无线传感器网络的中继节点自适应选择休眠机制

针对无线传感器网络节点能量有限的问题,设计一种中继节点自适应休眠方法,对网络节点的工作时间进行优化调度。在路由链路建立中,根据网络中节点的地理位置、剩余能量选择中继节点的方法进行节点休眠调度。网络工作时通过计算下一跳最佳节点位置,选取其附近区域内剩余能量多的节点作为下一跳的转发节点,设计出中继节点自适应选择的节点休眠机制。仿真结果表明,所设计的休眠机制提高了节点能量利用效率、延长了网络工作时间。     

协同认知无线网络中自适应中继节点选择算法

最优停止规则算法的优点是避免主用户考察所有次用户,使主用户能在较短观测时间内挑选出满足通信服务质量的中继节点。但存在些许不足之处,如仅考虑了单次协同通信情况,没有充分利用历史中继节点选择信息。为了克服上述缺点,需要优化该算法的性能,通过引入反馈机制,提出了自适应中继节点选择算法,在每次中继节点选择结束后更新信息库中次用户中继概率,主用户从中继概率高的次用户开始观测。研究结果表明:自适应中继节点选择算法的效率要比最优停止规则算法高;该算法可进一步减少观测次数,降低系统的传输时延和观测能耗,提高主用户的平均吞吐率。     

多跳无线传感器网络的高效中继节点快速选择算法

针对多跳无线传感器网络数据收集协议中继转发节点选择算法效率不高的问题,提出了一种能量有效的中继节点快速选择 (EERNFS)算法.EERNFS算法利用分时共享信道的方法维护网络同步和更新节点的邻居信息,使节点在每个网络侦听/睡眠周期依赖一定的概率同步激活唤醒,确保了网络节点瞬时连通度的稳定和一致;基于网络节点的地理优先级、节点价值和链路质量的分布式估计,EERNFS算法采用竞争的方法选择中继转发节点, 使用乘性增加时间窗口的方法,分解候选中继节点间的竞争.理论分析和模拟实验结果表明,EERNFS算法在能效、数据传递的平均时延、分组到达率等网络性能指标上显著优于FFS和GeRaF算法,极大地延长了网络的寿命.     

浅议无线协作通信中继选择

无线协作通信技术的广泛使用成为一种趋势,但是在使用过程中,因为中继节点和中继策略方案的选择出现的问题越发的突出起来。本文针对这种情况进行了研究和论述。     

基于协同机理的下一代宽带无线通信系统

介绍了协同技术基本原理,基于协同技术的先进性,提出了下一代宽带无线通信系统的异构性和泛在性等要求可以通过协同技术得到保证。介绍了一种基于协同机理的下一代宽带无线通信系统的网络结构,并详细介绍了其中的关键支撑技术。     

基于译码——转发的多中继协作节点选择方法

由于协作通信技术能够抵抗信道衰落的影响,提供分集增益,成为目前研究热点之一。针对传统多中继译码转发协作通信中,所有潜在中继均参与协作从而导致系统的低资源利用率问题,提出了一种基于信道容量增益的中继节点选择策略。仿真结果表明,该策略只需选择一半的中继节点数就能获得和最优中继选择方法非常相近的系统性能,同时降低了系统的功率损耗和实现复杂度。     

无线协同中继通信系统的传输技术分析

随着数字信息技术的发展,无线通信系统受到了人们的广泛关注,近年来,无线通信系统逐渐向高速率、低能耗、低成本的方向发展.而无线中继技术可以有效的提高通信系统的覆盖面积,增加边缘用户的使用数量,减少通信能耗.笔者在本文中着重分析了无线协同中继通信系统传输技术的相关问题.     

基于多点协同中继的无线传输技术

多点协同中继的无线传输技术作为LTE-Advanced系统中主要的新技术,对于扩大网络边缘覆盖、保证边缘用户服务质量有着至关重要的作用。文章主要介绍了多址接入、多用户协作通信、无线衰落信道和IDMA这几个多点协同中继无线传输中的关键技术。     

中继增强型蜂窝网络接入选择策略的研究

主要考虑中继接入选择策略对基于OFDMA的中继增强型蜂窝网络带来的系统性能影响.分别针对集中式和分布式控制两种情景,以最大化用户吞吐量为目标设计了基于信干噪比的接入选择策略.并通过搭建基于802.16j的系统级动态仿真平台对其性能进行仿真分析.与传统的接入方案相比.该方案在用户吞吐量分布,以及不同中继位置下的系统频谱效率指标下,均可获得更好的系统性能增益.     

