Collaborative Scheduling And Interference Suppression In Multi-cell Mimo System

In the configuration of LTE-A multi-cell with spectrum reuse factor of 1, the co-channel interference is one of bottlenecks for enhancing the system performance, while coordination of multi-cell is an effective way to counteract this impact. Comparing with the traditional multi-cell interference mitigation technologies in LTE, we should put more attention to cooperative multiple BS, data jointly processing and the compatible of developing of mobile communication network in multi-cell coordination. The technologies of multi-cell coordination can change the interference into useful signal effectively, extend the coverage of signal without increasing the time/spectrum, mitigate the interference of inter-cell especially the UEs those locate at the edge of cells and enhance the system performance. Thus in recent years, multi-cell coordination technology is concerned by communication circle in every possible way, among them, coordinated scheduling and joint transmission in multi-cell system both become the research hotspots. In this dissertation, we mainly investigate the coordinated scheduling and joint transmission in multi-cell coordination system.In chapter two, some essential conditions of multi-cell coordination are introduced. Firstly, the presentation of precoding technology can be used as the basis of later joint transmission research. Secondly, we introduce the multi-cell model construction based on SCM channel, and this model can be used as the simulation platform of coordinated scheduling and joint transmission schemes. Thirdly, we do the comparison of recent multi-cell coordination technologies and enumerate some interference mitigation schemes in LTE traditional multi-cell.In chapter three, we study the BS and UE scheduling in multi-cell system. Firstly, the topology of coordinated multi-cell and signaling transmission mechanisms are formulated. Secondly, a BS scheduling scheme based on judge threshold is proposed, and the simulation results shows that the complexity of composing cooperative multi-cell can be decreased extremely while holding the system performance. Thirdly, we investigate the UE pairing methods to compose the V-MIMO in the uplink system; the simulation results shows that there is a compromise between the UEs'fair and system capacity, and it should be considered in the implementation of specific schemes. In chapter four, we study the joint transmission schemes under the multi-cell coordination mechanisms. Firstly, some joint transmission schemes based on precoding are formulated, the system performance is compared by simulating these schemes and some determinable analysis of implementation complexity is given. Secondly, a power allocation scheme based on Nash equilibrium theory is proposed, it can find the maximal capacity in local area by iterating the power upward/downward; this scheme can be combine with the BS scheduling which mentioned in chapter three to enhance the system performance more. Thirdly, neither to divide spectrum /fixed transmission nor to judge the location of UEs, thus to confuse the cell boundary, a data transmission model decision method based on UE SINR feedback threshold is also proposed. The simulation results show this method can change the interference to useful signal effectively and enhance the communication quality of UEs which locate the cell edge.Finally, some conclusions of the dissertation are drawn, and the further research issues are pointed out.