GSMA announced that KDDI, NTT DOCOMO and SoftBank, three mobile operators in Japan, have launched Rich Communications Services (RCS).

The + message service — based on the GSMA’s specifications — is an upgrade to SMS and is available to customers on smartphones and tablets.

GSMA said all three telecom operators are planning to launch RCS Business Messaging. In addition, all three mobile operators will transition to the GSMA’s Universal Profile specification in the future.

Several brands are conducting trials with RCS Business Messaging that enables mobile phone users to engage with brands from a single messaging platform. For instance, mobile users in Japan can make restaurant reservations, book train tickets or retail purchases without accessing numerous apps.

GSMA Intelligence estimates that the RCS Business Messaging market will be worth over $74 billion by 2021.

“RCS is poised for explosive growth this year with more mobile operators launching the service, with many interconnecting their networks and brands trialling RCS Business Messaging,” Alex Sinclair, chief technology officer of GSMA, said.

Earlier this year, GSMA announced that Deutsche Telekom, Telenor Group, Telia Company and Vodafone Group had interconnected their networks in Europe, while America Movil, Rogers Communications and Sprint interconnected across the Americas.

GSMA Intelligence estimates that the number of RCS users is expected to double to 350 million by Q4 2018 from 165 million at present.

GSMA’s RCS initiative called GSMA RCS Business Messaging Labs bring top operators, marketing companies, messaging aggregators and brands together to work together on key topics such as customer experience, specifications, monetisation, privacy, security and interconnection.