Invariant productive transmit dimensions

In this paper, a subspace approach to the identification and use of invariant productive dimensions (beam patterns) at the transmitter in MIMO channel is presented. It is proposed that data is transmitted independently in these dimensions. The results of simulation shows that these solutions not only reduce the feedback rate in the use of perfect channel gain estimates at transmitter but also enhances channel capacity by comparing with the case where the transmitter sends data in the strongest dimension