Adaptive Rate Control Low Bit-Rate Video Transmission over Wireless Zigbee Networks

The emerging IEEE 802.15.4 standard is designed for low data rate, low power consumption and low cost wireless personal area networks (WPANs). Video transmission over such networks is considered an issue since video traffic demands high data rates. In this paper, the TES (transform-expand-sample) methodology is used to model low rate MPEG4 video. The performance of a surveillance video application is evaluated over wireless Zigbee networks. A rate control algorithm (RC-VBR) adapted to MPEG4 variable bit rate (VBR) video coders is studied over Zigbee networks. The algorithm avoids unpredictable rate variations of the VBR coding and removes the coding delay in constant bit-rate (CBR) coders. A region of interest (ROI) encoding is added to the rate control algorithm in order to capture the important parts of the frame which is suitable for IEEE 802.15.4 (Zigbee) networks. Zigbee networks will enable a large number of applications for surveillance networks. The ns-2 simulator is used to test and validate the MPEG4 real video and modeled video over ad hoc Zigbee networks and to test the different algorithms.