Convex Optimization
Dynamic Programming and Optimal Control, Vol. II
Dynamic Programming and Optimal Control, Vol. II
Introduction to Space-Time Wireless Communications
Introduction to Space-Time Wireless Communications
Limited feedback beamforming over temporally-correlated channels
IEEE Transactions on Signal Processing
Optimization and tradeoff analysis of two-way limited feedback beamforming systems
IEEE Transactions on Wireless Communications
Limited feedback unitary precoding for orthogonal space-time block codes
IEEE Transactions on Signal Processing
Interpolation Based Unitary Precoding for Spatial Multiplexing MIMO-OFDM With Limited Feedback
IEEE Transactions on Signal Processing
Space Division Multiple Access With a Sum Feedback Rate Constraint
IEEE Transactions on Signal Processing - Part II
Duplex distortion models for limited feedback MIMO communication
IEEE Transactions on Signal Processing
Efficient feedback methods for MIMO channels based on parameterization
IEEE Transactions on Wireless Communications
On the performance of random vector quantization limited feedback beamforming in a MISO system
IEEE Transactions on Wireless Communications
Communication over fading channels with delay constraints
IEEE Transactions on Information Theory
Opportunistic beamforming using dumb antennas
IEEE Transactions on Information Theory
On beamforming with finite rate feedback in multiple-antenna systems
IEEE Transactions on Information Theory
Grassmannian beamforming for multiple-input multiple-output wireless systems
IEEE Transactions on Information Theory
Achieving the Welch bound with difference sets
IEEE Transactions on Information Theory
Limited feedback unitary precoding for spatial multiplexing systems
IEEE Transactions on Information Theory
MIMO Broadcast Channels With Finite-Rate Feedback
IEEE Transactions on Information Theory
What is the value of limited feedback for MIMO channels?
IEEE Communications Magazine
Feedback assisted transmission subspace tracking for MIMO systems
IEEE Journal on Selected Areas in Communications
An overview of limited feedback in wireless communication systems
IEEE Journal on Selected Areas in Communications
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Transmit beamforming is a simple multiantenna technique for increasing throughput and the transmission range of a wireless communication system. The required feedback of channel state information (CSI) can potentially result in excessive overhead especially for high mobility or many antennas. This work concerns efficient feedback for transmit beamforming and establishes a new approach of controlling feedback for maximizing throughput under a constraint on the average feedback rate. The feedback controller using a stationary policy turns CSI feedback on/off according to the system state that comprises the channel state and transmit beamformer. Assuming channel isotropy and Markovity, the controller's state reduces to two scalars. This allows the optimal control policy to be efficiently computed using dynamic programming. Consider the unquantized feedback channel free of error, where each feedback instant pays a fixed price. The corresponding optimal feedback control policy is proved to be of the threshold type. This result holds regardless of whether the controller's state space is discretized or continuous. Under the threshold-type policy, feedback is performed whenever a state variable indicating the accuracy of transmit CSI is below a threshold, which varies with channel power. The practical quantized feedback channel is also considered. The optimal policy for quantized feedback is proved to be also of the threshold type. The effect of CSI quantization is shown to be equivalent to an increment on the feedback price. Moreover, the increment is upper bounded by the expected logarithm of one minus the quantization error. Finally, simulation shows that feedback control increases throughput of the conventional periodic feedback by up to 0.5 bit/s/Hz without requiring additional bandwidth or antennas.