Study On Video Transmission Over Wireless Sensor Networks Based On Cross-Layer Optimization

Cross-layer design technology is an active research area in video transmission over wireless sensor networks. As an efficient way of optimizing traditional layered structure and improving flexibility of the network, cross-layer design is widely used in wireless sensor networks.The video encoding mechanism and frames mapping strategy are the research objectives in this study, and we choose simulation experiment based on NS2 as the research method. Firstly, we analyses the Quality of Service (QoS) enhancement of 802.11e protocol by providing different priority. After introducing the MPEG-4 video coding standard, we explain the different importance of video frames. Based on the above knowledge, the idea of cross-layer design between application layer and MAC layer is studied. Then two classical mapping algorithms using cross-layer design jointly concerning the importance of video frames and queue priority are introduced.In the course of studying cross-layer mapping algorithms, a novel adaptive algorithm named Dual Probability Selection Mapping Algorithm (DPSMA) is proposed. By changing the decision threshold adaptively and reducing the algorithm contingency effectively, DPSMA provides more flexible and fairer mapping strategy. For testing transmission of sole video flow and various flows over wireless sensor networks, both two nodes simulation and six nodes simulation topology are adopted for simulation using NS2.We compare the performance of proposed mapping algorithm with that of other algorithms. The results show that the proposed algorithm can achieve better performance in aspects of packet delivery fraction and Power Signal-to-Noise Ratio (PSNR) with acceptable end-to-end delay.