Research On New Multicast Solutions Combining 5G Key Technologies

In the coming 5G era,mobile data traffic is expected to be larger than in the 4G era,which places higher requirements on transmission technologies.Multimedia Broadcast Multicast(MBMS)is a technology proposed in Long Term Evolution(LTE)that can effectively save wireless communication related resources.It realizes the conversion from point-to-point low-efficiency transmission to point-to-multipoint high-efficiency transmission..MBMS divides users into multicast groups in wireless cells,and the base station sends data to all users in the multicast group at the same data rate,achieving resource sharing and improving resource utilization.Although MBMS consumes less system resources,it also faces the problem of the balance between user fairness and throughput.In view of the shortcomings of traditional multicast throughput,hierarchical multicast technology has been evolved in the future,and multicast groups will continue to be divided.Form multiple sub-multicast groups,each of which has different quality of service requirements for users.At the same time,the multimedia data stream is divided into multiple subdata streams according to the number of multicast groups.This solution further improves the throughput of the multicast group,but Spectrum resource utilization is not high.The thesis first introduces the basic theory of LTE resource scheduling,MBMS basic theory and cooperative transmission technology,and then analyzes several classic multicast,layered multicast,and cooperative multicast schemes,and points out that traditional schemes play a role in user fairness or system throughput.There are some problems.In response to such problems,the paper introduces NOMA technology and proposes a new relay scheme,forming a new NOMA based two-phase cooperative multicast model,the NNDRCM scheme.This scheme first ensures that the base station is continuously working,and uses the two relays innovatively.Performing the NOMA signal forwarding improves the working efficiency and resource utilization of the base station.Users in the edge multicast group obtain a large throughput and fairnessgain between the multicast users.In order to solve the interference caused by relay forwarding in the traditional cooperative layered multicast system to improve the reception reliability of users in the enhanced layer,the paper introduces Cache technology and proposes a new two-stage based on cache and NOMA The cooperative layered multicast system is the NCLMBCN scheme.This scheme uses the cache accompanied by the user and the relay to eliminate interference caused by relay forwarding,and improves reception reliability of users in the enhanced layer.This scheme further improves the relay cooperation scheme,further improves the throughput of users in the base layer,and further improves the overall performance of the system.In order to verify the proposed scheme,the paper analyzes cooperative multicast schemes from the aspects of user fairness and throughput gain,and uses traditional multicast,layered multicast schemes and existing cooperative multicast,cooperative layered multicast schemes.As a comparison object,simulation results are obtained through the LTE system-level simulation platform.The results show that the scheme NNDRCM greatly improves the throughput of the celledge users and fairness of users;and the scheme NCLMBCN can improve the reliability of the reception of the users in the enhancement layer while improving the throughput of the edge users,thereby obtaining Improvement in overall performance.