共查询到19条相似文献,搜索用时 171 毫秒
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在如今网络直播爆发的时代背景下,传统的常规用户数据报协议(User Datagram Protocol, UDP)存在链路性能不稳定、可靠性低、高延时等问题,而多链路并行传输是克服该问题的重要技术途径之一。本文基于UDP传输协议设计了一种多路径协作传输协议,即MPUDP(Multi-path User Datagram Protocol)。协议通过数据训练对每条信道的丢包率、RTT和乱序情况进行实时监测,对每条路径是否参与传输进行管理,并且对传输路径进行速率分配,有效改善系统的传输带宽。仿真结果表明:本文提出的多路径协作传输协议相比于UDP传统协议,在相同的误码率情况下,带宽近似扩大链路数目的倍数,与MPTCP协议相比,在损失丢包率0.1%的情况下,带宽提升了链路数量倍的吞吐量。 相似文献
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在多对单P2P流模式下,如何选择多个发送端,并为其最优地分配发送速率和数据是一个难题.为此,提出了一种新的多发送端选择和最优速率及数据分配算法(MSRDA).首先把待解决的问题模型化为线性最优化问题,然后给出了求解最优化问题的算法.不同于已有的算法只按链路的丢包率来选择发送端,MSRDA根据到各发送端链路的丢包率与链路的可用带宽比升序排序来选择多发送端,并最优地分配发送速率和数据.理论分析和仿真实验结果表明:在不同的网络条件下MSRDA能有效地减少聚合带宽的丢包率,并具有自适应性,优于现有同类算法. 相似文献
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针对物联网(IoT)通信的低延时需求,为了保证数据传输的灵活性,本文构建一种基于短包传输的无人机(UAV)通信网络。由于非正交多址接入(NOMA)技术能够增加可服务的地面用户数量,故将该技术应用到无人机短包通信(UAV-SPC)系统中可以解决多用户的安全传输问题。与正交多址(OMA)技术相比,NOMA可有效提高用户接入公平性和频谱利用率,因此被广泛用于下行链路的通信传输。为解决复杂的安全传输问题,首先证明在功率和译码错误率约束的条件下,分别存在最优的功率分配,数据传输包长和系统传输比特数使目标用户的平均安全吞吐量最大。在此基础上,通过本文所提算法得到安全传输问题的优化解。实验结果验证了该算法的稳定性和可行性。此外,与基准方案相比,本文所提方案可有效降低短包传输的通信时延,提高系统中目标用户的平均安全吞吐量。 相似文献
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该文首次在多天线多信道802.11无线网状网中提出了时频信道的概念。时频信道是通过在时间和频率两个维度划分无线资源取得的。这种划分方法增加了信道数量,使信道划分更加精细,为提高系统的信道利用率做了准备。在时频信道的基础上,提出了准动态信道分配算法。该算法可以和现有的固定信道分配算法结合,实现准动态信道分配,根据链路上负载变化,取得最大的吞吐量。该算法先根据固定信道分配算法为各链路分配相同数量的时频信道,剩余部分当作公共信道。在通信过程中,各链路首先使用分配给自己的信道和空闲的公共信道。如果分配给一个链路的信道不够,且别的链路上的信道有空闲,该链路还可以暂时使用这些空闲信道。理论分析和仿真结果证明该算法可以有效提高系统的吞吐量。 相似文献
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For the current generation of cellular communication systems, long‐term evolution (LTE) has been the major protocol to support high‐speed data transmission. It is critical to allocate downlink spectral resource in LTE, namely, resource blocks (RBs), but the issue is not well addressed in the standard. Therefore, the paper develops an efficient RB allocation algorithm with 4 mechanisms to improve both fairness and throughput in LTE. For fairness concern, our RB allocation algorithm uses a resource‐reservation mechanism to prevent cell‐edge user equipments from starvation, and a credit‐driven mechanism to keep track of the amount of resource given to each user equipment. For throughput concern, it adopts both weight‐assignment and RB‐matching mechanisms to allocate each RB to a packet according to its flow type and length. Through simulations, we demonstrate that the proposed RB allocation algorithm can significantly increase both throughput and fairness while reducing packet dropping and delays of real‐time flows, as compared with previous methods. 相似文献
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该文给出了无线通信系统中MAC层可实现的评价用户VoIP业务和实时视频业务满意度的方法,该方法根据MAC层统计的丢包率及丢包模式等信息计算当前业务的用户满意度。基于文中的业务满意度评价准则,该文进一步提出一种在WiMax系统中基于满意度的包调度和资源分配算法。仿真结果表明,该方法在保证系统获得较高吞吐率的同时,能够更好的保证实时业务的满意度。 相似文献
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Providing reliable transmission for real-time traffic in wireless cellular networks is a great challenge due to the unreliable wireless links. This paper concentrates on the resource allocation problem aiming to improve the real-time throughput. First, the resource allocation problem is formulated as a Markov Decision Process and thus the optimal resource allocation policy could be obtained by adopting the value iteration algorithm. Considering the high time complexity of the optimal algorithm, we further propose an approximate algorithm which decomposes the resource allocation problem into two subproblems, namely link scheduling problem and packet scheduling problem. By this method, the unreliable wireless links are only constrained in the link scheduling problem, and we can focus on the real-time requirement of traffic in packet scheduling problem. For the link scheduling problem, we propose the maxRel algorithm to maximize the long-term network reliability, and we theoretically prove that the maxRel algorithm is optimal in scenarios with dynamic link reliabilities. The Least Laxity First algorithm is adopted for the packet scheduling problem. Extensive simulation results show that the proposed approximate resource allocation algorithm makes remarkable improvement in terms of time complexity, packet loss rate and delay. 相似文献
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Yutaka Fukuda Hiroyuki Koga Takeshi Ikenaga Yuji Oie 《Wireless Communications and Mobile Computing》2004,4(2):223-232
IMT‐2000 has attracted much attention as the Next Generation Mobile Communication System. IMT‐2000 can provide high‐bit‐rate data communication service, so that a great number of packets conveyed by TCP (transmission control protocol) can be transmitted over a wireless link. W‐CDMA, standardized in 3GPP (which standardizes IMT‐2000), allows dynamically allocating transmission rates to flow over a wireless link in response to a changing FER for each flow, which is thought to be essential for a next generation mobile communication system. Therefore, in this paper, we study the characteristics of the dynamic allocation scheme when TCP flows share a wireless link, and, in particular, we focus on the throughput performance of these TCP flows. First, we use simulations to examine the effectiveness of the dynamically allocating down‐link transmission rate for TCP flows in response to changing the frame error rate (FER). Through the simulation results, we will show how it can improve the total throughput performance of TCP flows. Furthermore, we can obtain an effective way to allocate transmission rates to flows with different FERs in order to achieve high total throughput. Finally, we will deal with a case of multiple flows from a fixed host to a mobile host. In actual networks, this often happens. In this case, we will show that the total throughput of TCP flows degrades less than in the single‐flow case, even when the FER is high. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
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