Design and Performance Evaluation of Fountain Codes in UDP Streaming Environments
| Autor: | Lu, Tung-Lung, 呂東融 |
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| Rok vydání: | 2016 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 104 The goals of this thesis are to utilize the network resources optimally and allowed to send real-time data as fast as possible. Excessive network traffic causes network congestion and it leads to packets loss. Transmission Control Protocol (TCP) congestion control avoid this kind of packets loss. However, packets losses could be caused by either network congestion or channel transmission errors. If packet losses are caused by transmission errors, TCP will slow down its sending rate that unnecessarily leads to low throughput. On the other hand, the receiver needs to wait the retransmitted packet when the sent packet is lost. If many packets are lost, it will lead to obvious latency and cause a lot of retransmitted packets, which cannot sustain high throughput. To solve the existing protocol inefficiency problem, we design fountain codes suitable in UDP streaming environments. In our research methods, the blocks of packets can transform them into the algebraic equations. Even if the packets within the block are lost, the receiver can synchronize by the seed number to reconstruct the random number generator matrix, and according to the gauss elimination to decode. The proposed LT encoding uses a characteristic 2 finite field with 256 elements, which can also be called the Galois field GF(2^8). These elements are derived from IETF (Internet Engineering Task Force) RFC 6330. We can use these elements to construct K×N random number matrix. Thus, we can extend K source packets to the N (N>K) encoding packets. If the receiver received the K packets, we could try to recover the K source packets. In the experimental results which indicate that the proposed fountain code in UDP streaming is very helpful in reducing inefficiency in the case of high packet loss rate. The demonstration is designed and implemented by the Network Simulator – NS2. Our results may serve as a basis to facilitate the related future fountain code research. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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