New Radio Research Articles

Inter-Numerology Interference in Mixed Numerology OFDM Systems in Time-Varying Fading Channels With Phase Noise

Mixed numerology has been adopted in the orthogonal frequency division multiplexing-based physical layer of 5G new radio (NR) to serve diverse use cases and services. Since the subcarriers of different numerologies have different bandwidths and symbol durations, they interfere with each other despite being centered at different frequencies. We analyze the inter-numerology interference (INI) encountered by these systems in wideband time-varying channels in the presence of phase noise. We derive novel expressions for the fading-averaged INI power at each subcarrier as a function of the channel’s power delay profile. These lead to insightful, tight bounds for the bandwidth-averaged INI power, which bring out the combined impact of Doppler spread and phase noise. Our comprehensive approach applies to the entire family of numerologies of 5G NR, and accounts for partial subcarrier loading, guard bands, and non-line-of-sight and line-of-sight channels. Our results show that INI affects high-rate modulation and coding schemes (MCSs). To mitigate its impact, we propose a novel statistical square root power allocation scheme that exploits the variation in the average INI powers across the subcarriers. It achieves a lower block error rate than uniform power allocation, which is used in 5G NR.

Bayesian Filtering for Joint Multi-User Positioning, Synchronization and Anchor State Calibration

Millimeter (mmWave) positioning can go beyond classical localization, allowing to extract more complete situational awareness in terms of, e.g, clock offsets, antenna orientations or landmark locations. In this article, we formulate an extended Kalman filtering (EKF)-based framework called MU-PoSAC ( <underline xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">M</u> ulti- <underline xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">U</u> ser <underline xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Po</u> sitioning, <underline xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">S</u> ynchronization and <underline xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">A</u> nchor State <underline xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">C</u> alibration), that allows to jointly estimate and track the locations and clock offsets of multiple users together with the unknown locations and orientation offsets of the anchors, building on angle-of-arrival (AoA) and time-of-arrival (ToA) measurements. We provide an extensive set of numerical results in the context of mmWave 5 G New Radio (NR) deployment in an industrial facility with moving robots and other industrial vehicles, incorporating full-scale ray-tracing for accurate propagation modeling as well as actual uplink reference signal based AoA and ToA estimators. Our numerical results show that estimating and tracking the overall system state is feasible, and that a single reference anchor can further enhance the estimation accuracy. In addition, more users are shown to lead to better performance, due to the beneficial coupling of the anchor state. Therefore, our study demonstrates that in order to maximize the estimation performance, it is desirable to have at least one anchor state precisely known, and to have multiple users in the system. Finally, the important practical aspect of Line-of-Sight (LoS) blockage is addressed. It is shown that in the considered industrial use case, the proposed MU-PoSAC framework can offer robustness against intermittent LoS blockage.

Dual-Band Dual-Output Doherty Power Amplifier for Unsynchronized Time-Division Duplexing

Conventional multiband power amplifiers (PAs), when working in time-division duplex (TDD), require the transmit–receive intervals of all bands to be synchronized. This is an undesirable constraint in modern radio base stations. This article proposes a dual-output dual-band Doherty PA (DB-DPA) that enables the loading of one band to be switched on-and-off without impacting the other band in normal transmission. A thorough analysis of the proposed dual-output DB-DPA architecture is presented, and a dual-output DB-DPA prototype operating at 1.4 and 2.6GHz has been designed as a proof of concept. The large-signal measurements of the prototype DB-DPA indicate Doherty behavior at both frequencies with over 56% saturation efficiency and 45% efficiency at 6-dB power back-off (PBO). Furthermore, single-band and concurrent dual-band linearized modulated measurements, using 10-MHz new radio (NR) signals with 6-dB peak-to-average power ratio (PAPR), demonstrate the linearizability of the proposed DB-DPA and its usefulness for unsynchronized TDD applications.

