Interference Management Scheme Research Articles

Interference management in 5G and beyond networks: A comprehensive survey

During the last decade, wireless data services have had an incredible impact on people’s lives in ways we could never have imagined. The number of mobile devices has increased exponentially and data traffic has almost doubled every year. Undoubtedly, the rate of growth will continue to be rapid with the explosive increase in demands for data rates, latency, massive connectivity, network reliability, and energy efficiency. In order to manage this level of growth and meet these requirements, the fifth-generation (5G) mobile communications network is envisioned as a revolutionary advancement combining various improvements to previous mobile generation networks and new technologies, including the use of millimeter wavebands (mm-wave), massive multiple-input multiple-output (mMIMO) multi-beam antennas, network densification, dynamic Time Division Duplex (TDD) transmission, and new waveforms with mixed numerologies. New revolutionary features including terahertz (THz) communications and the integration of Non-Terrestrial Networks (NTN) can further improve the performance and signal quality for future 6G networks. However, despite the inevitable benefits of all these key technologies, the heterogeneous and ultra-flexible structure of the 5G and beyond network brings non-orthogonality into the system and generates significant interference that needs to be handled carefully. Therefore, it is essential to design effective interference management schemes to mitigate severe and sometimes unpredictable interference in mobile networks. In this paper, we provide a comprehensive review of interference management in 5G and Beyond networks and discuss its future evolution. We start with a unified classification and a detailed explanation of the different types of interference and continue by presenting our taxonomy of existing interference management approaches. Then, after explaining interference measurement reports and signaling, we provide for each type of interference identified, an in-depth literature review and technical discussion of appropriate management schemes. We finish by discussing the main interference challenges that will be encountered in future 6G networks and by presenting insights on the suggested new interference management approaches, including useful guidelines for an AI-based solution. This review will provide a first-hand guide to the industry in determining the most relevant technology for interference management, and will also allow for consideration of future challenges and research directions.

A modified joint decoding scheme for RSMA-aided downlink

Rate splitting multiple access (RSMA) is envisioned as a promising next generation mobile communication. Numerous studies have demonstrated the superior performance of RSMA over conventional multiple access due to its powerful interference management strategy and flexible multi-user management. However, a potential issue of decoding at the receiver is ignored due to its unplanned power allocation to multi-user, which leads to a substantial reduction in outage performance and additional energy consumption. To overcome the above issues, in this paper, a novel joint decoding design for the RSMA is investigated to improve the overall performance in terms of outage probability and energy consumption. The focus of the investigation is to decode common and private messages at the receiver, providing the suboptimal power allocation to enhance decoding accuracy and reduce energy consumption. Unlike conventional RSMA decoding schemes, the common message and corresponding private messages will be superposed as a new desired signal to be decoded, in order to avoid the decoding signal power being smaller than the interference one by means of successive interference cancellation (SIC). Specifically, we investigate and analyze the outage performance by satisfying the rate constraints for our proposed joint decoding scheme. Assuming Rayleigh fading channels, from the provided numerical results and simulations, they are well matched in terms of outage probability to clarify the correctness of the theoretical analysis, as well as illustrate the superiorities of our proposed scheme compared with conventional RSMA. The research results provide a theoretical basis for the development of future multi-user decoding.

TD3-Based Optimization Framework for RSMA-Enhanced UAV-Aided Downlink Communications in Remote Areas

The need for reliable wireless communication in remote areas has led to the adoption of unmanned aerial vehicles (UAVs) as flying base stations (FlyBSs). FlyBSs hover over a designated area to ensure continuous communication coverage for mobile users on the ground. Moreover, rate-splitting multiple access (RSMA) has emerged as a promising interference management scheme in multi-user communication systems. In this paper, we investigate an RSMA-enhanced FlyBS downlink communication system and formulate an optimization problem to maximize the sum-rate of users, taking into account the three-dimensional FlyBS trajectory and RSMA parameters. To address this continuous non-convex optimization problem, we propose a TD3-RFBS optimization framework based on the twin-delayed deep deterministic policy gradient (TD3). This framework overcomes the limitations associated with the overestimation issue encountered in the deep deterministic policy gradient (DDPG), a well-known deep reinforcement learning method. Our simulation results demonstrate that TD3-RFBS outperforms existing solutions for FlyBS downlink communication systems, indicating its potential as a solution for future wireless networks.

