Motivated by the two-user beamforming in multiantenna interference channels, we characterize the upper boundary of the achievable single-user gain-region. The eigenvector corresponding to the maximum eigenvalue of the weighted sum of Hermitian forms of channel vectors is shown to achieve all points on the boundary in some given direction. Thereby, we solve three different beamforming problems, ...

In an Orthogonal Frequency Division Multiplexing (OFDM) system, downlink beamforming can be implemented either before IDFT (frequency domain) or after IDFT (time domain) module in a base station transmitter. We denote the former scheme as PreIDFT downlink beamforming, and the latter as Post-IDFT downlink beamforming. In this work, we have compared Pre-IDFT downlink beamforming with Space-Time B...

In a cooperative cognitive radio (CR) network, cooperative beamforming can enable concurrent transmissions of both primary and secondary systems at a given channel. However, such cooperative beamforming can introduce asynchronous interferences at the primary receivers as well as at the secondary receivers and these asynchronous interferences are overlooked in beamforming design. In order to add...

Localization of sources in patients with focal seizure has recently attracted many attentions. In the severe cases of focal seizure, there is a possibility of doing neurosurgery operation to remove the defected tissue. The prosperity of this heavy operation completely depends on the accuracy of source localization. To increase this accuracy, this paper presents a new weighted beamforming method...

Photoacoustic imaging (PAI) is a promising medical imaging modality which provides the resolution of Ultrasound (US) and the contrast of Optical imaging modalities. One of the most important challenges in PAI is image formation, especially in the case that a linear-array US transducer is used for data acquisition. This is due to the fact that in the linear-array scenario, there is only 60 degre...

Classical beamforming techniques rely on highly linear transmitters and receivers to allow phasecoherent combining at the transmitter and receiver. The transmitter uses beamforming to steer signal power towards the receiver, and the receiver uses beamforming to gather and coherently combine the signals from multiple receiver antennas. When the transmitters and receivers are instead constrained ...

An iterative optimization method for unitary beamforming in MIMO broadcast channels is proposed, based on successive optimization of Givens rotations. Under the assumption of perfect channel state information at the transmitter (CSIT) and for practical average SNR values, the proposed technique provides higher sum rates than zero forcing (ZF) beamforming while performing close to minimum mean s...

The aim of this paper is to study the use of a robust acquisition system based on a microphone array for speech related applications in real situations. A comparison is performed between two beamforming methods: the Delay and Sum beamforming (DS) and the Spatial Reference Optimal beamforming (SRO). Both of them are frequency domain designed, using harmonic spatial distributed microphones. The q...

Compressive sensing (CS) is compared with conventional beamforming using horizontal beamforming of at-sea, towed-array data. They are compared qualitatively using bearing time records and quantitatively using signal-to-interference ratio. Qualitatively, CS exhibits lower levels of background interference than conventional beamforming. Furthermore, bearing time records show increasing, but toler...

Adaptive beamforming is capable of separating user signals transmitted on the same carrier frequency, and thus provides a practical means of supporting multiusers in a space-division multipleaccess scenario. Moreover, for the sake of further improving the achievable bandwidth efficiency, highthroughput quadrature amplitude modulation (QAM) schemes have becomes popular in numerous wireless netwo...