Extended reality (XR) is unlocking numerous possibilities and continues attracting individuals and larger groups across different business sectors. With Virtual reality (VR), Augmented reality (AR), or Mixed reality (MR) it is possible to improve the way we access, deliver and exchange information in education, health care, entertainment, and many other aspects of our daily lives. However, to fully exploit the potential of XR, it is important to provide reliable, fast and secure wireless connectivity to the users of XR and that requires refining existing solutions and tailoring those to support XR services. This article presents a tutorial on 3GPP 5G-Advanced Release 18 XR activities, summarizing physical as well as higher layer enhancements introduced for New Radio considering the specifics of XR. In addition, we also describe enhancements across 5G system architecture that impacted radio access network. Furthermore, the paper provides system-level simulation results for several Release 18 enhancements to show their benefits in terms of XR capacity and power saving gains. Finally, it concludes with an overview of future work in Release 19 that continues developing features to support XR services.

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.

The efficient usage of power has become a matter of extreme importance in 5G New Radio. To enhance UE power saving, among other techniques of the 3GPP release 17, it is worth mentioning the relaxation of the measurements required for RLM (Radio Link Monitoring) and BFD (Beam Failure Detection). In this paper, we describe the design of the RLM and BFD measurements relaxation framework and evaluate the power saving gain provided by such relaxation for UEs in low mobility, at cell center and with a short DRX cycle. Our results show that the attainable power saving gain can be approximately between 5% and 40%. The gain greatly depends on factors such as the applied relaxation level, location in time of the reference signals used for the measurements, DRX configuration and whether the UE is also allowed to relax other measurement types (e.g. Radio Resource Management measurements). Furthermore, we study the impact of such relaxation on the mobility and QoS performance through numerical analysis. We conclude that the performance degradation due to relaxation can be bounded to acceptable levels if the applied relaxation level is limited and the UE is able to stop employing relaxation timely, whenever the radio quality deteriorates.

The paging functionality in New Radio release 15 can be energy consuming, especially if a UE is rarely paged or its Paging Occasion (PO) suffers from a high false paging alarm rate. Therefore, paging enhancements for UE power saving are being developed in New Radio release 17. In this work, the concept of Early Paging Indication (EPI), where a UE is notified in advance of its PO whether the UE has to monitor the PO, is examined. As a result, the UE can skip the time-frequency synchronization phase prior to a PO, if the UE need not monitor the PO. The EPI can be signaled via a Downlink Control Information (DCI) message carried in the Physical Downlink Control Channel or via a Reference Signal, e.g. the Secondary Synchronization Signal. Furthermore, the EPI may carry sub-grouping information to divide the UEs, sharing the same PO, into sub-groups, resulting in lower group paging rate and fewer false paging alarms.Simulation results show the EPI can lead to 17 %-34 % energy savings as compared to the release 15 basic paging procedure, depending on the UE SINR radio conditions. If the EPI is complemented with sub-group information an additional 10 % energy can be saved, while also mitigating the impact of high group paging rates. The DCI-based EPI can flexibly contain the sub-group indication, and potentially also Short Message and other information, and is therefore the preferred option.

This chapter begins by focusing on two main design elements: the 5G waveform and the antenna architectures. It describes the basic system design components such as frame structure and resource allocation, synchronization signals, and broadcast channels, the physical random access channel (PRACH). The chapter discusses various aspects of how the antenna arrays that are being used in 5G NR systems are implemented and configured for creating a 'beam-based air interface.' It describes some of the basics of beam forming for receiving and transmitting and describes the idea of antenna virtualization. The chapter explains how all these ingredients are put together to form a beam-based air interface. A short description on power control is also provided. The ends with a description of the downlink and uplink transmission framework.

