5G New Radio Research Articles

Flexible Numerology in 5G NR: Interference Quantification and Proper Selection Depending on the Scenario

The 3rd Generation Partnership Project (3GPP) adopted cyclic prefix OFDM (CP-OFDM) for both uplink and downlink communications (although DFT-s-OFDM is also allowed in the uplink) in 5G New Radio (NR) Release 15. However, due to the variety of proposed deployment options and scenarios, a single numerology will not be enough to fulfil all performance requirements. A scalable OFDM numerology was required to enable diverse services on a wide range of frequencies and deployments, and finding the right numerology for each scenario is of special relevance for the proper functioning of 5G NR. Using a simulator calibrated according to the parameters established for NR performance by the 3GPP, this paper presents the performance evaluation of NR for the main 5G scenarios and different CP-OFDM numerologies and device speeds. Results show that increasing subcarrier spacing boosts the strength of the system against intercarrier interference (ICI) caused my Doppler spread; however, to increase subcarrier spacing, the CP must be reduced proportionally, which makes intersymbol interference (ISI) and ICI caused by insufficient CP have a more predominant effect. Therefore, it is necessary to quantify the total interference of the system, in order to determine the proper numerology for each scenario, which will depend on all the factors mentioned above, and not only on the operation band, as suggested in the standardization process. All this allows concluding that the choice of the appropriate numerology for a particular system depends not only on the band of operation but also on the deployment scenario and the speed of the user equipment (UE). Likewise, it is concluded that it is even possible to use more than one numerology for the same scenario.

Sectoral dual-polarized MIMO antenna for 5G-NR band N77 base station

<span>Massive internet of things (IoT) in 5G has many advantages as a future technology. It brings some challenges such as a lot of devices need massive connection. In this case, multiple-input multiple-output (MIMO) systems offer high performance and capacity of communications. There is a challenge of correlation between antennas in MIMO. This paper proposes three-sectors MIMO base station antenna for 5G-New Radio (5G-NR) band N77 with dual polarized configuration to reduce the correlation. The proposed antenna has a maximum coupling of -16.90 dB and correlation below 0.01. The obtained bit error rate (BER) performance is very close to non-correlated antennas with bandwidth of 1.87 GHz. It means that the proposed antenna has been well designed.</span>

Remote interference management in 5G new radio: methods and performance

In time division duplexing based mobile networks, under certain atmospheric ducting conditions, the uplink reception may be interfered by the downlink transmissions of remote base-stations (gNBs) located hundreds of kilometers away. This paper addresses such remote interference problem in a 5G new radio (NR) macro deployment context. Specifically, two potential reference signal (RS) designs for remote interference management (RIM) are described. The first signal structure, denoted as the one OFDM symbol (1OS) based RIM-RS, is building on the channel state information reference signals of 5G NR. The second candidate is referred to as the two OFDM symbol based RIM-RS design, which builds on the design principles of LTE RIM-RS. The achievable detection performance is evaluated by introducing enhanced receiver algorithms together with three feasible propagation delay based gNB grouping and corresponding RIM-RS transmissions schemes. The performance results in terms of the receiver processing gain highlight that the improved detection algorithm assures sufficient performance to detect the remote interference for both RIM-RSs with all evaluated frequency domain comb-like patterns. The benefit of grouping corresponding RIM-RS transmissions from gNBs located on the same area is greater when using same frequency domain resources per transmitted sequence in practical interference scenarios. Furthermore, applying a common base sequence for all gNBs within a group allows to identify the group based on detected sequence and enables adaptive RIM mitigation schemes. On the other hand, it is shown that the 1OS RIM-RS provides smaller overhead and can be frequency multiplexed with the physical downlink shared channel, which opens up the possibility of using gNB group wise 1OS RIM-RS also for UE interference measurements.

