Cooperative multibeamforming in ad hoc networks
EURASIP Journal on Advances in Signal Processing
A diversity guarantee and SNR performance for unitary limited feedback MIMO systems
EURASIP Journal on Advances in Signal Processing
Adaptive codebook for limited feedback MIMO system
WOCN'09 Proceedings of the Sixth international conference on Wireless and Optical Communications Networks
Grassmannian predictive coding for delayed limited feedback MIMO systems
Allerton'09 Proceedings of the 47th annual Allerton conference on Communication, control, and computing
On MIMO beamforming systems using quantized feedback
IEEE Transactions on Communications
Optimal receive array beamforming for non-collaborative MIMO space division multiple access
IEEE Transactions on Communications
Differential feedback of MIMO channel gram matrices based on geodesic curves
IEEE Transactions on Wireless Communications
| Hi-index | 35.68 |
In this paper, a simple algorithm for adaptation of the complex baseband weights of a transmit antenna array using feedback from the receiver is proposed and analyzed. The system utilizes stochastic gradient adaptation to maximize the power delivered to the receiver for a constrained transmission power, which provides both fading diversity and beam steering gain. Dual perturbed transmission weight vectors are time multiplexed onto the pilot signal, and the receiver generates feedback selecting the perturbed weight vector which delivers greater power. This feedback is used to provide weight adaptation at the transmitter, and this adaptation is shown to be an update by a coarse estimate of the gradient of the delivered power. The performance of the algorithm is analyzed in terms of convergence and tracking of an AR1 fading channel, with simulations confirming the analysis. Bit error rate (BER) simulations in a dynamic fading channel show that the algorithm outperforms previously proposed vector selection feedback, and in slower fading, the algorithm substantially outperforms diversity space time coding.