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In this paper we consider interference-aware uplink transmission schemes for multicell multiple-input multiple-output (MIMO) system.Unlike conventional transmission schemes without considering the interference probably caused to other cell,we jointly optimize the transceiver beamforming vectors to maximize the desired signals while removing the intercell interference.Specifically,for a two-cell system where each transmitter is equipped with two antennas,we derive the closed-form expression for the transmit scheme called coordinated beamforming (CBF) via generalized-eigen analysis.Moreover,when asymmetric interference is considered,we give a balancing beamforming (BBF) scheme where the interfering transmitter is to strike a compromise between maximizing the desired signal andminimizing the generated interference.Simulation results show that both schemes perform better than conventional schemes under different scenarios. 相似文献
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A new efficient identity-based message authentication scheme for VANET was proposed. The proposed scheme decreased the complexity of cryptographic operations on signature by using elliptic curve cryptosystem (ECC) to construct authentication protocol without bilinear pairing and provided the function of conditional privacy-preserving. Security analysis demonstrated that the proposed scheme satisfies all security and privacy requirements for VANET. Per-formance analysis show that compared with the most recent proposed schemes the proposed scheme decreases the com-putation cost and communication cost. 相似文献
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Yi‐Ning Liu Song‐Zhan Lv Ming Xie Zu‐Bin Chen Peng Wang 《International Journal of Communication Systems》2019,32(5)
With the development of the vehicular ad hoc network, the security and privacy are now becoming vital concerns, especially when the attacker owns more and more resources. In order to address these concerns, a dynamic anonymous identity authentication scheme is proposed using Elliptic Curve Discrete Logarithm Problem and blockchain method, which guarantees the security and fast off‐line authentication for vehicle‐to‐infrastructure. Specifically, a dynamic pseudonym key is generated using tamper proof device (TPD) for off‐line authentication and anonymity when a vehicle roams among different roadside units' (RSUs) communication ranges. Even if all RSUs are compromised, vehicle's identity is still privacy. Moreover, two additional design goals are more suitable for the practical environment: (1) the reduced assumption of TPD; (2) certification authority can trace vehicle under the authorization by law. 相似文献
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Xiong Wang Luoyi Fu Yang Zhang Xiaoying Gan Xinbing Wang 《Wireless Communications and Mobile Computing》2016,16(17):2991-3003
Vehicular Ad Hoc Network (VANET) has been a hot topic in the past few years. Compared with vehicular networks where vehicles are densely distributed, sparse VANET have more realistic significance. The first challenge of a sparse VANET system is that the network suffers from frequent disconnections. The second challenge is to adapt the transmission route to the dynamic mobility pattern of the vehicles. Also, some infrastructural requirements are hard to meet when deploying a VANET widely. Facing these challenges, we devise an infrastructure‐less unmanned aerial vehicle (UAV) assisted VANET system called V ehicle‐D rone hybrid vehicular ad hoc Net work (VDNet), which utilizes UAVs, particularly quadrotor drones, to boost vehicle‐to‐vehicle data message transmission under instructions conducted by our distributed vehicle location prediction algorithm. VDNet takes the geographic information into consideration. Vehicles in VDNet observe the location information of other vehicles to construct a transmission route and predict the location of a destination vehicle. Some vehicles in VDNet equips an on‐board UAV, which can deliver data message directly to destination, relay messages in a multi‐hop route, and collect location information while flying above the traffic. The performance evaluation shows that VDNet achieves high efficiency and low end‐to‐end delay with controlled communication overhead. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
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车载自组网络-VANET(Vehicle Ad Hoc Network)作为移动自组网和传感器网络在道路交通领域的应用,节点具有对等性、高速移动等特点,这导致了VANET无线信道与无线蜂窝网络信道有着显著区别。文中主要研究开阔区域中车辆间通信的无线信道模型:在三维多径散射场景下,考虑配备定向天线的车辆终端,推导VANET双移动通信节点之间无线衰落信道的自相关函数与多普勒功率谱密度函数的解析表达式。该结果对于VANET网络下无线多媒体业务性能评估有着重要的作用。 相似文献
