The equation from paper are shown below

we know beta and alpha value. We need to choose the minimum value of SINR from a SINR vector having k values inside. Then we need to optimize eta to get maximum SINR.
In the paper, it says using bisection method to solve the problem. Since t is given, so I think I think it is a feasibility problem. However, when I set ‘maximize 0’, it said the object is given. As well as when i change SINR_k(eta)>=t to a equation, shown below,
the system still show me the error.
Looking for help!!! Thanks!!!