Beam Squint Assisted User Localization in Near-Field Communications Systems

Luo, Hong; Gao, Feifei

doi:10.48550/arxiv.2205.11392

Cited by 5 publications

(11 citation statements)

References 10 publications

(16 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…is the complex-valued channel gain 3 with β and r denoting the reference channel gain at a distance of 1 m and the distance between the BS center and the NU, respectively. b H (θ, r) denotes the near-field steering vector, which is given by [10] b…”

Section: System Modelmentioning

confidence: 99%

“…Next, based on the Fresnel integrals, we have • First, G(•) is symmetric with respect to β 1 . With β 1 defined in (10), this symmetry indicates that the normalized interference power keeps unchanged when the absolute values of the near-and-far user angle-difference θ − ψ are the same. Moreover, it is worth mentioning that G(•) is almost invariable with β 1 when β 2 is sufficiently small.…”

Section: Normalized Interference Power Analysis a Normalized Interfer...mentioning

confidence: 99%

See 1 more Smart Citation

Mixed Near- and Far-Field Communications for Extremely Large-Scale Array: An Interference Perspective

Zhang¹,

You²,

Chen³

et al. 2023

Preprint

View full text Add to dashboard Cite

Extremely large-scale array (XL-array) is envisioned to achieve super-high spectral efficiency in future wireless networks. Different from the existing works that mostly focus on the nearfield communications, we consider in this paper a new and practical scenario, called mixed near-and far-field communications, where there exist both near-and far-field users in the network. For this scenario, we first obtain a closed-form expression for the inter-user interference at the near-field user caused by the far-field beam by using Fresnel functions, based on which the effects of the number of BS antennas, far-field user (FU) angle, near-field user (NU) angle and distance are analyzed. We show that the strong interference exists when the number of the BS antennas and the NU distance are relatively small, and/or the NU and FU angle-difference is small. Then, we further obtain the achievable rate of the NU as well as its rate loss caused by the FU interference. Last, numerical results are provided to corroborate our analytical results.Index Terms-Extremely large-scale array/surface (XLarray/surface), mixed near-and far-field communications, interference analysis. I. INTRODUCTIONExtremely large-scale array/surface (XL-array/surface) has emerged as a promising technology to achieve the ever-increasing performance requirements of future sixth-generation (6G) wireless networks, such as super-high spectral efficiency and spatial resolution [1], [2]. This fundamentally leads to the communication paradigm shift from the conventional far-field communications (with planar-wave propagation) to the near-field communications (with spherical-wave propagation) [3] and even the new mixed near-and far-field communications (with both planar-/spherical-wave propagation). For example, consider an XL-array communication system where a base station (BS) equipped with an antenna of diameter 0.5 meter (m) communicates with users at 30 GHz frequency. In this case, the well-known Rayleigh distance is about 50 m [4]. As such, for a typical communication scenario, it may happen that some users reside in the nearfield region, while the others locate in the far-field region, thus leading to several new design issues such as mixed-field channel estimation, joint near-/far-field beamforming, etc.In particular, consider the inter-user interference in different communication scenarios. First, if the users considered are all in the far-field region, spatial division multiple access (SDMA) [5] or beam division multiple access (BDMA) [6] can be employed to simultaneously serve multiple users with low inter-user interference. This is because different far-field directional beams pointing towards different users are asymptotically orthogonal in Y. Zhang and C. You are with the

show abstract

Section: System Modelmentioning

confidence: 99%

Section: Normalized Interference Power Analysis a Normalized Interfer...mentioning

confidence: 99%

Mixed Near- and Far-Field Communications for Extremely Large-Scale Array: An Interference Perspective

