Technologies 5G / De la 3G a la 6G - Semestre 9
Annee academique : 2024-2025
Semestre : S9
Enseignant : Etienne Sicard
Categorie : Telecommunications et Reseaux Mobiles
PART A - Presentation Generale
Objectifs du module
Le cours "5G Technologies / From 3G to 6G", dispense par Etienne Sicard a l'INSA Toulouse, avait pour objectif principal d'explorer l'ensemble des technologies liees aux reseaux cellulaires, depuis la 3G jusqu'aux perspectives de la 6G, avec un accent particulier sur la 5G et ses technologies emergentes.
Objectifs pedagogiques :
- Comprendre l'evolution des reseaux cellulaires de la 3G a la 6G
- Maitriser les principes fondamentaux des technologies 5G (OFDM, MIMO, beamforming)
- Analyser les bandes de frequences et l'architecture reseau de la 5G NR
- Explorer les technologies emergentes pour la 6G (THz, IA, communication quantique)
- Evaluer l'impact societal et environnemental des nouvelles generations de reseaux
- Developper des competences en recherche, synthese et presentation technique
Competences visees
- Maitrise des concepts de modulation avancee (OFDM, OFDMA, QAM)
- Comprehension des architectures MIMO et massive MIMO
- Connaissance des bandes de frequences sub-6 GHz et mmWave
- Analyse du network slicing et de la virtualisation reseau
- Vision prospective sur les technologies 6G
- Capacite a synthetiser et presenter des sujets techniques complexes
Organisation du cours
Le cours employait une pedagogie inversee (reverse pedagogy) : les etudiants etaient responsables de la preparation et de la presentation de sujets specifiques. Cette approche permettait une immersion profonde dans chaque sujet grace a la recherche personnelle approfondie.
Format :
- Presentations par groupes d'etudiants sur des sujets varies
- Discussions et debats apres chaque presentation
- Partage de connaissances et apprentissage collaboratif
PART B - Experience et Contexte
Environnement et contexte
Au cours de ce module, nous avons aborde un large eventail de sujets lies aux telecommunications modernes. J'ai eu l'opportunite de collaborer avec Samia Boukouiss sur une presentation dediee aux technologies pour la 6G. Notre travail a couvert de nombreux aspects :
- Les applications et opportunites de la 6G
- Les technologies cles de la 6G (THz, IA, communication quantique, VLC, ultra-massive MIMO)
- Les defis dans le developpement de la 6G
- Le calendrier de developpement et les efforts mondiaux
- L'impact de la 6G sur la societe
Presentations des collegues
J'ai egalement participe activement aux presentations de mes camarades, couvrant des sujets tres varies :
| Sujet | Domaine |
|---|---|
| Starlink, Kuiper | Constellations de satellites |
| LTE-M pour l'IoT | Reseaux cellulaires pour objets connectes |
| Samsung et la 6G | Vision industrielle de la 6G |
| Drone-trains | Transport et telecommunications |
| Orange et la 6G | Strategie operateur pour la 6G |
| Impacts environnementaux | Ecologie et telecommunications |
| 5G : Vehicle to Everything (V2X) | Communications vehiculaires |
| Cancer et ondes EM | Sante et ondes electromagnetiques |
Ces presentations m'ont permis d'acquerir une vision large et transversale des enjeux des telecommunications modernes.
Ma fonction
Dans le cadre de ce cours, j'etais responsable de :
- Rechercher et presenter les technologies pour la 6G en binome
- Collaborer avec mes pairs pour explorer les implications de la 5G et des futures technologies 6G
- Participer aux discussions et echanges apres chaque presentation
- Prendre des notes et synthetiser les connaissances partagees par les autres groupes
Outils et ressources utilises
- Recherche documentaire : articles scientifiques IEEE, 3GPP, publications industrielles
- Outils de presentation : PowerPoint, documents de synthese
- Sources de reference : specifications 3GPP, livres blancs des operateurs et equipementiers (Ericsson, Nokia, Samsung, Huawei)
- Cours de reference : support de cours "3G6G-2024" du Pr. Sicard
PART C - Aspects Techniques Detailles
1. Evolution des reseaux cellulaires : de la 3G a la 5G
Chronologie des generations :
| Generation | Periode | Debit max | Technologie cle | Usage principal |
|---|---|---|---|---|
| 3G (UMTS) | 2001+ | 2 Mbps | WCDMA, HSPA | Internet mobile, video |
| 4G (LTE) | 2010+ | 100 Mbps - 1 Gbps | OFDMA, MIMO | Streaming HD, apps |
| 5G (NR) | 2020+ | 10-20 Gbps | mmWave, massive MIMO | IoT massif, URLLC |
| 6G (vision) | 2030+ | 1 Tbps | THz, IA, quantique | Holographie, jumeaux numeriques |
De la 3G a la 4G :
La transition de la 3G (UMTS/WCDMA) vers la 4G (LTE) a marque un tournant majeur avec l'adoption de l'OFDMA (Orthogonal Frequency-Division Multiple Access) comme technique d'acces, remplacant le CDMA. Cette evolution a permis une augmentation significative des debits et une meilleure efficacite spectrale, ouvrant la voie au streaming video et aux applications gourmandes en bande passante.
