Real-time video transmission over ad hoc networks faces many challenges including low bandwidth, long end-to-end
delay, high packet loss rate, frequently changing topology and limited-powered mobile nodes. This paper presents an
effective real-time video transmission scheme and improves implementation of DSR (Dynamic Source Routing)
protocol. We set up a test-bed by using DSR routing in the IP layer, and an application transmitting video stream over
UDP protocol. We get a continuous JPEG image stream from a ZC0301p web camera and split each image into small
blocks according to the MCU (Minimum Coding Unit) borderline. The strong point of splitting JPEG image is that IP
layer fragmentation can be avoided so we can determine which part of data in the frame gets lost to do loss recovery at
the receiver. By using JPEG image stream, the video encoding complexity is reduced, which can save computing power
of mobile nodes compared with MPEG and other Multiple Description Coding (MDC) methods. We also improve
implementation of DSR to make it suitable to transfer real-time multimedia data. First different priorities are given to
different traffic classes in DSR routing. Second the route maintenance scheme is modified to decrease overhead and link
failure misjudgments. We carry out two experiments both indoors and outdoors using six mobile nodes. The first is to
transmit continuous JPEG images using our former DSR implementation according to DSR draft. The second is that we
split JPEG images into blocks and then transmit them using improved DSR implementation. Results show the latter
gives better video stream fluency and higher image quality.
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