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Third International Conference on Information Technology and Applications (ICITA 2005), 4-7 July 2005, Sydney, Australia; 01/2005
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Third International Conference on Information Technology and Applications (ICITA 2005), 4-7 July 2005, Sydney, Australia; 01/2005
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ABSTRACT: Design of space-time codes is based on the statistical analysis of the propagation channel. As knowledge of the channel characteristics is not available at the transmitter, the improvement introduced by antenna diversity is primarily relying on the channel having uncorrelated signal paths. We introduce a combination of eigenbeamforming with orthogonal space-time block codes at the transmitter. This combines the benefits of decorrelation through eigen-analysis and achieving system diversity gain. The system has been simulated using four transmit antennas in both uncorrelated and correlated channels. Results showed that this scheme provides a significant improvement in the performance of spatially correlated channels.
02/2004;
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ABSTRACT: In W-CDMA systems, adaptive beamforming transmission requires feedback signalling of transmit antenna weights from the mobile to the base station. We introduce a new feedback signalling technique called direct feedback method (DFBM) and compare the error rate performance of eigenbeamforming system employing DFBM with a scheme assuming that the transmitter has perfect knowledge of beamforming weights, a scheme specified in 3GPP, and a scheme that uses partial channel phase information. Two channel conditions with different degrees of spatial channel correlation are considered. Results indicate that our proposed DFBM has nearly optimum performance.
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ABSTRACT: In this work we study the performance of the adaptive beamforming algorithm adopted by the 3GPP standards. Two radio channel models are used in this study for comparison: a recently proposed space-time channel model called GBHDS (geometrical-based with hyperbolically distributed scatterers) and the correlated antenna channel model used originally by the 3GPP for testing. Simulation results have shown that a 7.5dB performance gain is achievable (in terms of bit-error-rate) when employing eigenbeamforming in the transmission system for both models, and a 2.5dB difference between the above two channel models in a macro cell environment.
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ABSTRACT: In this paper we introduce a technique of eigenbeamforming based on the channel correlation matrix and paired with orthogonal space-time code (O-STBC) at the transmitter side of the link. This structure combines the spatial signal paths decorrelation with the diversity gain provided by the space-time code, which results in performance improvement. The probability distributions for both bit-error-rate (BER) and symbol-error-rate (SER) are presented based on the received signal-to-noise ratio (SNR) for this system. The system has been simulated using four transmit antennas in both uncorrelated and correlated channels. Results showed that the proposed scheme provides a significant improvement in the error rate performance of spatially correlated channels.
