Optimal Multi-View Video Transmission in Multiuser Wireless Networks by Exploiting Natural and View Synthesis-Enabled Multicast Opportunities

Abstract

Multi-view videos (MVVs) provide immersive viewing experience, at the cost of traffic load increase for wireless networks. In this paper, we would like to optimize MVV transmission in a multiuser wireless network by exploiting both natural multicast opportunities and view synthesis-enabled multicast opportunities. Specifically, we first establish a mathematical model to specify view synthesis at the server and each user, and characterize its impact on multicast opportunities. This model is highly nontrivial and fundamentally enables the optimization of view synthesis-based multicast opportunities. 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. 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. Finally, 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 in MVV transmission.Index Terms-Multi-view video, view synthesis, multicast, convex optimization, DC programming.

Optimal Multi-View Video Transmission in OFDMA Systems

“…First, we established a communication model for transmission 3 We omit the detailed view request model due to page limitation. Please refer to [6] for details. of an MVV to multiple users in an OFDMA system.…”

“…(x, y) are referred to as view selection variables [6]. Because of the coding structure of MVV, the values of (x, y) cannot be changed during the considered time duration.…”

“…where n 0 is the complex additive white Gaussian channel noise power for each subcarrier. Note that the communication model for transmission of an MVV to multiple users in an OFDMA system is more complicated than that in a TDMA system [6]. Let E b and E u,k denote the energy consumption for synthesizing one view per time slot at the server and user k, respectively.…”

“…Suppose that views are randomly requested by the K users in an i.i.d. manner, as in [6]. 3 100 realizations of r k , k ∈ K and 500 realizations of h are randomly generated.…”

“…As view synthesis and multicast opportunities are not considered, the proposed solutions in [1], Manuscript [2] cannot be directly extended to multiuser wireless networks. In [3]- [6], MVV transmission in multiuser wireless networks is studied. To reduce energy consumption, [3]- [6] propose transmission mechanisms which can exploit natural multicast opportunities.…”