The document summarizes the architecture of an Evolium A9100 indoor BTS. It describes three levels: the antenna coupling level which connects antennas to transceiver modules, the transceiver level which receives and transmits signals using radio frequency channels, and the base station control function level managed by a station unit module that synchronizes components. The BTS can provide wireless service to 96 users simultaneously using 12 transceiver modules connected to 8 time slots each.