果表明该机制能够有效地延长网络寿命。     

预测节点剩余能量组合预测的OLSR路由算法

针对传统OLSR路由算法存在的不足,提出了一种节点剩余能量组合预测的OLSR路由算法(MOLSR).首先采用回归移动平均模型对节点的剩余能量线性变化特点进行预测,然后采用神经网络对残差的时间序列建立非线性预测模型,对节点的剩余能量非线性变化特点进行预测,最后将两者的预测结果进行相加,并用于进行OLSR路由算法的路由选择中.仿真结果表明,MOLSR路由算法不仅减小了网络开销,有效防止节点剩余能量过早耗完,而且延长了网络的生存时间,具有一定的实际应用价值.     

基于节点选择的能量高效的协作频谱感知算法

针对认知无线电中协作频谱感知能耗高的问题,提出一种基于节点选择的能量高效的协作频谱感知算法。该算法在保证感知性能的同时优化感知节点数量,从而达到高效节能的目的,其核心是采用能量高效的节点选择算法。该算法综合考虑了感知性能和能耗,仿真结果表明该算法在保证感知性能的同时能有效降低协作频谱感知的系统能耗。     

无线传感器网络中协作通信的能耗优化方法研究

针对能量受限的无线传感器网络,该文综合考虑了协作节点数量和调制方式对系统能量有效性的影响,提出一种能量最优的综合优化方法。文中首先给出了在Rayleigh衰落信道环境下,协作通信系统采用二相相移键控(BPSK)和M进制正交幅度调制(MQAM)时误码率的闭式表达,同时对协作通信的系统能耗进行了分析。在此基础上,根据能耗最小化原则对协作节点数量和调制方式进行了联合优化。仿真结果表明,与调制方式固定或协作节点数固定的系统相比,该方案能进一步降低协作通信的系统能耗。     

基于接收信噪比和网络寿命的最优中继选择

为了增大网络寿命,降低误符号率,优化无直传链路协作通信系统的性能,本文提出基于接收信噪比和网络寿命的最优中继选择算法。由于网络寿命的问题无法直接求解,将其转化为中继节点剩余能量与目的节点达到接收信噪比门限时发射功率的比值。首先计算各个中继在目的节点的接收信噪比,将大于信噪比门限加入候选中继,然后依次计算候选中继的联合优化函数值并排序,值最大者即为最优中继。理论推导了系统误符号率的上下界,仿真表明理论值与仿真值较为吻合,验证了系统在保证较低误符号率的基础上延长了网络寿命。     

Energy‐efficient partner selection in cooperative wireless networks: a matching‐theoretic approach

In this paper, the problem of stable energy‐efficient partner selection in cooperative wireless networks is studied. Each node aims to be paired with another node so as to minimize the total energy consumption required to meet a target end‐to‐end signal‐to‐noise ratio requirement and thus maintain quality of service. Specifically, each node ranks every other node in the network according to their energy saving achievable through cooperation. Two polynomial time complexity algorithms based on the stable roommates matching problem are proposed through which nodes are paired according to their preference lists. The first algorithm, denoted Irving's stable matching, may not always have a stable solution. Therefore, the second algorithm—which is a modified version of Irving's algorithm and denoted maximum stable matching—is proposed to find the maximum number of stable disjoint pairs. Simulation results are provided to validate the efficiency of the proposed algorithms in comparison with centralized energy‐efficient partner selection as well as other matching algorithms, yielding a trade‐off between stability and total energy consumption, but comparable symbol error rate performance and network sum rate. Copyright © 2016 John Wiley & Sons, Ltd.     

DEC-MAC: delay- and energy-aware cooperative medium access control protocol for wireless sensor networks

This paper deals with two critical issues in wireless sensor networks: reducing the end-to-end packet delivery delay and increasing the network lifetime through the use of cooperative communications. Here, we propose a delay- and energy-aware cooperative medium access control (DEC-MAC) protocol, which trades off between the packet delivery delay and a node’s energy consumption while selecting a cooperative relay node. DEC-MAC attempts to balance the energy consumption of the sensor nodes by taking into account a node’s residual energy as part of the relay selection metric, thus increasing the network’s lifetime. The relay selection algorithm exploits the process of elimination and the complementary cumulative distribution function for determining the most optimal relay within the shortest time period. Our numerical analysis demonstrates that the DEC-MAC protocol is able to determine the optimal relay in no more than three mini slots. Our simulation results show that the DEC-MAC protocol improves the end-to-end packet delivery latency and the network lifetime significantly compared to the state-of-the-art protocols, LC-MAC and CoopMAC.     

