Title :
Low complexity space-time MMSE equalization in WCDMA systems
Author :
Melvasalo, Maarit ; Janis, Pekka ; Koivunen, Visa
Author_Institution :
Lab. of Signal Process., Helsinki Univ. of Technol.
Abstract :
In this paper we propose a low complexity frequency-domain method for finding the minimum mean square error (MMSE) equalizer. Special properties of circulant matrices are exploited in the method. Simulations show that only a minor performance loss is experienced compared to time-domain processing. We also compare joint space-time processing to decoupled equalization and spatial combining. The complexity reduction due to the decoupled processing is evident, while the performance loss remains small. Consequently, the proposed low complexity frequency-domain method can also be used with multiple receive antennas with tolerable performance loss compared to joint space time equalization. Additionally, different MMSE equalizer definitions for multiple receive antennas are considered, and their performance is studied in simulation using estimated channels. Simulations are carried out in high data rate WCDMA system model
Keywords :
antenna arrays; channel estimation; code division multiple access; computational complexity; equalisers; least mean squares methods; matrix algebra; time-frequency analysis; WCDMA systems; channel estimation; circulant matrices; decoupled equalization; frequency-domain method; minimum mean square error; multiple receive antennas; space-time MMSE equalization; spatial combining; time-domain processing; Computational complexity; Covariance matrix; Equalizers; Frequency domain analysis; Mean square error methods; Multiaccess communication; Performance loss; RAKE receivers; Receiving antennas; Time domain analysis;
Conference_Titel :
Personal, Indoor and Mobile Radio Communications, 2005. PIMRC 2005. IEEE 16th International Symposium on
Conference_Location :
Berlin
Print_ISBN :
9.7838007291e+012
DOI :
10.1109/PIMRC.2005.1651448