De la 4G a la 5G :
La 5G (New Radio - NR) represente une rupture technologique avec trois piliers fondamentaux :
- eMBB (enhanced Mobile Broadband) : debits tres eleves jusqu'a 20 Gbps
- mMTC (massive Machine-Type Communication) : connexion de millions d'objets IoT par km2
- URLLC (Ultra-Reliable Low-Latency Communication) : latence inferieure a 1 ms pour applications critiques (vehicules autonomes, chirurgie a distance)
2. Techniques de modulation : OFDM et au-dela
OFDM (Orthogonal Frequency-Division Multiplexing) :
L'OFDM est la technique de modulation fondamentale de la 5G NR. Son principe repose sur la division de la bande passante en de nombreuses sous-porteuses orthogonales, chacune transportant une partie des donnees.
Avantages de l'OFDM :
- Haute efficacite spectrale grace a l'orthogonalite des sous-porteuses
- Robustesse face au multi-trajet (fading selectif en frequence)
- Egalisation simple dans le domaine frequentiel
- Flexibilite dans l'allocation des ressources
Figure : Representation du canal 5G et des sous-porteuses OFDM Figure: 5G channel representation and OFDM subcarriers
Numerologie 5G NR :
La 5G NR introduit le concept de numerologie flexible avec differentes espacements de sous-porteuses (Subcarrier Spacing - SCS) :
| Numerologie (mu) | SCS (kHz) | Duree symbole | Bande passante typique | Usage |
|---|---|---|---|---|
| 0 | 15 | 66.7 us | Sub-6 GHz | eMBB bande basse |
| 1 | 30 | 33.3 us | Sub-6 GHz | eMBB bande moyenne |
| 2 | 60 | 16.7 us | Sub-6 GHz / mmWave | eMBB / URLLC |
| 3 | 120 | 8.33 us | mmWave | eMBB mmWave |
| 4 | 240 | 4.17 us | mmWave | Synchronisation |
Modulations QAM :
La 5G utilise des modulations QAM d'ordre eleve pour maximiser le debit :
- QPSK : 2 bits/symbole, robuste (utilise en conditions difficiles)
- 16-QAM : 4 bits/symbole
- 64-QAM : 6 bits/symbole
- 256-QAM : 8 bits/symbole (conditions optimales)
Figure : Schemas de modulation utilises en 5G Figure: Modulation schemes used in 5G
Limites de l'OFDMA pour la 6G :
Cependant, l'OFDMA presente des limitations pour supporter le nombre massif de dispositifs mobiles envisage pour la 6G. D'autres techniques de modulation sont envisagees pour les generations futures, telles que le multiplexage par moment angulaire orbital (OAM), qui exploite le domaine spatial pour transmettre simultanement plusieurs flux de donnees.
