The Research Of Interference Coordination For D2D Communications Underlaying LTE-A Cellular Network

With the development and evolution of cellular communication system, especially after the put forward of LTE-A standard, the requirements of Channel bandwidth, spectrum efficiency, transmission quality and transmission delay has grown to a new level. But under the heavy load, the cellular system with the core of base station is facing severe challenges. Now the D2D(Device-to Device) technique with the advantage of high frequency spectrum utilization and high transmission rate shows up, this technique brings us new train of thought to solve the problem of spectrum resource scarcity and break through the choke point of transmission rate. The D2 D communication technique allows UEs to communicate with each other directly without the relay of base station in a certain distance. So it can reduce transmission delay. It can also improve the spectrum efficiency by reuse wireless resource of cellular system. But it brings interference to system at the same time, if not take care of it, the interference will disturb the performance of hybrid system.In this paper, I have done a lot of research of LTE-A and D2 D hybrid communication system, analyzed the interference of the system by system modeling and summarized the main factors that related to the interference. Then put my hand to control the interference from the point of resource allocation and power control. The main works of this paper are as follow:1) In order to increase the distance of UEs that have interference, take ICI into consideration, I analyzed the shortcoming of ILA resource allocation algorithm and improve it, put forward the new DILA resource allocation algorithm.2) In order to control the transmission power of UEs that have interference, I analyzed the shortcoming of closed loop power control algorithm and improve it, put forward the new dynamic compensating factor algorithm.3) Improved the LTE-A system level simulation platform, added the D2 D protocol stack module, built the D2 D and LTE-A hybrid network system level simulation platform. Then simulate the resource allocation and power control algorithm, prove the fact that the new algorithm can improve system performance.