Many statistical models (mainly due to physical propagation studies and field measurements) have been proposed to characterize the statistics of the NLOS flat-fading wireless communication channel. There appears to have no known statistical theory on the formation of many of these fading envelope statistics. We offer the statistical modeling of fading envelope statistics under the NLOS assumption based on the SIRP representation. In practice, these channel statistics cannot be modeled with certainty. We advocated the use of moment-bound theory to obtain bounds on the system performance metrics. In this paper, we combine the theory of moment bounds with that of SIRP, and the use of the SDP optimization method to show how sharper bounds of the error rate and ergodic channel capacity of a communication system can be computed.