IEEE Int. Conf. on Acoustics,
Speech, and Signal Processing,
vol. 5, pp. 2869-2873, June 2000.
Self-Recovering RAKE Receiver for Asynchronous CDMA Systems
Murat Torlak (1) and
Brian L. Evans (2)
(1) Department of Electrical and Computer Engineering, ECS 33,
The University of Texas at Dallas,
Richardson, TX 75083
(2) Department of Electrical and Computer Engineering,
Engineering Science Building,
The University of Texas at Austin,
Austin, TX 78712-1084
In asynchronous code division multiple access systems,
transmission over frequency-selective channels subjects
the signal to interchip interference and intersymbol
interference, both of which cause multiple access interference.
The multiple access interference cannot be easily eliminated
without the knowledge of the channel parameters. Both
blind adaptive and subspace-based multiuser receivers
have been proposed to eliminate the interference. In
this paper, we propose a self-recovering RAKE receiver
that does not require training sequences or knowledge
of interfering user signature waveforms. The contribution
of this paper is the combination of
constant modulus algorithm and previously derived constraints.
The constraints depend on the multipath structure of the
desired signal. The proposed receiver converges faster
than the blind adaptive multiuser receivers. Its fast
convergence and low complexity make it well suited for
rapidly time-varying mobile radio frequency selective fading
channels. By simulation, we compare the proposed method
with blind adaptive constrained LMS RAKE receiver and
minimum output energy receiver.
Last Updated 11/24/00.