基于传输片段部分重叠的多路径传输技术

发布时间：2018-01-13 00:15

本文关键词：基于传输片段部分重叠的多路径传输技术　出处：《北京交通大学》2017年硕士论文　论文类型：学位论文

【摘要】：在线观看高清视频已经成为普遍的网络行为,并且占用了大量网络带宽。继续靠增加网络带宽提升用户观看体验的空间已经不大。多路径传输技术,即,通过客户端的多个网络接口实现数据在多条路径上共同传输,能够打破这种瓶颈。现有多种多路径传输技术。一种典型的方法是,采取在多条路径上同时传输完全相同数据;以保证数据及时到达,但是,这种方法会造成网络资源浪费。另一种典型的方法是,根据预测的带宽为每条路径分配相应大小的数据传输任务,以实现数据同时到达的目标;但是,由于路径带宽符合高斯变化,在一次数据块传输过程中,越晚被传输的数据(数据块尾部),越容易发生传输超时;一旦尾部数据无法及时到达,客户端播放质量就会受到影响。本文利用路径带宽的高斯变化,提出了一种新的多路径传输思想。按照这种思想,客户端下载数据的过程被分割为不同的下载周期;每个周期,客户端需要从服务器下载一定大小的数据块以供播放。由于路径带宽符合高斯变化,这将导致每个周期内,一条路径上较晚传输的数据(尾部数据)传输成功的概率较低;因此,对尾部数据进行重复传输并调节重复传输的数据量,可以提高尾部数据成功传输的概率,从而最大化一个周期内数据成功传输的概率。同时,因为只对尾部数据进行重复传输,所以引起的开销又不会太大。本文的主要工作和贡献如下:(1)本文建立了基于部分数据重叠的多路径传输技术的传输模型。在这一模型中,我们清晰地描述了本方法是如何最大化一个周期内数据成功传输的概率。(2)本文提出了基于部分数据重叠的多路径传输技术,PCT(Partial Overlapping Chunk Based Mutiple-Path Transmission)。本方法在每个周期内,为了以最大概率下载到所需的数据块,客户端会根据每条路径的传输能力(路径带宽的期望和方差),安排不同的数据传输任务:各路径所请求获取的数据具有相同的终止位置以及不同起始位置,而数据的起始位置由各路径带宽的高斯变化共同决定。(3)本文通过理论分析以及一系列的仿真实验证明了 PCT。与各路径传输完全不同数据的方法相比,基于模型的仿真分析显示PCT以最高14.4%的冗余率为代价,可以最多提高19.3%的传输成功率;更进一步,基于真实网络的仿真分析则显示PCT在路径总带宽较小时,对传输成功率的优化更明显。
[Abstract]:Viewing HD video online has become a common network behavior and occupies a large amount of network bandwidth. There is no longer much space to improve the user's viewing experience by increasing network bandwidth. Multipath transmission technology, that is. It is possible to break this bottleneck by means of multiple network interfaces of the client. A typical method is to transfer data over multiple paths. The same data is transmitted at the same time on multiple paths; In order to ensure the timely arrival of data, however, this method will lead to waste of network resources. Another typical method is to assign data transmission tasks of corresponding size for each path according to the predicted bandwidth. In order to achieve the goal that the data arrive at the same time; However, because the path bandwidth is in line with Gao Si's change, the later the data is transmitted in a data block transmission process, the more likely the transmission timeout will occur. Once the tail data can not arrive in time, the quality of client playback will be affected. This paper proposes a new multipath transmission idea based on Gao Si's change of path bandwidth. The process of downloading data by client is divided into different downloading cycles. Each cycle, the client needs to download a certain size of data blocks from the server for playback. Because the path bandwidth conforms to Gao Si changes, this will lead to each cycle. The probability of successful transmission of late data (tail data) on a path is lower; Therefore, repeat transmission of tail data and adjust the amount of data transferred repeatedly can improve the probability of successful transmission of tail data, thereby maximizing the probability of successful transmission of data in a period. At the same time. Because only the tail data is transferred repeatedly. The main work and contribution of this paper are as follows: 1) this paper establishes a transmission model of multipath transmission based on partial data overlap. We clearly describe how this method maximizes the probability of successful data transmission within a period. PCT(Partial Overlapping Chunk Based Mutiple-Path Transmission). This method is within each cycle. In order to download to the desired data block with the maximum probability, the client will base on the transmission capacity of each path (the expectation and variance of the path bandwidth). Schedule different data transfer tasks: the data requested by each path has the same stop position and different starting position. The starting position of the data is determined by the variation of the bandwidth of each path. Through theoretical analysis and a series of simulation experiments, this paper proves that PCT. is compared with the method of transmitting completely different data from each path. The simulation analysis based on the model shows that PCT can increase the transmission success rate of 19.3% at the cost of up to 14.4% redundancy rate. Furthermore, the simulation analysis based on real network shows that PCT is more effective in optimizing the transmission success rate when the total path bandwidth is small.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN919.8

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