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Wireless Lexicon

Cell site
A site where antennas and electronic communications equipment are placed in a mobile phone network (cellular network). The cell site/tower includes antennas, transceivers, signal processors, and power sources.

GSM
GSM (Global System for Mobile communications) is the most broadly-deployed standard for mobile phones and is used by more than 88 percent of the world. This dominant technology means that AT&T customers benefit from global roaming capability, prioritized research and development, the best options in cutting-edge devices, and a smooth evolution to newer technologies.

SIM card
The SIM (Subscriber Identity Module) card is used in 3GPP-based phones to identify a subscriber on a mobile telephony device and may also hold phone numbers and other information. Can be removed and inserted into other GSM/UMTS devices, providing for more openness for accommodating mobile devices. The SIM also controls interoperability with other carrier networks. SIM cards are typically unique to a customer’s account.

EDGE
(Enhanced Data rates for Global Evolution — or GSM Evolution) A 2.5G high-speed digital data service provided by cellular carriers worldwide that use the GSM technology.

UMTS
(Universal Mobile Telecommunications System) A 3GPP version of mobile broadband technology. UMTS carries the voice portion of a call while it utilizes the HSPA component to handle data.

HSPA
(HSUPA/HSDPA) - High Speed Packet Access for both the uplink and downlink. Falling under the UMTS umbrella, HSPA is a major enhancement with more speed and capacity.

LTE
A technology evolved from the 3GPP standard that could eventually allow much higher peak data transfer rates to and from mobile devices. AT&T is planning to begin deployment of the technology in mid-2011.

WiMAX
A telecommunications technology that provides for the wireless transmission of data using a variety of transmission modes, from point-to-point links to full mobile cellular-type access. One form of the standard is used for mobile broadband and another for fixed wireless service.

Spectrum
A range of airwaves in which wireless signals are sent and received. For mobile wireless, this typically refers to the amount of frequency range — or spectrum — allocated for use by a mobile carrier. AT&T utilizes specific bands of spectrum in the 850 MHz and 1900 MHz ranges to deliver mobile wireless services.

850 MHz
850 MHz is high-quality spectrum that can enhance capacity and offers improvements to in-building coverage via a signal that can better penetrate walls than spectrum at higher frequencies. We’re currently focused on using this spectrum to add capacity and improve our mobile broadband network.

Handoff/handover
Transferring a wireless connection between cell sites as a user moves through a cellular network.

Backhaul
The connection between a cell tower and the backbone, or core, network.