Massive MIMO has mainly been developed for TDD bands, but China Unicom is leading the way in bringing the advanced antenna array approach to paired spectrum bands. The operator has completed field tests and verification of FDD-LTE Massive MIMO with both the major homegrown operators. Last week, ZTE unveiled a solution, as part of its ‘Pre5G’ range, which it said it had tested with Unicom and also with China Telecom. Hard on its heels, Huawei said it had completed field verification of an FDD-based Massive MIMO technology, also with Unicom. ZTE said its field tests verified that the solution can increase cell throughput by over three times using existing spectrum and terminals and expects to announce commercial contracts this year.…