Zhang¹,

You²,

Chen³

et al. 2023

Preprint

View full text Add to dashboard Cite

show abstract

“…A widely recognized vision for the next generation wireless communication system, such as beyond 5G (B5G) or 6G networks, is to be combined with sensing systems, realizing efficient utilization wireless resources, wide environment sensing functions, and even pursuing mutual benefits [1], [2]. Therefore, integrated sensing and communication (ISAC) is considered as one of the most important and promising technologies in the future communication systems and has attracted increasingly research interest recently [3], [4], [19], [26]. Many ISAC technologies have investigated how to improve the efficiency and quality of data transmissions in wireless communication using sensing functions [5], [6].…”

Section: Introductionmentioning

confidence: 99%

“…The success of these works has proved to us that sensing can indeed help to improve the communication systems. Conversely, communication signals also have the potential to enable sensing abilities [3], [26], which has large application prospects in user searching, emergency rescues, and many other scenarios. In particular, in the harsh environment with severe dust, thick smoke or darkness that cause low visibilities, traditional optical sensing equipments are seriously affected or even fail.…”

Section: Introductionmentioning

confidence: 99%

Millimeter Wave Wireless Communication Assisted Three-Dimensional Simultaneous Localization and Mapping

Mou¹,

Gao²

2023

Preprint

View full text Add to dashboard Cite

In this paper, we study the three-dimensional (3D) simultaneous localization and mapping (SLAM) problem in complex outdoor and indoor environments based only on millimeterwave (mmWave) wireless communication signals. Firstly, we propose a deep-learning based mapping (DLM) algorithm that can leverage the reflections point on the first-order none lineof-sight (NLOS) communications links (CLs) to build the 3D point cloud map of the environment. Specifically, we design a classification neural network to identify the first-order NLOS CL and theoretically calculate the geometric coordinates of the reflection points on it. Secondly, we take the advantage of both the inertial measurement unit and the beam-squint assisted localization method to realize real-time and precise localizations. Then, combining the DLM and the adopted localization algorithm, we develop the communication-based SLAM (C-SLAM) framework that can carry out SLAM without any prior knowledge on the environment. Moreover, extensive simulations on both complex outdoor and indoor environments validate the effectiveness of our approach.

show abstract

“…Specifically, with the significant increase of the antenna number and carrier frequency, the users are more likely to locate in the nearfield region with spherical wavefront propagation, due to the smaller user/link distance than the enlarged Rayleigh distance. As such, the conventional transceiver designs based on the farfield channel model with the planar wavefront assumption may not be applicable, hence calling for new design approaches dedicated to the near-field communication [5]- [9].…”

Section: Introductionmentioning

confidence: 99%

Fast Near-Field Beam Training for Extremely Large-Scale Array

Zhang

You

2022

IEEE Wireless Commun. Lett.

View full text Add to dashboard Cite

In this letter, we study efficient near-field beam training design for the extremely large-scale array (XL-array) communication systems. Compared with the conventional farfield beam training method that searches for the best beam direction only, the near-field beam training is more challenging since it requires a beam search over both the angular and distance domains due to the spherical wavefront propagation model. To reduce the near-field beam-training overhead based on the two-dimensional exhaustive search, we propose in this letter a new two-phase beam training method that decomposes the twodimensional search into two sequential phases. Specifically, in the first phase, the candidate angles of the user is determined by a new method based on the conventional far-field codebook and angle-domain beam sweeping. Then, a customized polardomain codebook is employed in the second phase to find the best effective distance of the user given the shortlisted candidate angles. Numerical results show that our proposed twophase beam training method significantly reduces the training overhead of the exhaustive search and yet achieves comparable beamforming performance for data transmission.

show abstract

Beam Squint Assisted User Localization in Near-Field Communications Systems

Cited by 5 publications

References 10 publications

Mixed Near- and Far-Field Communications for Extremely Large-Scale Array: An Interference Perspective

Mixed Near- and Far-Field Communications for Extremely Large-Scale Array: An Interference Perspective

Millimeter Wave Wireless Communication Assisted Three-Dimensional Simultaneous Localization and Mapping

Fast Near-Field Beam Training for Extremely Large-Scale Array

Contact Info

Product

Resources

About