discrete baseband channel model wrt time

Need to tweak the following Matlab code shown below for the following problem. The problem statement and physical model of the distance between the transmitter and receiver are shown below. This time I am plotting the discrete baseband channel model h0 vs time and sampling every 1 ms starting from 0 seconds which is where the receiver is stationary as shown below, and ending sampling time at 1s when the receiver will have traveled 20m further away from the TX. The receiver is travelling away from the transmitter at 72 km/h. The discrete baseband channel model complex channel filter tap at time m equation is shown below. The following values for the gain(a) and the delay(tau) are shown below. The Matlab code which is shown below was used when a plot of hl vs l with a range of l from -5 to 5 was considered. I need to tweak the code, so we are plotting h0 vs time starting from time 0s to time 1s. Thank you in advance!

a = lambda/4*pi*d = 3E8/100E3/(4*pi*20) = 11.94

tau = d/c = 20/3E8 = 66.67E-6

% Define the range of l values

l = -5:5;

f = 100000;

W = 200E3;

tau = [0.2387 4E-6 3.40E-6 3.667E-6 3.59E-6];

a = [0.2387 -0.2 -0.2341 -0.217 -0.222];

b = a .* exp(-1i*2*pi*f*tau);

% Compute the discrete baseband channel model h

h = zeros(size(l));

for idx = 1:length(l)

for i = 1:length(a)

h(idx) = h(idx) + (1i*a(i)*b(i)/W)*sinc(l(idx)-tau(i)*W);

end

end

% Plot the amplitude of h vs l

stem(l, abs(h));

xlabel('l');

ylabel('|h_l|');

title('Amplitude of the Discrete Baseband Channel Model');