The investigation of power control schemes for a device-to-device communication integrated into OFDMA cellular system

Power control is one of the key functions which are able to co-ordinate the system interference. In this paper, several power control schemes are investigated for a hybrid LTE system, which combines the direct device-to-device (D2D) mode communication and the normal cellular mode communication. In the system study, the power control for the D2D mode communication is emphasized. In general, the utilization of local area transmission for D2D communications provides a better SINR than normal cellular communications. In this case, the proper power control for D2D communications can be a flexible way to improve (and balance) the overall system performance. Naturally, the low power transmission of D2D communications leads to many potential advantages, such as low interference level (to normal cellular users) and low power consumption. From the power control point of view, the low power transmission provides more freedom to tune the Tx power. However, power control is not an efficient solution to avoid the strong mutual (co-channel) interference between different types of UEs. In this case, the join consideration of mode selection, resource scheduling, link adaption and power control is needed.