3. MIMO et Massive MIMO
Principe du MIMO :
Le MIMO (Multiple Input Multiple Output) utilise plusieurs antennes en emission et en reception pour ameliorer les performances du lien radio :
- Multiplexage spatial : transmission de flux de donnees independants sur des chemins spatiaux differents, augmentant le debit
- Diversite spatiale : envoi du meme signal sur plusieurs chemins pour ameliorer la fiabilite
- Beamforming : focalisation de l'energie radio dans une direction specifique
Massive MIMO en 5G :
La 5G deploie le massive MIMO avec des antennes comportant 64, 128, voire 256 elements :
- Gain de beamforming significatif (concentration de l'energie vers l'utilisateur)
- Augmentation de la capacite du reseau par multiplexage spatial multi-utilisateur (MU-MIMO)
- Reduction des interferences inter-cellulaires
- Amelioration de l'efficacite energetique (energie dirigee au lieu d'etre rayonnee dans toutes les directions)
Beamforming :
Le beamforming est une technique essentielle en 5G, particulierement pour les bandes mmWave :
- Beamforming analogique : dephaseurs analogiques, un seul faisceau a la fois
- Beamforming numerique : traitement numerique complet, multiples faisceaux simultanement
- Beamforming hybride : combinaison analogique/numerique, compromis cout/performance
- Beam management : procedures de recherche, selection et suivi des faisceaux (beam sweeping, beam tracking)
4. Bandes de frequences 5G
Spectre 5G :
La 5G utilise un spectre beaucoup plus large que les generations precedentes, divise en deux categories principales :
FR1 (Frequency Range 1) - Sub-6 GHz :
- Bandes basses (< 1 GHz) : couverture etendue, penetration des batiments, IoT
- Bandes moyennes (1-6 GHz) : bon compromis couverture/debit, bande phare 3.5 GHz (bande n78)
- Largeur de bande : jusqu'a 100 MHz par porteuse
FR2 (Frequency Range 2) - mmWave :
- Bandes 24.25-52.6 GHz (principalement 26 GHz et 28 GHz)
- Tres haut debit (> 1 Gbps)
- Portee limitee (quelques centaines de metres)
- Fortement attenue par les obstacles, la pluie, le feuillage
- Necessite beamforming et deploiement dense de small cells
- Largeur de bande : jusqu'a 400 MHz par porteuse
Compromis fondamental :
| Critere | Sub-6 GHz | mmWave |
|---|---|---|
| Couverture | Large (km) | Limitee (100-300 m) |
| Debit | Moyen (1-2 Gbps) | Tres eleve (> 5 Gbps) |
| Penetration | Bonne | Tres faible |
| Densite antennes | Moderee | Elevee (small cells) |
| Latence | Bonne | Tres faible |
5. Architecture reseau 5G NR
Architecture 5G :
L'architecture 5G introduit des concepts fondamentaux de flexibilite et de virtualisation :
5G Core (5GC) :
- Architecture basee sur les services (SBA - Service-Based Architecture)
- Fonctions reseau virtualisees (VNF) et conteneurisees
- Separation du plan de controle et du plan utilisateur (CUPS - Control and User Plane Separation)
- Support natif du network slicing
gNodeB (gNB) :
- Station de base 5G NR
- Decoupe en unites : CU (Centralized Unit), DU (Distributed Unit), RU (Radio Unit)
- Interface fronthaul (eCPRI) entre DU et RU
- Support du Dual Connectivity avec LTE (EN-DC)
Modes de deploiement :
- NSA (Non-Standalone) : 5G NR avec coeur 4G LTE (deploiement initial)
- SA (Standalone) : 5G NR avec coeur 5G (architecture complete)
6. Network Slicing
Le network slicing est une innovation majeure de la 5G qui permet de creer des reseaux virtuels dedies sur une meme infrastructure physique :
- Slice eMBB : optimise pour le haut debit (streaming 4K/8K, realite virtuelle)
- Slice URLLC : optimise pour la faible latence et la haute fiabilite (vehicules autonomes, industrie 4.0)
- Slice mMTC : optimise pour la connexion massive d'objets IoT (capteurs, compteurs intelligents)
Chaque slice possede ses propres parametres de qualite de service (QoS), garantissant l'isolation et les performances requises par chaque type d'application.