5G NR-V2X: Toward Connected and Cooperative Autonomous Driving

5G New Radio (NR) is touted as a pivotal enabling technology for the genuine realization of connected and cooperative autonomous driving. Despite numerous research efforts in recent years, a systematic overview on the role of 5G NR in future connected autonomous communication networks is missing. To fill this gap and to spark more future research, this article introduces the technology components of 5G NR and discusses the evolution from existing cellular vehicle-to-everything (V2X) technology toward NR-V2X. We primarily focus on the key features and functionalities of the physical layer, sidelink communication and its resource allocation, architecture flexibility, security and privacy mechanisms, and precise positioning techniques. Moreover, we envisage and highlight the potential of machine learning for further performance enhancement in NR-V2X services. Lastly, we show how 5G NR can be configured to support advanced V2X use cases.

Joint Use of Guard Capacity and Multiconnectivity for Improved Session Continuity in Millimeter-Wave 5G NR Systems

The intermittent nature of millimeter wave (mmWave) links caused by human-body blockage is an intrinsic property of the 5G New Radio (NR) technology that may cause drops of sessions already accepted for service. To improve the session continuity, multiconnectivity and guard capacity mechanisms have been proposed recently. Multiconnectivity enables dynamic handover between multiple pre-established spatially-diverse links, while guard capacity reserves a fraction of radio resources for the already accepted sessions by ensuring that they will have sufficient provisions in case of link blockage. In this study, we combine the tools of queuing theory and stochastic geometry to develop a mathematical framework for capturing the joint operation of these two schemes as well as the features of mmWave radio propagation. The metrics are related to user- and system-centric performance including the system resource utilization and the new and ongoing session drop probabilities. Our results show that multiconnectivity benefits all of the considered parameters. However, the range of performance boost remains limited by the deployment density and the maximum supported degree of multiconnectivity. In its turn, guard capacity allows to further decrease the ongoing session drop probability at the expense of the new session drop probability and the system resource utilization. When implemented jointly with multiconnectivity, guard capacity does not produce noticeable negative effects on the system resource utilization as compared to its standalone use. Hence, one may prefer a joint implementation of these mechanisms for preserving the session continuity of users without compromising the resource utilization.

Low-Complexity High-Throughput QC-LDPC Decoder for 5G New Radio Wireless Communication

This paper presents a pipelined layered quasi-cyclic low-density parity-check (QC-LDPC) decoder architecture targeting low-complexity, high-throughput, and efficient use of hardware resources compliant with the specifications of 5G new radio (NR) wireless communication standard. First, a combined min-sum (CMS) decoding algorithm, which is a combination of the offset min-sum and the original min-sum algorithm, is proposed. Then, a low-complexity and high-throughput pipelined layered QC-LDPC decoder architecture for enhanced mobile broadband specifications in 5G NR wireless standards based on CMS algorithm with pipeline layered scheduling is presented. Enhanced versions of check node-based processor architectures are proposed to improve the complexity of the LDPC decoders. An efficient minimum-finder for the check node unit architecture that reduces the hardware required for the computation of the first two minima is introduced. Moreover, a low complexity a posteriori information update unit architecture, which only requires one adder array for their operations, is presented. The proposed architecture shows significant improvements in terms of area and throughput compared to other QC-LDPC decoder architectures available in the literature.

On Improving 5G Internet of Radio Light Security Based on LED Fingerprint Identification Method.

In this paper, a novel device identification method is proposed to improve the security of Visible Light Communication (VLC) in 5G networks. This method extracts the fingerprints of Light-Emitting Diodes (LEDs) to identify the devices accessing the 5G network. The extraction and identification mechanisms have been investigated from the theoretical perspective as well as verified experimentally. Moreover, a demonstration in a practical indoor VLC-based 5G network has been carried out to evaluate the feasibility and accuracy of this approach. The fingerprints of four identical white LEDs were extracted successfully from the received 5G NR (New Radio) signals. To perform identification, four types of machine-learning-based classifiers were employed and the resulting accuracy was up to 97.1%.

