Trust-based and social-aware coalition formation game for multihop data uploading in 5G systems.

In this paper a trust-based coalition formation game is proposed to design opportunistic hop-by-hop forwarding schemes, relying on cellular Device-to-Device (D2D) communications, to enhance content uploading services. The User Equipments (UEs) are sources of data to be uploaded to a cellular base station (eNodeB) and are assumed to be rational self-interested players as they aim at maximizing their own utility. To this aim, the UEs cooperate to opportunistically implement proximity-based data exchanges where the presence of malicious nodes in the network is a constant threat for the successful cooperation. To cope with this issue, reliability and reputation notions are considered to model the level of trust among the players. Taking inspiration from the recent Social Internet of Things (SIoT) paradigm, social-awareness of the devices is spotted as a key parameter to effectively define the wished trustworthiness. The effectiveness of the proposed solution is validated through a simulative analysis showing a relevant reduction in the data loss due to malicious behavior of a subset of the devices. In particular, up to 86% reduction in terms of data loss is obtained with respect to the case where the proposed trust model is not implemented. Moreover, the trust-based and social-aware solution also guarantees higher gains in terms of the uploading time for the devices taking part of the cooperative D2D-based content uploading.