UBC Theses and Dissertations
Transmission of JPEG compressed images over the wireless CDPD network Wong, Michael Kwokwing
Image transmission over bandwidth limited wireless networks is becoming increasingly popular . To transmit an image over a low bit rate wireless network efficiently is not an easy task, because wireless networks normally have a high bit error rate. In this thesis, we propose a Progressive Image Transmission Protocol (PITP) which transmits a JPEG progressively compressed image effectively over wireless networks that support the Internet Protocol (LP), and more specifically the Cellular Digital Packet Data (CDPD) network. In the first part of the thesis, we will study the CDPD network, the LP network protocol, and the TCP and the UDP transport layer protocols. In the second part of the thesis, we will study the JPEG compression algorithm. In the last part of the thesis, we will discuss the Progressive Image Transmission Protocol (PITP) that is used to transmit an image over the CDPD wireless network. The PITP is a selective re-transmission application layer protocol which employs a JPEG progressive compression algorithm, the UDP transport protocol and a segment re-transmission algorithm. The segment retransmission algorithm is based on the priority levels of the JPEG scans and the current wireless network conditions. The segment re-transmission algorithm is so flexible that the performance of the PITP system can be adjusted by simply optimizing a few parameters in the algorithm. Simulations were performed to evaluate the efficiency and the effectiveness of the PITP. Our simulation results indicate that the PITP yields a substantially better image transmission rate than that achieved by conventional TCP/IP.
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