On November 21, 2025, at 11:30 a.m., an open lecture titled “Evolution of Telecommunication Networks” was held at the Kyiv National Economic University named after Vadym Hetman. The lecture was delivered by Oleksandr Kosovskyi — Head of the Integration Department at J@Y and a specialist with many years of experience in the field of telecommunications.

The lecture was the result of cooperation between the university’s Department of Computer Sciences and the company J@Y, which actively develops interaction with educational institutions. The event took place in Building 2 of KNEU (49h Dehtiarivska St., Room 71) and gathered a large audience of students and lecturers of the “Computer Science” specialty, as well as everyone interested in the modern development of telecommunication technologies and career prospects in this field.

Representatives of the Department of Computer Sciences actively participated in the lecture: Head of the Department Bohdan Oleksandrovych Tishkov; Deputy Heads of the Department — Yurii Mykolaiovych Lozovyk and Yaroslav Yuriiovych Vozniuk; lecturers of the department and employees of the structural units of the Institute of Information Technologies in Economics.

During the lecture, Oleksandr Kosovskyi presented the key stages of the development of telecommunication networks — from the first analog systems (1G) to modern high-speed fifth-generation networks (5G) and projects forming the basis of future 6G technologies. In particular, he highlighted the historical prerequisites for transitions between generations and the main technological changes accompanying each stage. A detailed description was given of multiple access methods — from FDMA in 1G and CDMA in 2G/3G to OFDMA in 4G/5G. Special attention was paid to the evolution of network architectures and protocols: from the use of SS7 in early systems to the transition to IP-oriented technologies, including HTTP/2 and REST in 5G. The principles of NFV and SDN were also explained, which enable the cloud architecture of the 5G core, allowing network functions to be separated from hardware and enabling centralized network management.

In his lecture, Oleksandr Kosovskyi explained that 1G used the analog FDMA method, where each user was allocated a separate frequency band. In 2G (GSM), the transition to digital communication took place: the combination of TDMA/FDMA made it possible to distribute users into time slots within the same frequency. The transition to 3G (UMTS/WCDMA) was accompanied by the introduction of CDMA/WCDMA technologies, which allowed all subscribers to operate within one frequency band, separated by codes. When discussing 4G (LTE), the speaker focused on the use of OFDMA in the downlink and SC-FDMA in the uplink. Thanks to orthogonality, LTE provides high data transmission efficiency and significant mobile internet speeds.
Speaking about 5G (NR), Kosovskyi drew attention to the implementation of scalable bandwidth and Massive MIMO. Combined with OFDMA, these capabilities significantly increase the efficiency of radio spectrum usage and service quality.

The lecturer thoroughly described the features of network architectures across different generations, explaining how approaches to data transmission, capacity provision, and mobility support evolved. Continuing his presentation, he addressed the evolution of signaling and data transmission protocols, showing slides that demonstrated how network stack architectures changed across mobile communication generations. It was shown that in 2G the key protocols were SS7 and MAP, which provided signaling in circuit-switched networks; in 3G, MAP continued to be used, but RANAP was added to provide communication between radio networks and the core. In 4G, a transition to an IP-oriented architecture took place, where Diameter, NAS, S1-AP, and the GTP-C/U tunneling protocols for user traffic became central. In 5G, according to the speaker, modern web technologies — HTTP/2, REST, JSON-API — have become essential, while GTP-C/U remains the main data-plane protocol.

Explaining the architectural evolution of mobile network cores, Kosovskyi demonstrated the transition from Circuit-switched (voice-oriented) to Packet-switched (data-oriented), and later to the cloud-native architecture of the 5G Core, where network functions become modular, service-oriented, and scalable.

He then presented slides dedicated to NFV and SDN technologies, emphasizing their role in shaping modern cloud architectures of mobile networks. He stressed that NFV (Network Functions Virtualization) allows running network functions — such as vMME or vSGW — as software modules on standard server hardware instead of specialized platforms. The slides also illustrated how this makes networks more flexible, cost-effective, and easier to scale. Significant attention was also given to SDN (Software Defined Networking), which separates the control plane from the data plane. The presented diagram demonstrated how an SDN controller centrally manages network devices through software APIs, providing a more flexible and programmable infrastructure.

Kosovskyi emphasized that the combination of NFV and SDN has become the foundation of the cloud-native 5G Core, where network functions can be deployed dynamically, automatically, and according to load.

Special attention was given to practical cases the integration team works with, including: modernization of network infrastructure, ensuring connection stability, implementation of solutions for processing large volumes of data, integration of cloud technologies, and development of network virtualization. He presented real engineering solutions used by telecommunications companies to increase network performance and security.

During his talk, Kosovskyi emphasized the importance of digital transformation taking place in the telecommunications world. According to him, the development of 5G networks and the future introduction of 6G will require specialists not only to have deep technical knowledge but also to be able to work with big data, cloud platforms, automation systems, and cybersecurity tools.
The speaker also highlighted the competencies that are critically important for future engineers and programmers in telecommunications: analytical thinking, understanding of network protocols, experience with monitoring systems, and the ability to integrate modern technologies into large-scale infrastructure.

In the final part of the lecture, students had the opportunity to ask questions regarding career prospects in the telecommunications services market, modern challenges in network administration, and opportunities for professional growth for young specialists.

The event was extremely informative and useful. Students received not only a systematic understanding of the evolution of telecommunication networks, but also an overview of real technological processes and the requirements for modern specialists in this field. The lecture contributed to strengthening cooperation between the university and the IT industry, opening new opportunities for student development and future careers in telecommunications.

We express our gratitude to the management of J@Y and lecturer Oleksandr Kosovskyi for their openness to cooperation and their contribution to the development of young specialists, for giving students the opportunity to engage with modern trends in telecommunication technologies and to see what engineering work looks like in real conditions of the IT industry. The lecture and communication with the company’s specialist became a valuable experience for the students, as they received not only theoretical knowledge but also an understanding of the practical aspects of building mobile networks from 1G to 5G and the role of modern technologies in the development of communication infrastructure. We are convinced that together we will continue to strengthen cooperation between education and the IT industry, opening new opportunities for students and preparing them for successful careers in IT and telecommunications.