Research On Radio Resource Management In Hybrid Networks Based On LTE System

With the development of wireless communication,the demand for mobile data traffic is booming.However,the wireless services are provided with different kinds of UEs(User Equipment),by different types of base stations and different multiple access technologies.It brings about a lot of hybrid networks in LTE system under these multi-standard scenarios.For instance,the hybrid network of 3G and 4G,different release of LTE UEs,LTE UEs and D2D UEs,.Hybrid networks often cause low system performance for the interference among each other.Researches on the technology of wireless resource management in LTE hybrid network has gradually attracted people's attention.This thesis mainly focuses on the cases of different releases of LTE UEs and the hybrid network of LTE UEs and D2D UEs.In view of these two cases,the radio resource management problem,the establishment of the model,the optimization and the improvement plans,the simulation and the analysis of the results are presented.This thesis contains the following parts:1.This thesis studies the problem of dynamic slot adjustment that cannot be uniformed based on the hybrid network which is composed of two releases of LTE UEs.Due to the different periods of the two kinds of dynamic slot adjustment,the contradiction of the uplink and downlink scheduling is generated.In order to match the data service characteristics,this thesis present three algorithms of dynamic slot adjustment for two releases of UE.The simulation results show that the three algorithms can actually improve the overall performance of the hybrid networking system,which has great practical significance.2.This thesis analyses the hybrid networking scenario of LTE UEs and D2D UEs.With the introduction of D2D operating mode based on the LTE cellular mobile network,the coexistence of LTE UE and D2D UE is formed.The synchronization and demodulation process of D2D in the coexistence scenario is studied after this.Aiming at the synchronization process,the D2D identification delay detection algorithm is proposed firstly,moreover,in order to reduce the time delay,the suggested frame structure of D2D synchronous signal frame is designed based on the simulation.The simulation results show that the optimized sub-frame structure reduces the D2D synchronization identification delay.Then,the D2D measurement accuracy algorithm is proposed,and the D2D synchronization sub-frame structure is designed to carry the demodulation reference signal,and a D2D demodulation reference signal generation algorithm is implemented.Based on the reference signal of D2D demodulation process,the design and parameters of four kinds of D2D physical channels are analyzed and discussed.Finally,the simulation and comparison of different bandwidth,different frequency offset and different HARQ mechanism are carried out,and the optimization design of D2D physical channels is realized.