研究期間：10108~10207;This project references the specification defined in the 4G LTE-A system to study the channel capacity technology for high efficiency requirements of multiuser communications. Multi-antenna technologies are adopted to enhance the spectral efficiency and thus the high efficacy of multiuser communications. For LTE-A, multiinput multi-output (MIMO) is the main specification for the 4G evolution. Multi-antenna is employed for the MIMO in downlink where single antenna, two antennas, and four antennas are supported. Moreover, eight antennas can also be provided with the help of introducing the smart antenna’s application. Since our project focuses on the 4G heterogeneous networking technology with multi-antenna, there are two main topics in our research: one is the Precoder MIMO technology. We study the limited feedback method in the precoding system to reduce the information required for the return-channel. The specific interpolation scheme used in codebook is concerned to implement the channel pre-equalization through pilots at the transmit side. The other is the smart antenna technology in which we study some advanced adaptive algorithms such as Kalman filtering or particle filtering to improve the GSC method for more accurate results to reduce the interferences coming from pico networks. We hope the results obtained from this project can achieve much better performance compared to the existing methods in the literature.