Hybrid multiple-antenna transceivers, which combine large-dimensional analog pre/postprocessing with lower-dimensional digital processing, are the most promising approach for reducing hardware cost and training overhead in massive MIMO systems. This article provides a comprehensive survey of various incarnations such structures that have been proposed literature. We provide taxonomy terms required channel state information, is, whether processing adapts to instantaneous or average...

Accurate prediction of the large-scale channel fading is fundamental to planning and optimization in 5G millimeter-wave cellular networks. The current methods, which are either too computationally expensive or inaccurate, unsuitable for city-scale cell optimization. This paper presents FadeNet, a convolutional neural-network enabled alternative predicting with high computation speed accuracy. By using carefully designed input features architecture capture topographical information, FadeNet...

This paper studies a variant of hybrid beamforming, namely, beamforming with selection (HBwS), as an attractive solution to reduce the hardware cost multiuser Massive Multiple-Input-Multiple-Output systems, while retaining good performance. Unlike conventional in transceiver HBwS, antenna array is fed by analog matrix L̅ input ports, where larger than number up/down-conversion chains K̅. A bank switches connects instantaneously best K̅ out ports chains. The beamformer designed based on...

Current trends in spectrum regulation show that more and unlicensed shared bands are poised to be opened up for mobile communication. However, the question remains how best utilize this build efficient networks, if time has come newer approaches considered next generation system. In work, we propose a coordinated framework can cellular standardization. designing framework, aim improve upon current access schemes toward increasing spectral efficiency highly-dense networks. To end, demonstrate...

Hybrid beamforming is an attractive solution to build cost-effective and energy-efficient transceivers for millimeter-wave terahertz systems. However, conventional hybrid techniques rely on analog components that generate a frequency flat response such as phase-shifters switches, which limits the flexibility of achievable beam patterns. As novel alternative, this paper proposes new class called Joint phase-time arrays (JPTA), additionally use true-time delay elements in create...

Analog beamforming is an attractive and cost-effective solution to exploit the benefits of massive multiple-input-multiple-output systems, requiring only one up/down-conversion chain. However, presence chain imposes a significant overhead in estimating channel state information required for beamforming, when conventional digital estimation (CE) approaches are used. As alternative, this paper proposes novel CE technique, called periodic analog (PACE), which can be performed by hardware. By...

Abstract A study is made of differences in the colouration spectrum calcium fluoride cyrstals obtained by X‐ray irradiation at different temperatures and electrolysis. The changes occuring luminescence due to use are also considered. It shown that α‐ β‐bands, usually only observed additive electrolytic colouration, can be produced if temperature between 180 250°C. formation band (the F‐band this system) difficult detect lower because 1. small number free negative ion vacancies these 2. low...

Abstract The glow curve pattern obtained for CaF 2 crystals irradiated by X‐rays at room temperature is markedly affected even a small rise (say 30 °C) in the of irradiation. This presumably due to neutral fluorine atoms which are produced holes trapped ions during X‐ray irradiation and which, elevated temperatures irradiation, form molecular complexes or diffuse out crystal. spectral composition thermoluminescence with samples similar first three peaks, except minor changes relative...

Analog beamforming greatly reduces the implementation cost of massive antenna transceivers by using only one up/down-conversion chain. However, it incurs a large pilot overhead when used with conventional channel estimation (CE) techniques. This is because these CE techniques involve digital processing, requiring chain to be time-multiplexed across dimensions. paper introduces novel technique, called continuous analog (CACE), that avoids enables at receiver and additionally provides...

Many wireless transceivers, such as massive-MIMO and Rake, are designed to provide high diversity order. In order reduce cost, low-complexity switched e.g., hybrid antenna preprocessing with selection, or S-Rake, which employ a limited number of RF chains correlators, popular. This paper shows that the presence correlators in transceivers introduces an inherent trade-off between system performance channel estimation overhead. We prove maximize achievable rate, it is optimal perform for only...

Due to its ubiquitous and contact-free nature, the use of WiFi infrastructure for performing sensing tasks has tremendous potential. However, channel state information (CSI) measured by a receiver suffers from errors in both gain phase, which can significantly hinder tasks. By analyzing these different receivers, mathematical model phase is developed this work. Based on models, several theoretically justified preprocessing algorithms correcting such at and, thus, obtaining clean CSI are...

This work proposes a novel transmission scheme, namely Reference Tone Aided Transmission (RTAT), that can enable communication in massive MIMO systems with single analog-to-digital converter at the receiver. Unlike conventional low complexity transceivers, it perform receive beamforming without explicit channel estimation or use of phase shifters, thereby leading to significant reduction overhead and simpler initial access. In RTAT, sinusoidal reference tone is transmitted along data...

