Communication through BS suits conventional low data rate mobile services such as voice call and text messaging in which users are seldom close enough for direct communication.
However, mobile users in today's cellular networks use high data rate services (e.g., video sharing, gaming, proximity-aware social networking) in which they could potentially be in range for direct communications (i.e., D2D).
Hence, D2D communications in such scenarios can greatly increase the spectral efficiency of the network.
[1][2] Existing data delivery protocols in D2D communications mainly assume that mobile nodes willingly participate in data delivery, share their resources with each other, and follow the rules of underlying networking protocols.
Nevertheless, rational nodes in real-world scenarios have strategic interactions and may act selfishly for various reasons (such as resource limitations, the lack of interest in data, or social preferences).