The RF design process for in-building coverage systems begins with a comprehensive site survey and signal propagation analysis to determine the spatial layout and structural materials of the building. Engineers utilize specialized 3D simulation tools to model wall attenuation, floor penetration, and coverage zones, establishing the precise signal link budget required for optimal indoor connectivity. This phase defines whether a Passive Distributed Antenna System (DAS), an Active DAS, or a hybrid approach is best suited to meet the target capacity, floor area requirements, and multi-operator mobile frequency bands.
For Passive DAS deployments, the design focuses on RF power distribution through unpowered coaxial components such as directional couplers, power splitters, and indoor ceiling-mounted antennas. Calculations meticulously account for coaxial cable attenuation and insertion losses across long runs to ensure balanced power levels at every antenna node. Conversely, Active DAS designs incorporate master and remote units connected via low-loss fiber-optic cabling, converting RF signals to optical signals for long-distance distribution without quality degradation, making it ideal for high-rise buildings and expansive commercial complexes.
The final stage of the RF design involves interference management, sectorization planning, and handover optimization with the macro cellular network. Engineers map out donor antenna placements or direct Base Transceiver Station (BTS) integrations to prevent pilot pollution and back-reflections into the outdoor network. Upon completion of the initial layout design, coverage predictions for key Performance Indicators (KPIs)—such as Reference Signal Received Power (RSRP) and Signal-to-Interference-plus-Noise Ratio (SINR)—are finalized to guide physical installation and subsequent commissioning tests.
