Predictive transmit beamforming for MIMO-OFDM in time-varying channels with limited feedback
IWCMC '07 Proceedings of the 2007 international conference on Wireless communications and mobile computing
On Performance of Clustering-Based Limited Feedback Beamforming in Multiple-Antenna OFDM Systems
IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences
User resource structure design with enhanced diversity for OFDMA in time-varying channels
WCNC'09 Proceedings of the 2009 IEEE conference on Wireless Communications & Networking Conference
Limited feedback for multi-carrier beamforming: a rate-distortion approach
ISIT'09 Proceedings of the 2009 IEEE international conference on Symposium on Information Theory - Volume 1
On channel quantization and feedback strategies for multiuser MIMO-OFDM downlink systems
IEEE Transactions on Communications
Channel state feedback schemes for multiuser MIMO-OFDM downlink
IEEE Transactions on Communications
Time-domain transmit beamforming for MIMO-OFDM systems with finite rate feedback
IEEE Transactions on Communications
feedback reduction based on clustering in MIMO-OFDM beamforming systems
WiCOM'09 Proceedings of the 5th International Conference on Wireless communications, networking and mobile computing
QRD-based precoded MIMO-OFDM systems with reduced feedback
IEEE Transactions on Communications
Simplified maximum-likelihood precoder selection for limited feedback spatial multiplexing systems
GLOBECOM'09 Proceedings of the 28th IEEE conference on Global telecommunications
Reduced feedback designs for SDMA-OFDMA systems
ICC'09 Proceedings of the 2009 IEEE international conference on Communications
Using limited feedback in power allocation design for a two-hop relay OFDM system
ICC'09 Proceedings of the 2009 IEEE international conference on Communications
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Transmit beamforming and receive combining are simple methods for exploiting spatial diversity in multiple-input multiple-output orthogonal frequency division multiplexing (MIMO-OFDM) system. Optimal beamforming requires channel state information in the form of the beamforming vectors for each OFDM subcarrier. This paper proposes a limited feedback architecture that combines beamforming vector quantization and smart vector interpolation. In the proposed system, the receiver sends a fraction of information about the optimal beamforming vectors to the transmitter and the transmitter computes the beamforming vectors for all subcarriers through interpolation. A new spherical interpolator is developed that exploits parameters for phase rotation to satisfy the phase invariance and unit norm properties of the transmitted beamforming vectors. The beamforming vectors and phase parameters are quantized at the receiver and the quantized information is provided to the transmitter. The proposed quantization system provides only a moderate increase in complexity versus over comparable approaches. Numerical simulations show that the proposed scheme performs better than existing diversity techniques with the same feedback data rate.