Beamforming for Rotated 3D Multipanel Array Structures for 5G NR MIMO Transmission

Lee, Hyukjun; Ryu, Wonjae; Sung, Wonjin; Park, Jong‐Hyun

doi:10.1155/2019/2830792

Cited by 6 publications

(10 citation statements)

References 32 publications

(46 reference statements)

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“…■ Now we can define the Fresnel near-field region of the LIS, which is given by a distance d 0 such that when d is between d 0 and the Fraunhofer distance d F,1 , where only phase variations are noticeable but not the amplitudes and AoAs. This has been observed in [13], and from (18) to have an angle variation θ < π/8, d 0 is set to 1.2 D. However, we see from ( 14) that d 0 has to be at least 4 times large to copy with the Example 2. Therefore, although d 0 is proportional to D, it should be set larger.…”

Section: Negligible Amplitude and Angle Variationsmentioning

confidence: 96%

“…Although near-field BF has been studied in literature e.g., [5], [6], [14], [16]- [18], [25]- [27], to our best knowledge, it has not been considered from a practical implementation perspective that can cooperate with the existing far-field BF scheme such as in 5G-NR. For instance, in [14], the near-field BF vector for a microphone-array in an acoustic system is derived to be equal to the signal propagation vector, which is however, unknown at the transmitter side.…”

Section: Introductionmentioning

confidence: 99%

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Design of Near-Field Beamforming for Large Intelligent Surfaces

Hu¹,

Wang²,

ilter³

2023

Preprint

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<p> In this paper, we propose a novel near-field beamforming (BF) design for a Large Intelligent Surface (LIS) implemented as a discretized two-dimensional (2D) antenna array. We firstly investigate the definitions of near-field and far-field regions of the LIS, and determine the Fraunhofer distance which scales up linearly in the surface-area. Then, we derive the Fresnel near-field region where variations of amplitudes and angles are both negligible, as long as the distance from a user-equipment (UE) to the LIS is larger than a threshold that scales up linearly in the diameter of the LIS. Hence, in the majority region of near-field, only phase variations worsen the quality of received signal and yield significant losses of array gains. Following this observation, we present a decomposition theorem proving that in the Fresnel region, the optimal three-dimensional (3D) near-field BF can be decomposed into a conventional 2D far-field BF and a one-dimensional (1D) near-field BF. The 2D far-field BF compensates phase variations caused by the azimuth and elevation angles, while the 1D near-field BF compensates phases variations caused by distance differences among the UE and antenna-elements on the LIS. Such a 2D+1D BF design is fully compatible with existing 2D far-field BF schemes, and the 1D near-field BF can be treated as an additional step. From this perspective, we further derive an optimal codebook design of the 1D near-field BF with Lloyd-Max method. Numerical results show that the proposed 2D+1D BF is effective to recover losses of array gains in the near-field, and also robust against distance mismatches. Moreover, with a few optimized quantization points in the codebook, the 1D near-field BF performs close to optimal. </p>

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Section: Negligible Amplitude and Angle Variationsmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

Design of Near-Field Beamforming for Large Intelligent Surfaces

Hu¹,

Wang²,

ilter³

2023

Preprint

View full text Add to dashboard Cite

show abstract

“…Fig. 4 shows the number of feasible BIDs obtained using (21), when ∆β varies for three values of β 0 . Here, β 0 denotes the starting value of β bj .…”

Section: Simulationmentioning

confidence: 99%

“…The radiation pattern at a BS equipped with a full dimensional antenna array was optimized to maximize the received signal-to-noise ratio (SNR) at the location of a target user. A new class of array structures and design techniques for 3D beamforming was presented in [21].…”

Section: Introductionmentioning

confidence: 99%

Fast 3D Beamforming Technique for Millimeter-Wave Cellular Systems With Uniform Planar Arrays

2020

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The beam search protocol in cellular systems requires a significant amount of search time and network resources in order to select a serving base station with the optimal beam pair. In 3D beamforming, the processing time increases significantly because the azimuth and elevation angles need to be considered during beam search. In this paper, we propose a fast 3D beamforming technique for millimeter wave (mmWave) cellular systems with a uniform planar array (UPA). In the proposed technique, the beam search time is reduced significantly by decomposing a UPA into a set of horizontal/vertical uniform linear arrays (ULAs), from which the optimal beam direction in azimuth/elevation angle is obtained. Two types of signals, Zadoff-Chu sequence and linear frequency modulated waveform are used for designing the beam search preamble (BSP), which allows a mobile user to distinguish beams in multi-cell multi-beam environments. The strengths and weaknesses of the two proposed BSPs are analyzed after performing simulation using a simple mmWave cellular system model with UPA. Furthermore, it is demonstrated that the proposed technique significantly reduces the beam search time, i.e., number of beam scans, as compared with the conventional technique. INDEX TERMS Fast 3D beamforming, millimeter wave, uniform planar array, beam search preamble

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“…Although near-field BF has been considered in literature [5], [6], [11]- [14], to our best knowledge, it has not been considered from a practical implementation perspective that cooperates with the existing far-field BF. For instance, in [11], the near-field BF vector for a microphone-array in an acoustic system is derived to be equal to the signal propagation vector, which is however, unknown at the transmitter.…”

Section: Introductionmentioning

confidence: 99%

Near-Field Beamforming for Large Intelligent Surfaces

Ilter

Wang

2022

2022 IEEE 33rd Annual International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC)

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In this paper, we propose a novel near-field beamforming (BF) design with a Large Intelligent Surface (LIS) that is implemented as a discretized 2D-array. We first investigate the definitions of the near-field and far-field regions, and determine the Fraunhofer distance of the LIS, which scales up linearly in the surface-area of the LIS. Hence, a user-equipment (UE) can enter the near-field of a LIS in practice. In addition to Fraunhofer distance, we further derive the Fresnel near-field region where both amplitude and angle variations are negligible, as long as the distance from the UE to the LIS is larger than a threshold, which only scales up linearly in the diameter of LIS. Therefore, in the majority region of near-field, only phase variations worsen the the quality of received signal and result in significant array-gain losses. Motivated by this observation, we further propose a two-step near-field BF design that can effectively recover the array-gain losses in Fresnel near-field, and is fully compatible with a conventional far-field BF.

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Beamforming for Rotated 3D Multipanel Array Structures for 5G NR MIMO Transmission

Cited by 6 publications

References 32 publications

Design of Near-Field Beamforming for Large Intelligent Surfaces

Design of Near-Field Beamforming for Large Intelligent Surfaces

Fast 3D Beamforming Technique for Millimeter-Wave Cellular Systems With Uniform Planar Arrays

Near-Field Beamforming for Large Intelligent Surfaces

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