How to get a Rician fading channel matrix from a Rayleigh fading channel matrix? I have a Rayleigh fading channel matrix H. Let's say the dimension is 2000*128. Is there any way to convert this matrix into a Rician fading channel matrix for example κ = 5, 10, 15, etc.? Is there a formula for that?
A Rician fading  channel is just a Rayleigh fading channel with a specular (that is, unfaded) signal component.  Depending on what exactly you mean by the  Rayleigh fading channel matrix $H$, the answer could be as simple as changing the distribution of each element of $H$ from a complex zero-mean proper Gaussian random variable to a complex Gaussian random variable with mean of the form $A_{m,n} \exp(j\theta_{m,n})$.