Title :
Adaptive single-user receivers for direct-sequence spread-spectrum CDMA systems
Author :
Majmundar, Milap ; Sandhu, Nevena ; Reed, Jeffrey H.
Author_Institution :
SBC Technol. Resources Inc., Austin, TX, USA
fDate :
3/1/2000 12:00:00 AM
Abstract :
The capacity of a direct-sequence spread-spectrum code-division multiple-access (DSSS-CDMA) system is limited by multiple-access interference (MAI) and the near-far problem. Multiuser receivers provide a solution to these problems, but they require knowledge of parameters of the MAI and are computationally complex. Adaptive single-user receivers, however, do not require knowledge of MAI parameters and need fewer computations. This paper discusses a wide range of adaptive single-user receivers found in the literature and presents their performance results under a unified framework to provide a basis of comparison. Results indicate that, compared to the conventional receiver, adaptive single-user receivers provide large gains in system capacity and are near-far resistant. It is shown that fractionally spaced adaptive receivers, which exploit spectral correlation due to the cyclostationary nature of the DSSS signal, perform better than adaptive receivers that cannot exploit this correlation. Multipath results presented for two-ray and urban channels indicate that fractionally spaced adaptive receivers act as RAKE receivers
Keywords :
AWGN channels; Rayleigh channels; adaptive signal detection; cellular radio; code division multiple access; multipath channels; radio receivers; radiofrequency interference; spread spectrum communication; DSSS signal; MAI; RAKE receivers; adaptive single-user receivers; cellular radio; code-division multiple-access; direct-sequence spread-spectrum CDMA systems; fractionally spaced adaptive receivers; multipath results; multiple-access interference; near-far problem; performance; spectral correlation; system capacity; two-ray channels; urban channels; AWGN; Additive white noise; Detectors; Fading; Filters; Multiaccess communication; Multipath channels; Multiple access interference; RAKE receivers; Spread spectrum communication;
Journal_Title :
Vehicular Technology, IEEE Transactions on