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In this paper, we propose a scheme called "beam- nulling". In the beam-nulling scheme, the eigenvector of the weakest subchannel is fed back and then signals are sent over a generated subspace orthogonal to the weakest subchannel. Theoretical analysis and numerical results show that the capacity of beam-nulling is closed to the optimal water-filling at medium SNR. Additionally, signal-to-interference-plus-noise...
In this paper, we propose a scheme called ldquobeam-nullingrdquo using the same feedback bandwidth as beamforming but with higher capacity. In the beam-nulling scheme, the eigenvector of the weakest subchannel is fed back and then signals are sent over a generated subspace orthogonal to the weakest subchannel. Hence, the scheme can achieve high capacity. The capacities of water-filling, equal power,...
In this paper, we develop a new design for adaptation of linear dispersion code. A new adaptive parameter called spacetime symbol rate is applied in our design. We have studied the statistics of signal-to-interference-noise of a linear MMSE receiver over a Rayleigh fading channel. The average BER for a given constellation using the MMSE receiver is calculated numerically. With the statistics as a...
A novel scheme called multi-dimensional beamforming is proposed for adaptive MIMO systems, which can achieve higher capacity than eigen-beamforming when more feedback bandwidth is available. Theoretical analysis and numerical results show that multi-dimensional beamforming improves capacity as compared to eigen-beamforming at relatively high signal-to-noise ratio. By extension of the existing beamforming...
In this paper, "beam-nulling" is proposed to send signals over a generated subspace orthogonal to the weakest spatial subchannel fed back from the receiver. Signal-to-interference-plus-noise ratio (SINR) of MMSE receiver is derived for beam-nulling. Then the associated average bit-error rate (BER) of beam-nulling is given numerically and verified by simulation results. Simulation results...
In this paper, we present a study of error performance of linear dispersion codes. First, an upper bound of average error probability is derived for any signal-to-noise ratio. Based on this bound, a tight upper bound of average error probability at high signal-to-noise ratio is further derived to show the diversity advantage of linear dispersion codes. The tight bound demonstrates the relationship...
We have studied the statistics of signal-to- interference-noise for a MIMO transceiver using full-rate linear dispersion code and linear minimum-mean-square-error (MMSE) receiver over a Rayleigh fading channel. The associated probability density function of the signal-to-interference-noise is derived, which will benefit the future study, such as error- rate probability. Simulation results are provided...
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