MR2-GRADE:一种基于梯度值的无线传感器网络高能效多径干扰避免路由协议

无线传感器网络的径间干扰是多径路由亟待解决的重要问题,然而目前干扰避免策略的设计忽略了无线传感器网络最关心的能耗问题.本文提出基于梯度的MR2-GRADE路由协议框架,利用已建路径上各节点到目的节点的跳数构造干扰范围外节点的网络梯度,有效避免传统广播方式的高路由开销.针对基于梯度的局部路由决策导致后续路径创建成功率受网络节点分布密度影响较大的问题,设计了基于梯度的贪婪转发算法GRADE_GF和受限泛洪算法GRADE_RF.仿真实验结果表明:与已有的同类多径干扰避免路由相比,基于MR2-GRADE协议框架的路由可有效降低路由开销,随着网络规模扩大,优势越明显.     

基于干扰效率多蜂窝异构无线网络最优基站选择及功率分配算法

针对多蜂窝多用户异构无线网络干扰管理和效率提升问题,该文研究了基于干扰效率最大的下行链路基站(BS)-用户匹配和功率分配问题。首先,考虑宏用户和微蜂窝用户的服务质量,将问题建模为多变量混合整数非线性规划问题。其次将原问题分解为基站选择和功率分配两个子问题。针对基站选择问题,利用凸优化问题获得最优基站选择策略;针对功率分配问题,利用二次变换法和Dinkelbach辅助变量法,将功率分配问题转换为凸优化问题求解。仿真结果表明,与现有算法对比,该算法具有较好的干扰效率和干扰控制性能。     

基于环形搜索的WSN簇间最优路由选择

为了解决LEACH协议中由单跳路由算法造成的节点能量消耗不均衡的问题,首先,计算分析得出簇间多跳的最优跳数,得到簇头节点到基站的一条理想路径;然后,提出一种环形搜索方法去寻找与理想路径最接近的最优路径;最后,提出了簇头到基站的多跳路由算法。仿真实验结果表明,簇头到基站的多跳路由算法较LEACH协议在均衡节点能量消耗和延长网络生命时间方面的性能有明显的提高。     

多跳蜂窝网互连性研究

将Ad Hoc网络与蜂窝网融合首要解决的问题是Ad Hoc如何接入蜂窝网,多数方案使用的是移动IP。提出了一种基于扩展Ad Hoc路由协议的多跳转发网络方案。Ad Hoc多种路由协议中可以实现Ad Hoc网络与蜂窝网互连的只有DSDV,但在移动场景中的低性能限制了它的发展。AODV是Ad Hoc路由协议中最有前途的协议,但它并不支持Ad Hoc节点接入基站的路由搜索。研究对AODV协议进行改进,以使它能支持移动节点到固定基站以及有线网络的寻路。     

多天线系统中多中继传输的时间分配和功率分配优化方法

本文考虑单小区内的两个中继使用解码转发的方法为两个用户提供下行数据的场景,基站和中继配置多根天线,用户配置单天线.两中继使用相同的频率资源同时为两个用户提供服务.为减小两中继同时向两用户传输时产生的干扰,中继到用户的传输采用协作干扰避免的策略;相应的基站到中继的传输采用多用户空分复用的传输策略.本文在时间分配和功率分配两个方面对上述两跳传输过程进行了优化,提出了两跳传输最优的时间分配策略.由于功率分配最优化问题难以求解,本文提出了一种匹配链路容量的次优功率分配方法,并对其进行简化以降低复杂度.通过仿真可以看出,简化的功率分配方法与匹配链路容量的功率分配性能很接近;所提出的时间分配和功率分配方案可以获得有效的性能提升.     

B3G中的多跳蜂窝小区的结构分析

基于多跳通信及蜂窝通信的特点,提出了一种由中心基站及其周围的固定多跳中继节点共同实现小区覆盖范围的多跳小区结构。在此结构中,基站附近的移动台以一跳方式直接接入基站,而距离基站较远的移动台通过其与基站之间的多跳中继节点的中继以多跳通信方式接入基站。该结构提供了在低成本及低发射功率条件下完成区域覆盖的方法。并对多跳小区结构的覆盖特性进行了分析,通过仿真计算给出了多跳节点数目与小区覆盖范围的关系。     

基于能量和密度的WSNs动态分区成簇路由算法

针对传统的层次型网络存在的分簇不合理和能耗不均衡等问题,提出了一种基于能量和密度的动态非均匀分区成簇路由算法。该算法先根据节点与基站之间的距离将网络合理地进行动态的区域划分,在区域内成簇,使靠近基站的簇规模小于距离基站较远的簇,减少靠近基站的簇首负担和能量消耗;通过综合考虑节点剩余能量和节点密度等因素来优化簇的非均匀划分和簇首的选择,簇首间采取基于数据聚合的多跳传输机制。仿真结果表明,与经典路由算法LEACH相比,该算法能有效均衡节点能耗,延长网络生命周期。     

