Research On D2D Interference Coordination Algorithm Based On Multiplexing Mode Selection

Nowadays, with the advancement of communication technology and the increasing number of mobile communication terminals, the distributable cellular spectrum resources have been shorten seriously. In response to this situation, all kinds of technologies about improving the spectrum efficiency have been introduced into research agenda, including Device-To-Device(D2D) communication. As an important supplement of traditional cellular system, D2 D communication is an important LTE-A technology that two communication terminals can transmit directly in case of short distance, instead of relying on the data transforming by the base station.Compared with conventional communication of base station relaying, the decreasing of communication links makes D2 D technology significantly improve the spectrum efficiency.Before D2 D communication is set up, D2 D users could be allocated cellular or dedicated spectrum resources. Reusing cellular resources by D2 D users will cause the harmful interferences to the cellular system. Interference coordination technology is the critical technology of D2 D and its study is of great significance. To deal with the interferences problem, this thesis highly focuses on interference coordination algorithm.By analyzing the researches of typical interference coordination algorithms, we found that most researches only focus on one or two aspects of interference coordination which includes mode selection, resource allocation and power control, instead of joint consideration.But the performance of interference coordination of D2 D communication needs the combination of mode selection, resource allocation and power control to get better. To solve this problem, this thesis studies an algorithm that joint mode selection, resource allocation and power control based on the information of users' locations, which is the first innovation point of this thesis. In order to verify the feasibility of the purposed algorithm, we exploit the LTE-D2 D simulation platform based on Matlab. The results of simulation show that the purposed algorithm can effectively coordinate the interference between the D2 D users andcellular system, improve spectrum efficiency and total throughput.Further, in order to solve the actual problem of inadequate cellular spectrum and enable the connection between D2 D users and the cellular network as much as possible, this thesis puts forward an interference coordination algorithm based on the mode selection of resource reuse, which is the second innovation point of this thesis. This algorithm combines the reuse mode of multiple D2 D pairs reuse one cellular user's resources and one D2 D pairs reuse one cellular user's resources, called many-to-one and one-to-many reusing mode. The criterion of mode selection is given first, then the grouping strategy of D2 D users which are in the many-to-one reusing mode. Eventually, in order to set up connection the D2 D groups will be allocated the appropriate cellular resources and dynamically adjusted their transmit power.The simulation results show that even in the inadequate spectrum resources circumstances,the proposed algorithm still makes D2 D links successfully connected to the network as many as possible, and also further enhance cellular spectrum utilization.