Abstract :
Mobile data traffic, especially mobile video traffic, has dramatically increased in recent years with the emergence of smart phones, tablets, and various new applications. It is hence crucial to increase network capacity to accommodate these bandwidth consuming applications and services. Device-to-device (D2D) communication is a promising concept to improve user experiences and resource utilization in cellular networks, both for licensed and unlicensed spectrum. It enables two mobile devices in proximity of each other to establish a direct local link and to bypass the base station or access point. D2D communication may either be network-controlled where the operator manages the switching between direct and conventional cellular links, or the direct links may be managed by the devices without operator control. D2D allows combining infrastructuremode and ad hoc communication. Device-to-device communications may have advantages such as: 1) improved performance for devices; 2) improved spectrum reuse and system throughput; 3) offloading in cellular networks; 4) improved energy efficiency; 5) extended coverage; 6) creation of new services. It also poses new problems and challenges. A issue is how to share resources dynamically (e.g. spectrum and energy) between cellular communication and ad hoc D2D communication to accommodate larger volumes of traffic and to provide better service to users. Other challenges include: identification of services for which D2D communication is useful; radio resource allocation and resource management; self-organizing direct links; proximity-based offloading, and capacity evaluation and performance comparison. The special issue addresses research advances that enable D2D communications in cellular networks. The goal is to report on the most up-to-date contributions in this area.