Abstract The electrical and magnetic properties of uncoloured calcium fluoride crystals specimens these coloured by X‐rays electrolysis, are reported. dc conductivity dielectric loss measurements X‐ray CaF 2 show that in a freshly prepared crystal 1. the number free negative ion vacancies is very small 2. anti‐Frenkel defects which initially present associated form. These points explain why, for irradiation at room temperature, α‐band (the F‐band this system) not observed optical absorption....

Hybrid multiple-antenna transceivers, which combine large-dimensional analog pre/postprocessing with lower-dimensional digital processing, are the most promising approach for reducing hardware cost and training overhead in massive MIMO systems. This paper provides a comprehensive survey of various incarnations such structures that have been proposed literature. We provide taxonomy terms required channel state information (CSI), namely whether processing adapts to instantaneous or average...

Hybrid preprocessing, where an analogue preprocessing matrix is used to feed a large antenna array fewer up/down-conversion chains, helps reduce hardware cost of massive Multiple-Input-Multiple-Output systems. Here, we analyze variant hybrid namely with selection (HPwS), as attractive solution this while retaining good performance. In HPwS, the matrix, built from radio frequency (RF) hardware, has larger number input ports L than chains K. A bank RF switches connects instantaneously best K...

Thermoluminescence (TL) is used to study the effect of re-irradiation on Z1 centres in Ca-doped KBr crystals. The results show that with X-rays F bleached crystal destroys agreement observations made by earlier workers based purely optical absorption studies. However, present investigation clearly shows during → V recombination takes place instead conversion as suggested workers. Mittels Thermolumineszenz wird der Einfluß einer Bestrahlung von Z1-Zentren Cadotierten KBr-Kristallen...

Many practical communication systems have some form of restricted precoding or postcoding, such as antenna selection, selection combining, beam and limited feedback precoding, to name a few. The capacity analysis is, in general, difficult previous works the literature provide results only for certain simplified cases. This paper derives novel approach analyze under very generic setting. are based on asymptotic closed-form expressions second-order statistics joint distributions eigenvalues...

Many 5G applications require low complexity transceivers that can exploit the benefits of massive antenna arrays while still maintaining hardware, energy and computation costs. As a solution, this paper proposes novel multi- frequency shift reference (MA-FSR) receiver uses only one down-conversion chain, supports single spatial-stream wide-band transmission with non-coherent demodulation, perform receive beamforming without requiring phase-shifters, explicit channel estimation, or...

Abstract The optical absorption, thermoluminescence (TL), monochromatic TL, and TL spectra of potassium chloride crystals doped heavily with silver are measured after X‐irradiation at RT. effect bleaching on X‐irradiated light in the F, E, B bands both, separately together, as well thermal annealing effects defect centres studied. It is found that role holes form doubly charged impurity ions (Ag ++ ) predominant compared to host lattice Cl etc. Ag stabilised only cation sites different...

Abstract The optical transformation and thermal stability of Ag centres in KCl:Ag crystals stabilized different valence states after X‐irradiation are studied using thermoluminescence (TL) as the tool. much higher sensitivity TL over absorption enables to monitor processes with help data obtained from spectra. It is shown that 555 nm recombination luminescence emission predominant 90 °C glow peak due 0 atoms at cation sites while 543 135 + k : F centre complex. results further reveal...

A new transmission protocol for joint cooperation between a primary and secondary user in cognitive radio system is proposed. If successful decoding achieved, the primary/secondary transmitters behave as relays other system. With more efficient use of communication resource, performance enhanced. The proposed scheme builds on work [1] offers improved outage probabilities both systems. paper provides full characterization Markov Chain describing behavior closed form expression stationary...

Thermoluminescence (TL), optical absorption, and TL spectra are used to correlate the thermal annealing of Z2 centers with a peak occurring around 135 °C in Ca-doped KCl. The 210 is attributed F centers. activation energies (E) peaks, calculated using first order kinetics formula Chen found be (0.82 ± 0.03) (0.76 0.04) eV, respectively. It revealed that (i) formed along when crystal irradiated 100 °C, (ii) additional by F-bleaching at same temperature get destroyed upon reirradiation X-rays....

Millimeter-wave and Terahertz frequencies, while promising high throughput abundant spectrum, are highly susceptible to hardware non-idealities like phase-noise, which degrade the system performance make transceiver implementation difficult. While several phase-noise compensation techniques have been proposed, there limited results on post-compensation performance. Consequently, in this paper, a generalized reference-signal (RS) aided low-complexity technique is proposed for high-frequency,...