The GSM family of technologies has provided the world with mobile communications since 1991. In over twenty years of development, GSM has been continually enhanced to provide platforms that deliver an increasingly broad range of mobile services as demand grows.
Where the industry started with plain voice calls, it now has a powerful platform capable of supporting mobile broadband and multimedia services.
GSM is now used in 219 countries and territories serving more than five billion people and providing travellers with access to mobile services wherever they go.
What does GSM offer?
GSM supports voice calls and data transfer speeds of up to 9.6 kbps, together with the transmission of SMS (Short Message Service).
GSM operates in the 900MHz and 1.8GHz bands in Europe and the 1.9GHz and 850MHz bands in the US. GSM services are also transmitted via 850MHz spectrum in Australia, Canada and many Latin American countries. The use of harmonised spectrum across most of the globe, combined with GSM’s international roaming capability, allows travellers to access the same mobile services at home and abroad. GSM enables individuals to be reached via the same mobile number in up to 219 countries.
Terrestrial GSM networks now cover more than 90% of the world’s population. GSM satellite roaming has also extended service access to areas where terrestrial coverage is not available.
GPRS offers throughput rates of up to 40 kbps, enabling mobile handsets to access online services at a similar speed to a dial-up modem, but with the convenience of being able to connect from almost anywhere.
GPRS enables people to enjoy advanced, feature-rich data services, such as e-mail on the move, multimedia messages, social networking and location-based services.
Using EDGE, operators can handle three times more subscribers than GPRS, triple their data rate per subscriber, or add extra capacity to their voice communications.
EDGE enables the delivery of more demanding mobile services, such as the downloading of video and music clips, multimedia messaging, full web browsing and e-mail on the move.
EDGE uses the same structure as today’s GSM networks, which allows it to be overlaid directly onto an existing GSM network. For many existing GSM/GPRS networks, EDGE is a simple software-upgrade.
Due to the very small incremental cost of including EDGE capability in a GSM network deployment, virtually all new GSM infrastructure is now EDGE-capable and nearly all new mid- to high-level GSM devices also include EDGE radio technology.
As well as supporting conventional voice, text and MMS services, WCDMA (Wideband Code Division Multiple Access) can carry data at high speeds, enabling mobile operators to deliver richer mobile multimedia services such as music-on-demand, TV and video streaming and broadband Internet access.
Unlike many other mobile broadband technologies, HSPA supports the very efficient provision of voice services in combination with mobile broadband data services.
In most HSPA networks, the end-user can expect to enjoy data throughput speeds of at least 1Mbps, with actual performance varying according to local conditions and the peak downlink speed of the network, which can reach 14.4 Mbps, and the peak uplink speed, which can reach 5.7Mbps.
HSPA+ networks harness MIMO (Multiple-Input, Multiple-Output) capabilities and higher order modulation (64QAM) techniques, to run at even faster speeds, enabling theoretical peak data rates of up to 42Mbps.
Designed to be backwards-compatible with GSM and HSPA, LTE incorporates Multiple In Multiple Out (MIMO) technology, the Orthogonal Frequency Division Multiple Access (OFDMA) air interface in the downlink and Single Carrier FDMA in the uplink. This combination provides high levels of spectral efficiency and network performance, coupled with high network capacity and low latency. LTE will support spectrum channel bandwidths from 1.4 MHz to 20 MHz and can operate in both paired spectrum (in FDD mode) and unpaired spectrum (in TDD mode).
Although both LTE and WiMAX use the OFDMA air interface, LTE’s compatibility with existing GSM and HSPA networks enables mobile operators to continue to provide a seamless service across LTE and existing deployed networks.
LTE networks have now been launched by mobile operators Europe, Asia and North America. In the U.S., the largest CDMA operator, Verizon Wireless, for example, launched commercial LTE services at the end of 2010.
LTE-Advanced is designed to enable a further step change in data rates. Incorporating higher order MIMO (4×4 and beyond) and allowing multiple carriers to be bonded together into a single stream, LTE-Advanced’s target is to achieve peak data rates of 1Gbps.
Other innovations being incorporated into LTE-Advanced include the use of non-contiguous frequency ranges (to alleviate congestion in the increasingly-crowded core spectrum bands), base stations that will be able to connect themselves to an operator’s network and the seamless integration of femtocells using so-called self-organising network techniques.
Standards body 3GPP intends LTE-Advanced to be its technology candidate for the ITU-R IMT-Advanced process, which is intended to identify ‘4G’ technologies.
See more on roaming here.
For further information please see The Creation of Standards for Global Mobile Communication – GSM, UMTS and LTE from 1982 to 2012.