协同分集中的中继选择方法

协同分集是一种新颖的分集技术。在协同通信中合理地选择中继能给系统带来更大的增益。在介绍协同分集原理和模型的基础上，引出了基于协作区域与基于及时信道状况和计时策略的两种中继选择方法，并对这两种方法进行了分析和比较。     

能量高效利用的动态节点选择传感网路由算法

无线传感网中由于节点具有有限的能量,因此需最大化它们的网络生存期。在网络生存期问题中,所有节点都在发送广播信息,同时请求中继节点集。选择包含一个主节点的动态中继集是一种特殊情况,在一般性设置中它提供了最优生存期的下界。文中提供了一个基于动态主节点选择算法的初步分析,该分析比较了转播和直接路由。通过仿真结果表明,初始电池不均匀分布及几何设置时,最优主节点选择算法优于直接传输算法;均匀分布情况下,直接传输算法优于最优主节点选择算法。     

Game theory based distributed energy efficient access point selection for wireless sensor network

In this paper, the distributed energy consumption optimization of sensors in wireless sensor network (WSN) is studied. The access point selection for sensors is critical to the energy consumption because of the limited scope of wireless communication. Due to the high complexity of the central optimization, the desired approach of optimization is the distributed one with lower computation complexity. A game model is proposed for the energy efficient AP selection problem, which is proved to be an exact potential game. Also, a distributed learning algorithm is proposed to achieve the globally optimum in a distributed manner. Simulation results show that the proposed would improve the energy efficiency in the WSN.     

Hybrid access control algorithm based on relay node assistant in Femtocell network

A Femtocell hybrid access control algorithm assisted with relay note was proposed to supply higher performance for the Femtocell neighboring users (NUE) in heterogeneous network.Deploying relay outside the Femtocell networks was used and amplify-and-forward (AF) relaying protocol or direct link protocol was alternated to use for the data transmission of Femtocell NUE.An optimization problem was formulated with the constraints of the required transmission rates thresholds of Femtocell registered users (FUE),the thresholds of the cross-tier interferences to the macrocell users (MUE),and total transmit powers of the Femtocell base station (FBS).By using the dual decomposition method,a Femtocell hybrid access control algorithm was given based on the combination of the direct mode and relay mode.Simulation results have shown that the scheme can not only protect the QoS required by the FUE,but also decrease the cross-tier interferences suffered by the MUE.It also illustrates the better performance of the NUE through the dynamic and flexible access mechanism.Furthermore,based on the last simulation the relay link would help the NUE obtain about 25% more performance than the traditional direct link in some regions.     

博弈论方法在混合无线网络中网络选择问题研究中的应用

随着无线网络技术的日益发展以及人们对无线互联的需求,各种适用于不同工作环境的无线网络技术往往共同应用于人们的日常活动区域中.为了提高网络的利用率与最大化自身收益,用户往往会在不同的无线网络中切换,选择最合适网络的进行连接.这种情况下,一个无线网络用户的行为变化会对其他用户的网络环境带来严重的影响.博弈论在分析研究这类情况具有很大的优势.本文简单介绍了博弈论的基本概念,并总结了当前采用博弈论的方法研究解决混合无线网络中网络选择问题的代表的工作.     

基于模糊神经网络的异构无线网络接入选择算法

针对现有异构无线网络基于模糊逻辑及神经网络的接入选择方法未能合理考虑网络负载状况的问题,提出一种基于RBF(径向基函数)模糊神经网络的接入选择方法.该方法以可接入网络的接入阻塞率相等为模糊神经网络参数强化学习的目标,对网络负载程度具有很好的动态适应性,实现了智能化的接入判决.仿真结果表明,该方法能有效均衡异构无线网络间的负载,保障实时与非实时业务的QoS,并且相对于负载均衡算法(MLB算法)降低了网络的接入阻塞率.     

