The srsENB supports MIMO transmission modes 2, 3, and 4. You only need to set up the transmission mode and the number of eNb ports in the
... [enb] ... tm = 3 nof_ports = 2 ...
The eNb configures the UE for reporting the Rank Indicator for transmission modes 3 and 4. You can set the rank indicator periodic report in the file
m_ri. This value is multiples of CQI report period. For example, if the CQI period is 40ms and
m_ri is 8, the rank indicator will be reported every 320ms.