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arxiv: 2606.05600 · v1 · pith:6Z75GOFDnew · submitted 2026-06-04 · 💻 cs.IT · math.IT

Energy Efficiency Optimization for Rotatable Antenna-Enabled Uplink NOMA Systems

Yixuan Li , Jun Wang , Hongbo Xu , Ji Wang This is my paper

Pith reviewed 2026-06-27 23:54 UTC · model grok-4.3

classification 💻 cs.IT math.IT
keywords rotatable antennaNOMAenergy efficiencyuplinkbeamformingoptimizationaerial usersblock coordinate descent
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The pith

Joint optimization of rotatable antennas, beamforming and power boosts energy efficiency in uplink NOMA.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The paper studies an uplink NOMA setup in which a base station with multiple independently rotatable antennas serves both ground and aerial users. It formulates an energy-efficiency maximization problem that jointly tunes receive beamforming, user transmit powers, and antenna rotation angles. To solve the non-convex problem, the authors apply a block coordinate descent procedure that alternates minimum-mean-square-error beamforming updates with fractional-programming power allocation and successive-convex-approximation rotation optimization. Numerical experiments indicate that the resulting rotatable-antenna NOMA scheme attains higher energy efficiency than fixed-antenna NOMA and other reference schemes.

Core claim

By jointly optimizing receive beamforming via the minimum mean square error criterion, power allocation via fractional programming, and rotatable-antenna angles via successive convex approximation inside a block coordinate descent loop, the RA-NOMA scheme achieves higher energy efficiency than several fixed-antenna and orthogonal-access benchmarks in uplink scenarios containing both ground and aerial users.

What carries the argument

Block coordinate descent algorithm that decomposes the joint energy-efficiency problem into MMSE beamforming, fractional-programming power control, and successive-convex-approximation antenna rotation subproblems.

If this is right

  • Rotatable antennas supply extra spatial degrees of freedom that improve energy efficiency when users are located at different elevations.
  • The block coordinate descent procedure yields stationary points whose energy-efficiency values exceed those of schemes that fix antenna angles.
  • Fractional programming combined with successive convex approximation renders the originally intractable joint optimization tractable while preserving the observed gains.
  • The reported energy-efficiency ordering holds for both ground-only and mixed ground-aerial user populations under the stated NOMA decoding order.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • The same rotation optimization could be applied to downlink NOMA or to orthogonal multiple access to test whether the gains are specific to uplink NOMA.
  • Mechanical constraints on rotation speed and precision would need to be incorporated before claiming real-time feasibility.
  • Replacing perfect channel state information with estimated channels would reveal how robust the algorithm remains to estimation error.
  • Extending the model to multiple cells would show whether inter-cell interference reduces or preserves the rotatable-antenna advantage.

Load-bearing premise

The idealized channel models and perfect hardware assumptions used in the system model remain representative of real conditions when energy-efficiency gains are evaluated.

What would settle it

A hardware experiment with actual rotatable antennas and real channel measurements that shows no energy-efficiency advantage over fixed-antenna NOMA under the same user mix and power constraints would falsify the superiority claim.

Figures

Figures reproduced from arXiv: 2606.05600 by Hongbo Xu, Ji Wang, Jun Wang, Yixuan Li.

Figure 1
Figure 1. Figure 1: RA enabled uplink NOMA system. KG + KA single-antenna mobile users, including KG ground users and KA aerial users. Here, Nx and Ny denote the numbers of rows and columns of the RA array, respectively. To facilitate the subsequent mathematical formulation, we use N ∆= {1, ..., N} and K ∆= {1, ..., K} to represent the index sets of the RAs and users, respectively. We assume that the considered system is desc… view at source ↗
Figure 2
Figure 2. Figure 2: Convergence behavior of the proposed algorithms. [PITH_FULL_IMAGE:figures/full_fig_p004_2.png] view at source ↗
Figure 5
Figure 5. Figure 5: Number of antennas versus energy efficiency. [PITH_FULL_IMAGE:figures/full_fig_p005_5.png] view at source ↗
Figure 4
Figure 4. Figure 4: Antenna directivity factor versus energy efficiency [PITH_FULL_IMAGE:figures/full_fig_p005_4.png] view at source ↗
read the original abstract

This paper investigates a rotatable antenna (RA)-enabled uplink non-orthogonal multiple access (NOMA) system, where a base station equipped with multiple independently RAs serves both ground and aerial users. Specifically, we formulate an energy efficiency (EE) maximization problem by jointly optimizing receive beamforming, user power allocation, and RA rotation. To make the problem tractable, a new block coordinate descent-based algorithm is developed, in which the receive beamforming is updated via the minimum mean square error criterion, while the power allocation and RA rotation are handled by fractional programming and successive convex approximation. Numerical results demonstrate the EE superiority of the proposed RA-NOMA scheme over several benchmarks.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

0 major / 3 minor

Summary. The manuscript formulates an energy-efficiency maximization problem for an uplink NOMA system in which a multi-antenna base station equipped with independently rotatable antennas serves both ground and aerial users. The joint optimization of MMSE receive beamforming, power allocation, and antenna rotation angles is solved via a block coordinate descent algorithm that alternates MMSE updates, fractional programming, and successive convex approximation. Numerical results are reported to demonstrate that the proposed RA-NOMA scheme achieves higher energy efficiency than several benchmark schemes under the considered channel and hardware model.

Significance. If the reported gains hold, the work supplies a concrete algorithmic demonstration that rotatable antennas can improve energy efficiency in mixed terrestrial-aerial NOMA deployments. The approach relies on standard, well-understood techniques (BCD, MMSE, FP, SCA) whose convergence behavior and benchmark comparisons are presented at a level typical for the venue; the idealized CSI and hardware assumptions are explicitly stated.

minor comments (3)
  1. [Abstract] The abstract states that the scheme outperforms 'several benchmarks' but does not name them; the introduction or simulation section should list the exact benchmark schemes (e.g., fixed-orientation NOMA, OMA, etc.) for reproducibility.
  2. [Section IV] Section IV (algorithm description) presents the BCD procedure but does not include a short monotonicity or convergence-rate argument; adding one sentence referencing the standard properties of FP and SCA would strengthen the exposition without lengthening the paper.
  3. [Numerical Results] Figure captions for the numerical results should explicitly state the number of Monte-Carlo channel realizations and the precise parameter values (e.g., noise power, circuit power) used to generate each curve.

Simulated Author's Rebuttal

0 responses · 0 unresolved

We thank the referee for the positive assessment of our manuscript on energy efficiency optimization for rotatable antenna-enabled uplink NOMA systems and for recommending minor revision. No major comments were provided in the report.

Circularity Check

0 steps flagged

No significant circularity in derivation chain

full rationale

The paper formulates a standard EE maximization problem under an idealized system model and solves it via BCD with MMSE beamforming, fractional programming, and SCA. The central claim rests on numerical simulations comparing the RA-NOMA scheme to benchmarks; these results are generated from the optimization outputs rather than reducing any performance metric to a fitted quantity or self-citation by construction. No self-definitional steps, fitted-input predictions, or load-bearing self-citations appear in the derivation. The framework is self-contained against external benchmarks and uses conventional techniques without smuggling ansatzes or renaming known results.

Axiom & Free-Parameter Ledger

0 free parameters · 0 axioms · 0 invented entities

Only the abstract is available, so the full set of modeling assumptions, free parameters, and any invented entities cannot be audited from the provided information.

pith-pipeline@v0.9.1-grok · 5640 in / 999 out tokens · 19407 ms · 2026-06-27T23:54:46.590395+00:00 · methodology

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Reference graph

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