In Building

An In-Building Cellular Enhancement System, commonly implemented in conjunction with a distributed antenna system (DAS), is a telecommunications solution which is used to extend and distribute the cellular signal of a given mobile network operators (hereafter abbreviated as an MNO) within a building..


Below ground level, large buildings and high rises are examples where mobile phones are unable to properly reach the carrier’s macro or outdoor network. In these environments, the in-building cellular enhancement system will connect to the carrier’s signal source which is typically a bi-directional amplifier or a base transceiver station. This signal source transmits (and receives) the mobile network operator’s licensed radio frequency. This frequency is then transported within the building using coaxial cable, optical fiber or Category 5e/Category 6 twisted pair cable. In-building coverage antennas are strategically placed to provide the best overall coverage for users.

A cellular enhancement system does not read or modify the information represented within the radio frequency (RF) that passes though the system; rather, it reinforces the signal penetration of voice and data frequencies in low signal areas and in dead spots within structures, e.g. basements. Bolstering signal penetration via this method enables mobile subscribers to maintain connectivity to their carrier's voice and data services; additionally, such systems mitigate the mobile handset battery drain associated with heightened internal antenna activity when coverage is weak or insufficient. The cellular enhancement system cannot be used to eavesdrop on voice conversations, email messages, or web surfing. The system is unable to report application type statistics like the number of dropped calls per MNO or related information.

As the industry evolves, most MNO networks are now made up of 3G based services and are migrating towards 4G based services. In-building cellular enhancement systems designed for 2G or primarily voice-based services may not be sufficient to support 4G services since signal strength and signal quality specifications become more stringent as the applications move from a voice centric paradigm to a high speed data centric paradigm. Therefore a system designed to provide good quality 2G services may be insufficient or unable to provide quality 4G services. Traditionally, MNO services have been delivered within two frequency ranges which are the 800 MHz band and the 1900 MHz band. Additional frequency bands have been auctioned by the FCC resulting in increased capacity for the MNOs which are starting to implement 4G services in the 700 MHz and 2100 MHz frequency ranges.