| Nowdays, we are at the era of large-scale production and data sharing andapplications, the people’s desire for data is also increasing, which makestransmitting data to put forward higher requirements. In the data transmission,multimedia communications are becoming indispensable in people’s lives part,has been extensively studied and attention. Since Shannon’s separation principleis to source and channel were designed separately, resulting in low efficiency ofimage/video content transmit, and the joint of source and channel coding canachieve better system performance. Furthermore, consider the whole system thatconsider the source, channel coding and modulation together, will make thesystem performance is further improved, thus joint source-channel coding andmodulation technology has important significance.Currently research for transmit images is more reflected in the jointsource-channel coding techniques, and made a lot of breakthroughs, but notmuch in the joint source-channel coding and modulation scheme combiningconducted.First, in this article SPIHT coding algorithm is improved for the analysis ofthe code stream based on the contribution of the reconstructed image quality ofits group. And then proposed a system model for progressive image wirelesstransmission system and the corresponding distortion model according to themodel.At last proposed a combination of rate allocation and power allocationalgorithm combining unequal power distribution and applied in the proposedmodel system.Simulation results show that the system model with the unequal powerdistribution combining rate allocation proposed has better performance, and has alower time complexity, thus effectively improving the progressive image qualityin wireless transmission. |
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