This is an example of optimization model of energy efficiency 5G systems. Proposed Architecture is shown in "A Green Communication Model for 5G Systems" Link -https://ieeexplore.ieee.org/document/7918597. You can install IBM ILOG CPLEX Optimization Studio (Academic Version is free-of-charge.) (http://www-01.ibm.com/software/integration/optimization/cplex- optimizer)
You need two file: x.mod and x.dat file
Related Problem: https://www.youtube.com/watch?v=33NacILw1ug : shortest path problem https://ieeexplore.ieee.org/document/7117253