OFDM resource allocation using Genetic Algorithm

Hi I'm trying to apply resource allocation for a cell with OFDM resource blocks. I have for each cell a 100 Resource Blocks (RB) for N users, each user has its own capacity for each RB. I defined a binary variable x_{i,j} that is equal to 1 if RB i is assigned to user j. I tried GA of Matlab, but the results are not satisfying; it is either not optimum (I had better results using my own algorithm), or not respecting the constraint (an RB must be assigned for 1 user at most). in my optimization problem I'm trying to maximize the number of connected users for a certain CoS. Had anyone used Matlab's GA for resource allocation? and how were the results? regards