As a new fixed broadband wireless access technology, Local Multipoint Distribution System (LMDS) not only provides economical, fast and high-capcity two-way data transmission for network service providers, but also provides simple and convenient solutions for "last-mile" broadband access and interactive multimedia applications for operation providers. However, LMDS system works in frequency bands about 30GHz so that it is severely attected by the obstacles, such as trees and buildings, and suffers from rain attenuation especially. The quality of services will be satisfying only when there is a line-of-sight path during the transmission. In this thesis, based on reviewing the various existing methods to resist the effect of rain attenuation, a new compensative solution of rain attenuation is proposed using Multiple-Input Multiple-Output (MIMO) antenna technology. This solution can make effective use of array gain and multiplexing gain of MIMO systems without requiring additional power or bandwidth, so that the line reserve of LMDS systems is significantly increased and the ability to compensate rain attenuation is improved. In a word, LMDS systems with the proposed multiantenna solution will be highly robust and available.