On the Equivalence of Linear MMSE Chip-Level Equalizer and Generalized RAKE

Hadinejad-Mahram, H.

doi:10.1109/lcomm.2003.822519

Cited by 14 publications

(3 citation statements)

References 3 publications

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“…Our present G-RAKE formulation has been shown to be equivalent to MMSE chip equalization [8]. Thus, the numerical results presented below are applicable to both receivers.…”

Section: Conventional Sttd Demodulation In Cdmamentioning

confidence: 79%

“…Observe that due to the Alamouti space-time code, cross terms that couple the two symbols vanish when expanding (8). Thus, the symbols can be demodulated independently using common weight vectors.…”

Section: Conventional Sttd Demodulation In Cdmamentioning

confidence: 99%

“…8) Note that we have dropped terms independent of the symbol hypothesized values. By expanding (8) and continuing to drop terms unrelated to symbol hypothesized values 1 , we eventually obtain…”

mentioning

confidence: 99%

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Transmit Diversity and Receiver Performance in a WCDMA System

Wang

Bottomley

Khayrallah

2007

IEEE GLOBECOM 2007-2007 IEEE Global Telecommunications Conference

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In this paper, we study the performance of transmit diversity schemes in a wideband code-division multiple-access (WCDMA) system. We consider a space-time transmit diversity (STTD) scheme using the Alamouti code and a simple switch transmit diversity (STD) scheme in which the transmitter selects instantaneously the best antenna for transmission. Receiver impairment is generally modeled as a colored, complex Gaussian process, which gives rise to temporal and spatial correlations. First, we extend the G-Rake formulation to process a STTD signal, accounting for the space-time code structure as well as the temporal and spatial correlations of the impairments. The performance of STTD and STD for a WCDMA system is then evaluated. We show that STTD improves the coverage of low-to-medium rate services significantly for users at cell edge compared to the scheme without transmit diversity. Such improvements are observed even when the channels already have diversity through multipath and multiple receive antennas. Thus, STTD is well suited for broadcast when feedback from mobiles is not available. For high-data-rate availability, however, using one feedback bit to allow the STD scheme to transmit only on the better antenna achieves significantly better performance compared to STTD. This is because sending the desired signal through one radio channel makes it easier for linear equalizers to restore orthogonality. For mobiles dominated by self-interference due to loss of orthogonality, better equalization results in much improved data rates.

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“…Our present G-RAKE formulation has been shown to be equivalent to MMSE chip equalization [8]. Thus, the numerical results presented below are applicable to both receivers.…”

Section: Conventional Sttd Demodulation In Cdmamentioning

confidence: 79%

Section: Conventional Sttd Demodulation In Cdmamentioning

confidence: 99%