ZTE has made a significant breakthrough in research on next-generation radio access networks by completing the world’s first pre-commercial test of distributed multiple input and multiple output (D-MIMO) technology.
The field test conducted jointly by ZTE and a partner, demonstrated an up-to-9 times increase in data rate at the cell edge through the use of D-MIMO technology based on ZTE’s proprietary Cloud Radio solution. The outdoor portion of the test covered single-user and multiple-user scenarios in an environment with multiple overlapping base stations, and used commercially-available mobile device terminals.
The coherent joint-transmission (JT) technology used in ZTE’s new D-MIMO system ensures full phase synchronisation among base stations, the resulting jointly transmitted signal is amplified to the maximum level as it arrives at the antenna of a user terminal, minimising interference with other terminals. Compared with legacy non-coherent JT technology, coherent JT provides 3 dB of additional gain at the antenna of a target user terminal and forms null steering at the antennas of other user terminals to minimise signal interference, achieving multi-user joint transmission (MU-JT).
As a mobile communications system typically contains many base stations, interference causes degraded signalling at the cell edge, affecting user experience. D-MIMO technology can effectively improve the data rate at the cell edge through coordinated transmission among base stations, resolving a major challenge facing operators.
The indoor D-MIMO test result shows that the MU-JT technology can form null steering toward multiple users to guarantee effective multi-user joint transmission in an enclosed and small space. The service data rate of a single testing cell has been at least quadrupled in an ideal non-interference situation, and a number of testing cells have enhanced their resistance to interference by more than a hundred times.
