Incentive Mechanism and Relay Selection for D2D Relaying in Cellular Networks

The performance of the cell edge users (CUEs) can be improved if they transmit their data via suitable relay UEs (RUEs) exploiting device-to- device (D2D) communication. The critical aspect of the whole relaying concept is to offer convenient incentives for the RUEs to motivate them to act as relays. The contribution of this paper is twofold. First, we propose a new incentive mechanism for the RUEs that can exploit certain amount of resources allocated to the CUE. Depending on the preferences of users, the CUEs/RUEs can benefit from relaying in terms of capacity enhancement, reduction of energy consumption or both. In this respect, we provide a detailed analysis on how and when relaying is of benefit for both sides. Second, we propose a low-complexity greedy relay selection algorithm incorporating the incentive mechanism that increases capacity up to 32.1% and/or reduces energy consumption by up to 36.1% when compared to state-of-the-art schemes. Moreover, we show that the greedy approach gives close-to-optimal performance.