With the development of mobile communication technologies, there is an ever increasing demand for a bandwidth.  Since spectrum resources of mobile communications are limited, it becomes more important to effectively utilize the bandwidth. 
A D2D (Device to Device, device-to-device) system can provide services, such as information sharing, gaming, social interaction and mobile advertising.  The D2D device, as a broadcast node, broadcasts character string information so that its peer-to-peer device can know its identifying characteristic, service and content.  After the information is received, if there is a need to obtain more detailed information, the peer-to-peer device transmits “paging” signaling to the broadcast node, and the broadcast node directly establishes a connection with the peer-to-peer device after the signaling is received.  A local radio resource of the D2D system may be divided into 224 links, and each link is corresponding to a connection identifier.  The D2D device has a cognitive function, that is, it can autonomously perceive external environment, and perform autonomous resource management and configuration based on a perceived result. 
Currently, applying D2D communication technology in the cellular system can improve spectrum utilization.  For example, the D2D system can share the same resource with the cellular system by means of a sharing mode (Underlay), so as to improve the spectrum utilization.  However, the mutual switching between a D2D communication mode and a communication mode controlled by a base station have not yet been realized in the prior art, and thus spectrum resources of a cellular system cannot be utilized effectively.