Downlink Spectral Efficiency of Cell-Free Massive MIMO Systems With Multi-Antenna Users

Trang, C.; Ngo, Hien Quoc; Duong, Trung Q.

doi:10.1109/tcomm.2020.2990951

Cited by 88 publications

(72 citation statements)

References 34 publications

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“…The channel gain between k th UE and n th antenna of l th AP is given by Mai et al 18

g_{l n k} = L_{l n k}^{- b} F_{l n k}^{\frac{1}{2}} h_{l n k}

…”

Section: Radio Stripe Network Modelmentioning

confidence: 99%

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Analytical outage and coverage performance analysis of cell‐free massive MIMO system based on radio stripe

Mishra¹,

Ponnusamy²

2021

Int J Communication

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Summary Cell‐free mMIMO (massive multiple input multiple output) is slated to be beyond 5G (B5G) wireless technology, given the attractive features it offers, higher spectral efficiency, higher‐energy efficiency, and superior spatial diversity. However, large numbers of long cables between each access point (AP) and central processing unit (CPU) (front haul requirements) mar its practical adoption. Radio stripe is one such architecture of cell‐free mMIMO suitable for practical deployment. In this work, we derive the closed‐form expression of probability of outage in the uplink of Cell‐Free mMIMO System Based on Radio Stripe (CFMMSBRS) and coverage probability in the downlink of CFMMSBRS, respectively. We employ, Welch–Satterthwaite approximation for accurate approximation of sum of independent gamma random variables with different shape and rate parameter. Results indicate that both outage and coverage achieved good performance especially when numbers of APs L in radio stripe network are greater than numbers of user equipments (UEs) K in the network.

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“…The channel gain between k th UE and n th antenna of l th AP is given by Mai et al 18

g_{l n k} = L_{l n k}^{- b} F_{l n k}^{\frac{1}{2}} h_{l n k}

…”

Section: Radio Stripe Network Modelmentioning

confidence: 99%

“…Analysis of cell‐free mMIMO has been carried out mainly for SE and energy efficiency 16‐20 . Other important performance metrices such as probability of outage are difficult to derive exactly in closed form 21 .…”

Section: Introductionmentioning

confidence: 99%

Analytical outage and coverage performance analysis of cell‐free massive MIMO system based on radio stripe

Mishra¹,

Ponnusamy²

2021

Int J Communication

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show abstract

“…In cell-free massive MIMO systems, all APs are connected and cooperate with the central processing unit through a fronthaul network to provide services for all users through time division duplex technology on the same time-frequency resources [2]. Considering the large-scale deployment of APs, cell-free massive MIMO systems have favourable propagation and channel hardening characteristics, so they have significant advantages in spectral efficiency [3]. However, the benefits of cell-free massive MIMO come at the expense of increased fronthaul capacity requirements.…”

Section: Introductionmentioning

confidence: 99%

Performance of Cell-Free Massive MIMO With Joint User Clustering and Access Point Selection

et al. 2021

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We consider an uplink cell-free massive multiple-input multiple-output (MIMO) system, in which the access points are connected to the central processing unit (CPU) through a fronthaul network. This system has the advantages of wide coverage and flexible deployment. However, the performance of this system depends on a capacity-limited fronthaul, and when the fronthaul is saturated, the quality of service will be reduced. To address this issue, we propose a joint user clustering and AP selection scheme, which can reduce the pressure on the fronthaul link while taking into account the system performance and computational complexity. We first derive a closed-form expression for the uplink spectral efficiency over Rician fading channels. Based on the derived expression, we formulate the problem of maximizing the minimum uplink spectral efficiency across all users by jointly optimizing the large-scale fading decoding (LSFD) coefficient and power control coefficient. Then, combined with the optimization results and channel estimation error, a suboptimal access point selection scheme is proposed. In addition, we propose a user clustering scheme to further reduce the complexity of the AP selection scheme. The simulation results show that the joint user clustering and access point selection scheme can reduce the system fronthaul link pressure, while the performance degrades only slightly.INDEX TERMS Access point selection, cell-free massive MIMO, spectral efficiency, User clustering.

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“…However, in [8], multiple‐antenna APs have been analysed in order to improve channel hardening and to increase the likelihood that favourable propagation occurs. In the same way, [23] explores the downlink spectral efficiency in a scenario with multiple‐antenna APs and users. Additionally, in [24] it is shown that, in terms of costs, it is better to add more antennas to an AP than to install more APs.…”

Section: Introductionmentioning

confidence: 99%

Iterative AP selection, MMSE precoding and power allocation in cell‐free massive MIMO systems

et al. 2020

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In this work, the authors proposed the iterative access point (AP) selection (APS), linear minimum mean-square error (MMSE) precoding and power allocation techniques for cell-free massive multiple-input multiple-output (MIMO) systems. They considered the downlink channel with single-antenna users and multiple-antenna APs. They derive sum-rate expressions for the proposed iterative APS techniques followed by MMSE precoding and optimal, adaptive, and uniform power allocation schemes. Simulations show that the proposed approach outperforms existing conjugate beamforming and zero-forcing schemes and that performance remains excellent with APS, in the presence of perfect and imperfect channel state information.

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Downlink Spectral Efficiency of Cell-Free Massive MIMO Systems With Multi-Antenna Users

Cited by 88 publications

References 34 publications

Analytical outage and coverage performance analysis of cell‐free massive MIMO system based on radio stripe

Analytical outage and coverage performance analysis of cell‐free massive MIMO system based on radio stripe

Performance of Cell-Free Massive MIMO With Joint User Clustering and Access Point Selection

Iterative AP selection, MMSE precoding and power allocation in cell‐free massive MIMO systems

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