The Research Of Image Double-Unequal Error Protection Algorithm On UWB Channel

With the rapid development of Internet and Personal wireless communications, demand for multimedia communications is increasing and short-distance wireless communications, such as ultra-wideband technology, wireless sensor networks, is concerned about by the growing number of people in recent years. Thus the research of image transmission in short-distance wireless communication system is of important significance.In this paper, we apply Joint Source Channel Coding to Ultra Wideband (UWB) channel, where Set Partitioning In Hierarchical Trees (SPIHT) source coding and Rate Compatible Punctured Code (RCPC) channel coding is used. And an algorithm of Double-Unequal Error Protection (Double-UEP) is presented based on DS-UWB transform method. In this algorithm, the output bit stream of SPIHT is divided into a number of data blocks. The data blocks is protected by different channel coding rate and different repetitive coding period according to the visual importance of different data block, so that the bit stream of high visual importance can be transmitted in the lower bit error rate, and Unequal Error Protection is realized. According to the simulation result based on IEEE802.15.3a UWB channel model, it is shown that Double-Unequal Error Protection algorithm improves the PSNR and visual effect of reconstructed image more than Unequal Error Protection algorithm. Meanwhile, a scheme of image transmission based on Unequal Error Protection in Wireless Sensor Network is presented. In this scheme Double-Unequal Error Protection based on power distribution is applied to the image transmission of sensor nodes, thus to make good use of the limited power of sensor nodes and improve system performance.First, the development process, research and application status of Joint Source-Channel Coding and Unequal Error Protection is introduced briefly in this paper. Then Double-Unequal Error Protection algorithm based on Ultra-Wideband Channel and Double-Unequal Error Protection algorithm based on power distribution in sensor network is presented. At last, simulation module of image transmission based on DS-UWB is designed and simulation result is presented. Simulation result shows that Double-Unequal Error Protection algorithm improves the PSNR and visual effects of reconstructed image notably.