Offloading Multiple Mobile Data Contents Through Opportunistic Device-to-Device Communications

Opportunistic device-to-device (D2D) communication is the approach proposed to offload mobile data traffic for cellular networks. In opportunistic D2D communication, the network has to appoint relaying users to distribute content(s) to normal subscribers under a given delay-tolerance threshold. In general, the total number of relaying users is fixed. Identifying proper number of relaying users is one of the key challenges in opportunistic D2D communication. The network has to select proper number of relaying users for each content to minimize the amount of mobile data traffic. This paper presents a popularity-based relaying user selection algorithm to determine the number of relaying users for distributing multiple contents with different popularity. An analytical model is then presented to estimate the amount of reduced mobile data traffic under single-hop and multi-hop opportunistic forwarding scenarios. Results obtained by simulations as well as by our proposed analytical model show that the proposed popularity-based algorithm can find the total number of relaying users to the amount of reduced mobile data traffic. For services which have longer delay-tolerance threshold, the proposed popularity-based algorithm requires less relaying users and can achieve similar amount of reduced mobile data traffic as the state-of-the-art random fully-allocation algorithm does. For services which have shorter delay-tolerance threshold, the proposed popularity-based algorithm provide significant gain comparing with the random fully-allocation algorithm.