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ABSTRACT This paper investigates the green design of rate‐splitting multiple access (RSMA) for multicell, multiantenna downlink communication systems to maximize rate fairness under quality of service (QoS) constraints. An optimization framework is developed to minimize the weighted sum power consumption by jointly optimizing transmit beamformers, power allocation, and common/private rate split while ensuring per‐user minimum rate requirements. The algorithm design explicitly considers the rate fairness among users via a newly proposed green fairness index. The nonconvex transceiver design problems are transformed into tractable forms and efficiently solved by applying tools from alternating optimization and successive convex approximation. Extensive simulations demonstrate that the proposed green RSMA optimization framework can effectively balance the throughput among cell‐edge and cell‐center users, hence combating the near‐far effect. Simulation results show that at 20‐dB SNR, green RSMA achieves over 20% and 50% sum rate improvement compared with NOMA and OMA, respectively. Moreover, green RSMA maintains high fairness among users, even when the channel conditions are disparate. When the weakest user is located 120 m from the base station, green RSMA exhibits a 21.2% higher fairness index than NOMA, showcasing its ability to ensure equitable service quality across users. The framework also achieves substantial energy efficiency gains, consuming less power while providing higher data rates than baseline schemes. These results demonstrate the effectiveness of green RSMA in enhancing spectral efficiency, user fairness, and energy efficiency in multicell, multiantenna communication systems, making it a promising solution for sustainable and high‐performance wireless networks. [ABSTRACT FROM AUTHOR]

A multiple‐beam synthesis method is proposed to generate three‐dimensional (3D) shaped and contour patterns from a planar phased array antenna. Three‐dimensional radiation patterns are synthesized primarily with optimum beam positions and variable mainbeam power levels of multiple beams, followed by calculating the resultant element weights. Contour patterns are synthesized from multiple beam peaks by mapping the individual beam power levels to their corresponding 3 dB beamwidth coverage areas at each designated location on the contour. The far‐field contour shape affected by the influence of the element pattern, mutual coupling, and scan loss is compensated by the peak power of the scanned beam patterns. The proposed synthesis supports dynamically changeable contour shapes. Flat‐topped, stepped 3D patterns and arbitrary contour shapes with shaped null zones inside the contour are simulated and implemented on a 16 × 16 element 5G mmWave planar phased array. Measured radiation patterns are compared with simulations and presented. [ABSTRACT FROM AUTHOR]

A modular beamformer, fully scalable in amplitude and phase, to be used with transmitting antenna arrays operating in the Digital Cellular System (DCS)/Personal Communications Service (PCS) frequency band, is designed and fabricated in this paper. The implementation of the structure is simple and very low cost; its performance is evaluated by measuring the frequency response, as well as the radiation patterns produced by an antenna array connected to the output of the beamformer. The latter exhibits low return losses and average amplitude imbalance less than ±0.8 dB, whereas the phase deviations do not exceed ±6° on average, over its 300 MHz bandwidth. [ABSTRACT FROM AUTHOR]

Adaptive beamforming methods are sensitive to underlying assumptions on the environment, sources, or sensor array violation, especially when interferences are moving fast. In this study, the non‐stationary interference source is estimated during the period in which snapshots are taken. Then, a new interference‐plus‐noise covariance matrix reconstruction is introduced which is derived from a simplified power spectral density function that can be used to shape the directional response of the beamformer. Finally, the beamformer is designed to impose nulls towards the regions of the moving interference based on the reconstructed covariance matrix. The essence of the proposed method is to express the inverse of the reconstructed covariance matrix which needs less computational complexity calculation. The effectiveness of the proposed method is demonstrated by numerical results. [ABSTRACT FROM AUTHOR]

Background: The electroencephalography (EEG) abnormalities found in patients with dementia with Lewy bodies (DLB) are conflicting. In this study, we used magnetoencephalography, which has higher spatial resolution than electroencephalography, to explore neurophysiological features of DLB that may aid in the differential diagnosis. Methods: Six patients with DLB, 11 patients with Alzheimer's disease, and 11 age‐matched normal subjects were recruited. We investigated alterations in the ratio of event‐related synchronization (ERS) in the alpha band after eye‐closing. Results: Although the averaged ratio change of alpha ERS after eye‐closing appeared predominantly in the posterior brain regions in all study groups, DLB patients had the weakest ratio change of alpha ERS. In particular, DLB patients exhibited a significantly reduced ratio change of alpha ERS in the bilateral inferior temporal gyrus, right occipital pole, and left parieto‐occipital cortex compared to Alzheimer's disease patients or normal controls. Conclusion: Our findings indicated that a reduced ratio change of alpha ERS in the posterior brain regions elicited by eye‐closing is a brain electromagnetic feature of DLB. [ABSTRACT FROM AUTHOR]