7. Technologies pour la 6G
La presentation que j'ai realisee avec Samia Boukouiss portait sur les technologies cles de la 6G. Voici les principales technologies identifiees :
Communication Terahertz (THz) :
- Bande de frequence 0.1 - 10 THz
- Debits ultra-eleves (potentiellement > 1 Tbps)
- Portee tres limitee (quelques metres)
- Applications : realite virtuelle haute definition, holographie, communications intra-chip
- Defis : attenuation atmospherique importante, composants encore immatures
Intelligence Artificielle et Machine Learning pour la 6G :
- Optimisation en temps reel des performances reseau
- Gestion predictive de la congestion et des ressources
- Routage intelligent et allocation dynamique du spectre
- Auto-configuration et auto-reparation du reseau
- L'IA comme composante native de l'architecture reseau (non plus un ajout)
Communication quantique et securite avancee :
- Distribution de cles quantiques (QKD - Quantum Key Distribution)
- Communications resistantes aux attaques par ordinateur quantique
- Cryptographie post-quantique
- Securite intrinseque du canal de communication
Visible Light Communication (VLC) :
- Utilisation du spectre de lumiere visible pour transmettre des donnees
- Bande passante enorme (400-800 THz)
- Applications : communication sous-marine, navigation interieure, LiFi
- Pas d'interference avec les systemes RF existants
Ultra-massive MIMO :
- Tableaux d'antennes de plusieurs milliers d'elements
- Surfaces intelligentes reconfigurables (RIS - Reconfigurable Intelligent Surfaces)
- Holographic MIMO : controle continu du champ electromagnetique
- Gain de capacite exponentiel dans les zones urbaines denses
Autres technologies envisagees :
- Reseaux non-terrestres (NTN) : satellites LEO, drones, HAPS pour couverture globale
- Jumeaux numeriques reseau : replique virtuelle du reseau pour simulation et optimisation
- Sensing et communication integres (ISAC) : le reseau devient aussi un capteur (radar, localisation)
- Computing integre : convergence communication/calcul/stockage
8. Calendrier et efforts mondiaux pour la 6G
| Periode | Etape |
|---|---|
| 2020-2025 | Recherche exploratoire, definition des cas d'usage |
| 2025-2028 | Standardisation initiale (3GPP Release 20+) |
| 2028-2030 | Prototypes et essais terrain |
| 2030+ | Deploiement commercial initial |
Initiatives mondiales :
- Europe : projet Hexa-X (consortium EU), 6G-IA
- Etats-Unis : Next G Alliance (ATIS), programmes DARPA
- Chine : programme national 6G, prototypes THz
- Coree du Sud : Samsung 6G Vision, programme gouvernemental
- Japon : Beyond 5G Promotion Consortium
- Finlande : 6G Flagship (Universite d'Oulu)
9. Impact societal et environnemental
Applications societales de la 5G/6G :
- Sante : chirurgie a distance, telemedicine haute definition, monitoring patient en temps reel
- Transport : vehicules autonomes (V2X), gestion intelligente du trafic
- Industrie : usines intelligentes (Industrie 4.0/5.0), robots collaboratifs
- Education : realite virtuelle immersive, formation a distance augmentee
- Agriculture : agriculture de precision, drones de surveillance
Preoccupations environnementales :
Les presentations sur les impacts environnementaux ont mis en evidence :
- La consommation energetique croissante des reseaux mobiles
- L'empreinte carbone de la fabrication et du deploiement des infrastructures
- La necessite de concevoir des reseaux "green" et energetiquement efficaces
- L'objectif de la 6G : reduire la consommation energetique par bit transmis d'un facteur 100
PART D - Analyse et Reflexion
Competences acquises
Competences techniques :
- Comprehension de l'evolution technologique des reseaux cellulaires (3G a 6G)
- Maitrise des concepts de modulation avancee (OFDM, QAM, numerologie 5G NR)
- Connaissance des architectures MIMO et massive MIMO
- Comprehension des bandes de frequences et des compromis couverture/debit
- Vision des technologies emergentes pour la 6G
Competences transversales :
- Recherche bibliographique sur des sujets techniques de pointe
- Synthese et vulgarisation de concepts complexes
- Presentation orale devant un auditoire technique
- Travail en equipe et collaboration
Auto-evaluation
Ce cours m'a permis de me concentrer sur un sujet specifique, de l'etudier en profondeur et de presenter mes conclusions. Ce processus m'a permis de developper des competences en recherche, en presentation et en discussion de sujets techniques, competences indispensables dans le monde professionnel.
La pedagogie inversee presente l'avantage de rendre chaque etudiant acteur de son apprentissage. En preparant ma presentation sur les technologies 6G, j'ai du approfondir considerablement mes connaissances sur les communications THz, l'IA pour les reseaux, et la communication quantique.
Cependant, pour les sujets presentes par mes pairs, mon apprentissage restait au niveau de l'ecoute et de la prise de notes. Bien que cela m'ait permis de rester informe sur les technologies sans devenir un expert complet sur chaque sujet, c'est parfois un peu frustrant de ne pas pouvoir approfondir davantage.
