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Devices
Jargon
Here are some of the buzz words in the world of mobility...
Bluetooth: This technology got its unusual name in honor of Harald Bluetooth, king of Denmark in the mid-tenth century.
Bluetooth is a telecommunications industry specification that describes how mobile phones, computers, and personal digital assistants (PDAs) can be easily interconnected using a short-range wireless connection. Using this technology, users of cellular phones, pagers, and personal digital assistants can buy a three-in-one phone that can double as a portable phone at home or in the office, get quickly synchronized with information in a desktop or notebook computer, initiate the sending or receiving of a fax, initiate a print-out, and, in general, have all mobile and fixed computer devices be totally coordinated.
Bluetooth requires that a low-cost transceiver chip be included in each device. The tranceiver transmits and receives in a previously unused frequency band of 2.45 GHz that is available globally (with some variation of bandwidth in different countries). In addition to data, up to three voice channels are available. Each device has a unique 48-bit address from the IEEE 802 standard. Connections can be point-to-point or multipoint. The maximum range is 10 meters. Data can be exchanged at a rate of 1 megabit per second (up to 2 Mbps in the second generation of the technology). A frequency hop scheme allows devices to communicate even in areas with a great deal of electromagnetic interference. Built-in encryption and verification is provided.
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CDMA: CDMA (Code-Division Multiple Access) refers to any of several
protocols used in so-called second-generation (2G) and third-generation
(3G) wireless communications. As the term implies, CDMA is a form of
multiplexing, which allows numerous signals to occupy a single
transmission channel, optimizing the use of available bandwidth. The
technology is used in ultra-high-frequency (UHF) cellular telephone
systems in the 800-MHz and 1.9-GHz bands.
CDMA employs analog-to-digital conversion (ADC) in combination with
spread spectrum technology. Audio input is first digitized into binary
elements. The frequency of the transmitted signal is then made to vary
according to a defined pattern (code), so it can be intercepted only by
a receiver whose frequency response is programmed with the same code, so
it follows exactly along with the transmitter frequency. There are
trillions of possible frequency-sequencing codes; this enhances privacy
and makes cloning difficult.
The CDMA channel is nominally 1.23 MHz wide. CDMA networks use a scheme
called soft handoff, which minimizes signal breakup as a handset passes
from one cell to another. The combination of digital and spread-spectrum
modes supports several times as many signals per unit bandwidth as
analog modes. CDMA is compatible with other cellular technologies; this
allows for nationwide Roaming.
The original CDMA standard, also known as CDMA One and still common in
cellular telephones in the U.S., offers a transmission speed of only up
to 14.4 Kbps in its single channel form and up to 115 Kbps in an
eight-channel form. CDMA2000 and wideband CDMA deliver data many times
faster.
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EDGE: EDGE (Enhanced Data GSM Environment), a faster version of the
Global System for Mobile (GSM) wireless service, is designed to deliver
data at rates up to 384 Kbps and enable the delivery of multimedia and
other broadband applications to mobile phone and computer users. The
EDGE standard is built on the existing GSM standard, using the same
time-division multiple access (TDMA) frame structure and existing cell
arrangements. Ericsson notes that its base stations can be updated with
software.
GPRS: General Packet Radio Services (GPRS) is a packet-based wireless
communication service that promises data rates from 56 up to 114 Kbps
and continuous connection to the Internet for mobile phone and computer
users. The higher data rates will allow users to take part in video
conferences and interact with multimedia Web sites and similar
applications using mobile handheld devices as well as notebook
computers. GPRS is based on Global System for Mobile (GSM) communication
and will complement existing services such circuit-switched cellular
phone connections and the Short Message Service (SMS).
In theory, GPRS packet-based service should cost users less than
circuit-switched services since communication channels are being used on
a shared-use, as-packets-are-needed basis rather than dedicated only to
one user at a time. It should also be easier to make applications
available to mobile users because the faster data rate means that
middleware currently needed to adapt applications to the slower speed of
wireless systems will no longer be needed. As GPRS becomes available,
mobile users of a virtual private network (VPN) will be able to access
the private network continuously rather than through a dial-up
connection.
