Hello

I used big-M method to handle multiplication of binary (decision) variables ({q_i^n}) by continuous square matrix variables ({W_i^n}) where i=1,2,3 is index of users and n=1,2 is index of subchannels. As i expect that at least one subchannel is assigned to each user, the result is like q_1^1=1, q_1^2=1e-8, q_2^1=0.01, q_2^2=1e-8, q_3^1=1e-8, q_3^2=0.02. I mean for example about user 2, i expect q_2^1 be equal to 1 or almost 1 such that they are able to meet the required constraints (QoS constraints). i must say that i used transform the discrete binary variables to continuous and forced them by using a penalty-based approach with different penalty factors (small values to large values). Also, i added four straightforward constraints related to big-M. Can you guide me? Let me know in case of need more information. Regards