Guest editorial: Special issue on device-to-device service and network management for beyond 4G mobile networks

Device-to-device (D2D) communications refer to the technologies that enable devices to communicate directly without the intervention of a base station (e.g., eNodeB in LTE). D2D communication scenarios include public safety as well as proximity services, such as social networking and advertisement for by-passers. For cellular networks, D2D can improve spectrum utilization, offload traffic for the base station, and save energy of mobile devices. In Releases 12 and 13 of the 3rd Generation Partnership Project (3GPP), D2D is being standardized to support peer discovery and direct communication, which include peer synchronization and new channel definitions. However, research issues are not limited to the scope of such standards. For 5G networks, we need to tackle new topics of spectrum sharing, duplexing, interference management, and extension to vehicle-to-everything (V2X). The goal of this special issue is to present, exchange, and discuss the most recent advances in various aspects of the D2D solutions and provide non-precedent services to the end users with emerging technologies. The detailed topics of the special issue include D2D service architecture for 5G networks, D2D neighbor discovery, D2D radio resource