Optimum near-far resistance of linear detectors for code-division multiple-access channels

Summary form only given. In CDMA systems users are assigned signature waveforms which are known to the receiver, thereby permitting demodulation of the data streams upon observation of the sum of the transmitted signals imbedded in additive noise. Assuming white Gaussian background noise, detectors have been compared by analyzing the rate of exponential decay of the bit error rate in the low-background-noise region, focusing on the near-far resistance, defined as the worst-case performance with respect to the received energies of the interfering users. A linear detector has been found with a computational complexity that grows only linearly with the number of users and with a near-far resistance equal to that of the optimum multiuser detector for asynchronous Gaussian multiple-access channels. A way to find the optimum near-far resistance as a function of the signature waveform cross-correlations has been obtained.