Smart Building

Terms You Need to Know When Discussing Products that Support Wireless

Ron Tellas

As we mentioned in a recent blog, it’s no secret that wireless is on the move. It drives smart buildings, IoT and much more. As wireless becomes prolific across all types of environments – from education and healthcare to manufacturing and Corporate America – the terminology used to describe it is also growing.

Last week, we discussed the wireless terminology being used to refer to technology, speeds and standards. This week, we’re discussing – in alphabetical order – wireless terminology often used when describing products or solutions that support wireless.


Active DAS (Distributed Antenna System)

A system that utilizes several antennas to provide wireless coverage in which the components require a power source to operate. An active DAS consists of a head-end unit (HE), which receives the wireless signal from the donor antenna or directly from the service provider’s network core and sends the signal via riser-rated fiber optic cable to multiple remote radio units (RUs or RRUs) located on various floors of a building.



A series of rings or corrugations in an outer welded conductor used on hardline coax. Compared to braided cable, annular coax is rather stiff and inflexible, but can be bent and shaped into position. On smaller, “superflex” hardline cables, corrugations in the outer conductor are closer together and deeper. They aren’t referred to as “annular” but “helical.”



The connection from the carrier’s central network core to the wireless network.


Base Transceiver Station (BTS)

The equipment used in a DAS to receive, filter, amplify and transmit wireless communications between user devices and carrier networks. A BTS is unique to each carrier.


Bidirectional Amplifier (BDA)

Used in passive DAS, BDAs condition and strengthen signals received from outside the building.


C-RANs (Cloud or Centralized RANs)

A cellular network architecture, C-RANs centralize the baseband processing for a large number of radios. They support 2G, 3G, 4G and future wireless communication standards and are growing in popularity due to their significant performance and economic benefits.


DAS (Distributed Antenna System)

A system that provides two-way communication in a certain geographic area or structure through a distribution or array of antennas.


ERRCS (Emergency Responder Radio Communication Systems)

Also called a public safety DAS, an ERRCS is an in-building, first-responder radio network that picks up radio signals from an outdoor antenna and rebroadcasts them inside a building, allowing first-responder radios to operate during an emergency. An ERRCS system is a requirement in some municipalities to get a Certificate of Occupancy (CO).


Femto Cell

A type of small cell that supports between four and eight users and is used primarily in residences and enterprise buildings.



New architecture that allows the separation of the RU from the DU. Fronthaul links typically use eCPRI protocol, which increases capacity and reach while lowering latency.


Hardline Coax

A coaxial cable with a solid corrugated or smooth outer conductor and foamed dielectric, typically 50 Ohm or 75 Ohm. These cables typically have lower insertion loss and PIM performance as compared to a braided cable.


Macro Cells

Outdoor cell tower systems leased and controlled by mobile carriers, such as AT&T or Verizon.


Micro Cells

Part of a mobile phone network, a microcell is a type of small cell that supports between 128 and 256 users. It’s used in urban areas to fill macro coverage gaps.


Passive DAS (Distributed Antenna System)

A system that utilizes several antennas to provide wireless coverage; the components do not require a power source to operate. Passive DAS uses BDAs (bidirectional amplifiers) to boost and send signals.


Pico Cell

A type of small cell that supports between 64 and 128 users. It’s typically used in indoor or outdoor public areas, such as airports, malls and train stations.


Plenum Air Coax

A type of hardline coax with plenum-rated jacketing; the dielectric is a spiraled “spline” wrapped around the inner conductor. Air content is increased in the dielectric, which enables this coax to have low-loss electrical performance while meeting the flame requirements for plenum.


RAN (Radio Access Network)

This type of network connects end-user devices to other parts of the network through wireless radio connections.


RU or RRU (Remote Radio Unit)

Equipment that converts the digital network signal to RF signals – and vice versa. The RU may include, or is connected to, the antenna system.


Small Cells

A wireless access system that uses low-powered, limited-range remote units or access points (APs) with baseband, radio and antenna all in one box. Small cells consist of any combination of micro cells, pico cells or femto cells and can support multiple technologies operating in multiple frequency bands. Small cells are a competing technology with DAS.


If you missed our first post about wireless terminology, catch it here