本文選題：網(wǎng)絡(luò)編碼 + 調(diào)度方案　； 參考：《遼寧大學》2014年碩士論文

【摘要】：網(wǎng)絡(luò)編碼是一種新型的傳輸范例。近些年，特別是在無線傳輸領(lǐng)域中，學術(shù)界對網(wǎng)絡(luò)編碼的研究產(chǎn)生了濃厚的興趣。對于這個比較新的概念，最主要的吸引力就是，既能達到帶寬的高利用率，又能獲得高的網(wǎng)絡(luò)吞吐量。通過實驗，人們可以發(fā)現(xiàn)，網(wǎng)絡(luò)編碼可能使得呈現(xiàn)的點對點實時多媒體傳輸流，可以有更加細膩的顆粒感。傳統(tǒng)的路由協(xié)議中，中間節(jié)點存儲和轉(zhuǎn)發(fā)數(shù)據(jù)包，而網(wǎng)絡(luò)編碼就可以被視為是傳統(tǒng)的路由協(xié)議的擴展。有關(guān)網(wǎng)絡(luò)編碼的基本思想就是，在中間節(jié)點，數(shù)據(jù)包智能地混合或者編碼在一起，而后中間節(jié)點將這些數(shù)據(jù)包編碼成一個編碼數(shù)據(jù)包，隨后廣播發(fā)送出去。因此，這個過程不僅僅促進了網(wǎng)絡(luò)中的傳輸數(shù)量，還使得傳輸能攜帶更多的信息。除此以外，通過網(wǎng)絡(luò)編碼更多的帶寬用以傳輸新產(chǎn)生的數(shù)據(jù)，這也能提高網(wǎng)絡(luò)吞吐量。 盡管網(wǎng)絡(luò)編碼的概念提出的時間不長，但在學術(shù)界已有大量的學者針對網(wǎng)絡(luò)編碼的性能進行研究。在目前所開展的網(wǎng)絡(luò)編碼研究中，幾乎很少有文獻在傳輸調(diào)度中同時考慮TCP動態(tài)傳輸情況和無線網(wǎng)絡(luò)的通信鏈接情況，，并按照影響的大小計算權(quán)值。本文針對無線網(wǎng)絡(luò)編碼的調(diào)度方法問題作了以下研究： 首先，本文介紹了網(wǎng)絡(luò)編碼的主要理論和基礎(chǔ)，簡述網(wǎng)絡(luò)編碼的分類、策略以及優(yōu)勢，并對調(diào)制方案做了簡要的介紹。 其次，本文提出了一種具有魯棒性和彈性的網(wǎng)絡(luò)編碼方法，在無線網(wǎng)絡(luò)中，采用跨層的設(shè)計方法，同時考慮TCP動態(tài)傳輸情況和無線網(wǎng)絡(luò)的通信鏈接情況計算權(quán)值，以此來決定節(jié)點發(fā)送速度，即機會調(diào)度的TCP計算權(quán)值網(wǎng)絡(luò)編碼。 再次，在此基礎(chǔ)上，對于傳統(tǒng)的COPE方案，提出記錄路徑的改進PCOPE，以此來進一步提高編碼機會，獲得更大的網(wǎng)絡(luò)吞吐量。對于以上改進，引入了異或頭的開銷，采用可變等待時間方法，來將幀錯誤率控制在可接受的范圍之內(nèi)。本文提出的方法自適應(yīng)地調(diào)整數(shù)據(jù)包在本地緩沖池中的等待時間，以此來實現(xiàn)網(wǎng)絡(luò)吞吐量和開銷的平衡。 最后，實驗仿真結(jié)果表明，與其他網(wǎng)絡(luò)編碼相比較，機會調(diào)度的TCP計算權(quán)值網(wǎng)絡(luò)編碼方法對于網(wǎng)絡(luò)性能有著明顯的提升。在相同網(wǎng)絡(luò)條件下，與其他方案相比較，采用PCOPE可變等待時間方案，在帶寬利用率和網(wǎng)絡(luò)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.
【學位授予單位】：遼寧大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：TP393.02

【參考文獻】

相關(guān)期刊論文 前1條

1 熊志強;黃佳慶;劉威;楊宗凱;;無線網(wǎng)絡(luò)編碼綜述[J];計算機科學;2007年03期

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