Socially Aware Trust Framework for Multimedia Delivery in D2D Cooperative Communication

The continuous advances in the storage and transmission capabilities of smart devices have made them possible to share multimedia services with each other through device-to-device (D2D) communications. However, when D2D users transmit multimedia services in manner of cooperative communications, the relay users with non-cooperative behavior may lead to a sharp decline in the quality of services for the receivers. In this paper, a socially aware trust framework for multimedia delivery is proposed to choose the trustworthy D2D cooperative users from D2D relay users. By considering the different D2D cooperative scenarios, the trust relationships of entities in the network are divided into two cases: capability trust mainly from base station (BS) to relay users and social trust from sender to relay users. In particular, capability trust is quantified based on the service capability of a user, such as caching capability, processing capability, and transmission capability, and social trust is obtained based on the historical interactive behaviors among users, such as cooperative behavior, altruistic behavior, and reciprocal behavior. By analyzing such two types of trust, the trustworthy D2D cooperative users are selected from relay users to support different cooperative scenarios. The numerical results verify that the proposed trust framework can effectively identify the selfish users and notably enhance the delivery efficiency of multimedia services, such as delay and delivery success ratio.