Beamforming techniques using phased microphone arrays are one of the most common tools for localizing and quantifying noise sources. However, the use of such devices can result in a series of well-known disadvantages regarding, for instance, their very high cost or transducer mismatch. Virtual Phased Arrays (VPAs) have been proposed as an alternative solution to prevent these difficulties provi...

Synthetic time reversal (STR) is a technique for blind deconvolution of receiving-array recordings of sound from an unknown source in an unknown multipath environment. It relies on generic features of multipath sound propagation. In prior studies, the pivotal ingredient for STR, an estimate of the source-signal's phase (as a function of frequency ω), was generated from conventional beamforming ...

Spatial filtering (SF) constitutes an integral part of building EEG-based brain-computer interfaces (BCIs). Algorithms frequently used for SF, such as common spatial patterns (CSPs) and independent component analysis, require labeled training data for identifying filters that provide information on a subject's intention, which renders these algorithms susceptible to overfitting on artifactual E...

This paper addresses the problem of joint resource allocation and QoS assignment in multi-cellular uplink of wireless data networks. We show how to jointly optimize three degrees of design freedom: transmit power, bandwidth allocation, and spatial diversity through antenna beamforming, in order to maximize the network-wide utility as a function of attained QoS. Many existing formulations of pow...

This paper considers the so-called multiple-inputmultiple-output interference channel (MIMO-IC) which has relevance in applications such as multi-cell coordination in cellular networks as well as spectrum sharing in cognitive radio networks among others. We consider a beamforming design framework based on striking a compromise between beamforming gain at the intended receiver (Egoism) and the m...

On a multi-antenna broadcast (downlink) channel, simultaneous transmission to multiple users is capable of achieving very high throughput. Unfortunately, the optimal approach for such multi-user transmission, namely dirty paper coding, is highly complicated. Therefore, this paper proposes a practical joint beamforming and scheduling scheme that is enabled by feedback of quantized channel state ...

The objective of this project was to use a standoff microphone array to suppress feedback for a microphone-loudspeaker system in an indoor environment. When the gain on the amplifying loudspeaker is too high, the sounds from the loudspeaker that are picked by the microphone keep being re-amplified until there is a loud squeal in a process called feedback. This limits the amount of gain that can...

The need to extract a single audio signal of interest from a multi-source and noisy environment is common across many disciplines. Adaptive beamforming, due to its superior interference rejection and noise suppression, is a preferred processing technique for obtaining high quality audio in noisy environments. In a previous study, we have examined the performance of two classes of adaptive beamf...

Executive Summary This white paper compares and contrasts the two major implementations of beamforming found in the market today: ● Switched array beamforming ● Digital signal processing (DSP)-based beamforming This paper suggests that both methods do offer some performance gain but that DSP-based beamforming (such as used in ClientLink 2.0) is superior (especially when supporting a network wit...

Such techniques—known collectively as beamforming—have been the subject of intense interest in recent years within the acoustic array processing research community. Unfortunately, such techniques have been largely ignored in the mainstream automatic speech recognition field, although this may rapidly change given the recent release and widespread popularity of the Microsoft Kinect R © platform....