Efficient video transmission over wireless multiple antenna systems
Jubran, Mohammad K.
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I consider the problem of packet-based scalable video transmission over Multiple-Input Multiple-Output (MIMO) systems. Scalable video encoder produces a bitstream that can be partitioned into layers that form a hierarchy. In this work I use the scalable extension of H.264/AVC (SVC) that provides a combined temporal, quality and spatial scalability. It provides superior compression e±ciency and have error-resilient network adaptation layer (NAL) structure for transmission over varied networks. In this work, I first develop a method for the estimation of the distortion of the received video and propose different error concealment schemes. I show the accuracy of the distortion estimation algorithm in comparison with simulated wireless video transmission with packet errors. The scalable decoder distortion estimation algorithm at the encoder plays a key role in the proposed video transmission system. I also propose a bandwidth constrained video transmission over MIMO system with orthogonal space-time block codes (O-STBC). The O-STBC provides spatial diversity and guarantees independent transmission of different symbols within the block code. The bandwidth constrained allocation problem considered here is simplified and solved for one O-STBC symbol at a time. Furthermore, I take advantage of the hierarchical structure of SVC to attain the optimal solution for each group of pictures (GOP) of the video sequence. I incorporate the estimated decoder distortion to optimally select the application layer parameter, i.e., quantization parameter (QP), and physical layer parameters, i.e., channel coding rate and modulation type for wireless video transmission. Besides video transmission using O-STBC, I have considered video transmission over MIMO system using full-rate full-diversity quasi-orthogonal space-time block codes (quasi-orthogonal STBCs). These codes provide higher rate as compared to the O-STBC with a slight increase in the decoding complexity. In this work I show clearly the advantage of using the quasi-orthogonal STBC over O-STBC in a wireless video system in spite of the use of non-optimal signal constellation structure. The performance results are obtained after addressing the bandwidth allocation problem which employs the scalable decoder distortion estimation algorithm for the optimal selection of the application layer and physical layer parameters. As another part of this work, I show the performance gain by using the newly developed Hybrid Scalable/Multiple-Description Codec (HSMDC) over classical scalable codecs for optimal wireless video transmissions. HSMDC combines the functionality of scalable and multiple-description codecs. It produces a base layer and multiple-description enhancement layers. Any of the enhancement layers can be decoded (in a non-hierarchical manner) with the base layer to improve the reconstructed video quality. Two different channel coding schemes, Rate-Compatible Punctured Convolutional (RCPC)/Cyclic Redundancy Check (CRC) coding and, product code Reed Solomon (RS)+RCPC/CRC coding are used for unequal error protection of the layered bitstream. Optimal allocation of the bitrate between source and channel coding is performed for discrete sets of source coding rates and channel coding rates. Experimental results are presented for a wide range of channel conditions and show the effectiveness of using hybrid scalable/multiple-description coding for wireless transmission.