Research On Modulation And Precoding For Layered Video Transmission

The video media server in the network is more and more abundant, and hence it promotes the application of video stream transmission technology. However, the fluctuation of channel and network heterogeneity, the bandwidth of the channel error and other factors existing, the layered video transmission scheme with robust characteristics has catched our attention. However, many existing layered video transmission schemes still retain some characteristics of the traditional non-layered stratification, the advantages of layered video transmission have not been fully developed. This paper mainly focuses on some key technologies of layered video transmission, the main work and innovation are as follows:1. A Random Aliasing Modulation with Decision-Directed Demodulation(RAM-DDD) scheme is proposed. In this scheme, the encoder uses a current compression modulation scheme(modulation is the combination of compressed sensing and the traditional modulation scheme, this can improve the transmission rate) and extends it to random aliasing modulation. On the receiver side, the proposed method basically detects the signal without reconstructing it. This paper uses the decision feedback equalization(DFE) technique in the reconstruction process which means that a signal demodulation, interference to other signals can be eliminated. If the previous bit detection demodulation signal is correct, then their interferences can be cancelled, the next one will be detected correctly in better chance. This process is repeated until all of the signals detected. The experimental results show that the proposed scheme has obvious advantages compared with the traditional method.2. A layered video transmission scheme based on precoding is proposed. In this scheme, the layered video bits are obtained from scalable video coding at the encoding end. And the basic layer and enhancement layer bits for transmission are pre-coded after modulation to improve the coding gain. The experimental results show that this scheme can reduce the error rate in the decoder, so as to improve the quality of decoded video.