## FANDOM

186 Pages

The mathematical model of MIMO MAC is provided. In a MIMO MAC system with $N_r$ receiver antennas at AP and a transmit antenna for each user $k$ where $k=1,2, \ldots, K$, the channel of MIMO MAC can be described as

$\mathbf{y} = \sum_{i=1}^{K} s_i \mathbf{h}_i + \mathbf{n} = \mathbf{H}\mathbf{s} + \mathbf{n}$

where $s_i$ is the transmitted symbol for user $i$, $\mathbf{y}$ and $\mathbf{n}$ are the $N_r \times 1$ vector of received symbols and noise respectively, $\mathbf{h}_k$ is the $N_r \times 1$ vector of channel coefficients. Also, $\mathbf{H} = [\mathbf{h}_1, .., \mathbf{h}_K]$ is the concatenation matrix of the channel vectors for all users and $\mathbf{s} = [s_1, .., s_K]$ is the concatenation vector of the transmit symbols for all users.