Adaptive video transmission over wireless fading channel

Several novel components in a video transmission system over non-stationary wireless channels are examined in this thesis research, including efficient wireless channel modeling under non-stationary environments and the interaction and joint selection transmission parameters between the video source and the transmission module. The thesis work consists of three main contributions.;First, a novel adaptive mapping from a set of instantaneous observed channel SNRs in a non-stationary wireless environment to a variable length Markov chain (VLMC) model is proposed. The proposed scheme consists of two main components: estimation of an unknown fading channel signal-to-noise ratio (SNR) distribution and discrete VLMC modeling. First, to obtain the fading SNR distribution, a kernel density estimation algorithm is applied to the feedback channel SNRs. Then, with the estimated fading SNR distribution and feedback channel SNRs, an iterative partitioning mechanism and a construction of the context tree are performed to obtain the VLMC model, which yields a much larger and structurally richer class of models than ordinary higher order Markov chains. The frequency of channel model adaptation is dictated by the dynamic of fading statistics.;Second, we propose a dynamic QoS management scheme for adaptive prioritized video transmission under time-varying wireless channels. This framework employs QoS interaction between video coding and transmission modules, QoS mapping mechanism, video quality adaptation, and channel service rate estimation. The issues under study include: (1) the rate constraint derivation of transmitting multiple priority classes with QoS; (2) the development of a QoS mapping mechanism that maps the statistical QoS guarantees of multiple priority classes to its corresponding expected video quality optimally, and (3) a QoS interaction protocol to provide trade-off between the video quality requirement and the transmission capability of multiple priority classes under time-varying wireless channels.;Last, we present a robust video transmission scheme over fading wireless channels that relies on a coordinated protection effort in handling channel and source variations dynamically. Given the priority of each source packet based on the Relative Priority Index (RPI) and the estimated channel condition, an adaptive protection scheme via proactive forward error correction (FEC) is developed. (Abstract shortened by UMI.).