AGL Magazine: A Digital Distributed Antenna System for Public Safety In-Building Communications
Reliable public safety in-building radio communications are vital in today’s emergency services operation, from dispatch to mission-critical situations, and from voice-only capabilities to voice and data.
Public safety communications have evolved from fire call boxes and analog mobile radios to digital mobile radios and trunked radio systems. This evolution mainly stemmed from technological advancements and the need for higher reliability.
Traditionally, public safety uses lower frequency bands such as 150 MHz and 450 MHz. As the public safety network operations move to higher spectrum bands such as 700 MHz or 800 MHz, the propagation characteristics of the higher frequencies limit the in-building signal penetration.
In addition, with dense building materials such as aluminum or steel, energy-efficient windows and green buildings meeting LEED standards, signals can be even further reduced or blocked, impairing effective communications among the first responders.
Improving public safety coverage indoors is a long-standing challenge. An evolution in the in-building public safety infrastructure is required to allow two-way radios or trunked radio systems to work seamlessly and reliably inside buildings and in underground tunnels, metros or mines and remote or isolated areas.