Optimal radio resource management in 5G NR featuring network slicing

3GPP 5G New Radio (NR) has introduced several new features that the network slicing concept can leverage to guarantee the heterogeneous requirements in terms of throughput and delays of expected 5G network services. Mainly, these features are (i) Mixed-numerology to control the time slot duration, hence guaranteeing low latency requirements; (ii) Bandwidth Parts (BWP) to control the number of radio resources allocated to users, hence satisfying different throughput requirements. However, efficient radio resource management is already complex, and adding these new dimensions will further increase this complexity. In this paper, we first propose modeling radio resource management in 5G NR featuring network slicing through a Mixed Integer Linear Program (MILP). For our best knowledge, this is the first MILP modeling of the radio resource management featuring network slicing taking into account (i) Mixed-numerology, (ii) both latency and throughput requirements (iii) multiple slice attach per UE (iv) Inter-Numerology Interference (INI). After showing that solving the problem takes an exponential time, we considered a new approach to solve it in a polynomial time, which is highly required when scheduling radio resources. The new approach consists of formalizing this problem using a Deep Reinforcement Learning (DRL)-based solver. We evaluate the use of RL to solve the problem for different network configurations and compared its performance with the optimal solution obtained by solving the MILP problem.

Optimized MSA DPD method for improving 5G multiband optical fronthaul performance

AbstractA modified optimized magnitude‐selective affine (OMSA) model‐based digital predistortion (DPD) is presented that introduces the weighting function into our earlier proposed magnitude‐selective affine (MSA) method with an aim to further reduce the complexity overheads without affecting performance compared to the MSA method. This model utilizes a power‐reliant weighted function rather than the summation of MSA quantities for improving the multiband 5G new radio (NR) analog radio over fiber system performance. The OMSA‐DPD method is tested using 5G NR signals which are transmitted over a 10‐km fiber length. The performance of the OMSA‐DPD method is assessed in comparison to MSA and generalized memory polynomial (GMP) methods in terms of adjacent channel power ratio, error vector magnitude, and complexity. The experimental results show that the OMSA‐DPD method achieves better performance with lower complexity compared to the MSA and GMP models, meeting the 3GPP limits.

Compact four elements SUB-6 GHz MIMO antenna for 5G applications

This work proposes a four elements sub-6 GHz multiple-input multiple-output (MIMO) antenna to operate within a frequency range of 1.6–4.4 GHz to serve 5G new radio (NR) n77 (3.3–4.2 GHz) and n78 (3.3–3.80 GHz) bands. The antenna elements are orthogonally placed to increase isolation. Defected ground structure and parasitic elements are used to reduce mutual coupling. The suggested antenna has been designed over FR-4 substrate on high frequency structure simulator software. The overall size of the antenna is 40 mm × 40 mm × 1.6 mm. The dimension of each element is 16.2 mm × 14.3 mm × 1.6 mm. An “EH” slot into the radiating element and protruded stubs are incorporated to improve bandwidth and impedance matching. The overall characteristics of the antenna is found to be better than some of the recently reported works making it a potential candidate for MIMO applications.

Low-Rate and Short-Block-Length Random Permutation-Coded Modulations Achieve Finite-Length Bounds

Ultra-reliable low-latency communication (URLLC) is an important feature brought by 5G New Radio (NR). By using a block code, the low-latency requirement in general requires a short block length in order to reduce the latency of transmitting the entire code block. The ultra-reliable communication requires a low-rate code to achieve high decoding reliability even under low signal-to-noise ratios (SNRs). This paper proposes a new class of coding and modulation schemes, termed permutation-coded modulations, for low-rate and short-block-length applications, such as URLLC. We show that permutation-coded modulations under maximum-likelihood (ML) decoding have remarkable performance levels that achieve the dispersion bounds with normal approximation (NA) for short block lengths. However, their encoding and ML-decoding complexities are prohibitive if the number of message bits transmitted per code block increases. To reduce the encoding and decoding complexities, we propose a trapezoidal permutation-coded modulation scheme which can be decoded efficiently by successive cancellation list (SCL) decoders. We also show that the trapezoidal permutation-coded modulations under SCL decoding can achieve the dispersion bounds with NA for short block lengths.

