DocumentCode :
699480
Title :
Asymptotic analysis of reduced rank downlink CDMA Wiener receivers
Author :
Mouhouche, Belkacem ; Loubaton, Philippe ; Hachem, Walid ; Ibrahim, Nicolas
Author_Institution :
TSI Dept., Telecom Paris, Paris, France
fYear :
2004
fDate :
6-10 Sept. 2004
Firstpage :
201
Lastpage :
204
Abstract :
In this paper, we study the performance of reduced rank Wiener filters in the context of downlink CDMA systems corrupted by a frequency selective channel. For this, we consider the output signal to interference plus noise ratio (SINR), and study its convergence speed versus the order of the receiver. Unfortunately, this is a difficult task because the SINR expressions depend on the spreading codes allocated to the various users in a rather complicated way. In order to be able to obtain positive results, we follow the classical approach used for the first time in [12]: the code matrix is modelled as the realization of a certain random matrix, and the behavior of the SINRs is studied when the spreading factor N and the number of users K converges to +∞ in such a way that K over N → +α. As the code matrices used in the downlink of CDMA systems are very often orthogonal, we model the code matrix allocated to the various users as a realization of a Haar distributed random unitary matrix. In this context, we show that the SINR of each order n reduced rank receiver converge toward a deterministic limit βn independent of the spreading codes. In order to study the performance of the receiver versus n, we therefore study the convergence speed of βn when n → +∞, a simpler problem. For this, we use the results of [8] based on the theory of orthogonal polynomials for the power moment problem. We obtain the convergence rate of βn, and exhibit the parameters influencing the convergence speed.
Keywords :
Wiener filters; channel allocation; channel coding; code division multiple access; matrix algebra; radio receivers; radiofrequency interference; Haar distributed random unitary matrix; SINR expressions; asymptotic analysis; code matrix; frequency selective channel; orthogonal polynomial theory; output signal to interference plus noise ratio; reduced rank Wiener filters; reduced rank downlink CDMA Wiener receivers; spreading codes; Abstracts; Downlink; Entropy; Multiaccess communication; Receivers; Silicon compounds; Tin;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Signal Processing Conference, 2004 12th European
Conference_Location :
Vienna
Print_ISBN :
978-320-0001-65-7
Type :
conf
Filename :
7080010
Link To Document :
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