Performance Analysis of Spread Spectrum CDMA systems

In this lecture, we present the mathematical analysis on the average bit error rate for multi-users in a single channel of the spread spectrum, Code Division Multiple Access (SS-CDMA) mobile radio system. We present expressions of BER performance of CDMA systems for a wide range of interference conditions for both synchronous case and asynchronous case, including Gaussian approximations (GA), Improved Gaussian Approximation (IGA), and Simple Improved Gaussian Approximation (SIGA). After the discussion for the single user detection, we discuss the key idea of the multiuser detection in the CDMA systems for high speed data transmission. The rest of the paper is organized as follows: In section II, we present the multiuser CDMA system model. In section III, we discuss the single user detection for the CDMA systems. In section IV, we present in detail the probability of error of the synchronous case with the single user detection for the CDMA systems. In section V, we discuss the probability of error of the asynchronous case with the single user detection for the CDMA systems, including GA, IGA and SIGA algorithms. Finally, in section VI, we discuss the multiuser detection for the CDMA systems.