Cooperative quadrature physical layer network coding in wireless relay networks

This paper proposes a cooperative quadrature physical layer network coding (CQPNC) scheme for a dual‐hop cooperative relay network, which consists of two source nodes, one relay node and one destination node. All nodes in the network have one antenna, and the two source nodes transmit their signals modulated with quadrature carriers. In this paper, a cooperative quadrature physical layer network coded decode‐and‐forward (DF) relay protocol (CQPNC‐DF) is proposed to transmit the composite information from the two source nodes via the relay node to the destination node simultaneously to reduce the number of time slots required for a transmission. The proposed CQPNC‐DF relay protocol is compared with time‐division multiple‐access amplify‐and‐forward (TDMA‐AF), TDMA‐DF, cooperative network coded DF (CNC‐DF) and cooperative analog network coded AF (CANC‐AF) relay protocols to demonstrate its effectiveness in terms of bit error rate (BER) and system throughput under different propagation conditions. The simulation results reveal that the proposed CQPNC‐DF relay protocol can significantly improve the network performance. Compared with two TDMA schemes and CNC‐DF, the proposal can provide up to 100% and 50% throughput gains, respectively. Moreover, no matter what the scene, the proposed scheme always has the lowest BER in the low SNR region. Copyright © 2013 John Wiley & Sons, Ltd.     

Multi relay node selection strategy for energy capture collaborative relay network

An energy capture cooperative relay network was studied.Unlike traditional cooperative relay networks,the relay nodes generally did not have a fixed energy supply but could carry out energy capture.For this network,a natural question was how to determine whether the relay nodes perform energy capture or data forwarding,and how to select the relay node to assist the information transmission between the source node and the destination node.Based on this problem,a multi-relay node selection scheme was proposed,which select the operation according to the energy of the current time slot of the relay node.In each time slot,the relay node that meet the battery threshold requirements was selected to assist in transmission.The Markov chain was used to model the charging and discharging process of the relay node battery,and the probability of interruption and throughput of the wireless network was obtained.And the value of the battery threshold when the throughput was maximized,that is,when the probability of network breakage was minimum was solved.Finally,the advantages of this scheme were verified by numerical experiments.     

Weighted relay node placement for wireless sensor network connectivity

In wireless sensor networks (WSN), which are composed of unreliable sensor nodes, preserving the connectivity is a serious problem and one of the most effective solutions of this problem is to deploy powerful relay nodes (RN). The location of the RN is an important parameter for the network performance. In this paper, we investigate relay node placement (RNP) problem on a weighted terrain structure to satisfy WSN connectivity. Contrary to the existing studies, instead of minimizing the number of RN, the main objective of weighted RNP is to minimize the total weight of the points on which RN are deployed. In order to solve the weighted RNP problem, a mathematical formulation is proposed to find the optimal solution. However, because of the NP-complete nature of the problem, a polynomial time heuristic algorithm is also developed. Performance results show that the proposed heuristic algorithm can find near-optimal solutions in a reasonable time bound.     

Energy efficient networking via dynamic relay node selection in wireless networks

Mobile wireless ad hoc networks need to maximize their network lifetime (defined as the time until the first node runs out of energy). In the broadcast network lifetime problem, all nodes are sending broadcast traffic, and one asks for an assignment of transmit powers to nodes, and for sets of relay nodes so that the network lifetime is maximized. The selection of a dynamic relay set consisting of a single node (the ‘master’), can be regarded as a special case, providing lower bounds to the optimal lifetime in the general setting. This paper provides a preliminary analysis of such a ‘dynamic master selection’ algorithm, comparing relaying to direct routing.     

LTE-A系统中继网络中接入点选择算法的研究

LTE-A系统中引入中继技术后,用户可以根据不同的接入点选择算法选择接入基站或中继。传统的接入点选择算法只是直接对比接入链路和直接链路的链路质量,选择质量较好的一条链路接入,并没有考虑到选择接入中继时会在回程链路消耗额外的无线资源,因此并不能选择一个能够使系统单位带宽传输数据量较大的接入点进行接入。针对上述问题,文中提出了基于两跳链路的接入点选择算法,它综合考虑了链路质量和消耗的无线资源,然后选择相应的接入点。仿真结果表明新提出的接入点选择算法可以提高系统吞吐量。