AF-DSTC协同通信的节点选择策略研究

协同通信的节点选择问题是建立无线协同网络的一个关键问题,提出了一种AF-DSTC协同通信模型的分布式节点选择策略,通过对接收信噪比表达式的推导,以最大化接收端信噪比为基础,建立了一个仅与候选节点自身信道条件有关的选择函数,通过各候选节点的分布式运算来选择最优的协同节点。理论分析和仿真结果证明,该策略能够在性能上逼近理论最优的穷尽查找方法,并且能极大地减少实现复杂度。     

Performance analysis of energy efficient cooperations in WSNs over frequency-selective channels

Energy efficient cooperations in wireless sensor networks (WSNs) subject to flat fading channels have attracted a considerable amount of attention recently. However, wireless channels of WSNs operating in indoor environments are supposed to have a frequency-selective nature, yet a comprehensive analysis of cooperative communications in these WSNs practically does not exist. Therefore, this paper has studied energy efficient cooperative communications over frequency-selective fading channels. Investigations of the energy efficient decode-and-forward and the adaptive decode-and-forward cooperations are provided in terms of the optimal power allocation and the partner selection region. The study is based on a network geometry of a fixed source node and a destination node with a range of potential partner node locations. Numerical results of optimal power allocation and the partner selection region are generated, and contour graphs of the resulting cooperative energy savings achieved from cooperations are provided using MATLAB. Results have indicated that cooperations can seek for potential partner nodes within a specified region to form energy efficient communications in WSNs operating in indoor environments. Furthermore, we have compared our results to the existing work which studies cooperations over flat fading channels, and several interesting findings have been revealed.     

分簇ad hoc网络协同MIMO传输策略

对协同MIMO传输所具有的潜力进行研究,提出一种适用于分簇ad hoc网络的传输策略,包括2个主要方面:其一是加权协同节点选择算法,该算法综合考虑节点间不对称的双向信道状态、节点剩余能量和节点连接度等因素,选择最优节点的集合构成协同MIMO系统;其二是虚拟节点之间虚拟链路的建立及维护机制。仿真表明,有节点选择的协同MIMO比SISO传输能获得更大的信道容量,比无节点选择的协同MIMO传输降低能耗约70%。     

Improved LEACH protocol algorithm for WSN based on energy balance and high efficiency

The improved energy-saving algorithm for the energy efficient and balanced protocol (LEACH-improved) was proposed.In the algorithm,the residual energy factor,the distance factor and the node density factor was added to improve the threshold formula.Moreover,in the various application scenarios of WSN,based on the different effects on the selection of cluster heads caused by the residual energy and geographical location,the weighting factor was introduced.Results of simulation experiments show that the improved algorithm can effectively reduce the network energy consumption and prolong the network lifetime.     

协同伙伴选择的公平性研究

在协同网络中,协同伙伴的选择是一个非常关键的问题。以前关于这个问题的解决方案本质上是基于收发的性能而忽略了协同伙伴选择的公平性。该文提出通过下述机制来获得公平性的一种新策略。(1)通过用户各自的计数器建立帮助别人就是帮助自己的机制来抑制利己主义的用户;(2)在接收端设置阈值决定是否需要伙伴中继;(3)在最大吞吐量与网络节点寿命方差之间联立以建立动态平衡。仿真结果显示:这个策略能够在性能和公平性之间达到动态平衡,从而利于整个网络的公平,其公平性优于目前所知文献的方法。     

面向认知无线电网络能量高效协作感知的在线节点选择算法

面向认知无线电网络中能量高效协作感知任务需求,提出了面向单次协作感知过程的能量最小化节点选择问题EMNS和面向在线协作感知的能量高效节点选择问题OENS。证明了两问题均为NP-hard难题。针对EMNS问题,提出采用分枝定界算法BAB求最优解和贪婪节点选择算法GS求近似解。针对OENS问题,提出为每个节点引入考虑能量消耗负载均衡的动态权重系数,基于BAB和GS算法设计了启发式的在线节点选择算法OBAB、OGS1。仿真实验结果表明,提出的算法可显著增加网络完成的协作感知过程次数,可有效延长网络"生存期"。