Simulating a MIMO Ring Model

A Ring Model is a well known spatial channel model. It models the propagation channel as an unobstructed transmitter and a receiver surrounded by a ring of reflectors. The distance between the transmitter and receiver is usually much larger than the radius of the ring. The reflectors are distributed uniformly around the ring. This model is useful for modeling a scenario where a base station is located at sufficient altitude and is unobstructed whereas the mobile station is at ground level and is surrounded by a bunch of reflectors.

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function [Et]=ring_mod2(d,r,psi,l,B,alpha,a)
Et=0;
for phi=0:pi/4:(2*pi)-(pi/4);
R_=sqrt((d-l*cos(psi)-r*cos(phi))^2+(r*sin(phi)-l*sin(psi))^2);
r_=sqrt((r*cos(phi)-a*cos(alpha))^2+(r*sin(phi)-a*sin(alpha))^2);
E=exp(-i*B(r_+R_))/(r_+R_);
Et=Et+E;
end
return
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