Full Dimension MIMO (FD-MIMO): Demonstrating Commercial Feasibility

Xu, Gary; Li, Yang; Yuan, Jinying; Monroe, R. A.; Rajagopal, Sridhar; Ramakrishna, Sudhir; Nam, Young‐Han; Seol, Ji-Yun; Kim, Jaeweon; Gul, Malik Muhammad Usman; Aziz, Ahsan; Zhang, Jianzhong

doi:10.1109/jsac.2017.2711150

Cited by 36 publications

(30 citation statements)

References 12 publications

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“…To generate a wide beam with all antenna elements fully excited is challenging, because a fully excited antenna array generates a narrow radiation pattern. To ensure a wide coverage, the downtilt weight vectors need to be intelligently designed for control symbols so that their transmission from the BS has a wide beam width [49], [145], which is non-trivial in FD-MIMO settings that involve a much higher number of antenna elements as compared to conventional MIMO systems.…”

Section: Wide Beam Design For Control Signalsmentioning

confidence: 99%

Elevation Beamforming With Full Dimension MIMO Architectures in 5G Systems: A Tutorial

Nadeem

Kammoun

Alouini

2019

IEEE Commun. Surv. Tutorials

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Full dimension (FD) multiple-input multiple-output (MIMO) technology has attracted substantial research attention from both wireless industry and academia in the last few years as a promising technique for next-generation wireless communication networks. FD-MIMO scenarios utilize a planar two-dimensional (2D) active antenna system (AAS) that not only allows a large number of antenna elements to be placed within feasible base station (BS) form factors, but also provides the ability of adaptive electronic beam control over both the elevation and the traditional azimuth dimensions. This paper presents a tutorial on elevation beamforming analysis for cellular networks utilizing FD Massive MIMO antenna arrays. In contrast to existing works that focus on the standardization of FD-MIMO in the 3rd Generation Partnership Project (3GPP), this tutorial is distinguished by its depth with respect to the theoretical aspects of antenna array and 3D channel modeling. In an attempt to bridge the gap between industry and academia, this preliminary tutorial introduces the relevant array and transceiver architecture designs proposed in the 3GPP Release 13 that enable elevation beamforming. Then it presents and compares two different 3D channel modeling approaches that can be utilized for the performance analysis of elevation beamforming techniques. The spatial correlation in FD-MIMO arrays is characterized and compared based on both channel modeling approaches and some insights into the impact of different channel and array parameters on the correlation are drawn. All these aspects are put together to provide a mathematical framework for the design of elevation beamforming schemes in single-cell and multi-cell scenarios. Simulation examples associated with comparisons and discussions are also presented. To this end, this paper highlights the state-of-the-art research and points out future research directions.

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Section: Wide Beam Design For Control Signalsmentioning

confidence: 99%

Elevation Beamforming With Full Dimension MIMO Architectures in 5G Systems: A Tutorial

Nadeem

Kammoun

Alouini

2019

IEEE Commun. Surv. Tutorials

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“…A good overview of different calibration methods investigated for massive MIMO systems is provided in [20] and references thereof. In general, relative calibration [8], [35] requires calibration coefficients to be calculated as the ratio of the frequency responses measured between a reference RF chain and other RF chains. This is calculated as c i =…”

Section: Review Of Calibration Methodsmentioning

confidence: 99%

“…Several antenna calibration schemes have been proposed and analyzed in the literature for massive MIMO [20], [34]. However, there is very little experimental confirmation, such as [35], regarding their feasibility in practical systems. There are no verification results available in the literature on the impact of the duration or frequency of calibration on radiation patterns or transmission.…”

mentioning

confidence: 99%

Achieving Phase Coherency and Gain Stability in Active Antenna Arrays for Sub-6 GHz FDD and TDD FD-MIMO: Challenges and Solutions

