基于跨层不等重功率分配的渐进图像传输方案

为了在无线衰落信道下鲁棒和高效地编码传输渐进图像，提出了基于跨层不等重功率分配的编码传输方案。和以往基于不等重功率分配的传输优化方案不同，该方案综合考虑了反馈信道提供的物理层信道状态信息、链路层自动重传信息和应用层压缩编码率失真特性，采用基于解析表达的数值优化算法，求得各个层上最优不等重功率分配策略，减小给定期望传输功率约束下的图像传输失真。实验表明，相对于以往方案，所提方案不但避免了启发式优化算法的高搜索复杂度|而且能大大提高接收端重建图像的峰值信噪比。

Transmission scheme for progressive coded images based on cross-layer unequal power allocation

For efficient and robust transmission of progressive coded images under wireless fading channels,an optimal scheme based on cross-layer unequal power allocation is proposed.Unlike previous optimal transmission schemes based on unequal power allocation,through effective use of channel state information in physical layer,automatic repeat request(ARQ) information in link layer and rate distortion characteristics of compression stream in application layer,the optimal unequal power allocation policies across all three layers are calculated by numerical optimization methods based on analytical expressions to minimize the image transmission distortion.Extensive experimental results show that not only the high searching complexity of heuristic optimization algorithm is avoided,but also the peak signal-to-noise ratio(PSNR) of the reconstructed image is significantly improved in the proposed scheme.