Mobile Radio Networks

The course aims to provide students with the basic knowledge and methodological tools required for the analysis and design of mobile radio networks. The main characteristics of the radio channel and the phenomena of propagation and fading will be addressed, together with the evolution of architectures, technologies, and protocols of mobile networks from 2G to 5G generations.

Particular attention will be devoted to mobility management, radio resource allocation, and performance evaluation of mobile radio systems, providing students with the tools required to understand the main technological solutions adopted in modern cellular networks. Network planning and dimensioning will be addressed both from the perspective of radio coverage, through the study of propagation phenomena, and from the perspective of capacity and traffic, through the use of traffic models and queueing theory for the evaluation of network performance and resource dimensioning.

Theoretical knowledge will be complemented by laboratory activities aimed at the analysis and simulation of cellular transmission scenarios, the evaluation of propagation models and fading channels, and the implementation of algorithms for cellular coverage, power control, and radio resource allocation. Experimental activities will also be carried out on GSM, UMTS, and LTE networks, including coverage measurements and analysis of the main network procedures, as well as emulation and analysis of an LTE network, with particular emphasis on signaling, radio resource allocation, handover procedures, and VoLTE communications.

1. Knowledge and Understanding

• At the end of the course, students will be able to understand the fundamental principles of wireless communications and mobile radio networks, the characteristics of the radio channel and the main propagation and fading phenomena, as well as the architectures, technologies, and protocols of cellular systems from 2G to 5G generations.
• Students will also acquire knowledge of the principles of mobile network planning and dimensioning, with regard both to radio coverage and propagation aspects and to capacity and traffic, through the use of traffic models and queueing theory.
• Students will also be able to understand the main mechanisms for radio resource management, mobility management, and security, as well as the methodologies used for the analysis and performance evaluation of mobile networks.

2. Applying Knowledge and Understanding

The course aims to provide students with the ability:

• to analyze propagation and fading phenomena in mobile radio systems and apply this knowledge to the design of wireless links;
• to plan and dimension a mobile network by jointly considering radio coverage and capacity aspects, through the application of traffic models and queueing theory, and to evaluate its performance in terms of capacity, blocking probability, and quality of service;
• to analyze and evaluate the solutions and protocols adopted in mobile radio systems in relation to different application scenarios.

3. Making Judgements

Within the topics covered by the course, students will be able to independently make appropriate design choices based on the required specifications, as well as critically evaluate and interpret the results and data obtained through experimental and laboratory activities.

4. Communication Skills

Students will acquire the ability to communicate knowledge related to mobile cellular networks in a clear and well-structured manner, using the specialized terminology of the field with confidence and discussing design choices and the results of the analyses performed.

5. Learning Skills

Students will be able to independently consult standards, technical documentation, and scientific literature in the field, in order to update their knowledge in response to the rapid evolution of mobile radio technologies and to explore topics of particular complexity.

The course is mainly delivered through lectures, conducted both on the blackboard and with the aid of personal computers, which are used to present slides (49 hours).Practical classes (15 hours) are also provided, during which students are frequently asked to carry out the proposed exercises under the guidance of the instructor, in order to stimulate collective participation and enable a sample-based assessment of learning outcomes. In addition, 15 hours of laboratory activities are planned to facilitate the understanding of the topics covered. 

Essential knowledge:

• Multiplexing techniques: TDM, FDM, and OFDM
• Circuit switching and packet switching
• Concept of protocol architecture: User Plane and Control Plane
• Multi-layer modulation
• Relationship between BER and SNR
• Noise figure
• Logarithmic scale and decibels
• Principles of source and channel coding

Important knowledge:

• Traffic theory
• Queueing theory: M/M/n/n system
• Erlang B formula
• PCM frame
• SS7 signaling system

Useful knowledge:

• Use of the MATLAB environment
• Link budget

Attendance is not compulsory. 

However, attendance is strongly recommended, as participation in the practical classes and laboratory activities facilitates the understanding of the topics covered.

Part One: Basic Principles of Mobile Networks

1. Introduction and Basic Concepts of Mobile Networks

[Lectures: 4 hours – Practical Classes and Laboratory: 0 hours]

Classification, motivation, and requirements of mobile networks. Evolution of mobile networks and services. Mobile network architectures. Radio resource sharing. User mobility.

2. The Radio Channel and Cell Dimensioning

[Lectures: 5 hours – Practical Classes and Laboratory: 4 hours]

Radio channel and propagation models. Review of digital modulation and channel coding schemes. Cell dimensioning based on radio coverage considerations.

3. Radio Access

[Lectures: 5 hours – Practical Classes and Laboratory: 5 hours]

Multiple access techniques for broadcast channels: TDM/TDMA, FDM/FDMA, CDM/CDMA. Duplexing. Radio resource sharing models: review of traffic and queueing theory; application of the Erlang B formula; trunking gain.

4. Mobility Management

[Lectures: 5 hours – Practical Classes and Laboratory: 0 hours]

Cell selection and cell reselection. Location Area: updating and dimensioning. Handover: definition and strategies.

5. Radio Planning: Cellular Coverage and Network Capacity

[Lectures: 5 hours – Practical Classes and Laboratory: 6 hours]

Frequency reuse. Planning of a cellular system according to SIR and blocking probability requirements. Static and dynamic frequency allocation techniques. Capacity analysis in multicarrier TDMA systems and CDMA systems. Power control in CDMA networks. General principles of Call Admission Control.

