SoftBank teamed with ZTE to conduct pre-standard 5G trials on the 4.5GHz band in areas of metropolitan Tokyo.

The trials on the sub-6GHz band aim to verify the performance of ZTE’s pre-standard 5G network equipment under real world conditions in densely populated urban areas, the China-headquartered vendor said in a statement.

ZTE chief scientist Xiang Jiying said: “We have a long-term partnership with SoftBank in key 5G technologies such as massive MIMO, and we are pleased to expand that work to accelerate 5G New Radio readiness.”

SoftBank deployed massive MIMO on its 4G network in the second half of 2016, ZTE stated, opening the door to employing the technology when 5G becomes a commercial reality.

The sub-6GHz trials planned for Tokyo are the latest in a series of collaborations between SoftBank and ZTE in recent years. In 2015, the pair agreed a deal covering the use of ZTE’s TDD-based pre-5G equipment, which covered the deployment of test networks in early 2016.

Nine sub-6GHz candidate frequency bands were identified for future 5G networks in World the Radiocommunication Conference 2015 (WRC15).