DocumentCode :
3377482
Title :
Performance of CDMA smart antenna systems
Author :
Torlak, Murat ; Xu, Guanghan
Author_Institution :
Dept. of Electr. & Comput. Eng., Texas Univ., Austin, TX, USA
Volume :
1
fYear :
1995
fDate :
Oct. 30 1995-Nov. 1 1995
Firstpage :
383
Abstract :
Preliminary radio frequency (RF) field experiments were conducted to evaluate the performance of smart antenna systems for code-division multiple access (CDMA) systems. Besides conventional multipath fading problems, CDMA schemes are subject to near-far problems. The IS-95 CDMA system uses a 1/3 convolutional encoder and an interleaver to mitigate the fading problem and uses feedback power control schemes to equalize the powers of all the uplink co-channel signals. We evaluate the performance of the IS-95 standard implemented on a smart antenna system in a slow-fading environment. In particular, we evaluate the effects of imprecise power control, convolutional coding, and different beamforming techniques for a CDMA smart antenna system. Our results show that the smart antennas are not so sensitive to imperfect power control and that the optimal (Wiener) beamforming technique outperforms the simple beamforming approach. The most interesting result is that the effect of convolutional coding is not so significant for a smart antenna system than for an single antenna system. Based on our limited experimental results, we found that the 3 times bandwidth dedicated to the 1/3 convolutional encoding is better used to increase the spreading factor in a CDMA smart antenna system, leading to reduced cost and perhaps better performance.
Keywords :
code division multiple access; CDMA smart antenna systems; IS-95 CDMA system; IS-95 standard; adaptive uniform linear array; bandwidth; beamforming techniques; code-division multiple access; convolutional coding; convolutional encoder; cost reduction; experimental results; feedback power control; imperfect power control; interleaver; multipath fading; near-far problems; optimal Wiener beamforming; performance evaluation; radio frequency field experiments; single antenna system; slow fading environment; spatial diversity; spreading factor; uplink cochannel signals; Array signal processing; Bandwidth; Convolution; Convolutional codes; Encoding; Fading; Feedback; Multiaccess communication; Power control; Radio frequency;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Signals, Systems and Computers, 1995. 1995 Conference Record of the Twenty-Ninth Asilomar Conference on
Conference_Location :
Pacific Grove, CA, USA
ISSN :
1058-6393
Print_ISBN :
0-8186-7370-2
Type :
conf
DOI :
10.1109/ACSSC.1995.540576
Filename :
540576
Link To Document :
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