Currently the 3rd generation partnership project (3GPP) is studying how user equipment power saving can be improved for the fifth generation New Radio technology. To accomplish this objective, a power model has been developed for evaluation of power saving schemes related to Radio Resource Management in Radio Resource Control (RRC) Connected mode among other topics. In this work, we examine the power saving potential in RRC Connected mode using a single-user numerical simulation tool employing the user equipment power model. We demonstrate that the use of short Discontinuous Reception (DRX) can provide 26% energy saving and 74% latency reduction as compared to the long DRX-only baseline. Furthermore, the simulation results, based on the user equipment power model, show that four Physical Downlink Control Channel (PDCCH) optimization monitoring schemes: cross-slot scheduling, reduced blind PDCCH decoding candidate set, wake-up signaling and go-to-sleep signaling, may further reduce the energy consumption 17-20% at the cost of a latency increase and potentially lower overall network performance.

This paper investigates the 5G new radio (NR) uplink (UL) performance with CP-OFDM and DFT-s-OFDM based waveforms. The effects of highly non-linear PA behavior, inter-allocation interference, and UL multi-user MIMO on the relative performance of these waveforms are addressed. It is shown that with relaxed EVM and inband emission requirements for CP-OFDM, the coverage limited operation can be improved to achieve better link budget than DFT-s-OFDM based UL without performance penalty in the multi-user uplink. For high-throughput user equipment, the assumed highly non-linear PA behavior restricts the CP-OFDM based transmit power, which may limit the coverage compared to DFT-s-OFDM based waveform in UL without multi-user MIMO support. In UL multi-user MIMO scenario the CP-OFDM based waveform provides clearly better link performance and achieves better link budget than DFT-s-OFDM based waveform. Within the multi-user MIMO UL scenario, the requirement for substantially better PA linearity in high-throughput cases is also observed.

By the introduction of the fifth generation (5G) mobile communication networks and its physical layer entitled as new radio (NR), the question of link performance in coexistence scenario between the 5G NR and fourth generation (4G) mobile communication networks based on long term evolution (LTE) has been raised. In this paper, we evaluate the uplink (UL) performance of 5G NR and LTE links operating within a common channel. The need for subcarrier shift in 5G NR UL similar to LTE UL is addressed and analyzed, and the effect of guard band (GB) in frequency domain between 5G NR and LTE is studied. It is shown that with a single physical resource block GB no subcarrier shifting is required in 5G NR, as long as the power control accuracy is sufficient, in which case LTE performance is unaffected. From the 5G NR performance point of view no GB is required.

For the 5G new radio physical layer the CP-OFDM waveform has been chosen as the baseline for communications below 40 GHz. The requirement for multicarrier waveforms used for uplink is to achieve similar coverage as achieved by SC-FDMA in LTE uplink. In this paper, multiple candidate waveforms with enhanced CP-OFDM processing proposed for 5G incorporating realistic 3GPP compliant power amplifier model and peak clipping are evaluated in uplink transmission, and compared against SC-FDMA in terms of maximum average power amplifier output power and coded block error rate. It is shown that multicarrier waveforms have minor disadvantage in single-PRB transmission, but as the allocation size increases to encounter frequency selective fading the multicarrier waveforms provide similar or even improved link budget compared to SC-FDMA uplink. This implies that given the expected cell edge throughput requirements for 5G mobile broadband services and expected power amplifier development, enhanced CP-OFDM waveforms can achieve the uplink coverage requirement.

In 3GPP Rel-13, a narrowband system based on Long Term Evolution (LTE) is being introduced to provide wide-area cellular connectivity for the Internet of Things. This system, named Narrowband Internet of Things (NB-IoT), can be deployed in three different operation modes -(1) stand-alone as a dedicated carrier, (2) in-band within the occupied bandwidth of a wideband LTE carrier, and (3) within the guard-band of an existing LTE carrier. The design targets of NB-IoT include low-cost devices, high coverage (20-dB improvement over GPRS), long device battery life (more than 10 years), and massive capacity. Latency is relaxed although a delay budget of 10 seconds is the target for exception reports. This paper discusses the design and performance of the downlink and uplink data channels. Although the design of these channels is based on LTE, there are some differences, particularly in the uplink, with the introduction of subcarrier-level transmission. The similarities have enabled rapid specification, while the enhancements in the design enable the achievement of the stated targets for NB-IoT.