A Defensive Scheduling Scheme to Accommodate Random Selection Devices in 5G NR V2X

The newly completed 3GPP Release 16 for 5G New Radio (NR) vehicle-to-everything (V2X) communication assumes that all participating devices can continually sense the channel activities in terms of resource use. However, many non-vehicular devices such as smartphones of vulnerable road users (VRUs) and road-embedded sensors are constrained by battery, and cannot afford such “always-on” sensing. The deficiency will have undesirable impact on the existing resource allocation algorithm in the envisioned NR V2X integrated framework. As we start the efforts towards Release 17, therefore, there is a pressing need to develop a solution to smoothly integrate the limited-sensing devices into the framework. This letter develops a solution based on the new features available in Release 16 NR Sidelink Mode 2, such as resource reservation pointers and resource pre-emption checks. We demonstrate that a defensive transmission strategy employed by the full-sensing devices that jitters their transmissions around the resource double-booked by the limited-sensing devices can significantly mitigate the packet delivery performance degradation for both the full-sensing and the limited-sensing devices.

Design and performance analysis of joint control and shared channel scheduler for downlink in 3GPP narrowband-IoT

Narrowband-IoT (NB-IoT) is a low power wide area network technology introduced by the 3rd Generation Partnership Project (3GPP) in Release 13 specifications. The NB-IoT aims at providing cellular connectivity to low cost, low throughput, delay-tolerant devices, and hence, is a key technology for smart connected living. The NB-IoT specifications continue to evolve as part of 5G New Radio (NR), and the technology is expected to co-exist with 5G NR. A transmission bandwidth of 180 KHz is required to deploy the NB-IoT. In NB-IoT, the duration of the physical downlink control channel (NPDCCH) and the physical downlink shared channel (NPDSCH) changes dynamically. When the base station broadcasts the NPDCCH region, all the active NB-IoT devices try to decode it. Hence, to reduce the power consumption of the NB-IoT devices, more number of NB-IoT devices have to be scheduled in each scheduling attempt. For each payload in NPDCCH, there is a respective payload in NPDSCH. Thus, a base station should schedule the devices simultaneously in both NPDCCH and NPDSCH to reduce resource wastage. The time–frequency resources in NB-IoT are limited and valuable. Further, the NB-IoT devices have low battery power constraint. Thus, scheduling the devices by considering the above constraints has a significant impact on the NB-IoT system performance. Motivated by this, we propose a joint scheduling algorithm for both NPDCCH and NPDSCH. Further, we propose an adaptive repetition allocation algorithm and present a receiver design for NB-IoT. We also define performance metrics to evaluate the impact of the proposed scheduler and then present bounds on the performance gains with the proposed scheduler. With system-level and link-level simulations, we show that the proposed scheduler significantly outperforms the current state-of-the-art algorithms.

PC5-Based Cellular-V2X Evolution and Deployment.

C-V2X (Cellular Vehicle-to-Everything) is a state-of-the-art wireless technology used in autonomous driving and intelligent transportation systems (ITS). This technology has extended the coverage and blind-spot detection of autonomous driving vehicles. Economically, C-V2X is much more cost-effective than the traditional sensors that are commonly used by autonomous driving vehicles. This cost-benefit makes it more practical in a large scale deployment. PC5-based C-V2X uses an RF (Radio Frequency) sidelink direct communication for low latency mission-critical vehicle sensor connectivity. Over the C-V2X radio communications, the autonomous driving vehicle’s sensor ability can now be largely enhanced to the distances as far as the network covers. In 2020, 5G is commercialized worldwide, and Taiwan is at the forefront. Operators and governments are keen to see its implications in people’s daily life brought by its low latency, high reliability, and high throughput. Autonomous driving class L3 (Conditional Automation) or L4 (Highly Automation) are good examples of 5G’s advanced applications. In these applications, the mobile networks with URLLC (Ultra-Reliable Low-Latency Communication) are perfectly demonstrated. Therefore, C-V2X evolution and 5G NR (New Radio) deployment coincide and form a new ecosystem. This ecosystem will change how people will drive and how transportation will be managed in the future. In this paper, the following topics are covered. Firstly, the benefits of C-V2X communication technology. Secondly, the standards of C-V2X and C-V2X applications for automotive road safety system which includes V2P/V2I/V2V/V2N, and artificial intelligence in VRU (Vulnerable Road User) detection, object recognition and movement prediction for collision warning and prevention. Thirdly, PC5-based C-V2X deployment status in global, especially in Taiwan. Lastly, current challenges and conclusions of C-V2X development.

