İletişim Teknolojileri · · 31 views

5G Technology Explained: A Comprehensive Technical and Architectural Comparison with Previous-Generation Networks

Fifth-generation (5G) wireless systems represent not merely a speed increase but a revolutionary transformation that fundamentally redefines the architecture, service paradigm and application framework of mobile networks. This review article examines systematically and comprehensively the technical and architectural dimensions along which the 5G New Radio (NR) standard diverges from previous-generation networks, particularly 4G LTE.

5G'NİN FARKI : Önceki Nesil Ağlarla Kapsamlı Teknik ve Mimari Karşılaştırma
Open the original PDF (Turkish) Download PDF (Turkish)
Read the full article text

5G Technology Explained: A Comprehensive Technical and Architectural Comparison with Previous Generation Networks Review Article Keywords: 5G NR • Massive MIMO • Network Slicing • URLLC • mmWave ABSTRACT Fifth-generation (5G) wireless communication systems represent not merely a speed enhancement but a revolutionary transformation that fundamentally redefines the architecture, service paradigm, and application framework of mobile networks. This review article systematically and comprehensively examines how the 5G New Radio (NR) standard differentiates itself from previous generations — particularly 4G LTE — across technical and architectural dimensions. The analysis covers physical layer innovations (Massive MIMO, beamforming, millimeter-wave spectrum, new numerologies), architectural transformations (5G core network, service-based architecture, network slicing, edge computing), service scenarios (eMBB, URLLC, mMTC), and performance parameters (latency, reliability, connection density, energy efficiency). The article also evaluates the transformative role of 5G in Industry 4.0, autonomous vehicles, remote healthcare, and smart city applications, while examining its intersections with emerging 6G research. All comparisons and analyses are grounded in leading foreign-language academic sources and 3GPP standard documents.

Keywords: 5G NR, 4G LTE, Massive MIMO, network slicing, URLLC, eMBB, mMTC, millimeter wave, edge computing, service-based architecture 1. Introduction Mobile communication technologies have been in continuous transformation through generational transitions occurring roughly once every decade. Each new generation has been built upon its predecessor, delivering meaningful improvements in capacity, speed and coverage. 5G, however, moves beyond this linear evolution and fundamentally redefines mobile network architecture. Defined by the International Telecommunication Union (ITU) through the IMT-2020 framework and standardised in 3GPP Release 15 (2017), 5G New Radio (NR) departs from its predecessors not only in performance parameters but also, and distinctly, in design philosophy and target application ecosystem (ITU-R M.2083, 2015).

4G LTE brought mobile broadband to the masses and formed the infrastructure of the smartphone revolution. Its design was fundamentally oriented towards optimising human-centred communication — voice, video and data. 5G, by contrast, is designed to serve a far broader set of targets — people, machines, vehicles, industrial systems, medical devices — simultaneously and with radically different quality-of-service requirements. This has required a new physical layer, a new core network architecture and a new service framework (Dahlman et al., 2018).

The purpose of this article is to set out the differences between 5G and previous-generation networks — chiefly 4G LTE — from a multidimensional and academic perspective. The article presents a comprehensive comparison spanning the physical layer, network architecture, spectrum usage, service scenarios, energy efficiency and application domains, with all technical claims supported by leading foreign-language sources in the field. 2. A Paradigmatic Difference: Design Philosophy Across the evolution from 1G to 4G, each generation preserved the basic design logic of its predecessor — mobile voice and data transmission — while delivering it at higher speed, greater bandwidth and lower cost. This continuity eased backward compatibility between generations and allowed operators to convert their investments incrementally. 5G breaks that chain of continuity. For the first time, a network generation has been designed to serve not a single primary use case but three radically different scenarios concurrently. These three scenarios — eMBB, URLLC and mMTC — carry different latency, reliability, bandwidth and device-density requirements, and having a single hardware platform meet all of them presents a serious engineering challenge (IMT-2020 Requirements, 2017).

"5G is the first generation of wireless system designed to serve different use-case scenarios simultaneously; this characteristic separates it from earlier generations at a paradigmatic level." (Dahlman et al., 2018, p. 3) This paradigmatic difference is reflected across every layer of the network architecture — from the physical layer to the core network, from frequency allocation to service management. The sections below examine these differences layer by layer.

