For your convenience, we've assembled the glossary below that contains many of the technical terms used to describe the functionality and performance of in-building wireless systems. Please feel free to contact us for further information.

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Active (also, Active Electronics)
Within in-building wireless terminology, active refers to any equipment that utilizes powered electronics to transport (not generate) radio signals. Generally the term relates to systems using fiber.

Air Interface
The type of radio transmission protocol used by service providers to transmit and receive their signals. These include analog, TDMA, GSM, iDen, CDMA and newer data overlays such as GPRS, WCDMA and CDMA 2000 1x. WiFi™ and Bluetooth™ also contain their own specialized air interface protocols.

Antenna
Device used to radiate/receive radio waves for/from propagation through the atmosphere.

Attenuation
The effect of natural and man-made materials on the strength (or reduction thereof) of radio signals as they propagate along the intended path. Building exteriors, in particular, can severely limit the strength of radio frequencies received inside, making them unsuitable for reliable communications.

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Base Transceiver Station (BTS)
Typically the equipment owned and operated by a wireless service provider that generates the radio frequencies picked up by subscriber handsets or other mobile devices. Also called a base station, this equipment connects to the in-building wireless system and to high-speed lines providing backhaul to the service provider’s switch.

Battery Back-Up
Large numbers of interconnected batteries that provide temporary power for a service provider’s base station in the event of a primary power outage.

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Cable Tap
A small mechanical device that clamps onto a feeder cable and transfers radio frequency energy from the feeder cable to another cable or antenna. Highly efficient cable taps, such as those designed by InnerWireless, extract only the amount of energy required to provide the targeted level of radio signal within a space.

C/I Ratio
Carrier-to-interference ratio is the measure of the relative strength of the desired (carrier) signal to all other signals (interference). Modern digital communications systems can operate at much lower C/I ratios than earlier analog systems. C/I ratios are largely determined by the service provider’s macro network frequency re-use plan.

Coaxial Cable
A type of cable used to carry radio frequencies from one point to another. Coaxial cable consists of a conductive outer tube surrounding a conductive inner core separated by a non-conductive dielectric spacing material. Coaxial cable can be either non-radiating or radiating.

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dB
A logarithmic scale used to compare the relative magnitude of two quantities expressed in a common set of units.

dBm
A common engineering parameter to compare, in dB, an RF signal level to the specific reference value of 1 milliwatt.

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Fiber
Long, super-thin strands of glass or other material that very efficiently transport optical signals. When used for in-building systems requiring radio frequency waves to be transported from one location in a building to another, the radio frequencies must first be converted to optical signals for transport over the fiber. Upon reaching their destination, these optical signals are converted back to radio frequencies for distribution by antennas.

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Interference
Interference results when a desired signal must compete with other signals at the same or adjacent frequencies in the radio spectrum causing distortion of the desired signal.

Integrated Access Device
In the InnerWireless in-building system, this device is the point of demarcation between each service provider’s BTS and the in-building system. It combines radio signals from each BTS onto a common riser cable for the uplink, and then splits them out for the downlink.

Intermodulation
Intermodulation products are the result of two or more desired signals interacting with each other, due to non-linear effects within generation or transport equipment, to produce additional undesired frequencies which become interference for one or more service providers.

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Microcell
A smaller-sized BTS used by service providers for in-building applications or small fill-in areas outdoors.

Monitoring
The ongoing measurement and reporting of electrical performance of a fiber electronics-based in-building system to ensure that it is operating properly. If a malfunction occurs, a signal is sent to a call center where on-duty technicians can note and diagnose the problem.

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Neutral Demarcation Point
A central and common point where service providers with different radio frequencies or transmission technologies can introduce their signals into the in-building wireless system.

Noise Floor
In every environment, there is a certain level of radio “noise” from a variety of sources that a service provider’s signal must exceed in power in order to be properly received.

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Optical Conversions
In fiber electronics-based in-building systems, the conversion of radio frequency to optical signals for transport across a distance and their conversion back to radio frequencies for delivery to the end user. As electronic devices, optical converters inherently increase the noise floor of their transmission path. Optical converters are usually located in the equipment room on each floor of a building and must be powered and monitored.

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Passive
The transmission of radio frequency signals without the aid of powered electronic devices to boost their level, thus providing an unaltered delivery of the service provider’s signals.

Picocell
One of the smallest increments of BTS equipment, only used to provide enhanced coverage in very small areas.

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Riser
The backbone transmission cable or device that delivers radio frequency from an input device to antenna systems on each selected floor of a building.

RSSI
RSSI stands for “received signal strength indication” and is one of the measures a service provider will use to determine the quality of their signals inside of a building or other structure.

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Uplink/Downlink
Uplink is the signal sent from a subscriber radio device to the BTS; downlink is a signal received by a subscriber radio device from the BTS.

Uplink/Downlink Conversions
See Optical Conversions.

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WiFi®
A term referring to unlicensed services provided at 2.4 GHz using the IEEE-802.11 protocols.

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