LTE based technologies are now spreading well. Your smart phone easily gets LTE signals in almost all countries in the world. Though LTE bands vary depending on local carriers in a country, you can use data communication function without any problems as far as your smart phone supports the appropriate LTE band. According to the Ericsson Mobility Report in 2017, total mobile subscriptions number is 8 billion now and 3 billion of which are LTE based technology. It also estimates that mobile subscription number will reach 9.1 billion in 2023 with 5 billion LTE subscriptions. Regarding my case, I privately use an MVNO sim in Japan, Telkomsel simPATI in Asian countries, and Orange mobicarte-sim in Europe and North America since they offer affordable data roaming fees comparing with Japanese Mobile Operators.
LTE based technologies were developed by 3GPP. By limiting radio bandwidths to 200kHz and giving enough connections for IoT devices, NB-IoT standard was developing. By applying unlicensed band such as 5GHz, MulteFire specifications were developed. Well-established LTE based technologies are now applied for various radio frequencies associated with an appropriate bandwidth. This softens the devise development barrier and a rapid market creation is expected.
MulteFire specfications were developed by MulteFire Alliance based on 3GPP release 13 in February 2017. In 3GPP standards, PLMN(Public Land Mobile Network) has AAA functions. In MulteFire specifications, they define PSP(Participated Service Provider) and NHN(Neutral Home Network) and reuse 3GPP standards by mapping terms between PLMN and PSP/NHN.
Addition to 3GPP release 13 standards by MultiFire Alliance is very limited. The addition includes the use of IETF EAP(Extended Authentication Protocol) for mutual authentication between UE and PSP and an online singup service (OSU-service). You can download MultiFire specifications from MulteFire Alliance Homepage, https://www.multefire.org/
Some sources announced that 5G services will be launched in 2020. However, LTE based technologies will be dominant for the time being and many systems and networks will be based on LTE based technologies.
Nobuo FUJII was working for NTT R&D and NTT Groups where he studied and developed transport network operation systems. He also worked for ITU-T and other standard organizations, fora and consortia so as to develop operation system architectures and interfaces. He is an IEICE fellow. He joined CCI in 2014.