共查询到19条相似文献,搜索用时 187 毫秒
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《计算机工程》2017,(12):83-87
针对机载战术网络中节点的高速运动、大尺度稀疏分布、数据业务多样等特点,以及在时敏信息传输时高可靠、低时延的服务质量需求,提出一种基于RS-Polar编码技术的随机接入多信道媒质接入控制协议。采用RS-Polar级联的纠错编码技术、多包接收技术,使其在不采用信道预约和时隙分配的机制下仍然能够确保分组传输的实时性和可靠性,并有效提高网络吞吐量。通过建立突发包传播阶段的信道碰撞模型和接收阶段多包接收模型,理论推导了分组成功传输概率、分组端到端时延和网络吞吐量的数学表达式。仿真结果表明,该协议的分组端到端时延小于2 ms,当负载小于1 000 packet/s时,分组成功传输概率高于99%,能够有效满足机载战术网络性能需求。 相似文献
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在分析当前Ad Hoc网络多信道MAC协议的基础上,提出了一个衡量信道质量的度量参数CQ(Channel Quality)作为信道选择的依据。并提出了一个基于接收方信道质量的多信道MAC协议MMCQ(Multi-channel MAC protocol with Channel Quality of receiver),以解决多信道MAC协议常见的控制信道瓶颈和信道分配公平性问题。仿真表明:该协议在降低控制信道开销的前提下,能显著增加网络的平均吞吐量,并降低端到端平均时延。 相似文献
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编码机会路由是有损无线Mesh网络中提供高吞吐量和高可靠性传输的理想方案.该路由机制建立在无线广播的多用户分集优势和随机网络编码的纠删特性之上,为广播MAC的设计引入了新的机会和挑战.基于最优停止理论,研究面向编码机会路由的机会广播信道接入问题,提出一种在接入延迟和信道交付能力之间加以折衷,以获得最优的平均有效速率的方法,并在IEEE 802.11 DCF协议基础上设计实现面向NCOR的广播MAC协议O-BCast.仿真结果表明,该协议显著提高了编码机会路由的端到端吞吐量,具有网络负载自适应的良好特性. 相似文献
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基于802.11的多信道MAC协议性能分析 总被引:1,自引:0,他引:1
为了改善无线网络中信道带宽的利用率,提高网络的吞吐量性能,已有研究提出了采用多信道MAC协议的方法,将单个信道分割成控制子信道和数据子信道进行联合使用.针对基于802.11DCF的该类型MAC协议,采用离散Markov链对DCF的退避机制进行建模分析,研究了多信道下两种MAC机制的饱和吞吐量性能与信道带宽分配比例的关系,分析了网络节点数、数据分组大小和DCF竞争窗口等对优化多信道带宽分配的影响,并将多信道MAC机制下的网络性能与单信道MAC机制进行了对比.分析和仿真结果表明,采用优化的信道带宽分配,多信道的MAC机制可以一定程度上提高网络的吞吐量性能.但是,当允许控制帧以最大信道速率传输时,多信道MAC机制吞吐量性能并不比单信道MAC机制好. 相似文献
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多输入多输出(Multiple-Input Multiple-Output,MIMO)技术是能够实现多包接收(Multi-Packet Reception,MPR)功能。提出MIMO系统的MAC协议,该协议基于数据流控制方法实现多包接收功能,并在同一通信领域内支持多对一和并行通信。网络仿真中采用调用信道模型的方法,并利用OPNET和MATLAB进行了PHY/MAC跨层动静态联合仿真分析。仿真结果表明,所提协议能够有效地提高移动Ad Hoc网络吞吐量、端到端分组延迟等性能。 相似文献
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针对低轨卫星通信信道碰撞检测能力弱,时延较长和大业务量的特点,提出一种具有接入控制机制的自适应APRMA MAC协议。通过对信道负载和业务优先级判断来确定不同业务的接入概率函数,并且接入概率在每个时隙中通过更新来动态适应系统资源的变化。该MAC协议确保多个终端合理共享有限的无线资源同时,系统能达到高容量。通过仿真对语音业务丢包概率、数据包平均时延和数据业务吞吐量三个衡量协议性能指标与传统协议进行分析对比,证明了APRMA MAC协议显著改善系统性能。 相似文献
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The main investigation of this study is the performance optimization of a WDMA protocol suitable for a network architecture of passive star topology that uses the Multi-channel Control Architecture (MCA) and adopts asymmetric access rights over it. The access asymmetry defines that the MCA uses a separate control channel properly assigned for the free stations transmission, while the remaining control channels are used by the backlogged stations. The proposed asymmetric access protocol prevents from the data channels collisions, while it takes under consideration the loss due to the receiver conflicts. This is achieved by considering the propagation delay latency parameter as appropriate time interval in order to coordinate collisions-free data packets transmission. The performance parameters are derived through exhaustive analytical study based on a Markovian model of finite population, while the throughput optimization conditions are analytically investigated. Comparative results prove that the proposed asymmetric access protocol provides almost 11% throughput enhancement and significant delay deterioration as compared to a relative protocol with symmetric access rights over the MCA. The proposed protocol study is accomplished by examining its performance for various number of control channels and stations population. 相似文献
