EDGE
Allows GSM operators to use existing GSM radio bands
to offer wireless multimedia IP-based services and applications at theoretical
maximum speeds of 384 kbps with a bit-rate of 48 kbps per timeslot and
up to 69.2 kbps per timeslot in good radio conditions.
EDGE | EGPRS
Enhanced Data rates for GSM Evolution (EDGE) or Enhanced
GPRS (EGPRS),
is a digital mobile phone technology that allows for
increased data transmission rate and improved data transmission reliability.
It is generally classified as a 2.75G network technology. EDGE has been
introduced into GSM networks around the world since 2003, initially in
North America.
It can be used for any packet switched applications such as an Internet connection. High-speed data applications such as video services and other multimedia benefit from EGPRS' increased data capacity. EDGE Circuit Switched is a possible future development. Contents [hide]
EDGE/EGPRS is implemented as a bolt-on enhancement to 2G and 2.5G GSM and GPRS networks, making it easier for existing GSM carriers to upgrade to it. EDGE/EGPRS is a superset to GPRS and can function on any network with GPRS deployed on it, provided the carrier implements the necessary upgrades.
Although EDGE requires no hardware changes to be made in GSM core networks, base stations must be modified. EDGE compatible transceiver units must be installed and the base station subsystem (BSS) needs to be upgraded to support EDGE. New mobile terminal hardware and software is also required to decode/encode the new modulation and coding schemes and carry the higher user data rates to implement new services.
In addition to Gaussian minimum shift keying (GMSK), EDGE uses 8 phase shift keying (8PSK) for the upper five of its nine modulation and coding schemes. EDGE produces a 3-bit word for every change in carrier phase. This effectively triples the gross data rate offered by GSM. EDGE, like GPRS, uses a rate adaptation algorithm that adapts the modulation and coding scheme (MCS) according to the quality of the radio channel, and thus the bit rate and robustness of data transmission. It introduces a new technology not found in GPRS, Incremental Redundancy, which, instead of retransmitting disturbed packets, sends more redundancy information to be combined in the receiver. This increases the probability of correct decoding.
EDGE can carry data speeds up to 236.8 kbit/s for 4 timeslots (theoretical maximum is 473.6 kbit/s for 8 timeslots) in packet mode and will therefore meet the International Telecommunications Union's requirement for a 3G network, and has been accepted by the ITU as part of the IMT-2000 family of 3G standards. It also enhances the circuit data mode called HSCSD, increasing the data rate of this service.
Whether EDGE is 2G or 3G depends on implementation. While Class 3 and below EDGE devices clearly are not 3G, class 4 and above devices perform at a higher bandwidth than other technologies conventionally considered as 3G (such as 1xRTT). Because of the variability, EDGE is generally classified as 2.75G network technology.
EDGE is actively supported by GSM operators in North America. Some GSM operators elsewhere view UMTS as the ultimate upgrade path and either plan to skip EDGE altogether or use it outside the UMTS coverage area. However, the high cost and slow uptake of UMTS have resulted in fairly common support for EDGE in the global GSM/GPRS market.
The following companies have EDGE networks in production:
Cingular and T-Mobile have EDGE networks in the United
States.
GPRS
General Packet Radio Service (GPRS) is a mobile data
service available to users of GSM and IS-136 mobile phones. GPRS data transfer
is typically charged per megabyte of transferred data, while data communication
via traditional circuit switching is billed per minute of connection time,
independently of if the user actually has transferred data or been in an
idle state.
GPRS is different from the older Circuit Switched Data (or CSD) connection included in GSM standards. In CSD, a data connection establishes a circuit, and reserves the full bandwidth of that circuit during the lifetime of the connection. GPRS is packet-switched which means that multiple users share the same transmission channel, only transmitting when they have data to send. This means that the total available bandwidth can be immediately dedicated to those users who are actually sending at any given moment, providing higher utilisation where users only send or receive data intermittently. Web browsing, receiving e-mails as they arrive and instant messaging are examples of uses that require intermittent data transfers, which benefit from sharing the available bandwidth.
Usually, GPRS data are billed per kilobytes of information transceived while circuit-switched data connections are billed per second. The latter is to reflect the fact that even during times when no data are being transferred, the bandwidth is unavailable to other potential users.
The General Packet Radio Service (GPRS) is a new bearer
service for GSM that greatly improves and simplifies wireless access to
packet data networks, e.g., to the Internet. It applies a packet radio
principle to transfer user data packets in an efficient way between mobile
stations and external packet data networks.
GSM
The Global System for Mobile Communications, GSM (original
acronym: Groupe Spécial Mobile) is the most popular standard for
mobile phones in the world. GSM service is used by over 2 billion people
across more than 212 countries and territories.
May 2007
AT&T hopes for iPhone to be synonymous with the company in five year exclusive
Apple’s iPhone is arguably this year’s most hotly anticipated consumer device. AT&T already accelerated its plans to rebrand the Cingular properties in preparation of the iPhone’s arrival ? and apparently, its efforts may be well placed as the iPhone could be an AT&T-exclusive for five years, according to a USA Today story.
Being an AT&T-exclusive means that the iPhone will remain a GSM phone, leaving it clearly out of reach for CDMA wireless users. Verizon Wireless and Sprint are both CDMA shops, and customers of those carriers who wish to get the iPhone will have no other choice but to make the move to AT&T.
T-Mobile is another GSM carrier in the U.S., and its network would likely be able to support the iPhone’s calling features, but AT&T will be the only company authorized to officially sell and market the iPhone. Furthermore, all iPhone’s sold through AT&T will be ‘locked’ to the network, disallowing those phones to connect to another carrier even with a different SIM card.
"I'm glad we have (the iPhone) in our bag," says Stan Sigman, CEO of wireless at AT&T. "Others will try to match it, but for a period of time, they're going to be playing catch-up."
According to data collected by Forrester Research,
about 78 percent of U.S. households have a mobile phone. Charles Golvin,
an analyst at Forrester, believes anybody who wants a cell phone has one.
The other 22 percent without cell phones, he says, "are the very young,
the very old and the economically challenged" ? none of which are target
markets for the iPhone.
John in California
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