Design of a high isolation tri-band MIMO antenna for coal mine applications

ABSTRACT In this paper, a tri-band multiple-input multiple-output (MIMO) antenna with high isolation characteristic is designed and fabricated for coal mine applications. It is composed of two symmetrical trident planar monopoles which can achieve tri-band characteristics. The isolation between the elements is higher than 20 dB across the whole frequency region by firstly placing the two elements symmetrically, loading a T-shaped branch and etching two rectangular slots on the ground successively. The proposed antenna can operate at three bands, i.e., 1.85∼2.70 GHz, 3.24∼3.99 GHz and 4.65∼5.80 GHz, which simultaneously cover the operating frequency band of WiMAX, WiFi, 4G, and 5G New Radio (NR) for mining. Good agreements can be observed between the simulated and measured results. The designed tri-band MIMO antenna has the advantages of low profile, compact structure and easy to conform with the platform, thus having a broad prospect in coal mine applications.

A Study of Mutual Coupling Suppression between Two Closely Spaced Planar Monopole Antenna Elements for 5G New Radio Massive MIMO System Applications

5G NR (new radio) introduces the concept of massive MIMO (multiple-input multiple-output) technology, in which a larger number of antenna arrays are installed on the transceiver. Due to the increased number of antenna elements allocated close to each other (approximately at a distance of half a wavelength), mutual coupling becomes a serious problem leading to performance degradation of the MIMO communication system. In this communication, two different configurations of closely spaced antenna array elements are studied. In order to reduce the mutual coupling, a combination of a metamaterial-based frequency-selective surface (FSS), a metallic strip, and a slot element in the ground plane is examined. It is found that the proposed technique significantly suppresses mutual coupling from −12 dB to −25 dB. Both designs are fabricated and experimentally validated. The simulation results are in good agreement with the measurements. The proposed mutual coupling reduction technique may be suitable for massive MIMO systems in fifth-generation (5G) new radio applications.

Towards 5G new radio sidelink communications: A versatile link-level simulator and performance evaluation

Sidelink in cellular networks enables direct exchange of data packets between devices without the need for network infrastructure, resulting in various benefits, including communication in out-of-coverage areas and possible decrease in latency by a considerable extent. Thus, sidelink is a favorable choice for applications like public safety communications and Vehicle-to-Everything (V2X) communications. As 4G Long Term Evolution (LTE) advanced to 5G New Radio (NR) under the Third Generation Partnership Project (3GPP), several new features were introduced to sidelink, such as two-stage Sidelink Control Informations (SCIs), data and control multiplexing, and feedback-based Hybrid Automatic Repeat Request (HARQ) with a configurable maximum number of transmissions. To conduct extensive NR sidelink link-level evaluations, a comprehensive simulation platform is essential. In this paper, we introduce the first publicly accessible 5G NR Link-Level Simulator (LLS) that supports major 5G NR sidelink features and complies with the 3GPP standards. This MATLAB-based simulator allows for flexible control over various Physical Layer (PHY) configurations, facilitating customized simulations on algorithm development and performance evaluations. We discuss the simulator’s structure and the sidelink features implemented in detail and evaluate the 5G NR sidelink performance using the developed simulator. Our simulation results indicate that the Block Error Rate (BLER) curves are insensitive to error-prone 2nd-stage Sidelink Control Information (SCI2) and number of Resource Blocks (RBs) allocated; however, the sidelink communication range is sensitive to the deployment environment. We also highlight the need for a careful choice of numerology, device power class and HARQ configuration to balance performance metrics for a variety of services based on 5G NR sidelink deployment scenarios.

