Neighbor discovery algorithms for friendship establishment in the social Internet of Things

In the Social Internet of Things (SIoT), objects establish social relationships to create a social network of devices that fosters inter-object communications by improving network navigability and trustworthiness evaluation. An important process of this model is the neighbors discover that should be implemented by each object to create new relationships. Differently from past neighbors discovery works, in the SIoT scenario, the devices need to discover each other when they are assumed to be already able to communicate to the Internet and additionally they do not have to set up direct device-to-device communications after the discovery. These aspects call for the definition of new algorithms, which are the major contribution of this paper. Specifically, three solutions are proposed: the first one relies on the channel scanning; the second one assumes that channel scanning is not possible and makes use of the device localization features; the third one is similar to the second one, but the already existing objects social network is exploited.