Many Community Collaborative Downlink Transmission Scheme And Resource Management Technology Research

In the International Mobile Telecommunications-Advanced (IMT-A) technologyspecification, higher data rates and larger spectrum efficiency is proposeded comparedwith the3rdgeneration communication networks, especially for cell-edge user spectrumefficiency. However, in Long Tern Evolution (LTE), the same frequency reuse leads toserious (Inter Cell Interference) ICI. In order to solve the bottleneck, CoordinatedMulti-Point transmission and reception (CoMP) is presented. The key idea was to letmultiple base stations transmit data jointly or coordinated for terminals, which caneffectively result in interference suppression and great spectrum efficiencyimprovement in cell-edge area. However, too much information exchange incurs heavyoverhead by CoMP technique, which comes at the cost of system overhead. The mainproblem of CoMP is a tradeoff between performance improvement and the requirementof feedback overhead, signal designing, feedback and processing delay. Of the solvingmethods, how to exploit precoding schemes with limited feedback is a key issue in thedownlink transmission of multiple cells. On the other hand, proper resource allocationthrough coordinated cell scheduling can effectively avoid the ICI.In this dissertation, we focus on improving spectral efficiency of the cell-edge userin multiple-cell system. Firstly, multiple cell coordinated precoding schemes areexplored from the aspect of receiving processing and quantinization feedback. And anovel coordinated beamforming scheme based on Quantized based Combining(QBC) indownlink CoMP is proposed. Then an overview of scheduling techniques based on theutility function is introduced. Further, an adaptive multiple user scheduling schemebased on utility maximization is proposed and the scheduling steps are presented. Theoverview for each chapter is summarized as follows.Chapter1introduces the research background of coordinated precoding techniqueand resource management in the downlink system, including technique definition,classification and the hotpoint of research field. At last, we show the research work wefocus on in the dissertation. In chapter2, based on the feedback mechanism in CoMP system, a novelcoordinated precoding based QBC technique is proposedThe key idea is to find thecodebook closest to the channel subspace, which will extend the traditional vectormatching to space matching, reaching to better matching accuracy. Further by numericalsimulation, we verify the proposed algorithm underdifferent feedback parameters.To fully improve the system performance and explore the resource in space, timeand frequency domain, in the third chapter, we extend the time-domain resourcescheduling to frequency and space domain. An adaptive multiple user schedulingscheme based on utility maximization is proposed and a precise expression ofmulti-user scheduling guidelines is derived. Combined with the derivation, simulationresults based on single and multiple cell condition are shownIt shows that the proposedscheme can both maximize the system utility and ensure user fairness.In chapter4, in order to evaluate the CoMP technique, system-level simulationplatform is designed and constructed in appendix. Then the coordinated beamformingscheme in downlink CoMP is evaluated based2D and3D antenna configurationscenarios respectively. Finally, the numerical simulation results show that CoMPtechnique can effectively improve the spectral efficiency in practical system deployment,compare with Non-CoMP scheme.In chapter5, the previous research work is summarized. The suggestions for futureresearch direction are also presented. System-level platform designed by Matlab software is outlined in the Appendix.