Unequal Error Protection Transmission Scheme Based On Fountain Codes

In recent years,with the large-scale construction and deployment of the third and the fourth generation(3G and 4G)digital cellular mobile communication networks,and the fifth generation(5G)digital cellular mobile communication networks will be commercially available in the coming years,and new technologies for wireless communications are constantly emerging,e.g.,visible light communication(VLC)technology,intelligent mobile terminals have been consequently popularized and used widely,resulting in a large amount of multimedia information will be transmitted over the wireless communication networks.In the mobile Internet and big data era,higher expectations and greater demands are being placed on wireless communication networks,expecting the wireless communication networks can provide excellent network services,e.g.,higher requirements for validity and reliability.Owing to the spatial and temporal correlation of the compressed multimedia,the efficient and reliable transmission of the multimedia information over wireless communication networks is still a challenge.This dissertation focuses at the unique characteristics of compressed multimedia information of unequal importance,and unequal error protection(UEP)based on fountain codes used as an FEC solution is provided for the compressed multimedia information according to their importance so as to improve the effectiveness of the information transmission and the system performance.The main contributions and innovative content of this dissertation are as follows:1.In order to deal with the error propagation problem in both space and time of scalable video sequence due to the loss of scalable video layers in lossy packet networks,we propose a transmission scheme based on cross-layer optimization for scalable video sequence in wireless additive white Gaussian noise(AWGN)channels.Firstly,we investigate five efficient combinations of expanding window fountain(EWF)coding and hierarchical QPSK(H-QPSK)modulation in a cross-layer fashion,i.e.,EWF coding at the application layer and H-QPSK modulation at the physical layer.We evaluate the performance of five cross-layer transmission schemes for H.264 scalable video coding bitstreams over wireless AWGN channels.Secondly,cross-layer optimization based on a genetic algorithm is performed to find the optimal parameters so as to improve the effectiveness of the information transmission and the system performance.Both the theoretical optimization and Monte Carlo simulation results are provided,and the perfect match between the two results confirms the correctness and rationality of our cross-layer optimization.Finally,based on the cross-layer optimization results,we propose an adaptive transmission scheme for scalable video by using optimal combinations of these schemes,i.e.,we adaptively exploit these five cross-layer transmission schemes in specific SNR regions to accommodate varying channel conditions and achieve the best overall transmission performance.The experimental results show that the proposed adaptive transmission scheme provides much better overall transmission performance,especially in low SNR regions,than any single scheme used by itself.2.Due to the fact that the more the importance of symbols in the compressed multimedia,the more the protection required,the original information can be recovered with higher quality at the receiver in VLC systems.In order to effectively deal with this situation,we propose a novel unequal error control(UEC)scheme in dimmable VLC systems.Firstly,according to the system composition characteristics,the block diagram of the proposed VLC system and the corresponding UEC scheme are proposed.Secondly,we present the derivation of the relationships among the actual overhead at the transmitter,the dimming target value,and the actual reception overhead at the receiver for the same transmission duration that produces a dimming target value of 12.5% when using EWF coding with overhead.Finally,to evaluate the performance of the proposed UEC scheme for various dimming target values,we apply it to H.264 scalable video coding bitstreams in a VLC system.The results of the simulations that are performed using additive white Gaussian noises(AWGNs)with different signal-to-noise ratios(SNRs)are used to compare the performance of the proposed scheme and the equal error control(EEC)scheme for various dimming target values.The theoretical and simulation results demonstrate effectiveness of the proposed UEC scheme in VLC systems.3.Aiming at the characteristics of UEP and unequal recovery time(URT)of EWF codes,we propose a coding scheme for EWF code with intermediate feedback over binary input additive white Gaussian noise(BIAWGN)channels.Firstly,we propose a coding scheme for EWF codes with intermediate feedback with the purpose of enhancing the intermediate performance of EWF codes and improving the transmission efficiency of system over BIAWGN channels.Secondly,the effectiveness of the proposed coding scheme is analyzed and evaluated by using extrinsic information transfer(EXIT)chart to investigate the asymptotic performance before and after the intermediate feedback.The results of the asymptotic analysis and simulation of the proposed coding scheme verify the correctness of the asymptotic analysis.Finally,the bit error ratio(BER)performance of the LIB between EWF coding with intermediate feedback and the conventional EWF coding is compared and evaluated,and the result implies that the proposed coding scheme is capable of recovering the LIB through the collection of fewer encoded bits at the receiver's end,and thus enable more effective recovery of all the resource information compared to conventional EWF coding.The theoretical and simulation results demonstrate effectiveness of the proposed coding scheme for EWF code with intermediate feedback.