3. Physical Layer Innovations 3.1 Numerology and Flexible Frame Structure In 4G LTE the OFDM subcarrier spacing (SCS) is fixed at 15 kHz for standard operation. This fixed value constrains the system's flexibility to adapt to different use cases: in high-mobility environments Doppler shift adversely affects narrow subcarrier spacing, while wideband applications make carrier aggregation of multiple carriers unavoidable (Sesia et al., 2011).

5G NR, by contrast, adopts flexibility as a core design principle. 3GPP Release 15 defines five different SCS values: 15, 30, 60, 120 and 240 kHz. This diversity provides a configuration optimised for different band ranges, mobility conditions and service requirements (Dahlman et al., 2018). For example, the 240 kHz subcarrier spacing can be used in millimeter-wave bands to yield extremely short symbol durations and therefore low latency. This flexibility is one of the critical design decisions that makes the sub-millisecond latencies required by URLLC applications possible. 3.2 Massive MIMO and Beamforming Multiple Input Multiple Output antenna systems (MIMO) were used in the 4G LTE era as well, but deployments were typically limited to 2×2 or 4×4 antenna configurations. In 5G NR the concept of Massive MIMO has made it both possible and practical to use 32, 64, 128 or even 256 antenna elements on the base station side (Marzetta et al., 2016).

Massive MIMO differs from LTE MIMO along several dimensions. First, the large number of antenna elements allows signals to be focused into extremely narrow beams in the spatial domain; this is termed 3D beamforming or Full-Dimension MIMO (FD-MIMO). Second, multiple users can be served simultaneously over the same time-frequency resource — MU-MIMO (Multi-User MIMO) — so that sector capacity increases non-linearly. Third, as demonstrated theoretically by Marzetta et al. (2016), as the number of antennas tends to infinity the orthogonality between random channels strengthens (favourable propagation), and thermal noise and multi-user interference practically vanish. Beamforming architectures in 5G NR fall into three categories: (1) analog beamforming, in which all antenna elements are driven through a common phase-shifter chain; (2) digital beamforming, in which a separate baseband processor is attached to each antenna; and (3) hybrid beamforming, which offers the optimal balance between the two. The hybrid approach, which maximises performance while keeping hardware cost reasonable in millimeter-wave (mmWave) bands, has become the industry standard (Heath et al., 2016).

3.3 Millimeter-Wave Spectrum In terms of frequency spectrum, 4G LTE generally operates in the 700 MHz – 2.6 GHz range. This sub-6 GHz spectrum offers good propagation characteristics but faces serious congestion because of current usage density. 5G defines two distinct frequency ranges: FR1 (450 MHz – 7.125 GHz) and FR2 (24.25 GHz – 52.6 GHz). FR2, known as the millimeter-wave band, holds the genuinely transformative potential of 5G (Rangan et al., 2014).

The principal advantage of mmWave bands is that frequency blocks on the order of gigahertz can be allocated, which theoretically yields peak data rates of 10–20 Gbps. On the other hand, these bands present serious propagation difficulties: atmospheric absorption, attenuation from rain and humidity, high penetration loss through materials such as concrete and glass, and sharp signal drops when the line of sight (LoS) is interrupted. For this reason mmWave 5G cells are typically deployed in dense urban settings with a radius of 50–200 m and require dense base-station infrastructure (Rangan et al., 2014). 3.4 Modulation and Coding The highest modulation order used in 4G LTE is 64-QAM (256-QAM is supported in some configurations with LTE-Advanced Pro). 5G NR adopts 256-QAM as its standard modulation scheme, thereby obtaining a far higher bit rate from the same spectral resource. Theoretically 256-QAM provides 33% higher spectral efficiency than 64-QAM, but this gain can only be realised under high signal-to-noise ratio (SNR) conditions (Dahlman et al., 2018).

