Research On Mode Selection And Power Control Of D2D Communication

In recent years,the wireless communication technology develops fast.Due to the lack of spectrum resources,how to improve the utilization of spectrum resources in cellular networks has become an important research issue.Device to Device(D2D)communication technology can effectively improve the spectral efficiency of the system,and make the system get larger speed and capacity.However,the introduction of D2 D will also bring additional mode selection and interference problems to cellular networks.How to select communication modes effectively and reduce interference becomes more crucial to improve network performance.In this paper,D2 D communication in cellular system is taken as the research object.And two key technologies,mode selection and power control,are studied.Reasonable selection of user communication mode can improve the sum rate of the system and reduce interference.Firstly,the problem of power control is studied for users.In a single cell,the allocated resources and interference of users are analyzed.In order to increase system capacity and improve spectrum utilization,this paper focuses on the study of the interference problem when D2 D users share resources in dedicated mode.The same spectrum resources are pre-allocated to all dedicated mode D2 D users.Then the function of system sum rate is formulas are deduced.Binary power control is introduced to maximize the system sum rate,and open-loop power control and closed-loop power control are compared.For lower number of users,the simulation results show that the binary power control scheme can obtain optimal system sum rate.Secondly,three pattern selection algorithms are compared,which are distance-based pattern selection,SINR-based pattern selection and Hungarian algorithm.By deducing theoretical knowledge and analyzing simulation results,the advantages and disadvantages of three algorithms are compared.Combining mode selection algorithm with power control,a SINR-binary algorithm is proposed,which achieves the maximum system sum rate when the number of users is low,which has lower computational complexity and saves equipment overhead.A distance-closed-loop algorithm is proposed to allocate communication modes reasonably for D2 D users and maximize the system sum rate.