A feedback-based adaptive multi-input multi-output signaling scheme

Achieving MIMO capacity requires knowledge of the channel state at the transmitter, which is impractical in systems with a limited feedback resource and high channel dynamics. The paper presents a feedback-based adaptive scheme utilizing a set of predetermined linear transformations. Given a channel realization, a transformation is chosen at the receiver based on an optimality criterion. The selected transformation is signaled to the transmitter with a minimum amount of feedback. We demonstrate that, with judicious choice of optimality criterion and transformation set, the proposed scheme provides 4.5 dB SNR gain over the open-loop MIMO scheme for a 2/spl times/2 scenario with only 2 bit feedback.