Abstract: We employ the Simplified Improved Gaussian Approximation (SIGA) to estimate the performance of a connectionless-type CDMA packet communication system. In this system, a user�s station can asynchronously and randomly transmit, making performance analysis hard due to the fluctuation of interfering users. We address this performance hardness by simulating a real world setting of the unslotted ALOHA network. Our simulation provides means of observing and reporting the system�s specifications and performance under diverse boundaries.