You should define the variables you are going to use as inputs of function. The inputs are written in the paranthesis.
All outputs must be assigned also.
function [o, a, b, c, d] = ObjectiveFunction(throughputS,throughputT,throughputCN,throughputCR)
o = 'Luna';
Then you call this function as follows in another function:
function hPlot = anotherFunctionToPlotSomeData(w,x,y,z)
[o, a, b, c, d] = ObjectiveFunction(w,x,y,z)
hPlot = plot([a,b,c,d]);
Also check below link to learn more about how to create functions: