Research On System Structure And Key Technologies Of Dual Connectivity-based LTE-advanced System

In recent years,with the rise and development of the mobile Internet and the Internet of things,the demand for mobile broadband services is increasing.Therefore,the organization of 3GPP2 and 3GPP is gradually shifting to the next stage of LTE evolution.Some of the leading operators and manufacturers think that continue to study the deployment of low-frequency cell enhancement is no doubt important,but the performance enhancement technology research of higher frequency band small cell is more worthy of attention.Therefore,based on the deployments of small cell,3GPP proposed the Dual Connectivity architecture,in which a UE is simultaneously connected to both a Master eNodeB(MeNB)and a Secondary eNodeB(SeNB).The backhaul link between MeNB and SeNB is non-ideal and the RRC connection is maintained in MeNB and U-plane data can be transmitted from/to MeNB and SeNB.This thesis focuses on the architecture and key technologies of Dual Connectivity based LTE-Advanced system,including four aspects.Fistly,the thesis study the uplink control information transmission under Dual Connectivity architecture in which a shortened PUCCH format is proposed to transmit the ACK/NACK feedback for medium RF capability UEs in RF retuning subframe,Secondly,optimization for discontinuous reception(DRX)mechanism of Dual Connectivity is discussed to further save the tenninal energy.Thirdly,the thesis study the enhancement for the signaling of the interface between MeNB and SeNB to redece time delay and resource waste when SeNB can not transmit its downlink data.Finnally,technologies to deploy Dual Connectivity network in the unlicensed spectrum are studied to achieve friendly coexistence.Simulation and theoretical analysis results show that the proposed scheme can significantly improve the system performance of Dual Connectivity network.