A Brief History of Mobile Networks

The G in 4G stands for "generation." The first generation of wireless telephones (1G) was commercially introduced in the early 1980s and operated using analog technology that predated digital telecommunication networks.

Each generation marks the recognition of new performance expectations and regulatory standards. Not all revisions warrant the designation of a new generation, however, and sources may refer to these interstitial advancements as subsets of the current generation (i.e. 2.5G or 3.75G).

2G

2G was the first digital implementation of wireless voice communication. It launched the GSM standard, and its ubiquitous adoption enabled global "roaming" for the first time (letting mobile phones connect to the network of a different carrier). 2G also introduced secure mobile data services capable of delivering SMS text messages and multimedia messages (MMS). The first 2G network debuted commercially in 1991 with very limited Internet access.

CDMA was introduced during the 2G era as an alternative to GSM; it was adopted in North America and South Korea. The two competing standards -- CDMA and GSM -- divided cellular telecommunication for generations to come. Please refer to the Service Providers section of this manual for more details.

This generation was also the first to increment in half steps. The initial rollout of 2G cellular networks featured digital dial-up connectivity that could transfer data very slowly, though it was expensive for users because it ate up a lot of airtime in an era when minutes were pricey. A technology called General Packet Radio Service (GPRS) provided an always-on methodology for the wireless transfer of information; it was considered "narrowband" (in contrast to broadband) because of its somewhat constrained data rates yet permanent availability.

2G with GPRS is regarded as 2.5G. While it effectively quadrupled network speeds, it didn't meet the requirements set for 3G standards. A similar half-step was bolted on to 2.5G, bringing it to "2.75G," when Enhanced GPRS -- commonly referred to as EDGE -- further augmented transfer speeds prior to achieving true 3G connectivity.

3G

A decade after the previous generation debuted commercially, 3G marked the arrival of mobile broadband. While 2G peak transfer speeds capped out at a theoretical maximum roughly between 40 to 100 Kbit/s, 3G was designed with a theoretical minimum of 144 Kbit/s. By the time 4G was becoming commercially available, 3G connections were capable of facilitating transfers that surpassed 10 Mbps (or 10,000 Kbps).

There were also transitional stages for 3G, as advancements in wireless technology were incorporated into cellular networks without reaching the minimum bandwidth requirements for 4G classification (3.5G). The division between GSM and CDMA carriers persisted during this generation; the former migrated to the Universal Mobile Telecommunications Servce (UMTS) system -- which subsequently became HSPA+ -- and the latter turned to the EV-DO standard.

The line between 3G and 4G is blurred by branding decisions. It is important to keep in mind that cellular generations are labels given to networks using an amalgamation of technologies. In an effort to set newer services apart from older ones, carriers began referring their upgraded networks as "4G" before fully meeting the performance benchmarks of the true 4G standard.

Please read the following section to understand the distinctions between standard 4G and "true 4G" networks.

4G

The requirements for 4G standards were announced in 2008, setting peak speed requirements at 100 Mbps for high mobility connections (while in a car, for instance) and 1 Gbps -- or 1,000 Mbps -- for low mobility communication scenarios involving pedestrians and stationary equipment. This is the latest generation of cellular transmission technology available in commercial markets. It marks the convergence of HSPA+ (GSM) and EV-DO (CDMA) to the LTE standard, which has since been enhanced and repackaged as LTE-Advanced.

LTE & LTE-Advanced

Standing for Long-Term Evolution, LTE supports global roaming for multi-band phones at speeds that surpass what's achievable on a 3G network. As fast as LTE is, however, it isn't capable of reaching the performance threshold set for a true 4G designation. This is why LTE is increasingly referred to as a 3.9G standard -- it was on the cusp but not quite there.

LTE-Advanced (LTE-A) took mobile networks completely away from 3G expectations. It meets all of the requirements set for 4G connectivity while remaining backward compatible with LTE (standard) networks, which in turn would provide support for legacy systems derived from the old GSM and CDMA networks.

The performance boost of LTE-A is primarily driven by two new enhancements: expanded MIMO support and Carrier Aggregation.

Since LTE was standardized with future innovations in mind (hence the "evolutionary" element to its name), it is categorized in a manner similar to the Ethernet categories discussed here. Category 6 LTE is the first LTE-A release, with Category 4 being the most prevalent categorization for standard LTE.