Research On Concurrent Transmission Technology For Dual Connectivity Network

With the development of communication technology and increasing demand for wireless traffic,the future wireless communication networks have some high requirements for high bandwidth and low latency.The dual connectivity network proposed in the 3GPP release 12 supports user equipment(UE)to connect simultaneously to a master e NB(Me NB)and a secondary e NB(Se NB),which can effectively increase the communication bandwidth and support user mobility.However,since the e NBs are connected by non-ideal backhaul link in dual connectivity network and the differences between the two wireless channels always exist,complicated flow control and split strategies are necessary for Me NB and their may have some outof-order packet delivery problem at UE.In the dissertation,we firstly study raptor codes assisted concurrent transmission in dual connectivity network to address the problems above.Besides,considering the support for mobility of UEs by dual connectivity,we further study the concurrent transmission scheme of dual connectivity network in the vehicular network,which can enhance the robustness of the communication and reduce the transmission delay during handover events.The main contributions of this dissertation are summarized as follows:Firstly,with the studies the shortcomings of the traditional dual connectivity network,we analyze the problems existing in the downlink transmission of the 3C alternative in user plane of dual connectivity network.Aiming at the complex signaling control and the extra delay for out-of-order delivery problem,we propose a solution based on raptor codes.The data is encoded by using raptor codes technology and the encoded packets are forwarded by Me NB and Se NB respectively.Due to the unique feature of the raptor codes,UE only need to receive enough encoded packets to successfully recover the original data.The out-of-order problem can be effectively eliminated and no complicated signaling is needed between two e NBs since the received packets are independent of the order.Theoretical analysis and simulation results are provided to illustrate the performance of our proposed scheme.Secondly,considering the support of the mobility with dual connectivity network,the dissertation studies the dual connectivity network in vehicular networks.We first analyze the network delay in dual connectivity network considering the frequent handover events for Se NBs.Furthermore,we apply the raptor codes based dual connectivity network,providing the enhanced handover procedure which can effectively reduce the transmission delay of the handover.We use queuing models to describe the network delay in both two scenarios.Numerical analysis and simulation results are provided to prove the adaptation of two schemes.Finally,in order to meet the requirements of low energy consumption for e NBs and low latency for UE,the dissertation provides an optimal solution between the network delay and energy consumption in vehicular network.By optimizing the effective communication range of e NBs,we can find the balance between the network delay and energy consumption which can realize an optimal communication condition,which can reduce the energy consumption with a slight loss of network delay.The dissertation provide the theoretical analysis and the simulation to evaluate the effectiveness of this solution.