Coordinated Mutiple Point Technique Inheterogeneous Lte-Advancedsystem

With the accomplishment of LTE standardization,3GPP started its research on key techniques of LTE-A system. Several key techniques are adopted in LTE-A to enhance transmission rate, frequency efficiency and cell edge user performance. Multi-layer network built with nodes of different transmission power can improve system capacity and coverage well, but addition of these nodes makes interference coordination even more complicated. CoMP (Coordinated multiple points) as one of the key techniques of LTE-A is an effective approach to mitigate inter-cell interference, to improve performance of both cell edge users and the whole network.Structure and key techniques of LTE-A are introduced at the beginning part. Then interference problems caused by addition of small power nodes are studied. To decrease inter-cell interference in heterogeneous network, CoMP transmission is utilized.In the research of CoMP, adaptive selecting coordinating points according to user locations is proposed first, which can improve frequency efficiency of cell edge users and the whole system simultaneously. As to resource allocation in CoMP, continuous and adaptive allocating strategy is used. In each scheduling period, every coordinating cluster dynamically adjusts resource allocated to cell edge users according to cell edge user ratio, which realized better resource allocation meeting real situations and enhanced system performance is achieved.In research of CoMP-MU-MIMO transmission, modification has been made to the pre-coding algorithm, and the improved algorithm makes more users capable of being paired, which brings larger performance gain. With comparison of different pairing algorithms, effective pairing method is chosen for CoMP-MU-MIMO transmission. As to CQI feedback, compensation is made at eNB to better improve system throughput.System-level simulation platform has been built, and several scenarios of different number of user and antenna in each sector have been simulated. Resultsverify the algorithms above and indicate that CoMP transmission can improve both performance of cell edge users and throughput of the whole system.