Propagation Characteristics: The way radio signals propagate indoors is affected by construction materials, furniture, and the presence of people. This can lead to signal attenuation, diffraction, and multipath effects.
Indoor Coverage Solutions: Various solutions are used to improve indoor coverage, including:
Repeaters are tempting for low-cost coverage but introduce challenges:
Scenario: A 1990s concrete building with poor macro signal. Legacy 2G microcells exist but no 3G/4G inside. Users complain of dropped calls in elevators and slow data near windows (macro interference). Indoor Coverage Solutions : Various solutions are used
Solution per the practical guide:
Results after deployment:
A practical guide must address that 2G, 3G, and 4G often share the same DAS cabling via passive combiners. Key risks: Repeaters are tempting for low-cost coverage but introduce
A robust indoor plan starts with a link budget per technology.
Sample Calculation for LTE 1800 MHz (4G) indoors:
Then, using the indoor path loss model (e.g., COST 231 Multi-wall): a metro station
PL (dB) = 32.4 + 20*log10(f) + 20*log10(d) + Σ (Lw * Nw)
Where:
In the era of mobile broadband, over 80% of mobile traffic originates or terminates indoors. Yet, indoor environments remain the most challenging frontier for radio planners. External macro cells often fail to provide adequate coverage deep within buildings due to signal penetration losses, while user expectations for high data rates continue to rise.
This practical guide synthesizes the core principles of indoor radio planning for legacy (2G), transitional (3G), and modern (4G/LTE) networks. Whether you are designing a Distributed Antenna System (DAS) for a skyscraper, a metro station, or an underground shopping mall, the fundamentals remain critical.