how to act on a probability

I have a simulation for the Grade of Service of a circuit switched mobile network and I need to include how many calls get dropped I have the probabilities for each call and i need to find how many would be dropped in a given run of the simulation. I have no idea how to do this. are there any matlab functions built for realising a probability in a simulation?

Answer 1

[David Hill]

Just compare the array of probabilities of a dropped call to a rand uniform distribution array.

mu=.85;
sigma=.1;
p=mu+sigma*randn(1,1000);%load sample probability array of dropped calls
p(p>1)=1;

r=rand(1,1000);%generate randomn uniform array

nnz(r>p)%compare the two arrays, and count the number of instances.

[Walter Roberson]

Good point.

Answer 2

[Walter Roberson]

Well, there are two different approaches:

• you could calculate statistically, probability times number of calls, and round() or floor() or ceil() to get a integer. This assumes uniform random distribution; OR
• you could model time-step by time-step, creating new calls, hanging up existing calls normally, faulting existing calls. This might make it easier to model increased probability of dropping calls if the system is busier. You would have to decide whether the "hanging up" is processed before or after the "create new calls" since the creation of new calls needs to fail if you are over capacity.

The event modeling system is Simscape https://www.mathworks.com/products/simscape.html