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Cascade Hybrid Digital-Analog Video Multicasting Research

Posted on:2019-05-04Degree:MasterType:Thesis
Country:ChinaCandidate:J LiFull Text:PDF
GTID:2428330566476368Subject:Circuits and Systems
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Hybrid digital analog(HDA)video transmission scheme combines traditional digital scheme with SoftCast analog scheme to overcome both the cliff effect of digital scheme Channel heterogeneity.However,HDA still has some performance limitations.For HDA scheme,The main tasks of this article are as follows:Firstly,a DCS based cascade HDA scheme(HDA(DCS)is proposed.Combining the digital scheme with the distributed compression sensing-based analog scheme,The encoding side first encodes the incoming video sequence with H.264 / AVC and generates binary Bitstream,Then pass the code through FEC and channel modulation to get the digital signal;the code stream is transformed into digital signals,The quantized residuals are processed by the distributed compression sensing-based analog scheme,and the analog signals are obtained after block-based compressed sensing(BCS)and block interleaving package;Finally,the two parts of the signals are mixed and transmitted in cascade;Receiver regard the digital part as the base layer,the analog part as the enhancement layer,and receivers with different channel characteristics can obtain different numbers of analog packets in order to match its channel conditions.Experiments show that,in the case of video packet loss,the video quality of this scheme is better than HDA(SoftCast)scheme,and it can better deal with the heterogeneity of multicast users.Secondly,this paper proposes an optimal bandwidth allocation for cascade HDA video transmission scheme.The key of Hybrid Digital Analog(HDA)video transmission is the resource allocation between digital and analog signals,including bandwidth allocation and power allocation.This paper proposes an optimal bandwidth allocation for cascade HDA in order to improve the utilization of bandwidth resource in the wireless network.Firstly,the distortion model was deduced,which regards the problem of bandwidth allocation as the selection of optimal analog bandwidth;Then the distortion model is proved to be an opening up convex function so that the optimal analog bandwidth just corresponds to the minimum value of the convex function.Experimental resultsshow that our scheme achieves 1-7dB gain in Peak signal to noise ratio(PSNR)compared to the cascade HDA without optimized bandwidth allocation,which also shows more bandwidth heterogeneity in multicast users good performance.
Keywords/Search Tags:Wireless video multicasting, Hybrid digital analog video transmission, Compression sensing, Bandwidth optimization
PDF Full Text Request
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