Radio Resource Management For Secured Device-to-Device Communications Underlaying Cellular Networks

Device-to-Device communication is a technology proposed in the LTE-A, which contributes to the development of the cellular networks. Device-to-Device communication have a good performance on improving the spectrum utilization, enlarging the cellular coverage and o?oading the Base station, which will effectively reduce the spectrum intension. Hence,Device-to-Device communication has gain a lot of attention. The recent works have focused on the mutual interference introduced by the reuse spectrum between the cellular link and the Device-to-Device link. They consider the mutual interference is the mere obstacle for Device-to-Device connection applied in the cellular networks. However, they neglect that Device-to-Device communication will bring in harmful interference to the secure communication of the cellular networks.This paper novelly jointly research the interference management and physical layer security in the Device-to-Device communication underlaying the cellular network.According to this aim, we assume that the Device-to-Device receiver will be the potential wiretapper trying to eavesdrop the cellular data. We respectively propose the optimal power control to optimize the overall sum-rate with restrain to the cellular data leakage and the optimal power control to optimize the secrecy capacity of cellular users with guarantee the Quality-of-Service of Device-to-Device link, thus reducing the harmful interference and guaranteeing the secure communication of cellular users.Firstly, we analyze how to maximize the sum of the cellular data rate and the Device-to-Device data rate when cellular data leakage is restrained. In order to guarantee the secure communication of cellular users and the Quality-of-Service requirement of the cellular link, we set the cellular rate bigger than the pre-defined threshold. The solution to this model can solve the interference management and cellular information inhibition. However, the objective function is non-convex. we propose a three-step scheme to solve the problem. We derive the admission region of Device-to-Device transmitter, where the leakage data rate to the Device-to-Device receiver is minimized and the Quality-of-Service of the cellular user can be satisfied. We derive the optimal solution in closed form to optimize the sum-rate, which can be used to analyze the character of the sum rate. We propose the Device-to-Device pairing policy to select the transmitter when more than one users exist in the admission region. Numerical results demonstrate that the proposed scheme can improve the system performance effectively.Secondly, we analyze how to the secrecy capacity of the cellular user when the Quality-of-Service requirement of Device-to-Device link is guaranteed. In order to guarantee the Quality-of-Service requirement of the Device-to-Device link and reinforce the effect of Device-to-Device signal as a friendly jammer, we give the Deviceto-Device data rate a lower bound threshold. The solution to this model can improve the cellular capacity base on the secure communication of cellular users. We propose a three-step scheme to solve this model. We propose the secure region to select cellular users, where the secrecy capacity of cellular user can be kept positive when sharing spectrum with Device-to-Device pair. We derive the optimal solution in closed form to optimize secrecy capacity of cellular users and to analyze the character of the secrecy capacity of cellular users. We propose the pairing policy for the cellular and Device-to-Device pair. Numerical results are conducted to evaluate the performance of the proposed scheme and verify the characterization of the secure region.Our work can be definitely extend to guarantee the physical layer security and reduce the harmful interference when random wiretapper tries to eavesdrop the data of the cellular user who shares spectrum with the Device-to-Device pair.