Non-Standalone 5G NR FiWi System Based on a Photonic Integrated Multi-Wavelength Transmitter

This letter presents a non-standalone 5G new radio (NR) multiband fiber-wireless (FiWi) system implemented using an integrated multi-wavelength transmitter with direct modulation. In this system, three 4G/5G RF signals are simultaneously transported over a 12.5-km long radio over fiber (RoF) link, before being amplified and radiated: a 20-MHz 5G NR signal at 788 MHz; five 20-MHz LTE subcarriers at 2.6 GHz; a 100-MHz 5G NR signal at 3.5 GHz. Wireless transmissions through a 10-m long indoor picocell-like link and a 115-m long realistic outdoor wireless link are demonstrated. All 4G and 5G received signals comply with the 3GPP Release 15 requirements, in terms of EVM <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">RMS</sub> , except for 16 QAM at 3.5 GHz on the 115-m link. Experimental results demonstrate a total throughput of 1.36 Gbit/s and 230 Mbit/s on the 10-m and 115-m scenarios, respectively.

Hardware Sharing for Channel Interleavers in 5G NR Standard

Interleaver module is an important part of modern mobile communication system. It plays an important role in reducing bit error rate and improving transmission efficiency over fading channels. In 5G NR (5th Generation New Radio) standards, LDPC (low-density parity-check) and polar channel codes are employed for data channels and control channels, respectively. If multiple interleavers are implemented separately for them, the cost increases significantly. To address this issue, a hardware multiplexing scheme for channel interleavers based on LDPC and polar codes is proposed in this paper. Firstly, the formulas for the processes of the control channel interleaving and data channel interleaving are derived with respect to 5G NR standard. Then, the hardware implementation structures of the two interleavers are given. Subsequently, hardware reuse is proposed by sharing the similar or identical parts between the two hardware structures. Simulation results verify the correctness of our proposed scheme and demonstrate that it can realize the hardware sharing of the two kinds of channel interleavers to reduce the cost of silicon.

A Survey of Autonomous Vehicles: Enabling Communication Technologies and Challenges

The Department of Transport in the United Kingdom recorded 25,080 motor vehicle fatalities in 2019. This situation stresses the need for an intelligent transport system (ITS) that improves road safety and security by avoiding human errors with the use of autonomous vehicles (AVs). Therefore, this survey discusses the current development of two main components of an ITS: (1) gathering of AVs surrounding data using sensors; and (2) enabling vehicular communication technologies. First, the paper discusses various sensors and their role in AVs. Then, various communication technologies for AVs to facilitate vehicle to everything (V2X) communication are discussed. Based on the transmission range, these technologies are grouped into three main categories: long-range, medium-range and short-range. The short-range group presents the development of Bluetooth, ZigBee and ultra-wide band communication for AVs. The medium-range examines the properties of dedicated short-range communications (DSRC). Finally, the long-range group presents the cellular-vehicle to everything (C-V2X) and 5G-new radio (5G-NR). An important characteristic which differentiates each category and its suitable application is latency. This research presents a comprehensive study of AV technologies and identifies the main advantages, disadvantages, and challenges.