In terms of error-correction coding, 5G NR has moved from the Turbo codes used in 4G to LDPC (Low-Density Parity-Check) and Polar codes. LDPC codes are used for data channels and offer lower decoding latency at high data rates. Polar codes are adopted for control channels and stand out as the code family that theoretically comes closest to the Shannon limit. This transition is of critical importance particularly in URLLC scenarios (3GPP TS 38.212, 2021). Table 1. Comparison of 5G NR and 4G LTE Physical Layer Parameters Parameter 4G LTE / LTE-A 5G NR Subcarrier spacing 15 kHz (fixed) 15 / 30 / 60 / 120 / 240 kHz (flexible) Frequency bands 700 MHz – 2.6 GHz (FR1) 450 MHz – 7.125 GHz (FR1) + 24.25– 52.6 GHz (FR2) Peak data rate (DL) 1 Gbps (LTE-A) 20 Gbps (NR) MIMO structure Max. 8 layers (typically 2×2 / 4×4) Max. 256 antennas / Massive MIMO / 3D Beamforming Modulation (max.) 64-QAM (some: 256-QAM) 256-QAM (standard) Error-correction code Turbo code LDPC (data) + Polar code (control) User plane latency ~30 ms (typical) < 4 ms (eMBB) / < 1 ms (URLLC) Duplex mode FDD / TDD FDD / TDD / dynamic TDD Note. Values are compiled on the basis of 3GPP Release 15/16 standards. Performance obtained under real network conditions may vary depending on environment and hardware. Source: Dahlman et al. (2018); 3GPP TS 38.212 (2021).

4. Service Scenarios: The Triple Paradigm of 5G 4.1 eMBB: Enhanced Mobile Broadband Enhanced Mobile Broadband (eMBB) is the scenario in which 5G is the direct heir of 4G LTE, covering high-data-rate applications aimed at users. Even so, 5G eMBB differs significantly from LTE broadband in both quality and quantity. According to ITU-R IMT-2020 requirements, eMBB targets a 20 Gbps peak downlink rate and a 100 Mbps experienced data rate. These figures far exceed LTE-Advanced's 1 Gbps peak and ~10 Mbps experienced values. Applications such as 4K/8K video streaming, virtual reality (VR), augmented reality (AR), cloud gaming services and holographic communication are envisaged as the primary use areas of eMBB (IMT-2020 Requirements, 2017). 4.2 URLLC: Ultra-Reliable Low Latency Communication Ultra-Reliable Low Latency Communications (URLLC) is the area in which 5G differs most markedly from 4G LTE, since 4G was not designed to target such applications. URLLC targets 1 ms user-plane latency and 99.9999% (six nines) reliability (Popovski et al., 2018). These values are mandatory for applications with a direct effect on human life:

• Autonomous vehicles: V2X (Vehicle-to-Everything) communication requires sub-millisecond response times for emergency braking and collision-avoidance systems. • Remote surgery and robotics: the delay between the surgeon's hand movements and the robotic arm must remain below the threshold of human perception (10–20 ms). • Industrial automation: production-line PLC (Programmable Logic Controller) systems require synchronous and deterministic communication. • Smart electricity grids: fault detection and isolation operations must take place within milliseconds (Popovski et al., 2018).

These requirements cannot be met technically in 4G LTE. While LTE's minimum Transmission Time Interval (TTI) is 1 ms, in 5G NR the flexible subcarrier structure allows the TTI to be reduced to 0.125 ms (with 120 kHz SCS). This dramatic reduction is one of the fundamental physical-layer design decisions that make URLLC applications realistic (Dahlman et al., 2018).

4.3 mMTC: Massive Machine Type Communications Massive Machine Type Communications (mMTC) is defined to meet the large-scale connectivity requirement of the Internet of Things (IoT). mMTC targets a connection density of 1 million devices per km², roughly ten times what LTE is able to support (ITU-R M.2083, 2015).

mMTC devices generally feature low power consumption, long battery life (up to 10 years), deep coverage and low data rates. Smart water and electricity meters, agricultural sensors, urban lighting management systems and environmental monitoring stations are typical examples of this category. For backward compatibility the 5G standard also adopts the NB-IoT and LTE-M technologies developed during the 4G era for mMTC, although native 5G NR-based solutions are expected to come to the fore in future (Lin et al., 2020). 5. Network Architecture: The Transformation from 4G EPC to 5GC 5.1 Limitations of the 4G EPC Architecture The Evolved Packet Core (EPC), the core network of 4G LTE, represents one of the most important steps in the transition to an all-IP architecture. EPC comprises functional blocks such as the Mobility Management Entity (MME), Serving Gateway (S-GW), Packet Data Network Gateway (P-GW) and Home Subscriber Server (HSS), which communicate over defined interfaces (S1, S5/S8, SGi, etc.) (Sesia et al., 2011).