MILIMETER-WAVE MASSIVE MIMO: A PROMISING TECHNOLOGY FOR NEW AND EMERGING NETWORKS

This paper presents a review of the mm Wave technology and the massive MIMO technology first as individual technologies detailing their potentials and challenges. It also presents a review of the combined technologies, their channel models, various spectrum, interference and handover management schemes as a promising technology for new and emerging networks.

Interference mitigation in intentional jammers aided non-uniform heterogeneous cellular networks.

Coverage and capacity are optimized in fifth generation (5G) networks by small base station (SBS) distribution in the coverage realm of macro base station (MBS). However, system performance is significantly reduced by inter-cell interference (ICI) because of the orthogonal frequency division multiple access assumption. In addition to ICI, this work considers intentional jammers' interference (IJI) due to the presence of jammers. These Jammers try to inject undesirable energies into the legitimate communication band, which significantly degrade uplink (UL) signal-to-interference ratio (SIR). To reduce ICI and IJI, in this work, we employ SBS muting, where the SBSs near MBS are switched off. To further mitigate ICI and IJI, we use one of the effective interference management schemes a.k.a reverse frequency allocation (RFA). We presume that due to mitigation in ICI and IJI, the UL coverage performance of the proposed network model can be further improved.

A Primer on Rate-Splitting Multiple Access: Tutorial, Myths, and Frequently Asked Questions

Rate-Splitting Multiple Access (RSMA) has emerged as a powerful multiple access, interference management, and multi-user strategy for next generation communication systems. In this tutorial, we depart from the orthogonal multiple access (OMA) versus non-orthogonal multiple access (NOMA) discussion held in 5G, and the conventional multi-user linear precoding approach used in space-division multiple access (SDMA), multi-user and massive MIMO in 4G and 5G, and show how multi-user communications and multiple access design for 6G and beyond should be intimately related to the fundamental problem of interference management. We start from foundational principles of interference management and rate-splitting, and progressively delineate RSMA frameworks for downlink, uplink, and multi-cell networks. We show that, in contrast to past generations of multiple access techniques (OMA, NOMA, SDMA), RSMA offers numerous benefits: 1) enhanced spectral, energy and computation <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">efficiency</i> ; 2) <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">universality</i> by unifying and generalizing OMA, SDMA, NOMA, physical-layer multicasting, multi-user MIMO under a single framework that holds for any number of antennas at each node (SISO, SIMO, MISO, and MIMO settings); 3) flexibility by coping with any interference levels (from very weak to very strong), network loads (underloaded, overloaded), services (unicast, multicast), traffic, user deployments (channel directions and strengths); 4) <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">robustness</i> to inaccurate channel state information (CSI) and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">resilience</i> to mixed-critical quality of service; 5) <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">reliability</i> under short channel codes and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">low latency</i> . We then discuss how those benefits translate into numerous opportunities for RSMA in over forty different applications and scenarios of 6G, e.g., multi-user MIMO with statistical/quantized CSI, FDD/TDD/cell-free massive MIMO, millimeter wave and terahertz, cooperative relaying, physical layer security, reconfigurable intelligent surfaces, cloud-radio access network, internet-of-things, massive access, joint communication and jamming, non-orthogonal unicast and multicast, multigroup multicast, multibeam satellite, space-air-ground integrated networks, unmanned aerial vehicles, integrated sensing and communications, grant-free access, network slicing, cognitive radio, optical/visible light communications, mobile edge computing, machine/federated learning, etc. We finally address common myths and answer frequently asked questions, opening the discussions to interesting future research avenues. Supported by the numerous benefits and applications, the tutorial concludes on the underpinning role played by RSMA in next generation networks, which should inspire future research, development, and standardization of RSMA-aided communication for 6G.