Performance Analysis of Multi-Band Microwave and Millimeter-Wave Operation in 5G NR Systems

Blockage of millimeter-wave (mmWave) radio propagation paths in dense mobile scenarios requires advanced techniques to preserve session continuity in 5G New Radio (NR) systems. In this work, we employ the tools of stochastic geometry and queuing theory as well as rely on 3GPP cluster-based propagation modeling to formulate a mathematical framework, which captures session-level service dynamics of user equipment (UE) that supports multi-band operation. Accordingly, the sub-6 GHz NR base station (BS) is used to temporarily serve the sessions with strict throughput requirements that experience an outage at the mmWave NR BSs. We derive user- and system-centric key performance indicators, including new and ongoing session drop probabilities as well as radio resource utilization. Our numerical results confirm that the use of microwave BSs to serve mmWave sessions is only feasible in light traffic conditions. Particularly, the presence of throughput-hungry mmWave traffic increases the session drop probability at the sub-6 GHz band as well as decreases its utilization. Further, the support of sub-6 GHz radio may not improve the mmWave BS resource utilization, as many mmWave sessions are dropped during their service as a consequence of frequent blockage-induced outage situations.

Enhanced Uplink Coverage for 5G NR: Frequency-Domain Spectral Shaping With Spectral Extension

This paper describes and investigates a novel concept of frequency-domain spectral shaping (FDSS) with spectral extension for the uplink (UL) coverage enhancement in 5G New Radio (NR), building on discrete Fourier transform spread orthogonal frequency-domain multiplexing (DFT-s-OFDM). The considered FDSS concept is shown to have large potential for reducing the peak-to-average-power ratio (PAPR) of the signal, which directly impacts the feasible maximum transmit power under practical nonlinear power amplifiers (PAs) while still meeting the radio frequency (RF) emission requirements imposed by the regulations. To this end, the FDSS scheme with spectral extension is formulated, defining filter windows that fit to the 5G NR spectral flatness requirements. The PAPR reduction capabilities and the corresponding maximum achievable transmit powers are evaluated for a variety of bandwidth allocations in the supported 5G NR frequency ranges 1 and 2 (FR1 and FR2) and compared to those of the currently supported waveforms in 5G NR, particularly π/2-BPSK with FDSS without spectral extension and QPSK without FDSS. Furthermore, an efficient receiver structure capable of reducing the noise enhancement in the equalization phase is proposed. Finally, by evaluating the link-level performance, together with the transmit power gain, the overall coverage enhancement gains of the method are analyzed and provided. The obtained results show that the spectrally-extended FDSS method is a very efficient solution to improve the 5G NR UL coverage clearly outperforming the state-of-the-art, while being also simple in terms of computational complexity such that the method is implementation feasible in practical 5G NR terminals.

Emerging Tools for Link Adaptation on 5G NR and Beyond: Challenges and Opportunities

With the speeding up of the fifth generation (5G) new radio (NR) worldwide commercialization, one of the paramount questions for operators and vendors is how to optimize the radio links, considering the widely diverse scenarios envisioned. One of the key pillars of 5G has been an unprecedented flexibility on the configuration of the radio access network (RAN) on scenarios that include cellular, vehicular, and industrial networks among others. This flexibility has its main exponent on link adaptation (LA), which has evolved into a multi-domain technique where a plethora of parameters, like numerology, bandwidth part, radio frequency beam, power, modulation and coding scheme (MCS) or multiple antenna precoding can be adapted to the instantaneous link conditions. Although such enhancements open the door to a significant performance improvement, they also pose many challenges to LA optimization. In this article, we first present the signaling aspects of NR technology for multi-domain LA and the challenges that need to be faced. Then, we explore the latest advances on LA for wireless networks. We envision a combination of machine learning (ML) tools with multi-domain LA as a key enabler for 5G and beyond networks. Finally, we investigate emerging ML approaches for LA and present a promising application of ML for LA that is assessed with simulations. With this scheme, the training is performed at the network side to relieve the user equipment (UE) to do such a complex task. It is shown with simulations that our ML approach outperforms the well known outer loop link adaptation (OLLA) algorithm in terms of instantaneous block error rate (BLER), while reaching the same average spectral efficiency (SE). Interestingly, it is shown that the proposed scheme only requires 4 bits to represent the features used to train the model, which makes it suitable for implementation in real systems with limited feedback.