 Part Two: From the Second to the Fifth Generation

6. GSM
[Lectures: 7 hours – Exercises and Laboratory: 5 hours]

Network architecture and radio interface. Physical and logical channels. Overview of source and channel coding and interleaving. Signaling and main protocols in GSM. Numbers and identities. Signaling procedures, from basic access to mobility and security management.

7. Evolution from the Second to the Third Generation
[Lectures: 5 hours – Exercises and Laboratory: 2 hours]

Evolution of GSM towards GPRS and EDGE: network architecture and protocols, comparison with the GSM architecture, PDP context activation and routing.

Introduction to third-generation systems: UMTS network architecture and radio interface. Overview of radio resource management, with particular reference to power control, and mobility management, with reference to macrodiversity and soft handover. Security procedures.

8. LTE and its Evolutions
[Lectures: 7 hours – Exercises and Laboratory: 8 hours]

Main functionalities and performance offered by LTE. Network and service architecture. Interfaces and protocols. LTE radio interface. Introduction to the 3GPP standardization process and the concept of 3GPP Releases. Evolution from LTE to LTE-Advanced and LTE-Advanced Pro.

9. 5G and Beyond
[Lectures: 6 hours – Exercises and Laboratory: 0 hours]

Introduction to 5G. Role of and relationship between ITU and 3GPP in the standardization process. 5G use cases and requirements. Network architecture and QoS model. 5G New Radio. 5G RAN and 5G Core. Evolution of RAN towards Cloud-RAN.

Laboratory. Laboratory activities are an integral part of the course and will be carried out at the DIEEI Technology Center, with a variable schedule depending on the progress of the course. The topics covered are listed below.

• Computer-based implementation of indoor and outdoor cellular transmission scenarios, path loss models (free-space, Okumura-Hata, and 3GPP models), and fading channels.
• Computer-based implementation of heuristic algorithms for solving cellular coverage problems, power control in CDMA systems, and radio resource allocation in LTE systems.
• Introduction to software tools for testing and measuring network parameters in GSM, UMTS, and LTE systems. Indoor/outdoor coverage testing: test environment setup, coverage mapping, and data collection. Analysis of cell attach, cell reselection, location update, and generated and received call procedures.
• Introduction to the software and hardware available in the laboratory for emulating an LTE mobile network. Network performance analysis for streaming services and FTP server download/upload. Analysis of signaling message exchanges both on the access network and core network sides. Resource Block allocation and Modulation and Coding Scheme as a function of distance and channel quality. Handover procedures. Evaluation of calls using VoLTE technology.

If the course is delivered in distance-learning mode, the necessary changes may be introduced with respect to the specific laboratory activities described above.

CONTRIBUTION OF THE COURSE TO THE UNITED NATIONS 2030 AGENDA FOR SUSTAINABLE DEVELOPMENT

The topics covered in the course and the knowledge acquired directly or indirectly contribute to the development of sustainable technological solutions, as well as to quality education, in accordance with SDG 4, SDG 9, SDG 11, and SDG 13 of the United Nations 2030 Agenda for Sustainable Development.

[1] Martin Sauter, “From GSM to LTE‐Advanced Pro and 5G: An Introduction to Mobile Networks and Mobile Broadband”, IV Edition , John Wiley & Sons Ltd, 2021

[2] C. Cox, “An introduction to LTE: LTE LTE-Advanced, SAE, VoLTE and 4G Mobile Communications”, 2° Edizione, Wiley.

[3] Christopher Cox, “An Introduction to 5g: The New Radio, 5g Network and Beyond”, John Wiley & Sons Ltd, 2020

[4] Rajib Taid, “Mobile Communications Systems Development: A Practical Introduction to System Understanding, Implementation, and Deployment”, John Wiley & Sons Ltd, 2021

[5] Lecture slides: slide_1–slide_10, corresponding to Sections 1–9 of the course programme

The examination aimed at assessing the student's overall preparation consists of two written tests.

·        The 1st test (held on the dates indicated in the official examination schedule) consists of the solution of numerical exercises.

·        Students who pass the 1st test with a score of at least 15/30 are admitted to the 2nd test (on a date agreed upon with the instructor), which consists of open-ended theoretical questions that are discussed and assessed immediately.

Mid-term Assessments

Students may take an optional midterm test during the course. The test covers the Part One of the syllabus (Topics 1 to 5) and consists of numerical exercises and theoretical questions.

If passed, the midterm test allows students to take the 2nd test directly, with a reduced syllabus. In particular:

• Students who pass the midterm test with Grade A will take a 2nd test covering exclusively the Part Two of the syllabus (Topics 6 to 10).
• Students who pass the midterm test with Grade B will take a 2nd test covering the remaining part of the syllabus, together with an additional numerical or theoretical question addressing the topics in which deficiencies were identified during the midterm test.

The validity of each midterm test is limited to the Academic Year in which the test was taken and remains valid for six months from the end of the lectures of the relevant academic year.

• Describe the fading phenomenon and provide an example of its impact.
• How is the distance between a mobile user and the GSM base station to which the user is connected determined? Is there a relationship between power control and admission control in CDMA networks?
• What are the QoS attributes in LTE systems?
• How does the Location Updating procedure take place in GSM networks?
• Describe the LTE network architecture.
• Describe the radio interface of 5G systems.
• Describe the functional split in the 5G RAN.

A more extensive list of possible questions and some examples of the written tests can be found on Studium, in the Documents section of the course.