The principal limitations of the EPC architecture may be listed as follows: (1) Network functions are dependent on monolithic hardware platforms; flexibility and scalability are constrained. (2) Each new service type requires a separate core network layer or an upgrade. (3) Quality-of-service (QoS) management does not offer sufficient flexibility to isolate different service types from one another. (4) The integration of network virtualisation and software-defined networking (SDN) principles was achieved through a retrofit approach, which weakens the coherence of the architecture. 5.2 The 5G Core Network: Service-Based Architecture The 5G Core (5GC) is a core network designed from scratch on the principle of Service-Based Architecture (SBA). In SBA each Network Function (NF) exposes its services through RESTful APIs that other functions can consume; this approach converges with the microservice architecture of modern software engineering practice. The principal network functions may be listed as follows:

• AMF (Access and Mobility Management Function): access and mobility management; assumes the role of LTE's MME.

• SMF (Session Management Function): session management; corresponds to the control-plane function of the P-GW.

• UPF (User Plane Function): user-plane data transmission; the function that routes and forwards data traffic.

• PCF (Policy Control Function): policy and rule management; determines quality-of-service (QoS) parameters.

• AUSF (Authentication Server Function): authentication; provides secure network access (3GPP TS 23.501, 2021).

The most critical characteristic of the 5GC is the clear separation of control-plane and user-plane functions (CUPS — Control and User Plane Separation). This separation allows user-plane functions (UPF) to be moved to the edge of the network — to locations close to the base station — and thereby lays the groundwork for edge computing applications (Zhang, 2019). 5.3 Network Slicing Network slicing represents one of the most striking architectural innovations of 5G and one of the most important functional differences from 4G. In 4G an operator can offer only a single type of network service; 5G allows the creation of virtual networks (slices) that are logically fully isolated from one another on a shared physical infrastructure. Each slice has an independent QoS policy, resource quota and service configuration. For example: a medical monitoring system in an emergency ambulance receives an ultra-reliable connection over a URLLC slice; tens of thousands of spectators in a stadium stream 4K video over an eMBB slice; and factory sensors establish low-cost connectivity over an mMTC slice — all while sharing the same physical 5G network yet operating in complete isolation from one another. This capability makes it easier for operators to build vertical markets for different sectors, allowing them to offer customised connectivity services for healthcare, transport, energy and manufacturing.

5.4 Multi-Access Edge Computing (MEC) Multi-Access Edge Computing (MEC) is the architecture that moves computing capacity from centralised cloud data centres to the physical edge of the network — near base stations or to local data centres. Defined by ETSI in 2014 and now an inseparable part of the 5G architecture, MEC is of critical importance for URLLC applications. In 4G networks application traffic must travel a long path from the user to the content server on the internet backbone; the total latency of this journey is mostly in the 30–80 ms range. When processing is performed locally with MEC, the latency from the user to the application server can be reduced to 1–5 ms. Communication between autonomous vehicles and roadside infrastructure (V2I), real-time face recognition, industrial robot coordination and smart traffic management are among the applications that benefit directly from MEC.

6. Performance Parameters: A Cross-Generational Comparison 6.1 Data Rate and Latency Data rate and latency are the most visible dimensions of a cross-generational comparison. With each generational transition from 1G to 5G, peak data rate has increased roughly tenfold while latency has decreased dramatically. Because these two parameters are indicators that directly affect application quality and user experience, they are among the primary focal points of both industry and academia (Dahlman et al., 2018).

On the latency dimension the gain from 5G is particularly striking: whereas typical user-plane latency in 3G UMTS is 100–150 ms, 4G LTE reduced this to 30–50 ms. 5G NR targets < 4 ms user-plane latency for eMBB and < 1 ms for URLLC. This last figure is far below the human motor response time to a pain stimulus (150–200 ms) and makes real-time remote intervention applications realistic for the first time (Popovski et al., 2018). 6.2 Connection Density and Device Count Connection density is one of the parameters that has seen the most dramatic improvement in the transition from 4G to 5G. While 4G LTE supports roughly 100,000 devices per km², the mMTC scenario of 5G NR targets 1,000,000 devices/km². This tenfold increase makes densely deployed high-density sensor networks — smart city lighting systems, large shopping centres, industrial factory floors — genuinely practical (ITU-R M.2083, 2015).

