Despite all the work being done so far in scheduling for wireless networks, the transmission scheduling problem with specific constraints is not yet fully understood and explored. In this work, we find the minimum number of time-slots (or channels) required in any given network and the corresponding transmitting powers, such that all communication requests are being processed correctly, while fulfilling specific constraints that comply with the Quality of Service (QoS) requirements for successful transmissions. More specifically, in this paper, we formulate the optimization problem as a Mixed Integer Program (MIP) and solve the mathematical formulation by a Branch-and-Bound algorithm. Our computational study shows that our methodology is capable of solving exactly networks of varying size but can also provide a near optimal heuristic solution for the hardest instances. The results can be used as bounds for the study of distributed algorithms that aim for the optimal scheduling and power assignment without information about the whole network. Numerical examples are provided to illustrate the validity of our proposed methodology.