|
H |
|
Half-Rate |
A
variant of GSM, Half-Rate doubles system capacity by more
efficient speech coding. |
|
Handheld Device Markup Language (HDML) |
A
specialized version of HTML designed to enable wireless pagers,
cell phones and other handheld devices to obtain information
from Web pages. HDML was developed by Phone.com (formerly
Unwired Planet) before the WAP specification was standardized.
It is a subset of WAP with some features, not included in WAP.
AT&T Wireless launched the first HDML-based service in 1996. |
|
Handoff |
The process by which the Mobile Telephone Switching Office
passes a cellular phone conversation from one radio frequency in
one cell to another radio frequency in another. The handoff is
performed so quickly that users usually never notice. |
|
Hands-Free |
An
important safety feature that's included with most of today's
mobile phones. It permits drivers to use their cellular phone
without lifting or holding the hand-set to their ear. |
|
Handset Subsidy |
Frequently, a wireless company will sell a phone (handset) below
cost, with the hope of making up the loss later on customer
usage fees. The amount of loss per handset is called the handset
subsidy. |
|
Hertz (Hz) |
A
unit of measurement of one cycle per second when one radio wave
passes one point in one second of time. Named in honor of
Heinrich Hertz, the physicist who developed the theory of radio
waves. |
|
High-Speed Circuit Switched Data (HSCSD) |
The final evolution of circuit switched data within the GSM
environment. HSCSD enables the transmission of data over a GSM
link at speeds of up to 57.6kbit/s. This is achieved by
concatenating consecutive GSM timeslots, each of, which is
capable of supporting 14.4kbit/s. Up to four GSM timeslots are
needed for the transmission of HSCSD. |
|
Home Location Register (HLR) |
A
database residing in a local wireless network that contains
service profiles and checks the identity of a local subscriber. |
|
I |
|
I-Mode |
NTT DoCoMo's mobile Internet access, launched in February 1999.
I-mode is an alternative to WAP, though it is only implemented
in Japan. It offers Internet access and email service. While WAP
uses HDML, I-mode relies on Compact HTML (C-HTML). Both
languages are a simple version of HTML, for use on mobile
phones. Today more than 7000 sites are I-mode compatible and
offer a wide range of services over mobile phones: mobile
banking, ticket reservation, cartoons downloading, etc. |
|
Incumbent Local Exchange Carrier (ILEC) |
The historic local phone service provider in a market, often a
former Bell company. Distinct from competitive local exchange
carriers (CLECs), new market entrants. |
|
Independent Telephone Network (ITN) |
Companies not affiliated with the local telephone companies. |
|
Industrial Telecommunications Association (ITA) |
A
Washington, D.C. trade group serving private wireless licensees
such as airlines and oil companies. |
|
Infrared Data Association (IrDA) |
A
membership organization founded in 1993 and dedicated to
developing standards for wireless, infrared transmission systems
between computers. With IrDA ports, a laptop or PDA can exchange
data with a desktop computer or use a printer without a cable
connection. Like a TV remote control, IrDA requires
line-of-sight transmission. IrDA products began to appear in
1995. |
|
Integrated Circuit Card ID (ICCID) |
19
or 20-digit serial number of the SIM card. |
|
Integrated Digital Enhanced Network (iDEN) |
A
wireless communications technology from Motorola that provides
support for voice, data, short messages (SMS) and dispatch radio
(two-way radio) in one phone. Operating in the 800MHz and 1.5GHz
bands and based on TDMA, iDEN uses Motorola's VSELP (Vector Sum
Excited Linear Predictors) vocoder for voice compression and QAM
modulation to deliver 64 Kbps over a 25KHz channel. Each 25KHz
channel can be divided six times to transmit any mix of voice,
data, dispatch or text message. Used by various carriers around
the globe, Nextel Communications provides nationwide coverage in
the U.S. |
|
Intelligent Roaming Database (IRDB) |
A
list of acceptable and unacceptable networks for a phone to roam
with stored either on a SIM card or in the phone. |
|
Interactive Messaging |
Short Message Service that allows users to send alphanumeric
messages from their wireless handset to other wireless handsets
or to email addresses. Interactive Messaging also allows the
user to receive emails and web messages from the internet. |
|
Interconnection |
The connecting of one network with another, e.g. a cellular
carrier's wireless network with the local exchange. |
|
Interim Standard (IS) |
A
designation of the Telecommunications Industry Association
--usually followed by a number--that refers to an accepted
industry protocol; e.g., IS-95, IS-136, IS-54. |
|
International Mobile Equipment Identifier (IMEI) |
A
unique 15-digit number that serves as the serial number of the
GSM handset. The IMEI appears on the label located on the back
of the phone. The IMEI is automatically transmitted by the phone
when the network asks for it. A network operator might request
the IMEI to determine if a device is in disrepair, stolen or to
gather statistics on fraud or faults. |
|
International Mobile Subscriber Identifier (IMSI) |
A
unique 15-digit number which designates the subscriber. This
number is used for provisioning in network elements. |
|
International Mobile Telecommunications
Association (IMTA) |
A
trade group serving specialized mobile radio and public access
mobile radio carriers around the world. |
|
International Telecommunication Union (ITU) |
An
agency of the United Nations, headquartered in Geneva that
furthers the development of telecommunications services
worldwide and oversees global allocation of spectrum for future
uses. |
|
Interoperability |
The ability of a network to operate with other networks, such as
two systems based on different protocols or technologies. |
|
Ionizing Radiation |
Very high energy electromagnetic radiation that strips electrons
away from their normal locations in atoms and molecules. |
|
Iridium |
First LEO-based global communications system backed by Motorola.
Built primarily for voice transmissions, it was launched in 1998
and went into Chapter 11 in 1999. |
|
IS-136 |
The latest generation of the digital standard TDMA technology. |
|
IS-41 |
The network standard that allows all switches to exchange
information about subscribers. |
|
IS-54 |
The first generation of the digital standard TDMA technology. |
|
IS-661 |
North American standard for 1.9 GHz wireless spread spectrum
radio-frequency access technology based on a composite of CDMA
and TDMA technologies To reduce infrastructure costs and allow
higher data speeds than mainstream GSM or TDMA platforms. |
|
IS-95 |
The standard for CDMA. |
|
J |
|
Japanese Total Access Communication (JTAC) |
Like the European TACS, JTAC is the Japanese analog cellular
system. |