6.3 Energy Efficiency With sustainability concerns coming to the fore, energy efficiency has become one of the priority goals of 5G design. ITU-R IMT-2020 targeted 5G delivering 100 times higher energy efficiency than LTE. Various mechanisms have been introduced to reach this target: sleep mode management, load-aware resource allocation, cell sleeping strategies and the beam-focusing efficiency offered by Massive MIMO are foremost among them (Marzetta et al., 2016). Nevertheless, when assessed in terms of absolute energy consumption, 5G base stations — particularly Massive MIMO antennas — are seen to consume more hardware power than LTE base stations. Although energy consumption per bit falls, total infrastructure energy consumption tends to rise; this constitutes a critical area in which operators and regulators must develop policy (Dahlman et al., 2018). Table 2. Comparison of Key Performance Parameters Across Network Generations Parameter 2G (GSM) 3G (UMTS/HSPA) 4G (LTE-A) 5G (NR) Peak rate (DL) 384 kbps 42 Mbps 1 Gbps 20 Gbps Latency (typical) ~300 ms ~100 ms ~30 ms < 1 ms (URLLC) Connection density — — ~100 K/km² 1 M/km² Spectrum bands 900/1800 MHz 2100 MHz 700–2600 MHz FR1+FR2 (mmWave) Core network GSM Core GPRS Core EPC (all-IP) 5GC (SBA, slicing) Reliability target — — ~99.9% 99.9999% (URLLC) Note. Source: Dahlman et al. (2018); ITU-R M.2083 (2015); IMT-2020 Requirements (2017). Peak rate and latency values reflect standard targets.

7. Transformative Application Domains of 5G 7.1 Industry 4.0 and Connected Factories Industry 4.0 is a transformation paradigm that envisages the integration of production processes with cyber-physical systems, artificial intelligence and big-data analytics. The connectivity infrastructure that forms the backbone of this transformation requires low latency, high reliability and support for dense device populations — requirements that map precisely onto the design goals of the 5G URLLC and mMTC scenarios (Simsek et al., 2016).

In traditional factory environments, wired fieldbus systems (PROFINET, EtherCAT) are used for control communication; these systems are extremely reliable but lack flexibility and carry high installation costs. Private 5G Networks stand out for their potential to deliver the same reliability wirelessly. Many major manufacturers — Volkswagen, Bosch, BMW — are deploying or testing private 5G networks inside their factories. These networks serve critical applications such as AGV (Automated Guided Vehicle) coordination, real-time quality control and robot-arm synchronisation (Simsek et al., 2016).

7.2 Autonomous Vehicles and V2X Communication Vehicle-to-Everything (V2X) communication covers vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), vehicle-to-pedestrian (V2P) and vehicle-to-network (V2N) links. To guarantee the safety of autonomous driving, this communication must take place with latency below 5 ms; this threshold represents the maximum time within which an emergency braking decision can be taken. 5G C-V2X (Cellular V2X) makes a decisive contribution particularly in high-speed scenarios and dense urban environments where LTE-V2X falls short (Lin et al., 2020).

Among the principal contributions of 5G to V2X are lower latency, wider coverage, the sidelink enhancements defined in Rel-16, and direct vehicle-to-vehicle communication over the PC5 interface. On the other hand, the debate continues as to whether autonomous vehicles can rely on 5G alone for safe driving; most experts hold that 5G will play a complementary role alongside in-vehicle sensor data (LIDAR, radar, camera). 7.3 Remote Healthcare Services The COVID-19 pandemic laid bare both the potential of remote healthcare services and their infrastructure requirements. 5G makes two critical categories of medical application possible: (1) Applications requiring high bandwidth: 4K/8K medical image transmission, tele-radiology, real-time ultrasound streaming and virtual-reality-assisted medical training. (2) Applications requiring low latency: remote surgical robots (for example the da Vinci system), remote calibration of neurological stimulation devices and instantaneous physiological monitoring of intensive care patients (Simsek et al., 2016).

7.4 Smart City Applications The smart city concept envisages the optimisation of urban systems such as transport, energy, water management, environmental monitoring and public safety through interconnected sensors and platforms. The mMTC scenario of 5G allows a large number of low-power sensors per km² to remain connected simultaneously, while eMBB provides the basis for high-resolution camera streams across the city (ITU-R M.2083, 2015).