DRX in New Radio Unlicensed: A Step Beyond 5G Wireless

5G wireless has ushered in new promises of improved performance and ubiquitous connectivity. However, a continuous increase in connected devices and the proliferation of the Internet of Things have already created skepticism about the capacity of 5G wireless to satisfy the huge data requirements across a myriad of devices. This has made wireless researchers, vendors, and standards bodies look beyond 5G wireless by extending 5G New Radio (NR) in unlicensed bands. Operation in unlicensed bands requires additional channel sensing and fairness across different types of networks. This makes power consumption in bat-tery-constrained mobile devices more challenging. In this article, we introduce two different aspects of discontinuous reception (DRX) for energy and resource savings in 5G NR unlicensed networks. As 5G NR is based on directional beams, the proposed solutions are based on beam searching and beam awareness. Beam-aware DRX explores next generation NodeB's assistance to alleviate mobile user equipment's (UE's) beam searching burden and results in more power saving. Simulation experiments using real wireless traces demonstrate that our NR-U DRX solutions significantly improve UE's power saving and network resource utilization over existing 5G NR DRX.

Joint Delay and Phase Discriminator Based on ESPRIT for 5G NR Positioning

A joint delay and phase discriminator based on the ESPRIT algorithm is proposed for positioning with the fifth generation (5G) New Radio (NR) downlink cellular signals. Since ESPRIT requires knowledge of the number of paths of the radio channel to operate, the proposed discriminator is coupled and studied with two channel order estimators: minimum descriptive length (MDL) and efficient channel order determination (ECOD). To mitigate the delay and phase outliers appearing when the MDL overestimates the channel order, a path selection criterion based on the signal-to-noise ratio (SNR) of the path is proposed. The ESPRIT discriminator is evaluated in terms of the distribution of the estimated channel order, and the delay and phase errors in the absence and presence of multipath. It is observed that the path selection criterion makes the MDL suitable for positioning as no delay and phase outliers are produced. In the presence of multipath, the ESPRIT discriminator achieves lower mean and root-mean-square delay and phase errors than the commonly used early-minus-late power (EMLP) and 2-argument arctangent (ATAN2) discriminators.

5G NEW RADIO (5G NR) - AIR INTERFACE IN 5G MOBILE NETWORKS

The fifth generation of mobile networks promises a scalable platform that can effectively provide coexistence between existing services and future 5G services. 5G networks, despite connecting people, will provide interconnection and control between machines, objects and devices. In other words it is an innovation platform that can provide new services, enhance the user experience and connect new industries. The design of 5G not only focuses on improving mobile broadband, but also on providing control over services through ultra-reliable&nbsp; communication links with&nbsp; low latency and connection to massive internet services. At the heart of 5G network there is a new, unified radio interface - 5G New Radio (NR). 5G NR is part of the 3GPP standards defined in Release 15. This paper provides an overview of the specifications defined for standardization of the new generation of mobile networks, describes the key technologies that are subject for analysis about the development of 5G NR and gives a performance evaluation&nbsp; in order to make a comparison with the services we use today. This technology will start a new industrial revolution, providing high communication speeds, extremely low latency, reliable communication and services that have not been possible before.

A Tutorial on 5G NR V2X Communications

The Third Generation Partnership Project (3GPP) has recently published its Release 16 that includes the first Vehicle to-Everything (V2X) standard based on the 5G New Radio (NR) air interface. 5G NR V2X introduces advanced functionalities on top of the 5G NR air interface to support connected and automated driving use cases with stringent requirements. This paper presents an in-depth tutorial of the 3GPP Release 16 5G NR V2X standard for V2X communications, with a particular focus on the sidelink, since it is the most significant part of 5G NR V2X. The main part of the paper is an in-depth treatment of the key aspects of 5G NR V2X: the physical layer, the resource allocation, the quality of service management, the enhancements introduced to the Uu interface and the mobility management for V2N (Vehicle to Network) communications, as well as the co-existence mechanisms between 5G NR V2X and LTE V2X. We also review the use cases, the system architecture, and describe the evaluation methodology and simulation assumptions for 5G NR V2X. Finally, we provide an outlook on possible 5G NR V2X enhancements, including those identified within Release 17.