Skip to content
Conference

Hierarchical RSMA in Multi-Antenna Downlink Systems: Outage Performance and Power Allocation

Jul 2026 · International Mediterranean Conference on Communications and Networking · pp. 1-6 · 0 citations · 11 references

Abstract

Rate-Splitting Multiple Access (RSMA) has emerged as a robust interference management strategy for future wireless networks. This paper investigates the performance of a hierarchical RSMA scheme in the downlink of a multi-antenna system, designed to efficiently serve clustered user deployments. We derive exact and asymptotic closed-form expressions for the outage probability of users under Nakagami- $m$ fading channels, considering a two-layer message splitting architecture (systemcommon, group-common, and private streams). Furthermore, to ensure fairness and reliability, we formulate a min-max power allocation problem to minimize the worst-case outage probability among users. A Geometric Programming-based algorithm is proposed to solve the resulting non-convex optimization problem. The numerical results validate the theoretical analysis and demonstrate the impact of different strategies for using this model, such as the number of users per group, user allocation strategies, and the number of base station transmit antennas.

View source

Similar papers

Preprint Aug 2026

RSMA-Enabled ISAC Networks with Fluid Antenna Systems: Stochastic Geometry Analysis and Low-Complexity Resource Allocation

In this paper, we investigate the downlink performance of multi-cell RSMA-enabled ISAC networks in which base stations (BSs), communication users, and sensing targets are spatially distributed according to independent Poisson point processes (PPPs). Each BS simultaneously serves multiple users using RSMA while exploiting the common stream as a dual-functional communication and sensing waveform. The users are equipped with FAS that selects the best antenna port to maximize the received signal quality. Closed-form analytical expressions are derived for the ergodic sum-rates by combining stochastic geometry, order statistics, and Laplace-transform-based interference analysis. Furthermore, a tractable approximation for the average radar SINR is developed by characterizing the statistical properties of the common precoder. Leveraging the derived analytical expressions, a low-complexity analytical resource allocation framework is proposed to jointly optimize the RSMA power allocation, the communication-sensing beam tradeoff, and the number of scheduled users while sat- isfying the sensing quality-of-service constraint. Compared with conventional iterative optimization approaches, the proposed analytical design significantly reduces computational complexity while achieving nearly identical communication performance. Simulation results verify the accuracy of the developed analytical expressions and demonstrate substantial improvements in both RSMA sum-rate and sensing performance over conventional transmission schemes.

Abdelhamid Salem, Hana Shamata, Salma M. Elkawafi et al. · 0 citations
Conference Jul 2026

Multi-RIS-Aided Satellite-Terrestrial Downlink RSMA Communication for User Fairness Exploiting Statistical CSI

As the role of satellites in sixth generation mobile communications system becomes increasingly well defined, satellite-terrestrial communications face an urgent need to improve spectral efficiency while ensuring user fairness. In this paper, we propose a multiple transmissive reconfigurable intelligent surfaces (RISs)-aided satellite-terrestrial downlink transmission scheme with rate-splitting multiple access. Based on statistical channel state information, we formulate a max-min user ergodic rate problem by jointly optimizing the satellite precoding, the phase shifts of multiple RISs, and the common-rate allocation. To tackle the resulting non-convex problem, we derive approximate closed-form expressions of multi-user ergodic rates and equivalently reformulate the problem via fractional programming. We then design a block coordinate descent-based algorithm to solve the transformed problem. Simulation results verify that the designed transmission scheme achieves significant performance gains in improving minimum user ergodic rate.

Kai Feng, Tianheng Xu, F. Takawira et al. · 0 citations
Open access Aug 2026

Hierarchical Distributed Distortion Aware Beamforming with Dynamic User Association & BS Clustering for Cell-Free Massive-MIMO Systems

The simulation results reveal that the proposed HC-DA-UA framework always outperforms the existing counterparts in terms of sum-rate, whilst substantially decreasing the computational complexity and signalling overhead, thus it is an efficient and scalable solution for next-generation hardware-impaired distributed wireless communication networks.

P. Poojitha, Dr. D. Karunakar Reddy · 0 citations
Open access Aug 2026

Performance analysis of cognitive radio-based uplink SWIPT-NOMA system with optimal power allocation

With the increasing demand for efficient wireless communication services, researchers are actively seeking innovative solutions to optimize spectrum utilization. Two promising technologies, cognitive radio and non-orthogonal multiple access (CR-NOMA), have emerged as key enablers for next-generation wireless communication. By harnessing the available radio frequency spectrum, devices can cooperatively connect and communicate more efficiently, while also gathering energy to support green communication. This study investigates the uplink simultaneous wireless power and information transfer (SWIPT) using a CR-NOMA system over Rayleigh fading channel, focusing on energy harvesting at the secondary transmitter (ST) as a cooperation node. Here, primary/secondary receivers (PR/SR) communicate with the ST, during first phase, which then utilizes the harvested power to transmit the primary data to the primary transmitter. This paper enhances the proposed system cell-edge user performance and derives analytical frameworks for outage probability, throughput, and ergodic capacity of PR, SR, respectively. Additionally, our results determine the optimal power allocation scheme to enhance the performance of PR/SR signals.

Udari Naresh, Kothapalli Sravan Abhilash · 0 citations
Open access 2026

Efficient Approximation Algorithms for Link Scheduling With Power Assignment in Wireless Networks Under SINR and Rayleigh-Fading Models

This paper investigates the Maximum Link Scheduling and Shortest Link Scheduling problems with power assignment, considering two widely adopted interference models: the Signal-to-Interference-plus-Noise Ratio (SINR) model and the Rayleigh fading model, and proposes two approximation algorithms.

A. Amirkhani, Neda Mohammadi · 0 citations
Jul 2026

Joint Load Balancing and Transmit Power Control for Energy Efficiency Maximization in the Satellite-Cell-Free Massive MIMO Uplink

This work investigates a hybrid satellite-cell-free Massive MIMO system, where multiple low-Earth-orbit (LEO) satellites jointly serve users in unison with terrestrial access points (APs) under realistic imperfect channel state information and practical user association constraints.

Ngo Tran Anh Thu, Lo Hai Long, Le Duc Anh Vu et al. · 0 citations