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《Computer Networks》2007,51(14):3978-3988
In wireless ad hoc networks, the major quality of service (QoS) concern and challenge in the design and analysis of contention-based medium access control (MAC) protocols is to achieve good throughput and access delay performance in the presence of hidden terminals, which are defined as the terminals out of the radio coverage area of an intended transmitter but within that of the receiver. We propose and analyze in this paper a new dual-channel random access protocol, called “Double Sense Multiple Access” (DSMA), for improving QoS support in wireless ad hoc networks. By separating the transmissions of ready-to-send (RTS) and data packets into two time-slotted channels and by introducing a novel double sense mechanism, DSMA completely solves the hidden terminal problem and can guarantee the success transmission of data packets. By taking into account the most complex network scenario in which all transmitters are hidden terminals with respect to each other, key QoS metrics such as throughput, blocking probability and access delay are derived mathematically for the proposed DSMA protocol. These analytical results are verified by extensive computer simulations. 相似文献
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车载自组织网络(Vehicular Ad Hoc Network,VANET)的关键技术之一就是 设计一个高效的媒体接入控制(Medium Access Control,MAC)协议。MAC协议因对网络的吞吐量、时延和丢包率等具有重大影响而成为研究热点。针对车载自组织网络对MAC协议的特殊性要求,提出了一种基于协作方案的TDMA MAC协议,即C-TDMA MAC。该协议中,当源节点到目的节点间直接传输失败时,其邻近辅助节点利用未被预留的时隙协作重传其先前侦听到的数据包到目的节点,而不影响其它数据包的正常传输。数值分析和仿真结果表明,所提出的协议提高了数据包成功传输的概率。 相似文献
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对多信道条件下MAC协议功率控制机制进行了分析,提出一种能够根据各个接收节点的通信状况,动态地调整数据信道上数据帧的传输功率和控制信道上CTS帧的发送功率的多信道Ad Hoc网络能量高效的MAC协议(MPEMAC).仿真表明,该协议有效的节省了节点能耗,延长了网络节点的生存时间,同时还能够增大空间信道的利用率,从而进一步提高网络的平均吞吐量. 相似文献
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This paper proposes a novel MAC (media access control) protocol named CSMA/CP for a metropolitan area network for the next generation Internet, which is an OPS (optical packet switch) network that all-optically and directly transfers IP packets over a WDM (wavelength division multiplexing) ring network. The proposed protocol uses the concepts of CSMA (carrier sense multiple access) and CP (carrier preemption) to all-optically transfer the IP packets of the nodes in the WDM ring networks. This paper studies the length effect of FDL (fiber delay line) in each node to support variable packet transmission, and develops an analytical model to analyze and simulate the packet delay and throughput. 相似文献
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无线多通道MAC协议McMAC采用了基于同步通道切换机制的MAC框架,具有良好的抗干扰能力和吞吐量性能。然而该协议中存在的节点“消失”现象会导致大量的无效发送,造成带宽和能量浪费。提出了一种适用于该协议的新型通道访问控制机制,不仅可有效解决McMAC协议中存在的无效发送问题,而且具有良好的节能效果。仿真结果表明新的通道访问控制机制能够大幅提高McMAC协议的网络吞吐量和能量效率。 相似文献
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自组网介质访问控制协议是影响自组网性能的重要因素.形式化地描述并分析了结合多信道和功率控制技术的自组网MAC协议性能特征.NS-2仿真实验表明,与没有功率控制的AODV相比较,在功率控制技术中合理的引入多信道技术,可有效的降低功率控制所引发的碰撞增加问题,增加节点和网络的生存时间. 相似文献