在多媒体数据传输中,重要数据对可靠性要求比较高,在较差信道条件下需要更强的保护,为此提出了一种具有不等保护能力的级联型UEP-LT码方案。该方案先对重要比特(More Important Bits,MIB)数据进行预编码,并引入扩展窗技术进行优化设计,...在多媒体数据传输中,重要数据对可靠性要求比较高,在较差信道条件下需要更强的保护,为此提出了一种具有不等保护能力的级联型UEP-LT码方案。该方案先对重要比特(More Important Bits,MIB)数据进行预编码,并引入扩展窗技术进行优化设计,然后利用And-Or树分析法对误码率性能进行分析。仿真结果表明,基于扩展窗的级联型UEP-LT码增强了对MIB数据的保护程度,并且降低了对次重要比特(Less Important Bits,LIB)性能的损失,具有良好的UEP特性。展开更多
To model the underwater electric potential(UEP) of ships,a multiple point-electrodes method is commonly used.However,it is difficult to determine the total number of point-electrodes,their respective positions and cur...To model the underwater electric potential(UEP) of ships,a multiple point-electrodes method is commonly used.However,it is difficult to determine the total number of point-electrodes,their respective positions and current values.In this paper,the particle swarm optimization(PSO) method is applied to solve the number,positions and current values of these point-electrodes according to the UEP distribution at a known depth below the keel of a ship.A scaled ship model experiment is carried out to determine the effectiveness of the method.The results show that for hulls in a latural corrosion or cathodic protection state,the UEP inversion accuracy can reach 85% at different depths below the keel.This method is suitable for software implementation and can help the simulation and prediction of UEP signatures.展开更多
In order to improve the video transmission performance in Multiple-Input Multiple-Output Orthogonal Frequency Division Multiplexing （MIMO-OFDM） system, a new scheme, which integrates Multiple Description Coding （MD...In order to improve the video transmission performance in Multiple-Input Multiple-Output Orthogonal Frequency Division Multiplexing （MIMO-OFDM） system, a new scheme, which integrates Multiple Description Coding （MDC）, Low Density Parity Check （LDPC） coding and hybrid space time coding, is proposed in this letter. In particular, a hybrid space time coding algorithm is combined with LDPC codes to perform Unequal Error Protection （UEP） of MDC encoded video streams. Comparing with the UEP transmission with only LDPC codes, the proposed scheme achieves more than ldB gain in terms of Signal to Noise Ratio （SNR） when the Peak Signal to Noise Ratio （PSNR） of reconstructed video is above 30dB.展开更多
文摘在多媒体数据传输中,重要数据对可靠性要求比较高,在较差信道条件下需要更强的保护,为此提出了一种具有不等保护能力的级联型UEP-LT码方案。该方案先对重要比特(More Important Bits,MIB)数据进行预编码,并引入扩展窗技术进行优化设计,然后利用And-Or树分析法对误码率性能进行分析。仿真结果表明,基于扩展窗的级联型UEP-LT码增强了对MIB数据的保护程度,并且降低了对次重要比特(Less Important Bits,LIB)性能的损失,具有良好的UEP特性。
基金based on the support by the Research project“Deep Sea of Electromagnetic Detection System”,Initiated by Pilot National Laboratory for Marine Science and Technology(Qingdao,China)。
文摘To model the underwater electric potential(UEP) of ships,a multiple point-electrodes method is commonly used.However,it is difficult to determine the total number of point-electrodes,their respective positions and current values.In this paper,the particle swarm optimization(PSO) method is applied to solve the number,positions and current values of these point-electrodes according to the UEP distribution at a known depth below the keel of a ship.A scaled ship model experiment is carried out to determine the effectiveness of the method.The results show that for hulls in a latural corrosion or cathodic protection state,the UEP inversion accuracy can reach 85% at different depths below the keel.This method is suitable for software implementation and can help the simulation and prediction of UEP signatures.
基金the National Natural Science Foundation of China (No. 60328103).
文摘In order to improve the video transmission performance in Multiple-Input Multiple-Output Orthogonal Frequency Division Multiplexing （MIMO-OFDM） system, a new scheme, which integrates Multiple Description Coding （MDC）, Low Density Parity Check （LDPC） coding and hybrid space time coding, is proposed in this letter. In particular, a hybrid space time coding algorithm is combined with LDPC codes to perform Unequal Error Protection （UEP） of MDC encoded video streams. Comparing with the UEP transmission with only LDPC codes, the proposed scheme achieves more than ldB gain in terms of Signal to Noise Ratio （SNR） when the Peak Signal to Noise Ratio （PSNR） of reconstructed video is above 30dB.
