EDGE is a network enhancement in second-generation (2G) GSM networks and is represented by an E symbol on cell phones. It is a successor of the GPRS enhancement that introduced the packet-switched mobile internet in GSM networks.
EDGE or Enhanced Data for Global Evolution is a 2G technology introduced in GSM networks to increase the data rates of GPRS and HSCSD enhancements. EDGE is not 3G but is called 2.75G as it laid the foundation for 3G UMTS networks. EDGE is faster than GPRS and offers a peak download speed of 384 kbps.
EDGE is a 2G technology in second-generation GSM networks
EDGE was introduced in the most widely deployed second-generation GSM (Global System for Mobile Communications) networks. EDGE stands for Enhanced Data for Global Evolution, but the acronym EDGE can also mean Enhanced Data for GSM Evolution. Before EDGE, GSM networks used two separate technologies for offering mobile data, one based on circuit switching and the other based on packet-switching.
High-Speed Circuit-Switched Data or HSCSD was the technique that used the circuit-switched part of the GSM network to offer limited mobile data. GPRS or General Packet Radio Service is the technique in GSM networks that uses the packet-switched part of the GSM network to offer highly efficient mobile data services.
The EDGE enhancement consists of two separate technology updates: Enhanced General Packet Radio Service (EGPRS) and Enhanced Circuit Switched Data (ECSD). EGPRS is the enhancement for GPRS, whereas ECSD is the enhancement for HSCSD. The most significant part of EDGE is EGPRS which is for the packet-switched GPRS enhancement.
EGPRS employs a superior modulation scheme that essentially triples the download data rates of GPRS. EGPRS, as part of EDGE, can offer peak download data rates of up to 384 kbps. EDGE can deliver average download data rates of between 130 to 200 kbps.
EDGE and GPRS laid the foundation for 3G UMTS networks
When GSM (Global System for Mobile Communications) networks were introduced, they only had the circuit-switched capability that delivered voice calls and text messages. A circuit-switched data capability, CSD, was later added to enable limited mobile internet.
Circuit-Switched Data or CSD was inefficient as it permanently engaged network resources for the entire data session duration. CSD used one timeslot at a time to deliver a maximum download data rate of 9.6 kbps.
Later, with the High-Speed Circuit Switched Data enhancement (HSCSD), improvements were made to the error coding techniques within CSD to increase the data rate per timeslot. As a result, HSCSD could offer a maximum data rate of 64 kbps using multiple timeslots.
General Packet Radio Service or GPRS was a big breakthrough as it added the packet-switching technique to the existing GSM networks. GPRS is efficient as it does not engage the network resources permanently and communicates in bursts of data only when a user sends or receives. As a result, GPRS can offer peak download data rates of 171.2 kbps.
For GPRS implementation, two new network nodes, Serving GPRS Support Node (SGSN) and Gateway GPRS Support Node (GGSN), were introduced to the mobile core network of GSM. After GPRS, the circuit-switched part was used for voice calls and texts and the packet-switched part was used for mobile data.
The network architecture of 3G UMTS networks utilises the same SGSN and GGSN nodes introduced in the mobile core network for GPRS and EDGE enhancements. As a result, these two network nodes are also responsible for providing the packet-switching capability to HSPA and HSPA+.
Finally, EDGE or Enhanced Data for Global Evolution, was launched just before the arrival of 3G UMTS networks (Universal Mobile Telecommunication System). While EDGE improved both HSCSD and GPRS, the GPRS enhancement is more relevant in today’s mobile networks.
The key EDGE enhancement, Enhanced GPRS or EGPRS, employed superior a modulation scheme to triple the achievable data rates that GPRS initially delivered. Using all eight (8) timeslots, EGPRS can theoretically offer 473 kbps, but a maximum data rate of 384 kbps can be achieved in real life.
Which cellular technologies are 2G?
The second generation of mobile networks, 2G, was enabled by three key technologies GSM (Global System for Mobile Communications), IS-95 (Interim Standard 1995) and D-AMPS (Digital Advanced Mobile Phone System). Initially, GSM was more common in Europe, whereas D-AMPS and IS-95 were more common in the US.
2G mobile networks still exist today, but GSM has now become the most widely deployed second-generation technology standard. D-AMPS networks have now been decommissioned and replaced by either GSM or IS-95. IS-95 networks, also known as cdmaOne, are operational in many countries.
EDGE and GPRS technologies are relevant for GSM networks only. The IS-95 technology has its own variants for enabling mobile data, which you can learn about in our dedicated post on IS-95 and CDMA2000.
On the technology side, GSM and D-AMPS were based on a combination of FDMA and TDMA for the radio interface that is responsible for the wireless connectivity. FDMA stands for Frequency Division Multiple Access, and TDMA stands for Time Division Multiple Access.
By the mid-1990s, another technology standard, IS-95 (Interim Standard 1995), was launched, which was the first-ever mobile network based on the CDMA (Code Division Multiple Access) technology. GSM and IS-95 are the two key evolution tracks for mobile networks.
Mobile network evolution originally started in Europe, America, and Japan; however, the technologies developed in Europe and America were also used in other parts of the world. D-AMPS was mainly launched in America/Canada, and GSM was primarily a European technology that quickly reached the rest of the world.
Which cellular technologies are 3G?
The third generation of mobile networks, 3G, was enabled by two key technologies, UMTS (Universal Mobile Telecommunication System) and CDMA2000 (Code Division Multiple Access Year 2000). In addition, TD-SCDMA (Time Division Synchronous Code Division Multiple Access) is another 3G technology used in China.
UMTS was the 3G evolution track for 2G GSM networks. UMTS utilised the SGSN and GGSN network nodes that were originally introduced in GSM by GPRS and EDGE enhancements. UMTS could offer peak download data rates of up to 2 Mbps and average download speeds of around 384 kbps.
UMTS networks are CDMA-based, but they use wider bandwidths (generally 5 MHz or more). The radio access technology for UMTS is therefore referred to as Wideband CDMA (WCDMA).
CDMA2000 provided the 3G evolution path to IS-95 networks. IS-95 networks are commercially known as cdmaOne. CDMA2000, as the name suggests, is based on the CDMA technology but employs narrower bandwidths (1.25 MHz) compared to the WCDMA-based UMTS networks.
I have written a dedicated post that explains the differences between GSM and CDMA mobile network evolution tracks.
Here are some helpful downloads
Thank you for reading this post. I hope it helped you in developing a better understanding of cellular networks. Sometimes, we need extra support, especially when preparing for a new job, studying a new topic, or buying a new phone. Whatever you are trying to do, here are some downloads that can help you:
Students & fresh graduates: If you are just starting, the complexity of the cellular industry can be a bit overwhelming. But don’t worry, I have created this FREE ebook so you can familiarise yourself with the basics like 3G, 4G etc. As a next step, check out the latest edition of the same ebook with more details on 4G & 5G networks with diagrams. You can then read Mobile Networks Made Easy, which explains the network nodes, e.g., BTS, MSC, GGSN etc.
Professionals: If you are an experienced professional but new to mobile communications, it may seem hard to compete with someone who has a decade of experience in the cellular industry. But not everyone who works in this industry is always up to date on the bigger picture and the challenges considering how quickly the industry evolves. The bigger picture comes from experience, which is why I’ve carefully put together a few slides to get you started in no time. So if you work in sales, marketing, product, project or any other area of business where you need a high-level view, Introduction to Mobile Communications can give you a quick start. Also, here are some templates to help you prepare your own slides on the product overview and product roadmap.