一种基于随机仿真优化的反感知RGPO干扰方法

针对在随机优化环境下的距离门拖引干扰策略优化问题,提出一种基于假设检验的计算预算分配-粒子群优化的距离门拖引干扰建模与策略优化算法。首先,将距离门拖引干扰策略的优化问题建模为一个随机仿真优化问题,并提出一种不依赖于敌方雷达跟踪系统信息的拖引干扰策略评价方案;然后,为提升距离门拖引干扰策略性能,提出一种基于假设检验的计算预算分配-粒子群优化的距离门拖引干扰策略优化方法;最后,通过数值仿真验证了该方法的有效性。     

LTE-Advanced异构网中载波选择与波束成形联合算法

为解决LTE-Advanced异构网内宏小区及微小区间的相互干扰问题,提出了载波选择与波束成形联合算法.在高密度、多低功率微基站节点的异构网中,通过关闭部分基站的部分载波,并在开启载波的基站天线上进行波束成形,使接收端受到的干扰大幅度降低.另外,基于效用函数的约束,对载波、波束分别计算,使原本二维联合优化问题变成两个一维优化问题,降低了算法复杂度.仿真结果表明该方案增加了异构网中边缘用户及整个系统的吞吐量.     

传感器网络中基于三元多项式的密钥管理方案

提出一种新的密钥管理方案KMTP(key management based on ternary polynomial)。基站为每个节点建立唯一性标识,保证节点合法性;基于三元多项式设计簇内和簇间密钥预分配算法,可以保证秘密多项式的破解门限值分别大于簇内节点和分簇总数,理论上难以破解;通过构造安全连通邻接表,设计簇间多跳路由选择算法,保证通信阶段的安全;引入更新参数和更新认证数,保证密钥更新阶段的安全。仿真表明,相比已有方案,KMTP开销较小,且能够提供更高的安全性。     

多跳认知无线Mesh网络中频谱决策与路由的跨层设计

灵活高效的频谱共享技术能够实现频谱资源的最大化利用,有效地缓解了无线频谱紧缺的现状。在一个与TDMA/FDMA蜂窝网络共存的多跳认知无线Mesh网络环境下,基于覆盖式（Underlay）与机会式（Overlay）相结合的频谱共享机制,提出了一种有效的链路层频谱决策与网络层路由的跨层设计方案。仿真结果表明,该方案比基于最小跳数的随机信道选择算法在网络端到端传输性能上有显著的优势。     

一种基于Ad hoc网络的多网融合方案及其实验验证系统的实现

本文提出了一种基于Ad hoc网络的多网融合结构,系统中的移动终端可以形成自组织网络,通过多跳路由接入PSTN、3G蜂窝网络以及互联网等多种网络.文中给出了关于此方案的实验验证系统的设计和实现,包括组网协议、多跳路由协议以及多网接入网关和多模移动终端的设计与实现,并对系统的性能进行了分析与仿真,结果表明所提出的方案在组网效率、多跳路由发现时间等方面均有所改善.     

A Graph Route-Based Superframe Scheduling Scheme in WirelessHART Mesh Networks for High Robustness

WirelessHART is considered to be one of the most promising wireless network protocols for its high robustness comparing to other similar wireless networks. The high robustness comes from its unique routing protocol and redundant superframe scheduling scheme. This paper focuses on the time-slot scheduling and channel assignment of WirelessHART and a graph route-based superframe scheduling scheme is proposed. In order to improve the communication reliability, our scheme applies hop-level retransmission mechanism in a multi-hop and multi-channel circumstance. Moreover, time-slot conflict and channel interference are considered and an effective solution strategy is proposed. To meet the real-time communication requirements, time-slots are assigned in the order of actual communication sequence which can effectively reduce the retransmission delay. Further more, we propose the implementation algorithm of our scheme. The performance analysis shows that our scheduling scheme has a higher robustness than the traditional non-redundancy scheme.     

Energy-efficient routing for correlated data in wireless sensor networks

In this paper, we investigate the reduction in the total energy consumption of wireless sensor networks using multi-hop data aggregation by constructing energy-efficient data aggregation trees. We propose an adaptive and distributed routing algorithm for correlated data gathering and exploit the data correlation between nodes using a game theoretic framework. Routes are chosen to minimize the total energy expended by the network using best response dynamics to local data. The cost function that is used for the proposed routing algorithm takes into account energy, interference and in-network data aggregation. The iterative algorithm is shown to converge in a finite number of steps. Simulations results show that multi-hop data aggregation can significantly reduce the total energy consumption in the network.     