Guest Editorial Rate Splitting for Future Wireless Networks

Rate splitting (RS) and rate splitting multiple access (RSMA) have emerged as a promising and powerful multiple access, interference management, and multi-user strategy for next-generation wireless systems and networks. This Special Issue is entirely dedicated to the theory, design, optimization, and applications of RS and RSMA in various network configurations. It starts with a guest editor-authored tutorial paper [A1] that delineates the basic principles and applications of RS and RSMA. The tutorial paper is then followed by 17 technical papers.

When Virtual Reality Meets Rate Splitting Multiple Access: A Joint Communication and Computation Approach

Rate Splitting Multiple Access (RSMA) has emerged as an effective interference management scheme for applications that require high data rates. Although RSMA has shown advantages in rate enhancement and spectral efficiency, it has yet not to be ready for latency-sensitive applications such as virtual reality streaming, which is an essential building block of future 6G networks. Unlike conventional High-Definition streaming applications, streaming virtual reality applications requires not only stringent latency requirements but also the computation capability of the transmitter to quickly respond to dynamic users' demands. Thus, conventional RSMA approaches usually fail to address the challenges caused by computational demands at the transmitter, let alone the dynamic nature of the virtual reality streaming applications. To overcome the aforementioned challenges, we first formulate the virtual reality streaming problem assisted by RSMA as a joint communication and computation optimization problem. A novel multicast approach is then proposed to cluster users into different groups based on a Field-of-View metric and transmit multicast streams in a hierarchical manner. After that, we propose a deep reinforcement learning approach to obtain the solution for the optimization problem. Extensive simulations show that our framework can achieve the millisecond-latency requirement, which is much lower than other baseline schemes.

Exploiting Collaborative Computing to Improve Downlink Sum Rate in Satellite Integrated Terrestrial Networks

In this paper, we target at improving the downlink user sum rate in satellite integrated terrestrial network (SITN). Wherein, the densely deployed low earth orbit (LEO) satellites provide backhaul to terrestrial base stations (TBSs) and TBSs serve the ground users (GUs) over different bands. Note that the user sum rate is dependent on the user association and backhaul capacity. Moreover, the backhaul capacity is determined by multi-connectivity feature between the TBSs and LEO satellites. However, the densification and high dynamics of SITN aggravate the inter-satellite interference, which degrades the backhaul capacity. To this end, we propose a joint interference management and user association (JIMUA) scheme, which exploits collaborative computing to enhance the backhaul capacity and satisfy the user demands. The service demands of GUs and dwell duration of LEO satellites can be captured by introducing a collaborative computing coefficient. With this aid, the TBSs can predict the highly dynamic trajectory of dense deployed LEO satellites. Accordingly, the searching space of satellites can be reduced, the interference can be mitigated and backhaul capacity can be improved with high time efficiency. Moreover, the user association is achieved by dividing GUs into different groups, while the required user demands can be satisfied. Considering the dense deployment of LEO satellites, the user sum rate of SITN could be enhanced by JIMUA compared with the benchmark. With the well tuned collaborative computing coefficient, the backhaul capacity can be increased over 12%. Consequently, the user sum rate can be improved over 7%. Moreover, with the increasing user density, the gap between the user sum rate of JIMUA and the optimal solution can be reduced to less than 4%.

Integer Forcing Interference Management for the MIMO Interference Channel

A new interference management scheme based on integer forcing (IF) receivers is studied for the two-user multiple-input and multiple-output (MIMO) interference channel. The proposed scheme employs a message splitting method that divides each data stream into common and private sub-streams, in which the private stream is recovered by the dedicated receiver only while the common stream is required to be recovered by both receivers. Specifically, to enable IF sum decoding at the receiver side, all streams are encoded using the same lattice code. Additionally, the number of common and private streams of each user is carefully determined by considering the number of antennas at transmitters and receivers, the channel matrices, and the effective signal-to- noise ratio (SNR) at each receiver to maximize the achievable rate. Furthermore, we consider various assumptions of channel state information at the transmitter side (CSIT) and propose low-complexity linear transmit beamforming suitable for each CSIT assumption. The achievable sum rate and rate region are analytically derived and extensively evaluated by simulation for various environments, demonstrating that the proposed interference management scheme strictly outperforms the previous benchmark schemes in a wide range of channel parameters due to the gain from IF sum decoding.