L'ajout d'aspects pratiques (simulations, travaux de laboratoire) aurait pu renforcer la comprehension des concepts techniques, bien que la nature prospective de certains sujets (6G) rende cela difficile.
| Competence | Niveau avant | Niveau apres | Progression |
|---|---|---|---|
| Modulations OFDM/QAM | Notions de base | Bonne comprehension | Significative |
| MIMO / Beamforming | Faible | Bonne comprehension | Importante |
| Architecture 5G NR | Tres faible | Correcte | Importante |
| Technologies 6G | Aucune | Bonne vision d'ensemble | Tres importante |
| Network slicing | Aucune | Comprehension des principes | Importante |
| Presentation technique | Correcte | Bonne | Moderee |
Applications et perspectives
Ce cours m'a permis de plonger dans des technologies du quotidien que je n'avais pas envisage d'etudier auparavant, revelant leur complexite et leur fonctionnement. Il m'a egalement permis de me projeter dans l'avenir : apres avoir etudie la 6G, j'ai une idee plus claire de ce que pourrait etre la prochaine generation de reseaux.
Applications directes :
- Conception de systemes IoT exploitant la 5G (mMTC, URLLC)
- Developpement d'applications tirant parti du network slicing
- Integration de capteurs et objets connectes dans les reseaux 5G
- Veille technologique sur les evolutions vers la 6G
Lien avec les autres cours du cursus :
- Wireless Sensor Networks : protocoles radio et couches basses
- Embedded IA for IoT : IA embarquee dans les dispositifs connectes
- Energy for Connected Objects : contraintes energetiques des objets 5G/IoT
- Cloud & Edge Computing : infrastructure de calcul pour les services 5G
Les presentations constituaient un excellent moyen d'apprendre beaucoup en peu de temps. En les preparant et en y assistant, nous avons couvert de nombreux sujets en profondeur, ce qui nous a vraiment aides a mieux comprendre les technologies 5G et 6G.
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Cours suivi en 2024-2025 a l'INSA Toulouse, Departement Genie Electrique et Informatique, Specialite ISS (Innovative Smart Systems).
5G Technologies / From 3G to 6G - Semester 9
Academic year: 2024-2025
Semester: S9
Instructor: Etienne Sicard
Category: Telecommunications and Mobile Networks
PART A - General Overview
Module Objectives
The course "5G Technologies / From 3G to 6G", taught by Etienne Sicard at INSA Toulouse, aimed to explore the full range of technologies related to cellular networks, from 3G to the prospects of 6G, with a particular focus on 5G and its emerging technologies.
Learning objectives:
- Understand the evolution of cellular networks from 3G to 6G
- Master the fundamental principles of 5G technologies (OFDM, MIMO, beamforming)
- Analyze the frequency bands and network architecture of 5G NR
- Explore emerging technologies for 6G (THz, AI, quantum communication)
- Evaluate the societal and environmental impact of new network generations
- Develop skills in research, synthesis, and technical presentation
Target Skills
- Mastery of advanced modulation concepts (OFDM, OFDMA, QAM)
- Understanding of MIMO and massive MIMO architectures
- Knowledge of sub-6 GHz and mmWave frequency bands
- Analysis of network slicing and network virtualization
- Forward-looking vision of 6G technologies
- Ability to synthesize and present complex technical topics
Course Organization
The course employed a reverse pedagogy approach: students were responsible for preparing and presenting specific topics. This approach allowed deep immersion in each subject through extensive personal research.
Format:
- Group presentations on various topics
- Discussions and debates after each presentation
- Knowledge sharing and collaborative learning
PART B - Experience and Context
Environment and Context
During this module, we covered a wide range of topics related to modern telecommunications. I had the opportunity to collaborate with Samia Boukouiss on a presentation dedicated to 6G technologies. Our work covered many aspects:
- Applications and opportunities of 6G
- Key 6G technologies (THz, AI, quantum communication, VLC, ultra-massive MIMO)
- Challenges in 6G development
- Development timeline and global efforts
- The impact of 6G on society
Peer Presentations
I also actively participated in my classmates' presentations, covering a wide variety of topics:
| Topic | Domain |
|---|---|
| Starlink, Kuiper | Satellite constellations |
| LTE-M for IoT | Cellular networks for connected objects |
| Samsung and 6G | Industrial vision of 6G |
| Drone-trains | Transport and telecommunications |
| Orange and 6G | Operator strategy for 6G |
| Environmental impacts | Ecology and telecommunications |
| 5G: Vehicle to Everything (V2X) | Vehicular communications |
| Cancer and EM waves | Health and electromagnetic waves |
These presentations allowed me to gain a broad, cross-cutting view of the challenges in modern telecommunications.