NR5G-SAM: A SLAM Framework for Field Robot Applications Based on 5G New Radio.

Robot localization is a crucial task in robotic systems and is a pre-requisite for navigation. In outdoor environments, Global Navigation Satellite Systems (GNSS) have aided towards this direction, alongside laser and visual sensing. Despite their application in the field, GNSS suffers from limited availability in dense urban and rural environments. Light Detection and Ranging (LiDAR), inertial and visual methods are also prone to drift and can be susceptible to outliers due to environmental changes and illumination conditions. In this work, we propose a cellular Simultaneous Localization and Mapping (SLAM) framework based on 5G New Radio (NR) signals and inertial measurements for mobile robot localization with several gNodeB stations. The method outputs the pose of the robot along with a radio signal map based on the Received Signal Strength Indicator (RSSI) measurements for correction purposes. We then perform benchmarking against LiDAR-Inertial Odometry Smoothing and Mapping (LIO-SAM), a state-of-the-art LiDAR SLAM method, comparing performance via a simulator ground truth reference. Two experimental setups are presented and discussed using the sub-6 GHz and mmWave frequency bands for communication, while the transmission is based on down-link (DL) signals. Our results show that 5G positioning can be utilized for radio SLAM, providing increased robustness in outdoor environments and demonstrating its potential to assist in robot localization, as an additional absolute source of information when LiDAR methods fail and GNSS data is unreliable.

Extending 5G to Narrow Spectrum Allocations

5G New Radio (NR) has been a great success story since its introduction. It offers high reliability, low communication latency, flexibility, and efficiency that further enable 5G networks to be used for mission critical applications. Currently, there are specialized networks serving industry verticals that would benefit from the NR properties. Key use cases include communications for critical infrastructure such as railways, public safety, and smart energy and infrastructure. These networks often use dedicated spectrum allocations that are narrower than the original minimum operating bandwidth of NR. In this paper, we describe how new flexibility is being introduced into the NR design to allow operation with bandwidths between about 3 and 5 MHz. As a use case study, we focus on railway communications, and study the co-existence of the Global System for Mobile Communications – Railway (GSM-R) and Future Railway Mobile Communication System (FRMCS) based on NR during the decade-long migration period. We discuss the changes required for the NR control channels and signaling and study the effect of the changes on the system performance.

NR Enhancements for Downlink MIMO in Rel-18

Massive multiple-input multiple-output (MIMO) has been a key technology in 5G New Radio (NR) standard, which empowers significant system performance improvement in previous 5G NR Releases. To support higher data rate and multi-user simultaneous transmission in downlink, enhancement in massive MIMO is essential for NR Release 18 (Rel-18). In this article, we explore performance requirements, challenges, and potential technologies for MIMO enhancement. First, we summarize major performance requirements for MIMO in Enhanced Mobile Broadband scenario. Based on these requirements, we identify three critical challenges of MIMO enhancement for single transmission reception point (TRP) and multiple TRPs scheme, in which we highlight the promising coherent joint transmission (CJT) technique. For each challenge, we present specific description from requirement perspective and technique perspective, evaluate the pros and cons of potential solutions, and carry out simulations to illustrate the potential performance gain. Some insights on how to solve these challenges to enhance massive MIMO performance in NR Rel-18 are also provided.

A 2.7 W AC-Coupled Hybrid Supply Modulator Achieving 200 MHz Envelope-Tracking Bandwidth for 5G New Radio Power Amplifier

Envelope tracking is an effective way to improve the efficiency of radio frequency power amplifiers (PAs). This paper presents a wideband hybrid envelope tracking supply modulator (ETSM) for 5G New Radio (NR) PAs. To reach a wide envelope tracking bandwidth of 200MHz while maintaining high power efficiency, this work utilized a linear amplifier (LA) with accurate frequency compensation and enhanced driving capability. The proposed low-pass sense and control (LPSC) circuit ensures that the switching power amplifier (SPM) only tracks the low-frequency components of the envelope to reduce the switching power loss. The proposed dual-path duty modulator regulates the voltage across the AC-coupling capacitor. This supply modulator circuit is designed and fabricated using 0.18μm BCD technology. When tracking 200MHz bandwidth envelope signals, the prototype ETSM achieves 78.5% efficiency at the output power of 2.7W when taking a realistic 4Ω//600pF load as the PA model.

