A major advantage of spread-spectrum communication systems is their ability to exploit the multipath structure of the received signal. Different paths can be charaterized by their time delays, attenuations, and angles of arrival. A 2D RAKE receiver can exploit the spatial properties as well as the temporal properties of the multipath environment using multiple element antenna arrays, so outperforms a standard RAKE receiver. With the 2D RAKE receiver at each stage, two parallel interference cancellation schemes are proposed. First, it employs the same beam former at the first and second stage. Second, the beam former at the second stage adapts itself to the incoming signal, so it can suppress MAI again which remain after cancellation at the first stage. The detectors are compared with the 2D RAKE receiver and it is shown by computer simulations that they improve BER performance and the multistage beam forming can mitigate MAI more effectively.