One-bit signaling-based interference management for MIMO V2V sidelink

Massive multiple-input multiple-output can significantly increase the system capacity by allowing vehicle-to-infrastructure (V2I) and vehicle-to-vehicle (V2V) networks to share the radio resource pool, if the inter-network interference is constrained. However, in order to control the inter-network interference, it is necessary to exchange channel state information (CSI) between the V2I and V2V networks, which requires a huge amount of signaling resources. This paper proposes an one-bit signaling-based interference management scheme to reduce the signaling overhead while controlling the interference from the V2V network to the V2I network.

Joint Resource Allocation and Power Control for Full-Duplex V2I Communication in High-Density Vehicular Network

It is significant to satisfy the diverse Vehicle-to-everything (V2X) Quality of Service (QoS) demands for the high-density vehicular network. The wireless full-duplex (FD) technique focuses on improving the spectrum efficiency and raising the system throughput. In this paper, the vehicle-to-vehicle (V2V) links are deployed in an FD cellular network. However, the resource allocation and power control become challenging, due to the excess self-interference (SI) at the FD base station (BS) and the interference from the V2I uplink to downlink sharing the same resource block (RB). A Dual Graph Coloring-based Interference Management (DGCIM) scheme is proposed to solve the tricky problem. The DGCIM scheme includes a GrouPing Graph Coloring with Recursive Largest First (GPGC-RLF) algorithm and a GreedY Graph Coloring (GYGC) algorithm. The simulation results illustrate the guarantee of the stringent reliability and latency constraint for V2V links. The Jain’s index of the V2I link, nearly two times that of a half-duplex (HD) scheme, further verifies the validity of the DGCIM scheme.

Rate-Splitting Multiple Access for 6G—Part II: Interplay With Integrated Sensing and Communications

This letter is the second part of a three-part tutorial focusing on rate-splitting multiple access (RSMA) for 6G. As Part II of the tutorial, this letter addresses the interplay between RSMA and integrated radar sensing and communications (ISAC). In particular, we introduce a general RSMA-assisted ISAC architecture, where the ISAC platform has a dual capability to simultaneously communicate with downlink users and probe detection signals to a moving target. Then, the metrics of radar sensing and communications are respectively introduced, followed by a RSMA-assisted ISAC waveform design example which jointly minimizes the Cramér-Rao bound (CRB) of target estimation and maximizes the minimum fairness rate (MFR) amongst communication users subject to the per-antenna power constraint. The superiority of RSMA-assisted ISAC is verified through simulation results in both terrestrial and satellite scenarios. RSMA is demonstrated to be a powerful multiple access and interference management strategy for ISAC, and provides a better communication-sensing trade-off compared with the conventional benchmark strategies. Consequently, RSMA is a promising technology for next generation multiple access (NGMA) and future networks such as 6G and beyond.

Distributed Joint Channel Assignment and Power Control for Sum Rate Maximization of D2D-Enabled Massive MIMO System

Device-to-device (D2D) communications underlaid massive multiple-input multiple-output (MIMO) systems have been recognized as a promising candidate technology to achieve the challenging fifth-generation (5G) network requirements. This integration enhances network throughput, improves spectral efficiency, and offloads the traffic load of base stations. However, the co/cross-tier interferences between cellular and D2D communications caused by resource sharing is a significant challenge, especially when dense D2D users exist in an underlay mode. In this paper, we jointly optimize the channel assignment and power allocation to maximize the sum data rate while maintaining the interference constraints of cellular links. Due to the lack of network-wide information in large scale networks, resource management and interference coordination is hard to be implemented in a centralized way. Therefore, we propose a three-stage stable and distributed resource allocation and interference management scheme based on local information and requires little coordination and communication between devices. We model the channel allocation optimization problem in the first stage as a many-to-one matching game. In the second stage, the algorithm adopts a cost charging policy to solve each user’s power control problem as a non-cooperative game. In the third stage, the algorithm search for swap blocking pairs until stable matching exist. It is shown in this paper that the proposed algorithm converges to a stable matching and terminates after finite iterations. Simulation results show that the proposed algorithm can achieve more than 86% of the average transmission rate performance of the optimal matching with lower complexity.

