Simulation Tool and Metric for Evaluating Wireless Digital Video Systems

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Virginia Tech


This thesis focuses on the interaction between digital video quality and channel coding in a wireless communication system. Digital video is a high-bandwidth, computationally intensive application. The recent allocation of large tracks of spectrum by the FCC has made possible the design and implementation of personal wireless digital video devices for several applications, from personal communications to surveillance. Wireless video research has centered on contextual coding mechanisms; different sections of a video data stream are coded differently based on the perceived importance of the coded bits. Besides the complexity introduced into a system by this type of coding, no metric based solely on physical layer parameters can be used to predict video quality across different system architectures. A tool was built to explore the video/channel coding relationship. This tool simulates a packet-based digital wireless transmission in various noise and interference environments. The basic communications system models the DAVIC (Digital Audio-Visual Council) layout for the LMDS (Local Multipoint Distribution Service) system and includes several error control algorithms and a packetizing algorithm that is MPEG-compliant. This work introduces a statistical approach to monitoring the video quality. The error-event-mean-arrival-rate, lambda_distance, is a metric derived from the physical layer that can be used to predict the expected video quality across systems with different channel coding algorithms. This metric proved to be uniformly consistent in predicting video quality for sequences corrupted by Gaussian and non-Gaussian noise and protected by a variety of error correction techniques.



LMDS, wireless video, video, Simulation, RSVP