Consider a communication system which is designed without simulation testing. More exactly, some of functions in the system can not be evaluated by mathematical formulation because of its inherent complexity. Up to now, most communication systems are pre-evaluated and pre-tested before implementation.
One of most important constraints to design controllable communication systems is to use the orthogonal signalling condition. In order to avoid interference among wireless transmitting devices, orthogonality is mandated and controlled by the central station. One example of control station is a base station in cellular communication networks. The base station allocates different time or frequency slots for each mobile terminal, in order to avoid collision among the stations in its own cell.
Once the orthogonality assumption is applied as the system constraint, the analysis of the wireless communication systems falls down to a simple domain. The upper bound of the performance can be predicted by the famous formulation of Shannon theory. For example, the capacity of the communication link with the constraint can be given by
where SNR is the signal-to-noise ratio.