Analogue Wireless Beamforming Exploiting the Fiber-Nonlinearity of Radio Over Fiber-Based C-&lt;roman&gt;RANs&lt;/roman&gt;

Li, Yichuan; Ghafoor, Salman; Satyanarayana, K.; El‐Hajjar, Mohammed; Hanzo, Lajos

doi:10.1109/tvt.2019.2893589

Cited by 18 publications

(14 citation statements)

References 39 publications

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“…The RoF technology is suitable for the transport of wireless signals due to its transparency to the type of signal being transported and its support for dynamic spectrum allocation in wireless communications (Huang et al, 2018). The RoF architecture significantly reduces the complexity and cost of the RRHs, since most of the complex signal processing tasks such as frequency up-conversion, modulation and multiplexing are generally performed at the CU (Li et al, 2019).…”

Section: Conventional Analogue Radio Over Fiber Aided Centralised Ran System Modelmentioning

confidence: 99%

“…In a more recent study combining RoF with reconfigurable intelligent surface (RIS), in (Huang et al, 2021), an optical truetime delay pool-base hybrid beamforming is introduced in the RISaided C-RAN, where the analog beamforming is centrally deployed, presenting an effective algorithm for improved system performance for the RIS based C-RAN. Then, in (Li et al, 2019), the nonlinear phase shift introduced by a highly non-linear fiber is used to introduce delay over radio frequency (RF) modulated optical signals, which can be varied by controlling the optical power of each carrier passing through a parallel arrangement of highly nonlinear fibers. Meanwhile, in (Tsakyridis et al, 2021), a bandwidthreconfigurable intermediate frequency over fiber fronthaul is integrated using silicon photonic reconfigurable optical add/drop multiplexer (ROADM) with phase-shifter based 60 GHz phased array antenna, supporting a 32-element phased array antenna.…”

Section: Overview Of Radio Over Fiber Aided Beamformingmentioning

confidence: 99%

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Analog Radio Over Fiber Aided C-RAN: Optical Aided Beamforming for Multi-User Adaptive MIMO Design

Ghafoor

Butt

et al. 2021

Front. Comms. Net.

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Given the increasing demand for high data-rate, high-performance wireless communications services, the demand on the radio access networks (RAN) has been increasing significantly, where optical fiber has been widely used both for the backhaul and fronthaul. Additionally, advances in signal processing such as multiple-input multiple-output (MIMO) techniques, have improved the performance as well as transmission rate of communications networks. Beamforming has been used as an efficient MIMO technique for providing a signal to noise ratio (SNR) gain as well as reducing the multi-user interference. However, beamforming requires the employment of phase-shifters, which suffers from reduced phase resolutions, degraded noise figures as well as beam-squinting in addition to the implementation challenges. Hence, in this paper we employ an analogue radio over fiber (A-RoF) aided architecture for supporting the requirements of the current and future mobile networks, where we design a photonics aided beamforming technique in order to eliminate the bulky electronic phase-shifters and the beam-squinting effect, while also providing a low-cost RAN solution. Additionally, this photonics aided beamforming is combined with a reconfigurable multi-user MIMO technique, where users can communicate with one or multiple remote radio heads (RRHs), while employing stand-alone beamforming, beamforming combined with diversity or with multiplexing depending on the available resources and the user channel information as well as the quality of service requirements.

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Section: Conventional Analogue Radio Over Fiber Aided Centralised Ran System Modelmentioning

confidence: 99%

Section: Overview Of Radio Over Fiber Aided Beamformingmentioning

confidence: 99%

Analog Radio Over Fiber Aided C-RAN: Optical Aided Beamforming for Multi-User Adaptive MIMO Design

Ghafoor

Butt

et al. 2021

Front. Comms. Net.

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“…In particular, RoF technology can provide an essential platform for building centralized/cloud radio access network (C-RAN) which should be able to control the centralized base band units (BBU) coming from many base stations and remote radio heads (RRHs). The interconnectivity of these BBUs with RRHs is economically viable with the distribution network known as the 'fronthaul' [11], [12]. The RoF technology is then a suitable candidate for the fronthauling due to its inherent capillary properties.…”

Section: Introductionmentioning

confidence: 99%

“…The problem is particularly present in RoF systems that utilize Vertical Cavity Surface Emitting Lasers (VCSELs). Indeed, these systems, which beside mobile fronthauling [10][11][12], find applications in ever-changing scenarios like indoor distribution of wireless signals [18], machine learning methods [19] and radio astronomy [20], are attractive because these optical sources feature low cost and low power consumption.…”

Section: Introductionmentioning

confidence: 99%

Practically Feasible Closed-Loop Digital Predistortion for VCSEL-MMF-Based Radio-over-Fiber links

Hadi¹,

Nanni²,

Venard³

et al. 2020

RADIOENGINEERING

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The article demonstrates a novel Digital Predistortion (DPD) architecture for Mobile Front Haul links for the advanced Long-Term Evolution (LTE) and upcoming 5G networks. Precisely, the use of a feedback approximation method has been proposed and experimentally demonstrated herein that simplifies the complexities in realizing the practical DPD technique for Multi-Mode VCSELs and Multi-Mode Fibers based Radio over Fiber systems. As a figure of merit, linearization efficiency is provided in terms of Adjacent Channel Power Ratio, Normalized Mean Square Error and Error Vector Magnitude referring to a complete LTE frame occupying 10 MHz with 256-QAM modulation format.

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“…Another promising research direction to avoid PS ILs arose in the context of cloud radio access networks for radio over fiber systems [24]. Therein, authors design analog precoders relying on fiber non-linearity, enabling similar scanning capabilities as a phased array.…”

Section: Introductionmentioning

confidence: 99%

Wideband Hybrid Precoding Using Time Modulated Arrays

González-Coma

Castedo

2020

IEEE Access

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Hybrid digital-analog precoding is a cost effective solution for transmitting over the large bandwidths and huge antenna arrays available in the millimeter wave frequency bands. In this work we focus on the transmission of wideband signals over hybrid precoders that utilize Time-Modulated Arrays in the analog domain. We consider analog precoders constructed with Single-Pole-Double-Throw switches which are both flexible and efficient. We pose two Orthogonal Frequency-Division Multiplexing symbol configurations to cope with the harmonic interference introduced by the Time-Modulated Array. One does not take advantage of the wireless channel frequency diversity and the other does. We optimize digital and analog precoders to maximize the achievable rate in both symbol configurations. Optimization takes into account the switching devices efficiency and the inherent losses of this antenna technique. Finally, we show the excellent performance obtained with the proposed approach, in terms of achievable rate, compared to that of conventional phased arrays.

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Analogue Wireless Beamforming Exploiting the Fiber-Nonlinearity of Radio Over Fiber-Based C-<roman>RANs</roman>

Cited by 18 publications

References 39 publications

Analog Radio Over Fiber Aided C-RAN: Optical Aided Beamforming for Multi-User Adaptive MIMO Design

Analog Radio Over Fiber Aided C-RAN: Optical Aided Beamforming for Multi-User Adaptive MIMO Design

Practically Feasible Closed-Loop Digital Predistortion for VCSEL-MMF-Based Radio-over-Fiber links

Wideband Hybrid Precoding Using Time Modulated Arrays

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