GPRS will also complement Bluetooth, a standard for replacing wired
connections between devices with wireless radio connections. In addition
to the Internet Protocol (IP), GPRS supports X.25, a packet-based
protocol that is used mainly in Europe. GPRS is an evolutionary step
toward Enhanced Data GSM Environment (EDGE) and Universal Mobile
Telephone Service (UMTS).
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GSM: GSM (Global System for Mobile communication) is a digital mobile
telephone system that is widely used in Europe and other parts of the
world. GSM uses a variation of time division multiple access (TDMA) and
is the most widely used of the three digital wireless telephone
technologies (TDMA, GSM, and CDMA). GSM digitizes and compresses data,
then sends it down a channel with two other streams of user data, each
in its own time slot. It operates at either the 900 MHz or 1800 MHz
frequency band.
GSM is the de facto wireless telephone standard in Europe. GSM has over
120 million users worldwide and is available in 120 countries, according
to the GSM MoU Association. Since many GSM network operators have
roaming agreements with foreign operators, users can often continue to
use their mobile phones when they travel to other countries.
American Personal Communications (APC), a subsidiary of Sprint, is using
GSM as the technology for a broadband personal communications service
(PCS). The service will ultimately have more than 400 base stations for
the palm-sized handsets that are being made by Ericsson, Motorola, and
Nokia. The handsets include a phone, a text pager, and an answering
machine.
GSM together with other technologies is part of an evolution of wireless
mobile telemmunication that includes High-Speed Circuit-Switched Data (HCSD),
General Packet Radio System (GPRS), Enhanced Data GSM Environment
(EDGE), and Universal Mobile Telecommunications Service (UMTS).
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MMS: Multimedia Messaging Service (MMS) - sometimes called Multimedia
Messaging System - is a communications technology developed by 3GPP
(Third Generation Partnership Project) that allows users to exchange
multimedia communications between capable mobile phones and other
devices. An extension to the Short Message Service (SMS) protocol, MMS
defines a way to send and receive, almost instantaneously, wireless
messages that include images, audio, and video clips in addition to
text. When the technology has been fully developed, it will support the
transmission of streaming video. A common current application of MMS
messaging is picture messaging (the use of camera phones to take photos
for immediate delivery to a mobile recipient). Other possibilities
include animations and graphic presentations of stock quotes, sports
news, and weather reports.
According to MobileStreams, MMS will be developed in two separate
phases. Based on General Packet Radio Services (GPRS), the currently
available MMS is similar to a brief PowerPoint presentation. The second
phase of MMS will require a 3G network to enable streaming video. An
intermediate technology, Enhanced Messaging Service (EMS) has more
capabilities than SMS, but fewer than MMS. Unlike MMS, EMS doesn't
require upgrades to network infrastructures. Unlike SMS and EMS, the
size of an MMS message is unlimited, although service providers are
likely to impose their own size restrictions.
MMS-capable devices are available from a number of vendors, including
Ericsson, Motorola, and Nokia.
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PCS: PCS (personal communications services) is a wireless phone service
somewhat similar to cellular telephone service but emphasizing personal
service and extended mobility. It's sometimes referred to as digital
cellular (although cellular systems can also be digital). Like cellular,
PCS is for mobile users and requires a number of antennas to blanket an
area of coverage. As a user moves around, the user's phone signal is
picked up by the nearest antenna and then forwarded to a base station
that connects to the wired network. The phone itself is slightly smaller
than a cellular phone. According to Sprint, PCS is now available to 230
million people.
The "personal" in PCS distinguishes this service from cellular by
emphasizing that, unlike cellular, which was designed for car phone use
with transmitters emphazing coverage of highways and roads, PCS is
designed for greater user mobility. It generally requires more cell
transmitters for coverage, but has the advantage of fewer blind spots.