Joint Interference Alignment and Subchannel Allocation in Ultra-Dense Networks

In this paper, we propose one joint interference alignment and subchannel allocation (JIARA) interference management scheme, aiming at maximizing the number of satisfactory users with different degrees of freedom (DoF) demand in ultra-dense wireless networks, while the existing works only consider the same DoF demands. The original JIARA scheme is equivalent to the maximum <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$K$</tex-math></inline-formula> -colorable subgraph (MKCS) problem in graph theory for a given <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$K$</tex-math></inline-formula> -colors and the multicoloring demand at each vertex, hence NP-hard. Therefore, we propose one graph theory based low complexity sub-optimal JIARA scheme. Firstly, we propose one virtual allocation of subchannel based scheme to construct transformed the conflict graph, which is applicable for the different DoF demands and different size of the feasible IA group. Furthermore, we propose one greedy multi-coloring based algorithm to determine the maximum number of satisfactory users. Simulation results show that the proposed JIARA scheme outperforms the subchannel resource allocation only scheme.

Blind interference alignment: A comprehensive survey

SummaryInterference is a crucial impairment for trustworthy wireless communication. To overcome this interference problem, many interference management strategies have been established. Interference alignment (IA) is one such significant interference management approach that handles the positioning of signals so that they form an overlapping shadow at the unintended receivers; the desired interference‐free signals remain separable at the intended receivers. However, the need for global channel state information at the transmitter (CSIT) acts as a practical limitation for IA in the real‐world wireless communication system. IA can mitigate this limitation associated with channel state information with no CSIT, also termed as blind IA (BIA). Therefore, BIA is an interference management strategy that utilizes the concept of IA with no knowledge of CSIT. Therefore, based on the plethora of prevailing significant works, the objective of our paper is to provide a comprehensive survey to draw a picture of BIA in terms of network topologies, applications in different networks, trending research areas, degrees of freedom (DoF), open‐research problems, and future research directions.

Rate-Splitting Multiple Access for Downlink Multiuser MIMO: Precoder Optimization and PHY-Layer Design

Rate-Splitting Multiple Access (RSMA) has recently appeared as a powerful and robust multiple access and interference management strategy for downlink Multi-user (MU) multi-antenna communications. In this work, we study the precoder design problem for RSMA scheme in downlink MU systems with both perfect and imperfect Channel State Information at the Transmitter (CSIT) and assess the role and benefits of transmitting multiple common streams. Unlike existing works which have considered single-antenna receivers (Multiple-Input Single-Output–MISO), we propose and extend the RSMA framework for multi-antenna receivers (Multiple-Input Multiple-Output–MIMO) and formulate the precoder optimization problem with the aim of maximizing the Weighted Ergodic Sum-Rate (WESR). Precoder optimization is solved using Sample Average Approximation (SAA) together with the proposed vectorization and Weighted Minimum Mean Square Error (WMMSE) based approach. Achievable sum-Degree of Freedom (DoF) of RSMA is derived for the proposed framework as an increasing function of the number of transmitted common and private streams, which is further validated by the Ergodic Sum Rate (ESR) performance using Monte Carlo simulations. Conventional MU–MIMO based on linear precoders and Non-Orthogonal Multiple Access (NOMA) schemes are considered as baselines. Numerical results show that with imperfect CSIT, the sum-DoF and ESR performance of RSMA is superior to those of the two baselines, and is increasing with the number of transmitted common streams. Moreover, by better managing the interference, RSMA not only has significant ESR gains over baseline schemes but is more robust to CSIT inaccuracies, network loads and user deployments.

