The next generation mobile networks will to provide faster and more efficient communication for more and more user, hence they need to take into account the possibilities of Device-to-Device (D2D) communication. Accordingly, the networks should support this kind of connection. In this Thesis, I study D2D communications underlaying a 3GPP LTE cellular network.
The power control is one of the most important functions in an interference-limited multiuser system. It enables the transmitters to achieve a balanced Quality of Service. The main subject of this Thesis is the power control in a network controlled D2D environment. This problem is more complicated, when the system operates with MIMO (Multiple Input Multiple Output), like in LTE. I introduce the Iterative Channel Inversion Power Control algorithm, which was presented in , that provides a suboptimal solution for this problem in efficient way. This algorithm was made for cellular case, but we can use it for D2D case too, with some modifications. The algorithm depends on strong conditions. I try to ease these conditions and observe the changes in the algorithm’s performance. Cooperation with Ericsson allowed me of improve their simulation software, which helps me to analyse the performance of the algorithm. We will see that the Device-to-Device communication provides better performance in many cases.