Wireless Glossary – G

A method of increasing the transmission distance of a radio by the concentration its signal in a single direction, typically through the use of a directional antenna. Gain does not increase a radio’s signal strength, but simply redirects it. Therefore, as gain increases, the decrease in angle of coverage is inversely proportional.

A gateway is an internetworking system, a system that joins two networks together.

Guaranteed Bit Rate is a minimum bit rate required by an application. In LTE, minimum GBR bearers and non-GBR bearers may be provided.

Mobile data service available to users of GSM mobile phones. It is often described as “2.5G”, that is, a technology between the second (2G) and third (3G) generations of mobile telephony. It provides moderate speed data transfer, by using unused TDMA channels in the GSM network. Originally there was some thought to extend GPRS to cover other standards, but instead those networks are being converted to use the GSM standard, so that is the only kind of network where GPRS is in use. GPRS is integrated into GSM standards releases starting with Release 97 and onwards. First it was standardised by ETSI but now that effort has been handed onto the 3GPP.

GERAN is an abbreviation for GSM EDGE Radio Access Network. The standards for GERAN are maintained by the 3GPP (Third Generation Partnership Project). GERAN is a key part of GSM, and also of combined UMTS/GSM networks.

Gateway GPRS Support Node is a main component of the GPRS network. The GGSN is responsible for the interworking between the GPRS network and external packet switched networks, like the Internet and X.25 networks.

One billion cycles per second. A unit of measure for frequency.

A type of IPv6 address that is designed for global use (ie Internet communications) and has the broadest scope.

One of the most popular standard for mobile phones in the world. GSM phones are used by over a billion people across more than 200 countries. The ubiquity of the GSM standard makes international roaming very common between mobile phone operators which enables phone users to access their services in many other parts of the world as well as their own country. GSM differs significantly from its predecessors in that both signalling and speech channels are digital, which means that it is seen as a second generation (2G) mobile phone system. This fact has also meant that data communication was built into the system from very early on. GSM is an open standard which is currently developed by the 3GPP.

From the point of view of the consumer, the key advantage of GSM systems has been higher digital voice quality and low cost alternatives to making calls such as text messaging. The advantage for network operators has been the ability to deploy equipment from different vendors because the open standard allows easy inter-operability. Also, the standards have allowed network operators to offer roaming services which mean subscribers can use their phone all over the world.

GSM retained backward-compatibility with the original GSM phones as the GSM standard continued to develop, for example packet data capabilities were added in the Release ’97 version of the standard, by means of GPRS. Higher speed data transmission have also been introduced with EDGE in the Release ’99 version of the standard.

Guard Periods or Guard Intervals are used to ensure that distinct transmissions do not interfere with one another. These transmissions may belong to different users (as in TDMA) or to the same user (as in OFDM).

General Ppacket Radio Service is a packet oriented mobile data service on the 2G and 3G cellular communication system’s global system for mobile communications (GSM). GPRS was originally standardized by European Telecommunications Standards Institute (ETSI) in response to the earlier CDPD and i-mode packet-switched cellular technologies. It is now maintained by the 3rd Generation Partnership Project (3GPP).

Network of satellites that provides absolute time to networks on earth, which use the time signal to synchronize transmission and reception cycles (to avoid interference) and to provide reference for troubleshooting activities.

Third-from-left LED in the module. In the operating mode for an Access Point Module or Backhaul timing master, this LED is continuously lit as the module receives sync pulse. In the operating mode for a Subscriber Module or a Backhaul timing slave, this LED flashes on and off to indicate that the module is not registered. In the aiming mode for a Subscriber Module or a Backhaul timing slave, this LED is part of a bar graph that indicates the quality of the RF link.

Refractive index profile of an optical fiber. The refractive index of the fiber core decreases continuously – usually parabolically – toward the cladding.

Generic Routing Encapsulation is a tunneling protocol developed by Cisco Systems that can encapsulate a wide variety of network layer protocols inside virtual point-to-point links over an Internet Protocol internetwork.

Anti-buckling and strength member made of glass filaments (GRP = glass fiber reinforced composite).

Global System for Mobile Communications, originally Groupe Special Mobile, is a standard set developed by the European Telecommunications Standards Institute (ETSI) to describe protocols for second generation (2G) digital cellular networks used by mobile phones.

GPRS Tunnelling Protocol – User, for transfer of user data in separated tunnels for each Packet Data Protocol (PDP) context.