InterReach Unison Installation, Operation, and Reference Manual
D-5
D-620003-0-20 Rev J
CONFIDENTIAL
IS-54
Interim Standard-54. A U.S. TDMA cellular standard that operates in the
800 MHz or 1900 MHz band. IS-54 was the first U.S. digital cellular standard. It
was adopted by the CTIA in 1990.
IS-95
Interim Standard-95. A U.S. CDMA cellular standard that operates in the
800 MHz or 1900 MHz band. This standard was developed by Qualcomm and
adopted by the CTIA in 1993.
IS-136
Interim Standard-136. A U.S. TDMA cellular standard based on IS-54 that
operates in the 800 MHz or 1900 MHz band.
IS-553
Interim Standard-533. The U.S. analog cellular (AMPS) air interface stan-
dard.
ITU
International Telecommunications Union. The ITU is the principal interna-
tional standards organization. It is charted by the United Nations and it estab-
lishes international regulations governing global telecommunications networks
and services. Its headquarters are in Geneva, Switzerland.
LMDS
Local Multipoint Distribution Services. LMDS provides line-of-sight cover-
age over distances up to 3–5 kilometers and operates in the 28 GHz portion of the
spectrum. It can deliver high speed, high bandwidth services such as data and
video applications.
Local Loop
A communication channel (usually a physical phone line) between a
subscriber’s location and the network’s Central Office.
MHz
Megahertz. One million Hertz. One MHz equals one million cycles per sec-
ond.
Microcell
A network cell designed to serve a smaller area than larger macrocells.
Microcells are smaller and lower powered than macrocells. As the subscriber
base increases, operators must continue to increase the number of cells in their
network to maximize channel re-use. This has led to an increasing number of
microcells being deployed in wireless networks.
Microwave
Electromagnetic waves with frequencies above 1 GHz. Microwave
communications are used for line-of-sight, point-to-point, or point-to-multipoint
communications.
MSA
Metropolitan Statistical Area. The FCC has established 306 MSAs in the U.S.
The MSAs represent the largest population centers in the U.S. At least two wire-
less operators are licensed in each MSA.
MSC
Mobile Services Switching Center. A generic term for the main cellular
switching center in the wireless communications network.
MSS
Mobile Satellite Service. Communications transmission service provided by
satellites. A single satellite can provide coverage to the entire United States.
MTA
Major Trading Area. The U.S. and its territories are divided into 51 MTAs.
Each MTA is composed of a specific number of BTAs. The FCC grants licenses
