# SNR of SIMO model

Here is my question regarding SNR of a SIMO model (one transmitter antenna and K receiver antennas):

$$\vec{y}_{K\times 1}=\vec{h}_{K\times 1}x+\vec{n}_{K\times 1}$$

In a Matlab simulation, if say, I want to simulate the system performance under SNR=10 dB and noise is (0,$\sigma^2$), the general process would be: assign a power, say 1, to $x$, then use given SNR=10dB to assign corresponding value to $\sigma$.

The code of $\vec{n}$ should be: Noise=sigma*randn(K,1).

Here is my confusion: when we say SNR=10dB, does it mean:

1) On each receiving antenna, $SNR= h^2_i/\sigma^2 =10dB$?

2) Or, totally for all receiving antennas, $SNR= ||\vec{h}||^2/\sigma^2 =10dB$?

3) Or, since every antenna has a copy of noise, $SNR= ||\vec{h}||^2/(K\sigma^2) =10dB$ ?

So which understanding is correct? If none of them is right, could someone explain to me about the correct way to do the simulation?