Cost-Effective Broadband and Compact Patch Antenna Based on Ball Grid Array Packaging for 5G NR FR2 Band Applications

This brief introduces a compact, cost-effective broadband patch antenna based on ball grid array (BGA) packaging technology for 5G millimeter wave new radio (NR) FR2 band application. Based on the low-cost FR-4 substrate and single-layer configuration, the patch antenna achieves an ultra-low cost, which is attractive for large-scale 5G millimeter-wave array applications. Parasitic patches are added to the antenna to obtain broadband impedance bandwidth. To further reduce the antenna size and eliminate bulky connectors, solder balls are added to form a BGA package with connectorless interconnects. Consequently, the proposed antenna element achieves a compact size of 5.2 mm × 3.2 mm × 1.4 mm. Antenna elements and 1 × 8 array prototypes have been fabricated and verified. The measurement results show that the proposed antenna element has a -10 dB bandwidth of 56.1% (20-35.6 GHz), fully covering the 5G millimeter wave n257 (26.5-29.5 GHz), n258 (24.25-27.5 GHz), and n261 (27.5-28.35 GHz) bands. The maximum realized gains of the antenna elements and the 1 × 8 array prototype are 7.2 dBi and 13.9 dBi, respectively.

A comparative analysis of the semi-persistent and dynamic scheduling schemes in NR-V2X mode 2

Over the last years, the evolution of Vehicle-to-Everything (V2X) services from basic safety-related to enhanced V2X (eV2X) applications prompted the development of the 5G New Radio (NR)-V2X technology. Standardized by the Third Generation Partnership Project (3GPP) in Release 16, NR-V2X features a distributed resource allocation mode, known as Mode 2, that allows vehicles to autonomously select their transmission resources employing a Semi-Persistent Scheduling (SPS) or a Dynamic Scheduling (DS) scheme. The SPS approach relies on the periodic reservation of resources, whereas the DS scheme is a reservation-less solution that forces the selection of new transmission resources for every generated message. 3GPP standards do not indicate under which conditions each scheduling scheme should be used. In this context, this study analyzes and compares the performance of SPS and DS under different traffic types and Packet Delay Budget (PDB) requirements. Simulation results demonstrate that the SPS scheme represents the best solution for serving fixed size periodic traffic, whereas DS is more adequate for aperiodic traffic (of fixed or variable size). The study shows that the superiority of DS over SPS becomes more evident when tighter PDB requirements are considered, and that the performance of the DS scheme is independent of the PDB. It is also demonstrated that an adaptive scheduling strategy, which allows vehicles to select the scheduling scheme that best suits the type of generated traffic, is the best solution in mixed traffic scenarios where fixed size periodic traffic and variable size aperiodic traffic sources coexist.

Guest Editorial Special Issue on 3GPP Technologies: 5G-Advanced and Beyond

Since the start of 5G New Radio (NR) work in the 3rd Generation Partnership Project (3GPP) in early 2016, tremendous progress has been made in both standardization and commercial deployments. The first 5G NR release (Release 15) laid out a solid foundation in accommodating a diverse set of services, a wide range of spectra, and a variety of deployment scenarios, while being forward compatible. Expansion to vertical domain services [e.g., vehicle to everything (V2X), non-terrestrial networks (NTN)] was introduced in Release 16. Such an expansion was further accelerated in Release 17, with the standardization work being completed despite the extreme challenges due to COVID-19.

