Adaptive network abstraction layer packetization for low bit rate H.264/AVC video transmission over wireless mobile networks under cross layer optimization

Abstract

The key problem of video transmission over the existing wireless mobile networks is the incompatibility between the time-varying and error-prone network conditions and the QoS requirements of real-time video applications. As new directions in the design of wireless systems do not necessarily attempt to minimize the error rate but to maximize the throughput, this thesis first proposes a novel adaptive H.264/AVC Network Abstraction Layer (NAL) packetization scheme in terms of adaptive slice partition and a??Simple Packetizationa?? with 2 motivations: i) To take advantage of slice-coding in assisting error control techniques by localizing the burst errors occurred in wireless environment so that the end-user quality can be improved with the assistance of error concealment techniques; ii) To facilitate throughput adaptation in time-varying wireless environment so that the network or system efficiency can be improved in conjunction with lower layer error control mechanisms under cross layer optimization.This thesis also proposes a channel adaptive H.264/AVC video transmission framework under cross layer optimization. The novel adaptive H.264/AVC NAL packetization scheme works as built-in block with other channel adaptive blocks in the proposed framework to facilitate system throughput adaptation in time-varying wireless environment. Simulation results show that compared to the system with fixed NAL packetization under fixed error control configuration, the proposed framework can adapt system throughput to the variations of channel capacity with acceptable end-user quality such that channel usage and system efficiency can be enhanced whenever the channel condition is improved. And the proposed framework also shows better end-user quality compared to the system with fixed NAL packetization under channel adaptive error control configuration.