The works in [11, 13] proposed three relay selection algorithms based on the maximum channel gains, the maximum harmonic mean of the channel gains, and the detection mean square error (MSE).
Let us define ρ mi as the channel power gains of each link comparatively to the maximum channel power gain.
To enhance the secondary transmission, it is feasible to select the antenna with the maximum transmission channel gain between ST and SR [18], which is denoted as transmission channel gain maximum (TRAM -based meTRAM -based
At first, we select one user and its analog beam which provides the maximum effective channel gain among (Ktimes N_{text {user}}^{text {BSS}}) possible effective channels, which can be expressed as (i,mathbf{x}_{i})=argmax_{left kinOmega,mathbf{c}_{n}inmathcal{C}right)} left|mathbf{h}_{k}^{text{eff}}left(mathbf{G}_{m},mathbf{c}_{n}right)right|^{2}.
Hence, given the system load the maximum possible power index a user can accept in (15) is determined by the maximum transmit power and the channel gain.
It is worth noting that since each channel gain can range from zero to a maximum value, our formulation is similar to compound channels [26, 27] with one major difference.
The proportional fair algorithm (see, e.g., [9]), where all the resources are allocated to the flow with the maximum ratio of instantaneous spectral efficiency (which depends on the channel gain) to the average rate, has been analyzed in [10 14].
According to the ITU test environments [25] and the related introduction in [3], the system bandwidth B = 10 MHz, the maximum transmit power P max t = 15 W, and the channel gain γ = 10 dB) in the simulation.
In single stream multi-user eigenmode transmission, the receive antenna combining weights G u,i are computed such that the effective channel is in the direction of the maximum singular value of the channel matrix H u,i [22], thereby maximizing the effective channel gain g u, i = argmax g ∈ ℂ M u, i g H H u, i 2, subject to: g 2 = 1.
