## FANDOM

186 Pages

The transmit beamforming technique in a wireless communication system is a beamforming technique applied to the downlink channel where the downlink is the transmission link from the transmitter to a single receiver or multiple receivers.

In order to describe beamforming process efficiently, we assume that the transmitter has $M$ transmit antennas and each receiver has a single antenna. The received signal at the receiver in the transmit beamforming system is modelled as

$\mathbf{x} = \sum_{i=1}^K \mathbf{w}_i s_i = \mathbf{W} \mathbf{s}$

where $s_i$ in $\mathbf{s} = [s_1, s_2, \ldots, s_K]$ is the message signal (chosen from a complex Gaussian alphabet with a constraint of power $P/M$) intended for the $i$th receiver and $\mathbf{w}_i \in \mathbb{C}^{M \times 1}$ in $\mathbf{W} = [\mathbf{w}_1, \mathbf{w}_2, \ldots, \mathbf{w}_M]$ is the corresponding beamforming vector.

$y=ax+b$