An improved Gaussian approximation for probability of bit-error analysis of asynchronous bandlimited DS-CDMA systems with BPSK spreading

• Published in: IEEE transactions on wireless communications Vol. 1; no. 3; pp. 373 - 382
• Main Author: Yoon, Y.C.
• Format: Journal Article
• Language: English
• Published: Piscataway, NJ IEEE 01.07.2002; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Accuracy; Applied sciences; Approximation; Binary phase shift keying; Binary systems; Chip formation; Computational complexity; Exact sciences and technology; Gaussian; Gaussian approximation; Mathematical analysis; Mathematical models; Multiaccess communication; Multiple access interference; Performance analysis; Phase shift keying; Pulse shaping methods; Statistics; Studies; Systems, networks and services of telecommunications; Telecommunications; Telecommunications and information theory; Transmission and modulation (techniques and equipments); Wireless communication; Performance evaluation; Characteristic function; Phase shift keying; Gauss approximation; Error probability; Binary modulation; Pulse shaping; Wireless telecommunication; Code division multiple access; Direct sequence; Digital transmission; Asynchronous transmission
• ISSN: 1536-1276; 1558-2248
• DOI: 10.1109/TWC.2002.800536

This paper analyzes probability of bit-error (P/sub e/) performance of asynchronous bandlimited direct-sequence code-division multiple-access systems with binary phase-shift keying spreading. The two present methods of P/sub e/ analysis under bandwidth-efficient pulse shaping: the often-cited standard Gaussian approximation and the characteristic function (CF) method suffer from either a low accuracy in regions of low P/sub e/ (< 10/sup -3/) or a prohibitively large computational complexity. The paper presents an alternate method of P/sub e/ analysis with moderate computational complexity and high accuracy based on a key observation. A sequence of chip decision statistics (whose sum yields a bit statistic) forms a stationary, m-dependent sequence when conditioned on the chip delay and phase offset of each interfering signal. This observation permits the generalization of the improved Gaussian approximation previously derived for the rectangular pulse and the derivation of a numerically efficient approximation based on the CF method. Numerical examples of systems using the square-root raised-cosine and IS-95 pulses illustrate THE P/sub e/ performance, user capacity and the accuracy of the proposed method.