Analysis of PHY/application cross-layer optimization for scalable video transmission in cellular networks

We investigate the optimization of video transmissions over cellular networks by using the H.264 Scalable Video Coding (SVC) at the application layer and an Adaptive Modulation and Coding (AMC) scheme at the physical layer. We analyze how the cross-layer optimization (XLO) of these two techniques together performs compared to a sequential and independent selection of video packets and Modulation and Coding Schemes (MCS) with no cross-layer optimization (NXLO), in terms of goodput and packet delivery delay. We formulate an analytical model based on a Markov chain representing the wireless channel, where each state is associated to a different channel quality corresponding to a set of possible choices of video layer and MCS. Our numerical results show that XLO significantly outperforms NXLO for video transmissions, thereby pointing out the strong need for cross-layer solutions in video transmission.