My Role
In this course, I was responsible for:
- Researching and presenting 6G technologies as a pair
- Collaborating with peers to explore the implications of 5G and future 6G technologies
- Participating in discussions and exchanges after each presentation
- Taking notes and synthesizing the knowledge shared by other groups
Tools and Resources Used
- Documentary research: IEEE scientific articles, 3GPP, industry publications
- Presentation tools: PowerPoint, synthesis documents
- Reference sources: 3GPP specifications, white papers from operators and equipment manufacturers (Ericsson, Nokia, Samsung, Huawei)
- Reference course: "3G6G-2024" course material by Prof. Sicard
PART C - Detailed Technical Aspects
1. Evolution of Cellular Networks: From 3G to 5G
Generation timeline:
| Generation | Period | Max data rate | Key technology | Primary use |
|---|---|---|---|---|
| 3G (UMTS) | 2001+ | 2 Mbps | WCDMA, HSPA | Mobile internet, video |
| 4G (LTE) | 2010+ | 100 Mbps - 1 Gbps | OFDMA, MIMO | HD streaming, apps |
| 5G (NR) | 2020+ | 10-20 Gbps | mmWave, massive MIMO | Massive IoT, URLLC |
| 6G (vision) | 2030+ | 1 Tbps | THz, AI, quantum | Holography, digital twins |
From 3G to 4G:
The transition from 3G (UMTS/WCDMA) to 4G (LTE) marked a major turning point with the adoption of OFDMA (Orthogonal Frequency-Division Multiple Access) as the access technique, replacing CDMA. This evolution enabled a significant increase in data rates and better spectral efficiency, paving the way for video streaming and bandwidth-intensive applications.
From 4G to 5G:
5G (New Radio - NR) represents a technological breakthrough with three fundamental pillars:
- eMBB (enhanced Mobile Broadband): very high data rates up to 20 Gbps
- mMTC (massive Machine-Type Communication): connecting millions of IoT devices per km2
- URLLC (Ultra-Reliable Low-Latency Communication): latency below 1 ms for critical applications (autonomous vehicles, remote surgery)
2. Modulation Techniques: OFDM and Beyond
OFDM (Orthogonal Frequency-Division Multiplexing):
OFDM is the fundamental modulation technique of 5G NR. Its principle is based on dividing the bandwidth into many orthogonal subcarriers, each carrying a portion of the data.
Advantages of OFDM:
- High spectral efficiency due to subcarrier orthogonality
- Robustness against multipath (frequency-selective fading)
- Simple equalization in the frequency domain
- Flexibility in resource allocation
5G NR Numerology:
5G NR introduces the concept of flexible numerology with different subcarrier spacings (SCS):
| Numerology (mu) | SCS (kHz) | Symbol duration | Typical bandwidth | Usage |
|---|---|---|---|---|
| 0 | 15 | 66.7 us | Sub-6 GHz | Low-band eMBB |
| 1 | 30 | 33.3 us | Sub-6 GHz | Mid-band eMBB |
| 2 | 60 | 16.7 us | Sub-6 GHz / mmWave | eMBB / URLLC |
| 3 | 120 | 8.33 us | mmWave | mmWave eMBB |
| 4 | 240 | 4.17 us | mmWave | Synchronization |
QAM Modulations:
5G uses high-order QAM modulations to maximize throughput:
- QPSK: 2 bits/symbol, robust (used in difficult conditions)
- 16-QAM: 4 bits/symbol
- 64-QAM: 6 bits/symbol
- 256-QAM: 8 bits/symbol (optimal conditions)
OFDMA limitations for 6G:
However, OFDMA has limitations in supporting the massive number of mobile devices envisioned for 6G. Other modulation techniques are being considered for future generations, such as orbital angular momentum (OAM) multiplexing, which exploits the spatial domain to simultaneously transmit multiple data streams.
