面向VBLAST-OFDM系统的H.264/AVC视频传输策略优化

H.264/AVC video transmission strategy optimization over VBLAST-OFDM system

在H.264/AVC无线视频传输端到端失真进行理论分析的基础上,面向垂直-贝尔空时正交频分复用(vertical bell layered space time-orthogonal frequency division multiplexing,VBLAST-OFDM)系统,以视频图像组(group of pictures,GOP)为基本单元,提出了一种传输优化策略。该策略首先根据GOP内各图像帧对视频恢复质量贡献的不同,对GOP内各帧进行不等重要性划分;进而根据系统带宽的限制,提出一种联合信源端视频编码器编码量化参数(quantization parameter,QP)和信道编码器端信道编码参数选择的不等差错保护(unequal error protection,UEP)方法,实现整个系统的传输优化。数值仿真结果表明:以峰值信噪比(peak signal to noise ratio,PSNR)作为衡量标准,与同等差错保护(equal error protection,EEP)相比,经过该策略优化后的传输方案使得接收端视频恢复质量具有明显的提升。

By analyzing the end-to-end distortion of H. 264/AVC video transmission over wireless channels,a transmission optimization strategy is proposed inside a group of pictures（ GOP） over vertical bell layered space time- orthogonal frequency division multiplexing（ VBLAST-OFDM） system. Based on the different contributions to the video decoding,the frames inside the GOP are divided into two parts of different importance,and further the combined selection of quantization parameter（ QP） at the source encoder and the channel code parameter at the channel encoder is made under the limitation of the system＇s bandwidth. Simulation results demonstrate that,in terms of peak signal to noise ratio（ PSNR）,utilizing the transmission optimization strategy,the video reconstruction quality can be promoted effectively compared with equal error protection（ EEP）.