Technically, cellular systems in the United States operate in the
824-849 megahertz (MHz) frequency bands; PCS operates in the1850-1990
MHz bands.
Several technologies are used for PCS in the United States, including
Time Division Multiple Access (TDMA), Code Division Multiple Access (CDMA),
and Global System for Mobile (GSM) communication. GSM is more commonly
used in Europe and elsewhere.
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SMS: SMS (Short Message Service) is a service for sending messages of up
to 160 characters (224 characters if using a 5-bit mode) to mobile
phones that use Global System for Mobile (GSM) communication. GSM and
SMS service is primarily available in Europe. SMS is similar to paging.
However, SMS messages do not require the mobile phone to be active and
within range and will be held for a number of days until the phone is
active and within range. SMS messages are transmitted within the same
cell or to anyone with roaming service capability. They can also be sent
to digital phones from a Web site equipped with PC Link or from one
digital phone to another. Typical uses of SMS include:
* Notifying a mobile phone owner of a voicemail message
* Notifying a salesperson of an inquiry and contact to call
* Notifying a doctor of a patient with an emergency problem
* Notifying a service person of the time and place of their next call
* Notifying a driver of the address of the next pickup
An SMS gateway is a Web site that lets you enter an SMS message to
someone within the cell served by that gateway or that acts as an
international gateway for users with roaming capability.
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TDMA: TDMA (time division multiple access) is a technology used in
digital cellular telephone communication that divides each cellular
channel into three time slots in order to increase the amount of data
that can be carried.
TDMA is used by Digital-American Mobile Phone Service (D-AMPS), Global
System for Mobile communications (GSM), and Personal Digital Cellular (PDC).
However, each of these systems implements TDMA in a somewhat different
and incompatible way. An alternative multiplexing scheme to FDMA with
TDMA is CDMA (code division multiple access), which takes the entire
allocated frequency range for a given service and multiplexes
information for all users across the spectrum range at the same time.
TDMA was first specified as a standard in EIA/TIA Interim Standard 54
(IS-54). IS-136, an evolved version of IS-54, is the United States
standard for TDMA for both the cellular (850 MHz) and personal
communications services (1.9 GHz) spectrums. TDMA is also used for
Digital Enhanced Cordless Telecommunications (DECT).
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WiFi: Wi-Fi (short for "wireless fidelity") is a term for certain types
of wireless local area network (WLAN) that use specifications in the
802.11 family. The term Wi-Fi was created by an organization called the
Wi-Fi Alliance, which oversees tests that certify product
interoperability. A product that passes the alliance tests is given the
label "Wi-Fi certified" (a registered trademark).
Originally, Wi-Fi certification was applicable only to products using
the 802.11b standard. Today, Wi-Fi can apply to products that use any
802.11 standard. The 802.11 specifications are part of an evolving set
of wireless network standards known as the 802.11 family. The particular
specification under which a Wi-Fi network operates is called the
"flavor" of the network. Wi-Fi has gained acceptance in many businesses,
agencies, schools, and homes as an alternative to a wired LAN. Many
airports, hotels, and fast-food facilities offer public access to Wi-Fi
networks. These locations are known as hot spots. Many charge a daily or
hourly rate for access, but some are free. An interconnected area of hot
spots and network access points is known as a hot zone.
Unless adequately protected, a Wi-Fi network can be susceptible to
access by unauthorized users who use the access as a free Internet
connection. The activity of locating and exploiting security-exposed
wireless LANs is called war driving. An identifying iconography, called
war chalking, has evolved. Any entity that has a wireless LAN should use
security safeguards such as the Wired Equivalent Privacy (WEP)
encryption standard, the more recent Wi-Fi Protected Access (WPA),
Internet Protocol Security (IPsec), or a virtual private network (VPN).
All definitions provided by www.searchmobilecomputing.com and
www.whatis.com
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