Vaghefi¹,

Palat²,

Marzin³

et al. 2020

IEEE Access

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Full-dimension MIMO (FD-MIMO) using planar active antenna systems (AAS) is considered a critical technology for fifth-generation (5G) cellular systems to improve network capacity. An AAS is typically subject to hardware impairments that negatively impact network capacity. Hence, this paper focuses on impairments that cause phase and magnitude errors between radio frequency (RF) chains and shows why they are particularly difficult to avoid in practical AAS. Although previous investigations show these impairments to degrade performance, they are not useful in deriving measurable impairment margins for practical FD-MIMO deployments. Knowing impairment limits are critical for system designers to make hardware design tradeoffs such as AAS configuration, component selection, implementation complexity, and cost. Moreover, it also helps set conformance limits for critical lab verification. Therefore, the paper first investigates the impact of the impairments and derives their practical limits for FD-MIMO by explicitly considering the cumulative effects of the channel model, inter-cell interference, link adaptation, and channel aging due to feedback delays. It is shown that a lower number of digitized RF chains can be a better choice under lower impairments. Next, the sources of impairments are investigated by using measurements carried out in the lab and the field during live operation in a commercial LTE network. Phase drift from local oscillators (LO) and internal temperature variations are identified as two significant sources. The tradeoffs and shortcomings of some of the existing solutions in massive MIMO literature are discussed. Finally, in order to address the shortcomings, a novel and practical coherent LO distribution architecture and array calibration mechanism are proposed. This solution is shown to be applicable to both TDD and FDD FD-MIMO. Measurement results are provided to prove the high degree of coherency and stability achieved on a unique array architecture called high definition active antenna system (HDAAS). INDEX TERMS Massive MIMO, FD-MIMO, calibration, phase and magnitude error, array coherency. I. INTRODUCTION M ASSIVE multiple-input and multiple-output (MIMO) using large active antenna arrays are viewed as a critical solution to solve capacity demands in Fifth Generation New Radio (5G-NR) cellular networks operating in sub-6 GHz bands. Full-dimension MIMO (FD-MIMO) defined in the 3rd Generation Partnership Project (3GPP) [1] has adopted principles of massive MIMO. It specifies the use of planar rectangular active antenna arrays at the base station (BS) to support simultaneous data transmission to multiple user equipment (UE) terminals (referred to as multiuser MIMO or MU-MIMO) to achieve significant improvement in network capacity. This topic is of active research in academia and industry [2]. A. CHALLENGES IN FIELD OPERATION DUE TO HARDWARE IMPAIRMENTS AND RELATED WORK Antenna installations on tower tops and buildings for a macro-cell network are typically limited in space and weight due to win...

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“…In the ith iteration of our DSSLNR algorithm, the elevation precoding matrix w e k,i is w e 1,Φ i , where w e 1,Φ i is the first column of matrix W e Φ i in (34). According to the matrix inversion lemma [45], we can rewrite (34) as…”

Section: Proof Of Propositionmentioning

confidence: 99%

Domain Selective Precoding in 3-D Massive MIMO Systems

Song

Liu

Wang

et al. 2019

IEEE J. Sel. Top. Signal Process.

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Three-dimensional multiple input multiple output (3-D MIMO) with a large number of active antennas equipped in a uniformly rectangular antenna array has a significant potential in improving the system capacity. In this paper, we present an efficient two-dimensional (2-D) downlink precoding scheme for single-cell 3-D massive MIMO systems. Considering instantaneous channel state information at the base station, we show that either the elevation or azimuth domain can be used for interference cancellation. We divide the interference into two components, one of which is canceled in the elevation domain, while the other is canceled in the azimuth domain. Based on this domain selective (DS) strategy, two DS precoding algorithms are proposed for the single-path scenario based on the zero forcing and signal-to-leakage-plus-noise ratio criteria. Next, we extend our DS precoding scheme to a multi-path scenario. In the proposed algorithms, the precoding vectors of different users are determined in parallel, so as to reduce the computational complexity. Simulation results are provided to demonstrate that the proposed algorithms can achieve better spectral efficiency performance with a low computational complexity. Index Terms-Three dimensional multiple-input multipleoutput (3D MIMO), inter-user interference, 2D precoding, domain selective precoding scheme. I. INTRODUCTION M ULTIPLE-INPUT multiple-output (MIMO) technology has been widely used to improve the capacity and reliability of wireless communication systems [1]-[4]. By employing tens or hundreds of antennas and simultaneously serves tens of users at the base station (BS), the massive MIMO systems have many advantages such as reduced uplink transmissions power [5], [6] and improved spectral and energy efficiencies, which

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Full Dimension MIMO (FD-MIMO): Demonstrating Commercial Feasibility

Cited by 36 publications

References 12 publications

Elevation Beamforming With Full Dimension MIMO Architectures in 5G Systems: A Tutorial

Elevation Beamforming With Full Dimension MIMO Architectures in 5G Systems: A Tutorial

Achieving Phase Coherency and Gain Stability in Active Antenna Arrays for Sub-6 GHz FDD and TDD FD-MIMO: Challenges and Solutions

Domain Selective Precoding in 3-D Massive MIMO Systems

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