Abstract: Specialization of the auditory cortices for pure tone listening may develop with age. In adults, the right hemisphere dominates when listening to pure tones and music; we thus hypothesized that (a) asymmetric function between auditory cortices increases with age and (b) this development is specific to tonal rather than broadband/non‐tonal stimuli. Cortical responses to tone‐bursts and broadband click‐trains were recorded by multichannel electroencephalography in young children (5.1 ± 0.8 years old) and adolescents (15.2 ± 1.7 years old) with normal hearing. Peak dipole moments indicating activity strength in right and left auditory cortices were calculated using the Time Restricted, Artefact and Coherence source Suppression (TRACS) beamformer. Monaural click‐trains and tone‐bursts in young children evoked a dominant response in the contralateral right cortex by left ear stimulation and, similarly, a contralateral left cortex response to click‐trains in the right ear. Responses to tone‐bursts in the right ear were more bilateral. In adolescents, peak activity dominated in the right cortex in most conditions (tone‐bursts from either ear and to clicks from the left ear). Bilateral activity was evoked by right ear click stimulation. Thus, right hemispheric specialization for monaural tonal stimuli begins in children as young as 5 years of age and becomes more prominent by adolescence. These changes were marked by consistent dipole moments in the right auditory cortex with age in contrast to decreases in dipole activity in all other stimulus conditions. Together, the findings reveal increasingly asymmetric function for the two auditory cortices, potentially to support greater cortical specialization with development into adolescence. [ABSTRACT FROM AUTHOR]

Background Simultaneous bilateral cochlear implantation promotes symmetric development of bilateral auditory pathways but binaural hearing remains abnormal. To evaluate whether bilateral cortical processing remains impaired in such children, cortical activity to unilateral and bilateral stimuli was assessed in a unique cohort of 16 children who received bilateral cochlear implants (CIs) simultaneously at 1.97 ± 0.86 years of age and had ~4 years of CI experience, providing the first opportunity to assess electrically driven cortical development in the absence of reorganized asymmetries from sequential implantation. Methods Cortical activity to unilateral and bilateral stimuli was measured using multichannel electro-encephalography. Cortical processing in children with bilateral CIs was compared with click-elicited activity in 13 normal hearing children matched for time-in-sound. Source activity was localized using the Time Restricted, Artefact and Coherence source Suppression ( TRACS) beamformer method. Results Consistent with dominant crossed auditory pathways, normal P1 activity (~100 ms) was weaker to ipsilateral stimuli relative to contralateral and bilateral stimuli and both auditory cortices preferentially responded to the contralateral ear. Right hemisphere dominance was evident overall. Children with bilateral CIs maintained the expected right dominance but differences from normal included: (i) minimal changes between ipsilateral, contralateral and bilateral stimuli, (ii) weaker than normal contralateral stimulus preference, (iii) symmetric activity to bilateral stimuli, and (iv) increased occipital lobe recruitment during bilateral relative to unilateral stimulation. Between-group contrasts demonstrated lower than normal activity in the inferior parieto-occipital lobe (suggesting deficits in sensory integration) and greater than normal left frontal lobe activity (suggesting increased attention), even during passive listening. Conclusions Together, findings suggest that early simultaneous bilateral cochlear implantation promotes normal-like auditory symmetry but that abnormalities in cortical processing consequent to deafness and/or electrical stimulation through two independent speech processors persist. [ABSTRACT FROM AUTHOR]

