Optimal Multi-view Video Transmission In Multi-user Wireless Network With View Synthesis-enabled Multicast

With the development of wireless communication technology and the popularization of smart terminals,video-on-demand services face greater challenges.For example,user's demands for video have gradually changed from standard definition video to 4K video,from traditional video to immersive video,etc.These requirements lead to the majority of mobile data traffic on the Internet being video data traffic,and bring a heavy burden on wireless communication systems with limited spectrum resources.Multiview video(MVV),as a type of immersive video,allows user to choose freely among multiple view angles,hence enjoying immersive viewing experience.However,a MVV is in general of a much larger size than a traditional single-view video.Therefore,how to design an efficient multiuser MVV transmission system in wireless networks with limited bandwidth is an urgent problem.Although some literatures have proposed some strategies for efficiently transmitting multi-view video,they do not consider joint optimization of view selection and resource allocation.Therefore,we consider joint optimization of view selection and resource allocation in MVV transmission systems,and study the solutions in Time Division Multiple Access(TDMA)mode and Orthogonal Frequency Division Multiple Access(OFDMA)mode.The main contributions of this thesis are summarized as follows:First,we establish a mathematical model to specify view synthesis at the server and each user and characterize its impact on multicast opportunities.Note that this model is highly nontrivial and fundamentally enables the optimization of multicast opportunities.To the best of our knowledge,this is the first work providing an elegant mathematical model for specifying and controlling view synthesis at the server and all users.In addition,we establish TDMA-based and OFDMA-based MVV transmission models.Then,based on the TDMA-based transmission model,we formulate the minimization problem of the average weighted sum energy consumption and the maximization of the total utility of the system.For given video quality requirements of all users,we consider the optimization of view selection,transmission time and power allocation to minimize the average weighted sum energy consumption for view transmission and synthesis.In addition,under the energy consumption constraints at the server and each user respectively,we consider the optimization of view selection,transmission time and power allocation and video quality selection to maximize the total utility tge.These two optimization problems are challenging mixed discrete-continuous optimization problems.For the first problem,we propose an algorithm to obtain an optimal solution with reduced computational complexity by exploiting optimality properties.For each problem,to reduce computational complexity,we also propose a low-complexity algorithm to obtain a suboptimal solution,using Difference of Convex(DC)programming.Numerical results show the advantage of the proposed solutions over existing ones,and demonstrate the importance of the optimization of view synthesis-enabled multicast opportunities for MVV transmission in TDMA systems.Finally,based on the OFDMA-based transmission model,we formulate the minimization problem of the average weighted sum energy consumption and the maximization of the total utility of the system.For given video quality requirements of all users,we consider the optimization of view selection,transmission power allocation and subcarrier allocation to minimize the average weighted sum energy consumption for view transmission and synthesis.In addition,under the energy consumption constraints at the server and each user respectively,we consider the optimization of view selection,transmission power allocation,subcarrier allocation and video quality selection to maximize the total utility of the system.These two optimization problems are challenging mixed discrete-continuous optimization problems with huge numbers of variables and constraints and need jointly optimize two kinds of discrete variables(i.e.,view selection variables and subcarrier allocation variables).For each problem,we propose a low-complexity algorithm to obtain a suboptimal solution using DC programming.Numerical results show the advantage of the proposed solutions over existing ones,and demonstrate the importance of the optimization of view synthesis-enabled multicast opportunities for MVV transmission in OFDMA systems.