Solution for weak RSRP reception and improvement of signal coverage in different rooms. 

The solution includes an outdoor antenna, lightning protection, BDA, indoor dome antennas, Splitter (if BDA has only one output port to the indoor antenna connection), and low-loss cables with appropriate connectors.

The drawing attached is specific for 1900MHz. For other carriers, if multi-band cellular BDA is used, use appropriate multi-band outdoor yagi antenna and indoor dome antennas. 

4G LTE  or  5G NR router anywhere in the room should be able to receive sufficient signal propagated from the the dome antenna.