Research On IDMA Systems Based On Universal Filter Multi-Carrier

New types of communication,such as Internet of Things(IoT)and Machine Type Communi-cation(MTC),will play an important role in the era of the Fifth Generation Mobile Communica-tion(5G).To support burst short packet transmission that frequently appears in IoT and MTC,new air interface technologies are required in 5G to meet the demand of the system.Universal Filtering Multi-Carrier(UFMC)technology uses sub-band filtering to obtain better ability to resist inter-carrier interference than Orthogonal Frequency Division Multiplexing(OFD-M).In addition,UFMC filters each group of sub-carriers,while Filter Bank Multi-Carrier(FBMC)need to filter each sub-carrier.So the length of filter being used in UFMC is short and it is possible to maintain high transmission efficiency in short packet transmission.Interleave Division Multi-ple Access(IDMA)technology takes the interleavers as the key feature to distinguish the users and can accommodate a large number of users for information transmission simultaneously.As the detection complexity of IDMA is linear with the number of users,it allows numerous users to transmit information with low detection complexity.Therefore,the combination of UFMC and IDMA technology can meet the requirements of specific application scenarios in 5G.The research of this thesis is carried out on the UFMC-IDMA system.Multiuser detection algorithm is the key technology of the UFMC-IDMA system.In terms of multiuser detection algorithm in the UFMC-IDMA system,this thesis firstly studies the mul-tiuser detection algorithm without Carrier Frequency Offset(CFO)and shows the advantages of the UFMC-IDMA system through simulations.Then,the influence of CFOs on the UFMC-IDMA system is analyzed from the perspective of multiuser detection algorithm.For the cases that the users are affected by the same CFOs and different CFOs,we propose the corresponding multiuser detection algorithms which can eliminate the effect of CFOs.In the former condition,impact is eliminated by the pre-compensation of CFOs.And in the latter condition,CFOs are considered in multiuser detection.In this way,we can achieve accurate estimation and eliminate the influence of CFOs.Finally,as the multiuser detection algorithm for the UFMC-IDMA system with different CFOs has relatively high complexity,we also develop an approximation algorithm to reduce the system complexity,which estimates the noise term by selecting a small number of effective values.We can reduce the complexity of the algorithm while keeping the system performance not to be significantly degraded by choosing appropriate number of the effective values.To further reduce the complexity of the system,this thesis presents and explores the UFMC-IDMA system based on user grouping.After outlining the concept of user grouping,this thesis proposes the system model of the grouped UFMC-IDMA system.Then,the efficiency and com-plexity of the system are discussed and the simulation results show that the proposed scheme can reduce the system complexity with constant system efficiency.Furthermore,the grouped UFMC-IDMA system is extended to the case of multi-antenna reception to increase the diversity order of the system.A new multiuser detection scheme based on outer information merging technolo-gy for the multi-antenna receiving system is proposed.Simulation results indicate the significant advantages of the grouped UFMC-IDMA system with multiple receiving antennas on system per-formance improvement.Furthermore,in order to effectively suppress the interference between adjacent sub-bands used by users of different groups and enhance the robustness to CFOs of the system,this thesis proposes an inter-group interference cancellation scheme based on Active In-terference Cancellation(AIC)technology for the grouped UFMC-IDMA system,which reduces interference to adjacent user groups by setting interference canceling sub-carriers on both sides of each sub-band.The validity of the proposed scheme is verified by simulations.