ctron. Syst., vol. 15, pp. 181-185, Jan. 1979. [28] S. Verdu, "Minimum probability of error for asynchronous gaussian multiple- access channels," IEEE Trans. Inform. Theory, vol. 32, pp. 85-96, Jan. 1986. [29] S. Verdu, "Optimum multi-user asymptotic efficiency," IEEE Trans. Comm., vol. 34, pp. 890-897, Sept. 1986. R. Lupas and S. Verdu, "Linear multiuser detectors for synchronous code-divi- sion multiple-access channels," IEEE Trans. Inform. Theory, vol. 35, pp. 123- 136, Jan. 1989. [31] M. K. Varanasi and B. Aazhang, "Near-optimum detection in synchronous code-division multiple-access systems," IEEE Trans. Comm., vol. 39, pp. 725- 736, May 1991. [32] H. V. Poor and S. Verdu, "Single-user detectors for multiuser channels," IEEE Trans. Comm., vol. 36, pp. 50-60, Jan. 1988. [33] R. Lupas and S. Verdu, "Near-far resistance of multiuser detectors in asyn- chronous channels," IEEE Trans. Comm., vol. 38, no. 4, pp. 496-508, Apr. 1990. [34] M. K. Varanasi and B. Aazhang, "Multistage detection in asynchronous code- division multiple access communications," IEEE Trans. Comm., vol. 38, no. 4, pp. 509-519, Apr. 1990. [35] Z. Xie, R. T. Short, and C. K. Rushforth, "A family of suboptimum detectors for coherent multiuser communications," IEEE J. Select. Areas Comm., vol. 8, pp. 683-690, May 1990. [36] Y. C. Yoon, R. Kohno, and H. Imai, "A spread-spectrum multi-access system with a cascade of co-channel interference cancellers for multipath fading channels," Proc. IEEE 2d Int. Symp. Spread Spectrum Tech. Appl., pp. 87-90, Dec. 1992. [37] S. Tachikawa, "Performance of M-ary spread spectrum multiple access com- munication systems using co-channel interference cancellation techniques," Proc. IEEE 2d Int. Symp. Spread Spectrum Tech. Appl., pp. 95-98, Dec. 1992. [38] P. B. Rapajic and B.S. Vucetic, "Linear asynchronous code-division multiple access single-user receiver," Proc. IEEE 2d Int. Symp. Spread Spectrum Tech. Appl., pp. 99-102, Dec. 1992. Commercial Applications [39] M. Abdulrahman, D. D. Falconer, and A. U. H. Sheikh, "Eq