ITU and the industry is starting the process to define the technical requirements for 6G radio interface technologies. The ITU-R Recommendation M.2160 “IMT-2030 Framework” (see https://www.itu.int/en/ITU-R/study-groups/rsg5/rwp5d/imt-2030/Pages/default.aspx) expands the 5G use case triangle into an hexagon and the massive Machine Type Communication (mMTC) into the massive Communication use case with device density in the range of 10⁶ to 10⁸devices/km².

But what about legacy IoT cellular-based solutions? Ericsson in their Mobility Reports (https://www.ericsson.com/en/reports-and-papers/mobility-report/dataforecasts/iot-connections-outlook) indicated that Cellular IoT connections reached 3.4billion in 2023. In particular, 2G and 3G IoT devices were 0.9 billion, while massive IoT devices (NB-IoT and LTE-M) were 0.7 billion. Ericsson forecasts that massive IoT devices will reach 2.3 billion in 2029, just before the possible launch of 6G in 2030. In 2019 the European Commission published the study “Study on the current and prospective use of the 900 MHz band by GSM as a technology of reference, considering present and future Union policies,” (https://digital-strategy.ec.europa.eu/en/library/study-current-and-prospective-use-900-mhz-band-gsm-technology-reference-considering-present-and). In the report the usage of GSM for different services is assessed with the main stakeholders providing their view on the required support of GSM networks. As an example, starting from 2018, new cars in Europe are required to support automatic emergency calls (eCall) in case of emergency. The current implementation is based on GSM/UMTS circuit switched calls while the mobile network operators would like to move to next Generation eCall (NGeCall), based on 4G/5G. On the other hand, the automotive industry requires an update in the type approval legislation to start directly migrating to NGeCall, and will expect 2G service to continue throughout the lifetime of 2/3G enabled vehicles from the last year when such devices are put on the market. The transition period i.e. continuity of GSM service would be expected up to 2040 if new legislation becomes applicable by 2024-25. Another example is related to Distribution System Operators (DSOs). They indicated that there are around 4.6-5.6 million devices relying on GSM connectivity for smart metering and remote control services in European energy grids. Given that rollouts based on GSM have been taking place until recently, DSOs expect 2G networks to continue throughout the lifetime of such devices (10 to 15 years) i.e. 2030.

NB-IoT and LTE-M are also experiencing a strong interest from the satellite industry. Inmarsat is committed to provide 3GPP IoT solutions firmly believing that satellite communications can facilitate IoT in new places and describes the provide immense potential and benefits satellite-enabled IoT has to offer for the future (https://www.inmarsat.com/en/insights/corporate/2023/satellite-iot-the-future-of-networking.html). The Spanish company Sateliot announced the launch of the first LEO satellites of their constellation and start of commercial service (https://sateliot.space/2024/05/31/sateliot-to-launch-four-satellites-with-spacex/).

In summary we can expect billions of NB-IoT and LTE-M devices deployed at the end of this decade, including a large number of satellite IoT devices. In the meantime, the industry requires to ensure support of GSM services for IoT application well beyond 2030. Can the telco operators afford to migrate to a new radio access technology (6G) and in the meantime have to provide service continuity to billions of legacy 2G and 4G devices? Or should 6G be designed to take into account the longer life cycle of IoT applications (easily more than 10 years for many applications)? The answer is not simple, but the sustainability of deploying 6G in parallel to older network generations should be carefully taken into account in the design of the new system.

(c) Giovanni Romano, Novamint