Carrier aggregation using 5G frequency bands

Carrier aggregation was achieved using the 3.7 and 4.5GHz bands designated for 5G networks. In addition to this dual connectivity achieved by bundling LTE bands, downlink speeds of 4.2 Gbps will be achievable, enabling ultra-fast data transmission.

DOCOMO already provides commercial 5G services in Japan through a multi-vendor RAN that connects baseband units and remote radio units manufactured by Fujitsu and NEC based on O-RAN’s open fronthaul specifications. The same system configuration was used to achieve this 5G carrier aggregation.

Naoki Tani, Senior Vice President at DOCOMO, said: "The deployment of O-RAN-compliant products will enable DOCOMO to flexibly build networks and provide 5G services that meet customer needs. Carrier aggregation furthering 5G high-speed data communication in a multi-vendor RAN developed jointly with Fujitsu and NEC is an important achievement. DOCOMO will continue to work with industry partners to promote open RAN and 5G services."

Shingo Mizuno, EVP and Vice Head of System Platform Business at Fujitsu, commented: "We are delighted to have succeeded in achieving carrier aggregation for 5G high-speed data communication in an environment featuring interconnection of multi-vendor equipment compliant with O-RAN specifications. This key milestone in the evolution of O-RAN will contribute greatly to the delivery of convenient 5G services and RAN openness, which Fujitsu is actively supporting with the aim of enhancing 5G services."

Atsuo Kawamura, Executive Vice President at NEC and President of the company's Network Services Business Unit, added: "The success of carrier aggregation in the 5G bands is a critical step in the ongoing enhancement of 5G network performance. I am very pleased that in collaboration with DOCOMO and Fujitsu we have now achieved high-performance O-RAN multi-vendor connectivity. This will lay the foundation for more open 5G services and business."

The results of the interoperability verification were presented between September 25 and 30, during the O-RAN Plugfest web conferences organized by the O-RAN Alliance. Plugfest was held concurrently in Japan, China, India, Europe, and North America, facilitating proofs of concept and interoperability tests of O-RAN products and solutions.

Going forward, DOCOMO, Fujitsu, and NEC will continue working toward the early introduction of commercial 5G carrier aggregation services.