3. MIMO and Massive MIMO
MIMO principle:
MIMO (Multiple Input Multiple Output) uses multiple antennas for transmission and reception to improve radio link performance:
- Spatial multiplexing: transmission of independent data streams over different spatial paths, increasing throughput
- Spatial diversity: sending the same signal over multiple paths to improve reliability
- Beamforming: focusing radio energy in a specific direction
Massive MIMO in 5G:
5G deploys massive MIMO with antenna arrays featuring 64, 128, or even 256 elements:
- Significant beamforming gain (concentrating energy towards the user)
- Increased network capacity through multi-user spatial multiplexing (MU-MIMO)
- Reduction of inter-cell interference
- Improved energy efficiency (directed energy instead of omnidirectional radiation)
Beamforming:
Beamforming is an essential technique in 5G, particularly for mmWave bands:
- Analog beamforming: analog phase shifters, one beam at a time
- Digital beamforming: full digital processing, multiple simultaneous beams
- Hybrid beamforming: analog/digital combination, cost/performance tradeoff
- Beam management: beam search, selection, and tracking procedures (beam sweeping, beam tracking)
4. 5G Frequency Bands
5G Spectrum:
5G uses a much wider spectrum than previous generations, divided into two main categories:
FR1 (Frequency Range 1) - Sub-6 GHz:
- Low bands (< 1 GHz): extended coverage, building penetration, IoT
- Mid bands (1-6 GHz): good coverage/throughput tradeoff, flagship 3.5 GHz band (n78 band)
- Bandwidth: up to 100 MHz per carrier
FR2 (Frequency Range 2) - mmWave:
- 24.25-52.6 GHz bands (mainly 26 GHz and 28 GHz)
- Very high throughput (> 1 Gbps)
- Limited range (a few hundred meters)
- Strongly attenuated by obstacles, rain, foliage
- Requires beamforming and dense small cell deployment
- Bandwidth: up to 400 MHz per carrier
Fundamental tradeoff:
| Criterion | Sub-6 GHz | mmWave |
|---|---|---|
| Coverage | Wide (km) | Limited (100-300 m) |
| Throughput | Medium (1-2 Gbps) | Very high (> 5 Gbps) |
| Penetration | Good | Very low |
| Antenna density | Moderate | High (small cells) |
| Latency | Good | Very low |
5. 5G NR Network Architecture
5G Architecture:
The 5G architecture introduces fundamental concepts of flexibility and virtualization:
5G Core (5GC):
- Service-Based Architecture (SBA)
- Virtualized (VNF) and containerized network functions
- Control and User Plane Separation (CUPS)
- Native network slicing support
gNodeB (gNB):
- 5G NR base station
- Split into units: CU (Centralized Unit), DU (Distributed Unit), RU (Radio Unit)
- Fronthaul interface (eCPRI) between DU and RU
- Dual Connectivity support with LTE (EN-DC)
Deployment modes:
- NSA (Non-Standalone): 5G NR with 4G LTE core (initial deployment)
- SA (Standalone): 5G NR with 5G core (complete architecture)
6. Network Slicing
Network slicing is a major 5G innovation that enables the creation of dedicated virtual networks on the same physical infrastructure:
- eMBB slice: optimized for high throughput (4K/8K streaming, virtual reality)
- URLLC slice: optimized for low latency and high reliability (autonomous vehicles, Industry 4.0)
- mMTC slice: optimized for massive IoT device connectivity (sensors, smart meters)
Each slice has its own Quality of Service (QoS) parameters, ensuring isolation and the performance required by each application type.
7. Technologies for 6G
The presentation I delivered with Samia Boukouiss focused on the key technologies of 6G. Here are the main technologies identified:
Terahertz (THz) Communication:
- Frequency band 0.1 - 10 THz
- Ultra-high data rates (potentially > 1 Tbps)
- Very limited range (a few meters)
- Applications: high-definition virtual reality, holography, intra-chip communications
- Challenges: significant atmospheric attenuation, still immature components
Artificial Intelligence and Machine Learning for 6G:
- Real-time optimization of network performance
- Predictive management of congestion and resources
- Intelligent routing and dynamic spectrum allocation
- Network self-configuration and self-healing
- AI as a native component of the network architecture (no longer an add-on)
Quantum communication and advanced security:
- Quantum Key Distribution (QKD)
- Communications resistant to quantum computer attacks
- Post-quantum cryptography
- Intrinsic security of the communication channel
Visible Light Communication (VLC):
- Use of the visible light spectrum to transmit data
- Enormous bandwidth (400-800 THz)
- Applications: underwater communication, indoor navigation, LiFi
- No interference with existing RF systems
Ultra-massive MIMO:
- Antenna arrays with several thousand elements
- Reconfigurable Intelligent Surfaces (RIS)
- Holographic MIMO: continuous control of the electromagnetic field
- Exponential capacity gain in dense urban areas
Other considered technologies:
- Non-Terrestrial Networks (NTN): LEO satellites, drones, HAPS for global coverage