A particularly notable application is smart traffic management: intelligent signalling systems at intersections detect vehicle density in real time and adjust signal durations dynamically; this process requires both V2I communication and data sharing with a central artificial intelligence platform. 5G is the first generation of network technology able to meet these two requirements simultaneously and reliably.

8. Security Architecture: The Innovations Brought by 5G Security architecture is an area substantially strengthened in the transition from 4G to 5G. The 4G LTE security architecture contained many weaknesses: fake base station (IMSI-catcher) attacks, authentication performed only on the network side (one-way), and unencrypted signalling messages in certain protocols are among the prominent vulnerabilities (3GPP TS 33.501, 2021).

5G NR incorporates comprehensive security improvements to close these gaps. Transmitting the subscription identity (SUPI — Subscription Permanent Identifier) in encrypted form as SUCI (Subscription Concealed Identifier) makes IMSI-catcher attacks considerably harder. The 5G-AKA (Authentication and Key Agreement) protocol makes mutual authentication mandatory; the network must prove itself to the terminal. User Plane Integrity Protection verifies that data packets are delivered unaltered (3GPP TS 33.501, 2021). The network slicing architecture also offers significant advantages on the security dimension: because each slice has an independent security policy and resource isolation, a security breach in one slice does not affect the others. This property is decisive for improving the security of critical infrastructure applications — public safety, energy grids. 9. Challenges and Limitations of 5G Alongside the opportunities 5G offers, serious technical, economic and regulatory obstacles stand in the way of its widespread adoption. An honest assessment of these obstacles matters for gaining a realistic perspective. 9.1 Intensive Infrastructure Investment The short propagation distance in mmWave bands requires dense base-station deployment. The number of base stations needed for an mmWave 5G network to provide coverage equivalent to LTE in a given urban area can be 10–100 times greater (Rangan et al., 2014). This substantially increases installation costs and timelines and indicates that the true coverage promise of mmWave will remain limited in the short term. 9.2 Device Ecosystem and Battery Life 5G modem and Radio Front-End technology causes significant power consumption problems, particularly in mmWave-capable devices. The battery drain of first-generation 5G smartphones was markedly higher than that of 4G devices under similar usage conditions. Chip designers are moving to 4nm and smaller process technologies to overcome this problem, but this transition keeps costs high (Heath et al., 2016). 9.3 Spectrum Complexity and Regulatory Obstacles The simultaneous operation of 5G in different bands (sub-1 GHz, 3.5 GHz, mmWave) complicates device design and validation processes. Moreover, the fact that different frequency bands are licensed in each country makes international device compatibility and roaming scenarios more difficult. Some mmWave bands (particularly 26 GHz) overlap with existing satellite services (Fixed Satellite Service), which requires regulatory coordination (Rangan et al., 2014).

10. From 5G to 6G: Points of Intersection and Research Agendas While 5G is still in the process of worldwide deployment, academic circles and leading research institutions are conducting intensive work on sixth-generation (6G) systems targeting the early 2030s. The ITU published its IMT-2030 recommendation framework in 2023, and alongside technology giants such as Samsung, Nokia, Ericsson and Huawei, publicly funded research programmes such as Hexa-X (EU), B5G/6G (Japan) and FCC NextG (USA) have been launched (Dang et al., 2020).

Academic consensus on how 6G will surpass 5G concentrates on the following axes: (1) Terahertz (THz) communication: Tbps speeds are theoretically possible in the 100 GHz–10 THz range, but atmospheric absorption and component maturity are critical obstacles. (2) AI-native networks: AI/ML is being designed in 6G not merely as an optimisation tool but as an inseparable part of network protocols and channel management. (3) Integrated sensing and communication (ISAC): radio signals will be used both for communication and for radar-like environmental sensing (Dang et al., 2020). (4) Non-terrestrial network integration (NTN): global uninterrupted coverage through LEO satellite networks; this trend, which began in the 5G era, will become a standard architectural element in 6G.

11. Conclusion This article has sought to set out comprehensively how and along which dimensions 5G NR differs from previous-generation networks, primarily 4G LTE. The comparison undertaken shows clearly that 5G is not merely a faster LTE, but represents a genuine generational leap in architecture, paradigm and target ecosystem. At the physical layer, Massive MIMO, flexible numerologies, millimeter-wave spectrum and advanced coding schemes make possible data rates and latency figures that 4G could not reach. In network architecture, the service-based structure, network slicing and edge computing give operators the capacity to offer customised services for different sectors. On the service-scenario dimension, the simultaneous support of eMBB, URLLC and mMTC opens a new ecosystem centred on machine, vehicle and infrastructure connectivity beyond human communication.

