Effective Collaboration to Maximize Throughput Based on Multiuser Cooperative Mobility in Social-Physical Ad Hoc Networks

Social networks are playing an increasingly important role in information dissemination in wireless ad hoc networks with the wide adoption of the mobile Internet. In particular, in social application scenarios such as Facebook and Twitter, the questions of how to fully consider the social relationships between users to ensure the quality of service (QoS) urgently needs to be explored. This paper investigates an optimal social relay selection scheme with high intimacy requirements to maximize the system throughput for social-physical ad hoc networks with device-to-device (D2D) communication. Different from previous studies, we jointly consider feasible relays and multiuser cooperative mobility with satisfactory link reliability for throughput maximization. On the one hand, we formulate a nonlinear and nonconvex problem, which is typically NP-hard, for throughput optimization. Specifically, this optimization problem is divided into two subproblems: i) selecting the optimal relays and ii) determining the best mobility strategy in terms of throughput. On the other hand, we first convert the relay selection subproblem into an optimal stopping phase problem, and then propose a definition of a graph representing the degrees of interference between physical links, transforming the original optimization problem into a convex problem that is solvable using the Lagrange multiplier method. Based on the above, we propose the Relay selection and Link Interference Degree Graph (RS-LIDG) algorithm to solve the two subproblems. Numerical simulations verify that the proposed RS-LIDG method improves the throughput gain by 26.29%, 123.43%, and 236.47% compared to the intuitive method (IM), the social-trust-based random mobility selection method (STS-RM), and the physical-based random mobility selection method (PHS-RM), respectively.