The first generation of the mobile network was created in the 1980s, and it was the only network that operated on the analog principle. Shortly after that in 1991, the second generation of wireless cellular network - 2G, under the GSM standard and defined by the Phase 1 specification, was put into operation in Finland. 2G enabled things like sending text messages - SMS, and multimedia messages - MMS. In the beginning, the GSM network reached a speed of 9.6 kbit/s, which gave rise to 2.5G, also known as GPRS, or Release 97. This network provided higher speeds, and was further upgraded to the EDGE network, standardized under Release 98, which provided speeds of up to 500 bit/s. GPRS and EDGE networks are still used even in the 21st century because, compared to more modern networks, they provide much better coverage thanks to their architecture. In 2001, the third generation of wireless cellular networking, also known as 3G, was launched, standardized under the name Release 4 (originally called Release 2000), with the aim of standardizing the network protocols used by vendors. In practice, this meant that users were able to access data anywhere in the world, known as roaming. The 3G network brought a core that worked exclusively on the IP protocol, and it was a next-generation network. For using the 3G network it was only necessary to replace the SIM card with one that supported 3G. Compared to 2G, the 3G connection provided up to 4x faster data transfers, which gave rise to services such as video conferencing, video broadcasting and Internet Protocol voice transmission, with Skype being one of the most famous platforms. One of the devices that was able to make full use of the 3G network was the iPhone from Apple. In 2008, 3GPP came up with the fourth-generation wireless cellular network specification Release 8, known as 4G, which is currently the most widespread cellular network in the world. The first 4G network was launched in 2009 in the Swedish city of Stockholm and in the Norwegian city of Oslo under the name LTE. When switching to 4G, it was necessary for the device to fully support the given specification, only changing the SIM card was not enough. Compared to previous generations, 4G has a much smaller reach, especially in terms of availability in indoor spaces, the reason being the higher frequencies on which 4G transmits. It was known that 3G and even 4G networks would not be able to support technologies such as IoT to such a large extent, therefore 5G was approached with this idea from the beginning. However, the first 5G networks were, or still are, dependent on existing 4G networks, because even though the network broadcast on 5G frequencies, the core of the architecture was still based on 4G.[V4]