A Novel Fairness Allocation Strategy With Minimum Mainlobe Interference for mmWave Networks

In the fifth-generation (5G) communication system, millimeter-wave (mmWave) technology brings superior capabilities, such as higher capacity, lower latency, and a flexible beamforming structure. The interference management strategies play an important role in mmWave beamforming networks to support the multibeam operation and maximize the overall data rates for user equipments (UEs). Currently, most of the existing research do not jointly consider designs, including the mainlobe interference (MI) avoidance and resource blocks (RBs) fairness allocation. In this article, a novel fairness allocation strategy is proposed to achieve the minimum MI and a fair RB assignment for mmWave networks. To achieve the minimum MI, an MI mitigation (MIM) algorithm is designed to maximize the data rate for each UE. With the adaptive mini-timeslot design, the MIM algorithm can achieve MI cancelation for all UEs at each identical timeslot and beam. To combine MIM and fairness for RB allocation among all UEs, the MIM-fairness allocation (MIM-FA) algorithm is also presented. Based on a novel mini-timeslot with designed multiple frames, the MIM-FA algorithm can simultaneously guarantee the fairness among all UEs and mitigate MI at each mini-timeslot for each beam. Additionally, the MIM-FA algorithm can be verified that it achieves the maximum user data rate with the identical number of RBs under the lowest number of frames. Simulation results validate that the proposed MIM and MIM-FA algorithms can provide a higher data rate and better fairness for different scenarios compared to current state-of-the-art competitive approaches.

Interference Mitigation for Non-Overlapping Sub-Band Full Duplex for 5G-Advanced Wireless Networks

With new services emerging in fifth generation (5G)-advanced, the evolution in duplex modes plays an important role to meet more stringent requirements for both downlink (DL) and uplink (UL) transmissions. In this paper, sub-band full duplex (SBFD) at base station (BS) is studied as an attainable evolution of the traditional time division duplex (TDD). Both user equipment (UE) transparent SBFD and UE perceptive SBFD are proposed and studied to serve different types of UEs. To tackle the interference introduced by SBFD, a model including both BS self-interference and cross-link interference (CLI) is presented as a first step, and new interference management schemes are proposed. Three approaches to mitigate BS self-interference, namely the passive suppression, analog interference cancellation and digital interference cancellation are analyzed. A new framework for CLI management is illustrated along with enhancements for interference identification, spatial domain interference coordination and power domain adjustment. To validate the feasibility and performance of the proposed SBFD methods under indoor and dense urban scenarios, system-level simulations (SLSs) are carried out and a proof-of-concept (PoC) is developed for the purpose of obtaining experimental results.

Rate-Splitting Multiple Access: Fundamentals, Survey, and Future Research Trends

Rate-splitting multiple access (RSMA) has emerged as a novel, general, and powerful framework for the design and optimization of non-orthogonal transmission, multiple access (MA), and interference management strategies for future wireless networks. Through information and communication theoretic analysis, RSMA has been shown to be optimal (from a Degrees-of-Freedom region perspective) in several transmission scenarios. Compared to the conventional MA strategies used in 5G, RSMA enables spectral efficiency (SE), energy efficiency (EE), coverage, user fairness, reliability, and quality of service (QoS) enhancements for a wide range of network loads (including both underloaded and overloaded regimes) and user channel conditions. Furthermore, it enjoys a higher robustness against imperfect channel state information at the transmitter (CSIT) and entails lower feedback overhead and complexity. Despite its great potential to fundamentally change the physical (PHY) layer and media access control (MAC) layer of wireless communication networks, RSMA is still confronted with many challenges on the road towards standardization. In this paper, we present the first comprehensive overview on RSMA by providing a survey of the pertinent state-of-the-art research, detailing its architecture, taxonomy, and various appealing applications, as well as comparing with existing MA schemes in terms of their overall frameworks, performance, and complexities. An in-depth discussion of future RSMA research challenges is also provided to inspire future research on RSMA-aided wireless communication for beyond 5G systems.