- Network digital twins: virtual replica of the network for simulation and optimization
- Integrated Sensing and Communication (ISAC): the network also becomes a sensor (radar, localization)
- Integrated computing: convergence of communication/computing/storage
8. Timeline and Global Efforts for 6G
| Period | Milestone |
|---|---|
| 2020-2025 | Exploratory research, use case definition |
| 2025-2028 | Initial standardization (3GPP Release 20+) |
| 2028-2030 | Prototypes and field trials |
| 2030+ | Initial commercial deployment |
Global initiatives:
- Europe: Hexa-X project (EU consortium), 6G-IA
- United States: Next G Alliance (ATIS), DARPA programs
- China: National 6G program, THz prototypes
- South Korea: Samsung 6G Vision, government program
- Japan: Beyond 5G Promotion Consortium
- Finland: 6G Flagship (University of Oulu)
9. Societal and Environmental Impact
Societal applications of 5G/6G:
- Healthcare: remote surgery, high-definition telemedicine, real-time patient monitoring
- Transport: autonomous vehicles (V2X), intelligent traffic management
- Industry: smart factories (Industry 4.0/5.0), collaborative robots
- Education: immersive virtual reality, augmented remote training
- Agriculture: precision agriculture, surveillance drones
Environmental concerns:
The presentations on environmental impacts highlighted:
- The growing energy consumption of mobile networks
- The carbon footprint of infrastructure manufacturing and deployment
- The need to design "green" and energy-efficient networks
- The 6G objective: reducing energy consumption per transmitted bit by a factor of 100
PART D - Analysis and Reflection
Skills Acquired
Technical skills:
- Understanding of the technological evolution of cellular networks (3G to 6G)
- Mastery of advanced modulation concepts (OFDM, QAM, 5G NR numerology)
- Knowledge of MIMO and massive MIMO architectures
- Understanding of frequency bands and coverage/throughput tradeoffs
- Vision of emerging technologies for 6G
Transferable skills:
- Bibliographic research on cutting-edge technical topics
- Synthesis and simplification of complex concepts
- Oral presentation before a technical audience
- Teamwork and collaboration
Self-assessment
This course allowed me to focus on a specific topic, study it in depth, and present my conclusions. This process helped me develop skills in research, presentation, and discussion of technical topics -- skills that are essential in the professional world.
The reverse pedagogy approach has the advantage of making each student an active participant in their learning. While preparing my presentation on 6G technologies, I had to significantly deepen my knowledge of THz communications, AI for networks, and quantum communication.
However, for topics presented by my peers, my learning remained at the level of listening and note-taking. While this allowed me to stay informed about the technologies without becoming a complete expert on each topic, it was sometimes a bit frustrating not to be able to delve deeper.
The addition of practical aspects (simulations, lab work) could have strengthened the understanding of technical concepts, although the forward-looking nature of some topics (6G) makes this difficult.
| Skill | Level before | Level after | Progress |
|---|---|---|---|
| OFDM/QAM modulations | Basic notions | Good understanding | Significant |
| MIMO / Beamforming | Low | Good understanding | Important |
| 5G NR architecture | Very low | Adequate | Important |
| 6G technologies | None | Good overview | Very important |
| Network slicing | None | Understanding of principles | Important |
| Technical presentation | Adequate | Good | Moderate |
Applications and Perspectives
This course allowed me to dive into everyday technologies that I had not considered studying before, revealing their complexity and how they work. It also allowed me to project myself into the future: after studying 6G, I have a clearer idea of what the next generation of networks could look like.
Direct applications:
- Designing IoT systems leveraging 5G (mMTC, URLLC)
- Developing applications taking advantage of network slicing
- Integrating sensors and connected objects into 5G networks
- Technology watch on evolutions towards 6G
Links with other courses in the curriculum:
- Wireless Sensor Networks: radio protocols and lower layers
- Embedded IA for IoT: embedded AI in connected devices
- Energy for Connected Objects: energy constraints for 5G/IoT devices
- Cloud & Edge Computing: computing infrastructure for 5G services
The presentations were an excellent way to learn a great deal in a short time. By preparing and attending them, we covered many topics in depth, which really helped us better understand 5G and 6G technologies.
Course taken in 2024-2025 at INSA Toulouse, Department of Electrical and Computer Engineering, ISS (Innovative Smart Systems) specialization.