Title page for etd-0911112-173124


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URN etd-0911112-173124
Author San-Tai Lin
Author's Email Address No Public.
Statistics This thesis had been viewed 5589 times. Download 700 times.
Department Electrical Engineering
Year 2012
Semester 1
Degree Master
Type of Document
Language zh-TW.Big5 Chinese
Title Multicasting Retransmission Mechanism Using Negative ACK for WiFi Network
Date of Defense 2012-09-05
Page Count 70
Keyword
  • Retransmission
  • RTP
  • NACK
  • RTO
  • WiFi
  • Multicast
  • Abstract Multicast is an effective technology to save network bandwidth while transmitting data packets in WiFi networks. However, it lacks of a mechanism to recover lost packets. When interference or congestion occurs in wireless networks, the receiver cannot receive complete data. In this Thesis, we propose a multicast retransmission mechanism which integrates NACK in WiFi networks. Also, the sender can dynamically adjust retransmission parameters according to the network status reported from the receiver. To demonstrate our proposed mechanism, three parts are implemented on the Linux platform. First, the RTP header is added in each packet and the buffer is maintained in both the sender and the receiver before the sender can transmit data. Second, a module is installed in the wireless card driver to examine the CRC errors caused by interference. Then the sender can be notified by NACK such that the sender may know the reasons of packet loss and the numbers of dropped packets. Third, the sender utilizes RTCP to calculate RTT and derive RTO. The retransmission time is calculated based on RTO, interferences, and congestion. Finally, our measurement results show that the sender can effectively use multicast retransmission according to various background traffics. Besides, the number of retransmitted packets can be significantly reduced.
    Advisory Committee
  • Kao-Shing Hwang - chair
  • Cheng-Shong Wu - co-chair
  • Zi-Tsan Chou - co-chair
  • Tsung-Chuan Huang - co-chair
  • Tsang-Ling Sheu - advisor
  • Files
  • etd-0911112-173124.pdf
  • Indicate in-campus at 3 year and off-campus access at 5 year.
    Date of Submission 2012-09-11

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