Multilevel Cross-Layer Feedback Based Adaptive Video Coding for Wireless Transmission

In this paper, a multilevel cross-layer feedback based adaptive video coding scheme is proposed to enhance the robustness of the wireless video transmission. Two level cross-layer feedbacks are developed in this work to achieve timely and accurate channel-aware: one is the feedback from physical (PHY) to applying (APP) layer, named PHY-APP feedback, which is used to get the available bandwidth of the physical channel using the feedback mechanism of adaptive modulation and coding (AMC); The second one is the feedback from data link (DL) layer to APP layer: an agent is deployed at the DL layer to predict the possible frame losses by analyzing the DL layer´s automatic repeat request (ARQ) , and then the frame losses information is sent to APP layer for proper reference picture selection (RPS). By exploiting the two-level feedback, the methods of rate control and RPS are combined to achieve channel-adaptive video coding. Experimental results show that: compared to the existed scheme without the multilevel feedback, the proposed method can get a significant improvement in Peak Signal-to-Noise Ratio (PSNR) for the wireless video transmission.