Here, we discuss the fundamental limit of the clasical Shannon theory in terms of performance evaluation of complex wireless networking systems. Then, we investigate the concept of the evolved Shannon theory and effective spectral efficiency (or net capacity). Using the (conventional) Shannon theory, the channel capacity of an wireless link is denoted as where the wireless link consists of a single antenna transmitter and a single reception user. The ignores the performance loss by overhead signaling regardless whether we put realistic SINR instead of SNR or not.