无线网络中基于网络编码的调度方案研究

发布时间：2018-05-22 16:59

本文选题：网络编码 + 调度方案　；参考：《辽宁大学》2014年硕士论文

【摘要】：网络编码是一种新型的传输范例。近些年，特别是在无线传输领域中，学术界对网络编码的研究产生了浓厚的兴趣。对于这个比较新的概念，最主要的吸引力就是，既能达到带宽的高利用率，又能获得高的网络吞吐量。通过实验，人们可以发现，网络编码可能使得呈现的点对点实时多媒体传输流，可以有更加细腻的颗粒感。传统的路由协议中，中间节点存储和转发数据包，而网络编码就可以被视为是传统的路由协议的扩展。有关网络编码的基本思想就是，在中间节点，数据包智能地混合或者编码在一起，而后中间节点将这些数据包编码成一个编码数据包，随后广播发送出去。因此，这个过程不仅仅促进了网络中的传输数量，还使得传输能携带更多的信息。除此以外，通过网络编码更多的带宽用以传输新产生的数据，这也能提高网络吞吐量。尽管网络编码的概念提出的时间不长，但在学术界已有大量的学者针对网络编码的性能进行研究。在目前所开展的网络编码研究中，几乎很少有文献在传输调度中同时考虑TCP动态传输情况和无线网络的通信链接情况，，并按照影响的大小计算权值。本文针对无线网络编码的调度方法问题作了以下研究：首先，本文介绍了网络编码的主要理论和基础，简述网络编码的分类、策略以及优势，并对调制方案做了简要的介绍。其次，本文提出了一种具有鲁棒性和弹性的网络编码方法，在无线网络中，采用跨层的设计方法，同时考虑TCP动态传输情况和无线网络的通信链接情况计算权值，以此来决定节点发送速度，即机会调度的TCP计算权值网络编码。再次，在此基础上，对于传统的COPE方案，提出记录路径的改进PCOPE，以此来进一步提高编码机会，获得更大的网络吞吐量。对于以上改进，引入了异或头的开销，采用可变等待时间方法，来将帧错误率控制在可接受的范围之内。本文提出的方法自适应地调整数据包在本地缓冲池中的等待时间，以此来实现网络吞吐量和开销的平衡。最后，实验仿真结果表明，与其他网络编码相比较，机会调度的TCP计算权值网络编码方法对于网络性能有着明显的提升。在相同网络条件下，与其他方案相比较，采用PCOPE可变等待时间方案，在带宽利用率和网络吞吐量方面也有一定的提升。
[Abstract]:Network coding is a new transmission paradigm. In recent years, especially in the field of wireless transmission, there has been a strong interest in the research of network coding. The main attraction of this new concept is that it can achieve both high bandwidth utilization and high network throughput. Through experiments, it can be found that network coding may make point-to-point real-time multimedia transmission stream more granular. In traditional routing protocols, intermediate nodes store and forward packets, while network coding can be regarded as an extension of traditional routing protocols. The basic idea of network coding is that data packets are intelligently mixed or encoded together at intermediate nodes, and then the intermediate nodes encode these packets into an encoded packet, and then broadcast and send them out. Therefore, this process not only promotes the number of transmissions in the network, but also enables the transmission to carry more information. In addition, the network encodes more bandwidth to transmit newly generated data, which also improves network throughput. Although the concept of network coding has not been put forward for a long time, a large number of scholars have studied the performance of network coding in academic circles. In the current research of network coding, few literatures consider the dynamic transmission of TCP and the communication link of wireless network in the transmission scheduling, and calculate the weight according to the size of the influence. In this paper, the scheduling method of wireless network coding is studied as follows: First of all, this paper introduces the main theory and foundation of network coding, briefly describes the classification, strategy and advantages of network coding, and briefly introduces the modulation scheme. Secondly, a robust and flexible network coding method is proposed in this paper. In wireless network, cross-layer design method is adopted, and the weights of TCP dynamic transmission and wireless network communication link are taken into account at the same time. In this way, the transmission speed of nodes is determined, that is, the TCP computing weight network coding of opportunistic scheduling. Thirdly, for the traditional COPE scheme, an improved PCOPE-based recording path is proposed to further improve the coding opportunities and achieve greater network throughput. For the above improvements, the cost of the XOR head is introduced, and the variable waiting time method is used to control the frame error rate within an acceptable range. The proposed method adaptively adjusts the waiting time of packets in the local buffer pool to achieve the balance between throughput and overhead. Finally, the simulation results show that compared with other network codes, the TCP weighted network coding method of opportunistic scheduling has a significant improvement on network performance. Under the same network conditions, compared with other schemes, the PCOPE variable waiting time scheme can also improve the bandwidth utilization and network throughput.
【学位授予单位】：辽宁大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TP393.02

【参考文献】