Nevertheless, the practical spread of 5G faces real difficulties such as mmWave infrastructure density, device power consumption, spectrum regulation and investment cost. Overcoming these difficulties requires cooperation between technology companies, operators, regulatory bodies and academic researchers. This process will accelerate further alongside 6G research, and in the early 2030s a new network paradigm uniting communication, sensing and computation in a single architecture will take shape.

References 3GPP TS 23.501. (2021). System architecture for the 5G System (5GS) (Release 16). 3rd Generation Partnership Project.

3GPP TS 33.501. (2021). Security architecture and procedures for 5G system (Release 16). 3rd Generation Partnership Project.

3GPP TS 38.212. (2021). NR; Multiplexing and channel coding (Release 16). 3rd Generation Partnership Project.

Dahlman, E., Parkvall, S., & Sköld, J. (2018). 5G NR: The next generation wireless access technology. Academic Press.

Dang, S., Amin, O., Shihada, B., & Alouini, M.-S. (2020). What should 6G be? Nature Electronics, 3(1), 20–29. https://doi.org/10.1038/s41928-019-0355-6 Goldsmith, A. (2005). Wireless communications. Cambridge University Press. Heath, R. W., González-Prelcic, N., Rangan, S., Roh, W., & Sayeed, A. M. (2016). An overview of signal processing techniques for millimeter wave MIMO systems. IEEE Journal of Selected Topics in Signal Processing, 10(3), 436–453. https://doi.org/10.1109/JSTSP.2016.2523924 IMT-2020 Requirements. (2017). Minimum requirements related to technical performance for IMT-2020 radio interface(s) (Report ITU-R M.2410). International Telecommunication Union.

ITU. (2023). Measuring digital development: Facts and figures 2023. International Telecommunication Union.

ITU-R M.2083. (2015). IMT Vision – Framework and overall objectives of the future development of IMT for 2020 and beyond. International Telecommunication Union. Lin, X., Li, J., Baldemair, R., Cheng, J.-F. T., Parkvall, S., Larsson, D. C., Koorapaty, H., Frenne, M., Falahati, S., Grovlen, A., & Werner, K. (2020). 5G new radio: Unveiling the essentials of the next generation wireless access technology. IEEE Communications Standards Magazine, 3(3), 30–37. https://doi.org/10.1109/MCOMSTD.001.1800036 Marzetta, T. L., Larsson, E. G., Yang, H., & Ngo, H. Q. (2016). Fundamentals of massive MIMO. Cambridge University Press.

Molisch, A. F. (2011). Wireless communications (2nd ed.). John Wiley & Sons. Popovski, P., Trillingsgaard, K. F., Simeone, O., & Durisi, G. (2018). 5G wireless network slicing for eMBB, URLLC, and mMTC: A communication-theoretic view. IEEE Access, 6, 55765–55779. https://doi.org/10.1109/ACCESS.2018.2872781 Rangan, S., Rappaport, T. S., & Erkip, E. (2014). Millimeter-wave cellular wireless networks: Potentials and challenges. Proceedings of the IEEE, 102(3), 366–385. https://doi.org/10.1109/JPROC.2014.2299397 Rappaport, T. S. (2002). Wireless communications: Principles and practice (2nd ed.). Prentice Hall.

Sesia, S., Toufik, I., & Baker, M. (Eds.). (2011). LTE: The UMTS long term evolution — From theory to practice (2nd ed.). John Wiley & Sons.

Simsek, M., Aijaz, A., Dohler, M., Sachs, J., & Fettweis, G. (2016). 5G-enabled tactile internet. IEEE Journal on Selected Areas in Communications, 34(3), 460–473. https://doi.org/10.1109/JSAC.2016.2525398 Tse, D., & Viswanath, P. (2005). Fundamentals of wireless communication. Cambridge University Press.

Zhang, S. (2019). An overview of network slicing for 5G. IEEE Wireless Communications, 26(3), 111–117. https://doi.org/10.1109/MWC.2019.1800234