Research On Power Allocation And Relay Selection Algorithm In D2D Systems

Recentlya technology without the assistance of basestation called Device-To-Device(D2D) has attracted lots of attention,D2D has been considered as the prominsing scheme of enhancing the LTE system.Meanwhile D2D(Device to Device) technology is considered to be one of the key technologies in 5G wireless communication system,since it has several advantages over the traditional cellular network with low end to end latency and high spectrum efficiency.D2D introduced into the LTE cellular communication system are able to significantly improve the spectrum utilization and total capacity of the cellular and D2D hybrid system,which leads to much more complex mutual interference problem. This paper proposes a power allocation algorithm with the target of maximizing the total capacity of hybrid network.The optimal power solution is derived by the Lagrange method.In view of the optimal power allocation, based on the hybrid network system to maximize the total capacity as the optimization goal,compared with the traditional average power allocation algorithm, this paper proposed algorithm can reduce the interference of cellular link at the same time, significantly improve the D2D and cellular subscribers hybrid network system composed of the total capacity.D2D communication system for introduction of relay nodes, based on the interference and lower the original cellular link to the user of the hive to interference from the D2D relay link control in a certain range at the same time, to maximize the D2D relay link in hybrid network capacity as the optimization target, this paper proposes a relay selection algorithm in the D2D communication system and power allocation algorithm is proposed.It can maximize the D2D link throughput as the optimal relay relay node, and using the method of Lagrangian multipliers convex optimization allocation of each sending node on the D2D link to send power, the simulation results show that compared with traditional algorithm, this paper puts forward the relay selection algorithm and power allocation algorithm can reduce in the cellular link on the D2D relay link interference at the same time, which can improve the capacity of the D2D relay link.