The Research On The Transmission Scheme In Multicell Multiuser Mimo System

With the development of wireless communication, traditional 2G mobile communication can no longer satisfy the transmission requirement. The new generation mobile communication systems, such as 3G, 3G LTE, IMT-A, are designed to achieving up to 100Mb/s~1Gb/s the transmission rate. MIMO as a efficient technique to improve the transmission quality, simultaneously provide the diversity gain and the spatial multiplexing gain, and optimize the diversity-multiplexing tradeoff. Point to point MIMO has matured, however the networking based point to multipoint MIMO and multipoint to multipoint MIMO are still have many issues for the further studying. On the other hand, full frequency reuse, though will bring the inter-cell interference which will affect the transmission rate of the communication system and the quality of service for users, is another efficient technique to improve the spectral efficiency. As a result the ICI problem becomes a key issue for the new generation mobile communication systems, and the inter-cell coordination as an effective technology for ICI issue becomes a hot spot.To solve the above problems, this thesis investigates the transmission strategy, and the multiuser scheduling and feedback that base on the transmission strategy, as follows:For the transmission strategy, the multicell downlink transmission schemes base on beamforming are studied. Coordinated beamforming based Signal-to-leakage and Noise Ratio and joint processing based Block Diagonalization are proposed. For the multiuser scheduling, the scheduling schemes of cell edge users in the multi-user environment are studied. Two scheduling schemes considering the fairness are proposed, which tradeoff the capacity and the fairness. The simulation results show that our schemes perform well.Finally, for user feedback, performance comparisons between frequency domain feedback and time domain feedback in multicell MIMO-OFDM system are studied. We propose the antenna decomposition and threshold feedback to improve the frequency domain feedback scheme. Simulation results show that the time domain feedback outperform the frequency domain feedback when users have single antenna. However, the frequency domain feedback performs better in multi user antenna case.