Maximizing the Geometric Mean of User-Rates to Improve Rate-Fairness: Proper vs. Improper Gaussian Signaling

Yu, Hongwen; Tuan, Hoang Duong; Dutkiewicz, Eryk; Poor, H. Vincent; Hanzo, Lajos

doi:10.1109/twc.2021.3095174

Cited by 33 publications

(33 citation statements)

References 39 publications

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“…IGS was employed as an interference-management technique for the first time in [8], where the authors showed that IGS can increase the degrees-of-freedom (DoF) of the 3-user IC. In the last decade, IGS has been applied to various interference-limited systems, showing that it can increase the spectral and energy efficiency of such systems with TIN [9]- [31]. For instance, the papers [11]- [14] showed that IGS can improve the rate and/or energy efficiency (EE) of the secondary user in cognitive radio systems.…”

Section: A Related Workmentioning

confidence: 99%

“…How to solve the aforementioned challenges remains an open question in RIS-assisted systems. RIS is an emerging technology, which has been shown to be able to improve the spectral and energy efficiency of various systems [1]- [4], [31], [36]- [46]. For example, the papers [37]- [39], [46] considered various performance metrics such as global energy efficiency (GEE), sum rate, minimum SINR and showed that RIS can improve the spectral and energy efficiency of a single-cell BC with a multi-antenna BS and multiple single-antenna users.…”

Section: A Related Workmentioning

confidence: 99%

“…After updating the covariance matrices, we fix them and solve (47) over the reflecting-coefficient matrices. The resulting problem has a structure similar to (31), and hence we can employ a similar approach to solve it. However, due to the rate constraint and the format of EE functions, we have to modify the constraints.…”

Section: Maximizing the Minimum Weighted Eementioning

confidence: 99%

See 2 more Smart Citations

Improper Signaling for Multicell MIMO RIS-Assisted Broadcast Channels With I/Q Imbalance

Soleymani

Santamarı́a

Schreier

2022

IEEE Trans. on Green Commun. Netw.

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In this paper, we study the performance of reconfigurable intelligent surfaces (RISs) in a multicell broadcast channel (BC) that employs improper Gaussian signaling (IGS) jointly with non-orthogonal multiple access (NOMA) to optimize either the minimum-weighted rate or the energy efficiency (EE) of the network. We show that although the RIS can significantly improve the system performance, it cannot mitigate interference completely, so we have to employ other interference-management techniques to further improve performance. We show that the proposed NOMA-based IGS scheme can substantially outperform proper Gaussian signaling (PGS) and IGS schemes that treat interference as noise (TIN) in particular when the number of users per cell is larger than the number of base station (BS) antennas (referred to as overloaded networks). In other words, IGS and NOMA complement to each other as interference management techniques in multicell RIS-assisted BCs. Furthermore, we consider three different feasibility sets for the RIS components showing that even a RIS with a small number of elements provides considerable gains for all the feasibility sets.

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Section: A Related Workmentioning

confidence: 99%

Section: A Related Workmentioning

confidence: 99%

Section: Maximizing the Minimum Weighted Eementioning

confidence: 99%

See 1 more Smart Citation

Improper Signaling for Multicell MIMO RIS-Assisted Broadcast Channels With I/Q Imbalance

Soleymani

Santamarı́a

Schreier

2022

IEEE Trans. on Green Commun. Netw.

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“…C. Algorithm Algorithm 1 provides the pseudo-code for the proposed steep descent computational procedure of (7) as the iterations ( 22) and (32) seek a descent direction by seeking a better feasible point for the nonconvex problem (7).…”

Section: B Programmable Reflecting Elements' Descent Iterationmentioning

confidence: 99%

Finite-Blocklength RIS-Aided Transmit Beamforming

M.¹,

Tuan²,

Nguyen³

et al. 2022

Preprint

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This paper considers the downlink of an ultrareliable low-latency communication (URLLC) system in which a base station (BS) serves multiple single-antenna users in the short (finite) blocklength (FBL) regime with the assistance of a reconfigurable intelligent surface (RIS). In the FBL regime, the users' achievable rates are complex functions of the beamforming vectors and of the RIS's programmable reflecting elements (PREs). We propose the joint design of the transmit beamformers and PREs, the problem of maximizing the geometric mean (GM) of these rates (GM-rate) and show that this aforementioned results are providing fair rate distribution and thus reliable links to all users. A novel computational algorithm is developed, which is based on closed forms to generate improved feasible points, using its execution. The simulations show the merit of our solution.

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“…Contributing to the general line of work outlined above, we propose in this article a novel joint AP access configuration, power allocation, and beamforming algorithm for dynamic TDD-based CF-mMIMO systems, which aims at a reasonable optimized solution that balances system throughput and user fairness. To this end, we consider the maximization of the geometric mean of the UEs' throughput so as to maximize the total throughput utility while reducing the variance among the UE's achievable throughputs, which is motivated by recent studies such as those in [26], [27]. The resulting maximization problem involving the geometric mean objective function is highly intractable, due not only to the non-convexity of the signal-to-interference-and-noise ratio (SINR) expression, but also to the binary (discrete) feasibility set of DL/UL AP access configuration.…”

Section: Introductionmentioning

confidence: 99%

Joint Access Configuration and Beamforming for Cell-Free Massive MIMO Systems With Dynamic TDD

et al. 2022

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We address the trade-off between system throughput and user equipment (UE) fairness in dynamic time division duplex (TDD) cell-free (CF)-massive multiple-input multiple-output (mMIMO) systems, developing to that end a joint access point (AP) access configuration, power allocation, and beamforming design scheme. Unlike state-of-the-art (SotA) methods, which mostly focus on sum-rate maximization or max-min worst case optimization, our design approach is to maximize the geometric mean of the UEs' throughput performance under a constrained transmit power, which is shown to yield an excellent compromise between system throughput and user fairness. The direct reformulation of the resulting optimization problem is, however, hard to solve due not only to the non-convexity of the objective function, but also to the binary constraint induced by the AP access configuration. We thus present an efficient (i.e., polynomial time complexity) solution for the problem via a combination of fractional programming (FP) and convex-concave procedure (CCP), assisted by a negative entropy regularizer that promotes a binary solution. Numerical simulations are offered to evaluate the throughput performance and fairness index of the proposed algorithm in comparison not only to conventional TDD-based solutions, but also to recent dynamic TDD SotA designs, which illustrate the effectiveness of the proposed approach over existing methodologies both in throughput and fairness.INDEX TERMS Cell-free massive multiple-input multiple-output, convex optimization, convex-concave procedure, dynamic time-division duplex, geometric mean, fractional programming.

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Maximizing the Geometric Mean of User-Rates to Improve Rate-Fairness: Proper vs. Improper Gaussian Signaling

Cited by 33 publications

References 39 publications

Improper Signaling for Multicell MIMO RIS-Assisted Broadcast Channels With I/Q Imbalance

Improper Signaling for Multicell MIMO RIS-Assisted Broadcast Channels With I/Q Imbalance

Finite-Blocklength RIS-Aided Transmit Beamforming

Joint Access Configuration and Beamforming for Cell-Free Massive MIMO Systems With Dynamic TDD

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