ABSTRACT This letter presents for the first time the development of a variable gain CMOS phase shifter using 0.18 µm CMOS process in the S-band frequencies to be integrated with conformal phased array beamforming antenna for smart communication radar applications. The vector modulator based phase shifter has an integrated variable gain amplifier codesigned with the phase shifter circuitry in order to be capable of controlling both phase and gain simultaneously which is necessary to recover the degraded radiation pattern due to the conformal shaping of the phased array antenna. The phase shifter achieves measured continuous phase shift of 303° along with measured 7 dB gain control range over 2-2.60 GHz and an insertion loss of 7.12 dB at 2.2 GHz. The measured DC power consumption of the phase shifter is 34.2 mW from a 2 V supply with a smaller chip area of 1.12 mm2 including all pads. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:324-328, 2017 [ABSTRACT FROM AUTHOR]

The article addresses the debate on the ability to detect neuronal activity emanating from deep brain structures such as the hippocampus using magnetoencephalography. The researchers concluded that the ability to detect neuronal activity in evoked responses depends on several factors, including signal strength, amount of brain noise background, and the experimental design parameters. They also showed that a weight-normalized beamformer combined with a multisphere head model can be biased in the presence of correlated brain noise.

A nonlinear association and a source localization technique were used to describe the onset and propagation of spike-and-slow-wave discharges (SWDs) in children with absence seizures. Previous studies have emphasized a leading cortical role in the generation of absence seizures in genetic epileptic rats. Synchronization between all magnetoencephalography (MEG) sensor-couples before and during SWDs in five patients was investigated over time. A source localization [beamformer, SAM(g2)] technique was used to find brain regions associated with the origin of the spikes of the SWDs. The onset of SWDs was characterized by high associations at left and right frontal regions. An alternating pattern of high synchronization was found during trains of SWDs: generalized during the wave and localized during the spike; the origin of the spike was different from the onset of SWDs, more frontal lateral and medial parietal. The localization of this latter region was confirmed with SAM(g2). The outcome of the nonlinear association techniques demonstrated that SWDs have a local cortical onset, whereas the association and beamformer technique support a local or even a focal cortical involvement in the occurrence of the spike in a train of SWDs. In all, the cortex contains local frontal and parietal sites relevant before the onset of the generalized pattern of SWDs and other ones that might contain the driving force behind the spike in trains of 3–4 Hz SWDs. [ABSTRACT FROM AUTHOR]

Previous functional magnetic resonance imaging (fMRI) studies have demonstrated that the human visual motion area V5/MT+ is differentially activated by stimuli in which the presence of motion is implied by the content of static photographs, compared with similar static scenes in which no motion is implied. Here, using a group magnetoencephalography study, we confirm the role of V5/MT+ in the perception of implied motion (IM) by the measurement and localization of task-related evoked and induced oscillatory responses, and demonstrate the temporal sequence of these responses. Within the lateral occipital complex, including V5/MT+, statistically significant differential oscillatory responses to IM and implied-static (IS) stimuli were only found in the beta band (15–20 Hz). An early, evoked, beta power increase (IM > IS) occurred at about 150 ms, whilst a power decrease (IM < IS) occurred at approximately 700 ms. We additionally show that the difference between the early evoked beta responses for the IM and IS conditions only occurs when participants are able to ascertain whether an IM or IS photograph is expected. We therefore hypothesize that the enhanced early response represents covert priming of V5/MT+ for the arrival of a motion stimuli, whilst the late-induced beta power increase for IS stimuli indicates suppression of activity within V5/MT+. [ABSTRACT FROM AUTHOR]

In research into induced neuromagnetic fields using multichannel magnetoencephalography (MEG), methods for extracting spatiotemporal information regarding neuronal activity related to a stimulus from the neuromagnetic field data obtained are sought. In this paper, we propose the virtual beamformer as one method for estimating the contribution of specific neuronal activity in neuromagnetic field data. The virtual beamformer method consists of applying directional beamforming to spatiotemporal features of neuromagnetic field data from the observation of specific neuronal activity. We apply this method to auditory evoked magnetic field data resulting from perceptual primitives of sound source movement and confirm that this method can estimate the contribution of specific neuronal activity from such data. © 2005 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 88(6): 27–33, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.20188 [ABSTRACT FROM AUTHOR]

Axially located slots are introduced into wide strip lines in high-power beamformers to suppress the excitation of higher order modes. A variational finite-element technique is used to calculate the higher order model parameters and to evaluate the operation of the slot for a typical discontinuity. © 1998 John Wiley & Sons, Inc. Microwave Opt Technol Lett 18: 1–3, 1998. [ABSTRACT FROM AUTHOR]