Joint Channel Allocation, Mode Selection and Power Control in D2D-Enabled Femtocells

Femtocells and the device-to-device (D2D) communication can improve the system capacity in heterogeneous networks. To mitigate the interference caused by users in femtocells and improve the uplink capacity of femtocells, we investigate the users' uplink capacity maximization problem in D2D-enabled femtocells with channel allocation, mode selection and power control. Considering the rate requirement of cellular users and D2D users in femtocells and the interference limit of users served by the macro base station, the problem is formulated as a non-convex mixed integer optimization problem which is difficult to be solved directly. Firstly, the problem is transformed into a convex problem with the channel allocation variable relaxed. Then the dual decomposition method is utilized to solve the transformed problem. Numerical results confirm that the proposed method can enhance the uplink capacity of femtocells significantly.