AODV_RR: A Maximum Transmission Range Based Ad Hoc on-Demand Distance Vector Routing in MANET

Nodes in a mobile ad hoc network are battery constrained devices and energy efficiency becomes an important consideration. In a multi-hop mobile ad hoc network the most common method to achieve energy efficiency is the transmission power control scheme in which a node transmits the data packets to its nearest neighbor which is at minimum required power level. However this scheme minimizes only the transmission power within the node’s neighborhood and energy efficiency at the link level is possible. With this scheme it is not possible to minimize the overall energy consumption of the network and the communication overhead of the network is not minimized. An analysis has been performed and our results have proved that instead of using low transmission power, the routing strategy needs to be controlled and only certain nodes are to be allowed to receive and process this routing request based on the received signal strength, then the overall energy consumption of the network can be minimized and the communication overhead is also minimized. The modified routing strategy is applied to the basic ad hoc on-demand distance vector (AODV) routing protocol and a maximum transmission range based ad hoc on-demand distance vector routing protocol named AODV range routing (AODV_RR) is proposed and studied under different network sizes. Measurable difference in performance is realized and the proposed AODV_RR perform better than normal AODV with respect to all the selected metrics.     

ad hoc网络中一种基于信任模型的机会路由算法

由于ad hoc网络具有缺乏足够的物理保护、拓扑结构动态变化、采用分布式协作、节点的带宽和计算能力有限等特点,导致传统的路由安全机制不再适合ad hoc网络路由协议的设计。最近当前研究热点之一的机会路由能够在链路不可靠的情况下充分利用无线广播和空间多样性的特性提高网络的吞吐量。因此,考虑在机会路由中引入信任相似性概念设计信任机会路由,建立了基于节点信任度和最小成本的信任机会转发模型,提出了最小成本的机会路由算法MCOR,并对算法进行了理论上的分析和证明。最后采用仿真实验对该算法进行验证,又与经典机会路由协议ExOR以及其他经典的信任路由协议TAODV和Watchdog-DSR进行性能对比。仿真结果表明,MCOR算法能够防范恶意节点的攻击,在吞吐量、端到端时延、期望转发次数(ETX)和成本开销等方面都比其他3种协议表现出性能上的优势。     

Environment-Driven Opportunity Forwarding Cross-Layer Optimization for Ubiquitous Wireless Networks

In this paper, an environment-driven cross-layer optimization scheme is proposed to maximize packet forwarding efficiency. The proposed algorithm is aimed to improve the performance of location-based routing protocol in respect of greedy forwarding and avoid void regions for ubiquitous wireless networks. In greedy forwarding mode, we use a new routing metric IAPS which can estimate the forwarding distance, link quality and the difficulty of channel access during the process of the next hop node selection. When the packet forwarding comes into a local minimum, the proposed scheme uses an opportunistic forwarding method based on competitive advantage to bypass the void regions. NS2 simulation results indicate that the proposed algorithm can improve network resource utilization and the average throughput, and reduce congestion loss rate of wireless multi-hop network comparison with existing GPSR algorithm.     

Interference avoidance strategy for ultra dense network with pilot reuse

In the ultra dense network (UDN),the pilot reuse scheme would produce significant interference,which will affect the accuracy of channel estimation.To solve this problem,an interference avoidance strategy for UDN with pilot reuse was proposed.An interference model of subcarriers for UDN was provided and the interference probability of subcarriers was derived.Then,based on the model,a pilot position selection model was proposed and an interference avoidance strategy for UDN with pilot reuse was provided.The simulation results show that compared with the traditional channel estimation algorithm,the channel estimation with proposed interference avoidance strategy can effectively avoid the interference and ensure the accuracy of channel estimation in UDN with pilot reuse.     

基于Netlink的DSDV路由协议实现

无线自组网（MANET）是一种无中心的自组织网络,其在各种场景下得到了越来越多的应用。DSDV路由协议作为一种先验式路由协议,具有协议流程设计简单、延迟很低等特性,能较好地适用于移动性较弱的小规模自组织网络。文中介绍了DSDV路由协议的工作原理,提出了基于Linux系统Netlink通信机制的DSDV路由协议的软件实现架构方案,并阐述了关键模块的实现。另外,还在多台实体计算机上运行DSDV路由协议软件,并测试了多跳路由、延迟时间和通信速率。测试结果表明,文中所提方案具有可行性和有效性。     

Inter-cell downlink co-channel interference management through cognitive sensing in heterogeneous network for LTE-A

Heterogeneous network for long term evolution advanced (LTE-A) creates severe interference. It is an urgent task to overcome the interference in macro cellular with low-power base stations (BSs), such as relay, pico, and femto called subnet nodes. In this paper, the cognitive interference model in interference zone (IZ) of the practical heterogeneous scenario is proposed. Based on investigation of interaction between the macro BS and subnet nodes in this model, the strategy framework of the cognitive critical ratio and power reward factor is set up for interference management aiming to get the maximum net saving power. The study of interference management is transformed into a multiple objective non-linear programming (MONLP) of the maximum saving power for the macro BS and subnet nodes. To facilitate the best compromise solution for both, the MONLP is changed into single objective programming and genetic algorithm (GA) is employed to obtain the global optimum solution. In addition, the practical implementation using the proposed algorithm in heterogeneous network for LTE-A is designed. Finally, numerical evaluation is used to test the applicability of the proposed algorithm, and system level simulation results demonstrate the effectiveness of the proposed interference management scheme.