Deep Reinforcement Learning Based Link Adaptation Technique for LTE/NR Systems

Outdated channel quality indicator (CQI) feedback causes severe performance degradation of traditional link adaptation (LA) techniques in long term evolution (LTE) and new radio (NR) systems. This paper puts forth a deep reinforcement learning (DRL) based link adaptation (LA) technique, referred to as deep reinforcement learning link adaptation (DRLLA), to select efficient modulation and coding scheme (MCS) in the presence of the outdated CQI feedback. The goal of DRLLA is to maximize the link throughput while achieving a low block error rate (BLER). We first give explicit definitions of state, action, and reward in DRL paradigms, thereby realizing DRLLA. Then, to trade off the throughput against the BLER, we further develop a new experience replay mechanism called classified experience replay (CER) as the underpinning technique in DRLLA. In CER, experiences are separated into two buckets, one for successful experiences and the other for failed experiences, and then a fixed proportion from each is sampled to replay. The essence of CER is to obtain different trade-offs via adjusting the proportion among different training experiences. Furthermore, to reduce the signaling overhead and the system reconfiguration cost caused by frequent MCS switching, we propose a new action selection strategy termed as switching-controlled <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\epsilon$</tex-math></inline-formula> -greedy (SC- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\epsilon$</tex-math></inline-formula> -greedy) for DRLLA. Simulation results demonstrate that compared with the state-of-the-art OLLA, LTSLA, and DRLLA with other experience replay mechanisms, DRLLA with CER can achieve higher throughput and lower BLER in various time-varying scenarios, and be more robust to different CQI feedback delays and CQI reporting periods. Furthermore, with the SC- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\epsilon$</tex-math></inline-formula> -greedy policy, DRLLA can capture better trade-offs between the link transmission quality and the MCS switching overhead compared with other baselines.

Toward 6G Vehicle-to-Everything Sidelink: Nonorthogonal Multiple Access in the Autonomous Mode

The cellular vehicle-to-everything (C-V2X) sidelink technology, specified in the long-term evolution (LTE) and further improved in the 5G new radio (NR) standards to facilitate direct data exchange between vehicles, will play a crucial role in revolutionizing transportation systems. However, the demand for very high reliability and ultralow latency services especially challenges the sidelink resource allocation mechanism when performed by distributed vehicles, in the so-called <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">autonomous</i> mode. One of the major causes of ­performance degradation is the resource allocation mechanism, which was designed for orthogonal multiple access (OMA) and can generate interference and collisions under high load conditions. In this context, here we argue in favor of the use of non-OMA (NOMA) as a game changer for the sidelink in the upcoming 6G V2X, and the purpose of this article is to provide a reference for further intriguing studies in the field. Additionally, the gain achievable over conventional allocation schemes by enabling NOMA through the use of successive interference cancelation (SIC) at the receiver is measured through realistic simulations conducted when considering the latest C-V2X specifications.

Improving FEC layer frame for DVB-S2 link system based on 5G NR polar coding

Within the scope of this investigation, the MATLAB simulation code for digital video broadcasting–for satellite–second generation (DVB-S2) has been constructed. Forward error correction (FEC) rates as 3/5, 2/3, and 3/4 across additive white Gaussian noise (AWGN) and Rayleigh fading channels are used to evaluate the system's performance, mainly while working on quadrature phase-shift keying (QPSK), 8-ary phase-shift keying (8PSK), 16-ary amplitude phase-shift keying (16APSK), and 32-ary amplitude phase-shift keying (32APSK) official modulation types. The system's redesign has been achieved to investigate high performance and reliability based on a cascade of new radio (NR) fifth generation (5G) Polar coding with low-density parity-check (LDPC). Some signal-to-noise ratio (SNR) levels were changed when evaluated in contrast to the conventional model. It has been determined that five iterations of the LDPC decoder were performed. In comparison to the traditional model. The proposed design's performance accomplished the highest possible value for reducing the bit error rate (BER) value and investigated better-transmitted power gain for most testing cases.