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为了提高VANET中节点的吞吐量性能,提出基于协议序列平均分配算法的信道接入机制。在高速公路场景下,规划IEEE 802.11p业务信道与竞争区段的映射,并根据用户保障序列的特性设计帧结构。通过少量反馈确定竞争区段的节点数,并提出循环轮流分配法实现平均意义上非整数个序列的分配。仿真结果证明了理论分析的有效性,在实际路况中均分法与经典方法相比吞吐量性能明显改善,并且节点越稀疏、物理层数据传输速率越高,吞吐量性能提升越明显,同时可保持较低的网络开销和较好的信道接入公平性。 相似文献
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In vehicular ad hoc networks (VANET), the medium access control (MAC) protocol was of crucial importance to provide time-critical multihop broadcast. Contemporary multihop broadcast protocols in VANET usually choose the farthest node in broadcast range as the forwarder to reduce the number of forwarding hops. However, it was demonstrated that the farthest forwarder may experience long contention delay in case of high vehicle density. An IEEE 802.11p-based multihop broadcast protocol vehicle density based forwarding (VDF) was proposed, which adaptively chose the forwarder according to the vehicle density. The evaluation results in safety warning and online game applications show that, VDF could shorten broadcast delay by achieving the proper trade-off between the contention delay and coverage speed. 相似文献
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VANET网络中一种新的认证方法 总被引:1,自引:1,他引:0
针对现有车载自组织网络(VANET,Vehicular Ad-hoc Network)存在的安全威胁及车辆与车辆之间,车辆与基础设施之间建立可信的连接问题,提出基于ECDH(Elliptic curve-Diffie-Hellman)公钥加密算法和UsbKey双因子身份鉴别的方案,设计出新的双向安全认证协议及详细算法,并对协议方案进行详细的安全分析,分析表明该认证协议具有更强的安全性、保密性及抗攻击能力。 相似文献
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随着车联网的发展,车辆通信将在提高行车安全,驾驶效率和舒适度方面发挥重要作用。车辆将访问多种应用,考虑到现有行车安全应用面临的严峻威胁,加之对用户验证、授权和计费的需求,攻击防护安全对于车载自组网来说尤为重要。在车辆使用基于位置的服务或行车安全服务时,攻击者可能会窃听通信内容,获取用户身份信息和位置隐私。为了提高车载自组织网安全,提出了一种采用分布式车辆公钥基础设施(VPKI)对车辆通信安全、位置隐私和身份匿名进行保护的方案。该方案采用票据为应用服务提供匿名访问控制和认证,并且可以解析和撤销不法车辆身份。最后,通过实验分析方案的效率来证明VPKI的可实施性。 相似文献
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针对基于802.11p的车载自组织网络(VANET, Vehicular Ad hoc Network)的吞吐量最优化问题,采用启发式搜索优化的思想,在数据传输方面提出了改进的搜索者优化算法(ISOA, Improved Seeker Optimization Algorithm)。该算法通过对节点发送概率的最优化实现节点平均吞吐量的最大化;通过对吞吐量变化的检测调整发送概率,实现对通信环境变化的自适应性;通过对在VANET场景下传统SOA的改进,提高了搜索全局最优解的成功率。仿真结果表明,ISOA较传统算法在环境变化自适应性方面更好,在收敛速度及准确度等方面性能也更优。 相似文献
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VANET中路由协议分析 总被引:1,自引:0,他引:1
分析目前大多数VANET路由算法,将其归类为基于位置的贪婪路由算法、基于锚节点路由算法、基于街道集路由算法和基于簇路由算法,并着重于这些特点设计每类算法,通过NS2仿真实验对比和分析,为进一步的研究提出新的课题。 相似文献
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In vehicle Ad-hoc netwok (VANET), traffic load is often unevenly distributed among access points (APs). Such load imbalance hampers the network from fully utilizing the network capacity. To alleviate such imbalance, the paper introduces a novel pricing game model. The research scene is at the intersection when the traffic light is green. As vehicles are highly mobile and the network typology changes dynamically, the paper divides the green light time into equal slots and calculates APs’ prices with the presented pricing game in each time slot. The whole process is a repeated game model. The final equilibrium solution set is APs’ pricing strategy, and the paper claim that this equilibrium solution set can affect vehicles’ selection and ensure APs’ load-balancing. Simulation results based on a realistic vehicular traffic model demonstrate the effectiveness of the game method. 相似文献
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随着汽车和道路交通系统中电子信息化的高速发展,基于车载无线自组织网络(Vehicular Ad Hoc Network,VANET)提供辅助驾驶、安全信息和数据服务以使日常交通更加高效、安全、舒适,已经成为目前的研究热点之一.针对基于VANET技术的专利文献,给出了该领域申请人的申请量和申请时间的分布,并对该领域专利申请的主要技术主题和研究情况进行了分析. 相似文献
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信任管理成为车载自组织网络(VANET)应用的重要问题。针对该问题提出一种基于角色和事件信任等级评价的信任模型,结合以往方法的直接信任和邻居节点推荐信任的基础上,引入节点角色和事件等级并分配相应权重,综合判定信息是否可信。信任值计算采用角色信任等级评价的方法,受评价节点信任等级的影响,在一定程度上降低恶意节点共谋攻击,恶意评价。仿真后证明,该方法在安全性能、过滤恶意节点、降低系统开销等几个方面有较好表现,进一步加强了VANET网络环境中对恶意节点和恶意信息的识别和过滤,更有效地进行信息传递。 相似文献
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当今车辆运行环境更加复杂,双移动节点,无线链路带宽不稳定以及链路级丢包较多是车载自组网的显著特点之一,而车载自组网无线链路质量,对其网络上层协议的设计具有重要意义。这里分析无线电波在车载自组网中的传播特点,提出一种以无线信道传播模型为基础,通过OMNET++来仿真车载自组网无线链路丢包率的方法。通过该方法可以方便、有效地仿真不同车辆运行环境下车载自组网的无线链路丢包率。 相似文献
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To minimize the number of RSU deployed to cover a specific area,a c street model transforming the area covering problem to streets covering problem was designed,and a greedy-based polynomial (GBP) time approximation algorithm was developed to obtain the optimal RSU deployment for area coverage.For complex urban environments,a Cue model (complex urban environments model) was proposed.In this model,the target area was divided into different partitions.Then,based on shifting strategy,a polynomial time approximation scheme was designed.Theoretical analysis that include the approximation ratio and time complexity of the proposed algorithm were also presented.Simulation results show that GBP can efficiently solve the coverage problem in urban VANET. 相似文献