Simple adaptive partial feedback method for full multiple-input multiple-output channel estimation

Partial feedback in multiple-input multiple-output communication systems provides tremendous capacity gain and enables the transmitter to exploit channel condition and to eliminate channel interference. In the case of severely limited feedback, constructing a quantised partial feedback is an important issue. To reduce the computational complexity of the feedback system, this study introduces an adaptive partial method in which at the transmitter, a set of easy to implement least-square adaptive algorithms is engaged to compute the channel state information. In the proposed method, at the receiver, the time-varying step-sizes of the algorithms are computed and replied to the transmitter via a reliable feedback channel. The transmitter iteratively employs this feedback information to estimate the channel weights. This method is independent of the employed space-time coding schemes and gives all channel components. Complementary solution is given to reduce the computational complexity and simulation examples are given to evaluate the performance of the proposed method.