Abstract
We propose an optimal power allocation scheme that maximizes the achievable rate of device-to-device (D2D) communications in an OFDM-based cellular system. We first formulate an optimization problem under the condition that a D2D link intends to reuse the uplink resources of the cellular links. We then develop an efficient algorithm for computing the optimal solution to the problem. The performance of the proposed power allocation scheme is verified by presenting numerical results.