结合JSCC的VBLAST-OFDM自适应图像传输方法  

Adaptive image transmission method combined with JSCC for VBLAST-OFDM systems

作　　者：李俊[1,2] 景小荣[1,2] 陈前斌[1,2] 张祖凡[1,2] 

机构地区：[1]重庆邮电大学移动通信技术重庆市重点实验室,重庆400065 [2]重庆邮电大学通信与信息工程学院,重庆400065

出　　处：《重庆邮电大学学报（自然科学版）》2012年第5期657-663,共7页Journal of Chongqing University of Posts and Telecommunications(Natural Science Edition)

基　　金：国家科技重大专项(No.2011ZX03003-001-01);重庆市自然科学基金(CSTC;2010BB2471);重庆市教委科研项目(No.KJ110526)~~

摘　　要：结合信源信道联合编码(joint source channel coding,JSCC),提出了一种基于分组长度优化选择的VBLAST-OFDM图像自适应传输方法。首先对基于分层树集合分割(set partitioning in hierarchical trees,SPIHT)算法的信源编码器输出码流,采用分级排序进行改进,然后依据JSCC为改进后的码流提供不等差错保护(unequal error protec-tion,UEP),最后采取自适应比特分配,在VBLAST-OFDM各子信道上实现自适应调制,进而实现系统自适应组长优化选择,使系统性能得到整体优化。该方法可根据无线信道质量,实现信源编码、信道编码与传输分组长度选择之间的优化匹配,使终端图像重建质量得到明显改善。数值仿真结果验证了其有效性。An adaptive image transmission method is proposed,being combined with the joint source and channel coding（JSCC）for VBLAST-OFDM systems.The method firstly improves the bitstream from the source coder based on the SPIHT algorithm by reclassification and sorting.Then,the UEP of the improved bitstream is designed by JSCC.Finally,the adaptive modulation over each subchannel of the VBLAST-OFDM systems is realized by the adaptive bit allocation,and further by the optimized selection of the packet length.Thereby the overall system performance is optimized.The method can realize the optimized matching among the source coding,channel coding and selection of the packet length according to the channel environments,and can dramatically improve the quality of the image reconstruction.Simulation results confirm its effectiveness.

关 键 词：垂直贝尔分层空时码(VBLAST) OFDM 联合信源信道编码 不等差错保护 自适应传输 

分 类 号：TN911.7[电子电信—通信与信息系统]