Title :
A simple combined conjugate gradient beamforming and interference cancellation scheme for DS-CDMA in a multipath fading channel
Author :
Mohamed, Nermin A. ; Dunham, James G.
Author_Institution :
Dept. of Electr. Eng., Southern Methodist Univ., Dallas, TX, USA
Abstract :
A simple DS-CDMA receiver that combines adaptive beamforming together with parallel interference cancellation in a multipath fading channel is presented. A fast adaptation, a conjugate gradient (CG) algorithm is used to find the optimum beamformer weights. By CG beamforming, the desired user´s signal is enhanced and the cochannel interference from other directions is reduced. For in-beam multiple access interference reduction, a parallel interference canceller is used in each RAKE finger. The average uncoded bit error rate (BER) as a function of the average antenna signal-to-noise ratio (SNR) and the number of receiving antennas is examined in a frequency selective Rayleigh fading channel. Simulation results show an increase in system capacity as a function of the number of antennas and the number of interferers canceled per finger
Keywords :
Rayleigh channels; array signal processing; cellular radio; cochannel interference; code division multiple access; conjugate gradient methods; error statistics; interference suppression; multipath channels; multiuser channels; radio receivers; receiving antennas; spread spectrum communication; BER; DS-CDMA receiver; RAKE finger; SNR; adaptive beamforming; average antenna signal-to-noise ratio; average uncoded bit error rate; cellular systems; cochannel interference; conjugate gradient algorithm; conjugate gradient beamforming; fast adaptation; frequency selective Rayleigh fading channel; in-beam multiple access interference reduction; interference cancellation; multipath fading channel; optimum beamformer weights; parallel interference cancellation; parallel interference canceller; receiving antennas; simulation results; system capacity; Array signal processing; Bit error rate; Character generation; Fading; Fingers; Interchannel interference; Interference cancellation; Multiaccess communication; Multiple access interference; Receiving antennas;
Conference_Titel :
Wireless Communications and Networking Conference, 1999. WCNC. 1999 IEEE
Conference_Location :
New Orleans, LA
Print_ISBN :
0-7803-5668-3
DOI :
10.1109/WCNC.1999.796793
