Q&A: EDGE

What is EDGE?

What is EDGE Evolution?

What are the advantages of EDGE?

How is EDGE deployed?

How does a GSM operator deploy EDGE?

How does an analog or TDMA operator deploy EDGE?

How much do operators spend to deploy EDGE?

Is EDGE a 3G technology?

Is EDGE a global technology?

Does EDGE affect voice capacity?

Which companies offer EDGE products?

Is EDGE compatible with UMTS?

Why deploy EDGE when UMTS is already available?

What is EDGE?

Enhanced Data rates for GSM Evolution (EDGE) is a third-generation (3G), high-speed data technology, with theoretical network peak rates of 473 kbps and average throughput of 100-130 kbps. The average rates are fast enough to support a wide range of advanced data services, including fast Internet access and large file downloads. EDGE also supports push-to-talk (PTT) services.

EDGE is occasionally referred to as Enhanced GPRS (EGPRS) because it increases the capacity and data throughput of GPRS by three to four times. Like GPRS, EDGE is a packet-based service, which provides customers with a constant data connection. The ITU, which sets telecom standards for worldwide use, approved EDGE as a 3G standard in July 2000. In July 2003, the world’s first commercial EDGE network launched. As of December 2007, EDGE services were available from more than 263 networks in 131 countries with another 79 networks in planned, trialing or in construction stages.

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What is EDGE Evolution?

As its name implies, EDGE Evolution is an upgraded version of EDGE that completed standardization work in 2007 within Release 7 at 3GPP, an international standards body. EDGE Evolution is also referred to as EDGE II or Evolved EDGE by some industry sources. EDGE Evolution will boost data speeds by up to 300 percent and will significantly improve latency, coverage, and spectrum efficiency of existing GSM/EDGE equipment. This improved data performance in GSM will be as important as high-speed HSPA is today and LTE will be in tomorrow’s networks.

Compared to existing versions of EDGE, EDGE Evolution is expected to provide:

• A dramatic increase in data rates. In total, the peak rate per user will be as high as 1 Mbps for the downlink and 500 kbps for the uplink. The actual amount depends on the version used, but EDGE Evolution is expected to quadruple the throughput rates for EDGE with peak theoretical network speeds of 1184 kbps to 1894 kbps in type 1 or type 2 respectively for the downlink and and 473 to 947 kbps for the uplink.

• A 50% increase in spectral efficiency and capacity.
• Reduced latency for initial access and round-trip time, enabling better quality of service (QoS) for PTT and voice over IP (VoIP).
• Compatibility with existing frequency plans, thus facilitating rapid deployment in existing networks.
• A simple upgrade to existing GSM equipment allowing a more efficient use of scarce existing spectrum.
• A better seamless experience for subscribers as they roam from HSPA networks to EDGE networks.
• Compatibility with existing frequency plans, thus facilitating rapid deployment in existing networks.

For more information, see page 20 of the white paper Mobile Broadband: EDGE, HSPA and LTE.

Press Release: Ericsson EDGE to triple data speeds by 2009 (March 14, 2007)

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What are the advantages of EDGE?

EDGE’s advantages can be divided into two categories: user benefits and operator benefits. The key user benefits include:

• Speed: EDGE supports theoretical network peak data rates of 473 kbps and average rates of 100-130 kbps. The average rates are fast enough to support a wide range of advanced data services, including fast Internet access and large file downloads. For example, a 100-KB Multimedia Messaging Service (MMS) video clip takes 26.7 seconds to download on GPRS but only 10 seconds on EDGE, according to Nokia. EDGE Evolution will further improve performance and user experiences.

• An "always-on" connection: Like cable broadband and DSL, EDGE provides a constant Internet connection, eliminating the need to log on each time to access the Internet. The always-on connection also means that users can receive "pushed" services, such as stock alerts. EDGE lets customers maintain a data session while answering a phone call, a feature that’s unique to GSM-based technologies.

• Low latency: A version of EDGE called Release 4 (R4) has latency of about 300 milliseconds, which helps improve the performance of delay-sensitive applications and services such as Virtual Private Networks (VPNs) and multiplayer games. EDGE R4 networks and user devices have been widely available since 2004.

• Value: EDGE is packet-based, which is a more efficient way for operators to provide services. Those savings can be passed on to customers in the form of lower rates. The packet architecture also means that customers pay only for the data that they send and receive instead of also paying for the airtime to set up a connection and then waiting for a server to respond.

• Coverage: EDGE is a relatively inexpensive, simple upgrade for operators. That’s one of the main reasons why EDGE coverage quickly expanded beyond cities to suburbs and rural areas. EDGE also is compatible with GPRS, so when customers move out of an area with EDGE coverage, they're automatically switched to a GPRS network, which is available in more than 100 countries. As a result, EDGE customers are assured of having some level of packet-data service at home and when traveling. EDGE signals also are more robust, so they cover a significantly larger geographic area than GPRS. As a result, EDGE customers encounter fewer coverage holes.

• Device selection: Users have a variety of choices for EDGE handsets, modems and other devices, with more than 500 models currently available from leading manufacturers such as including RIM (Blackbery), HTC, LG, Motorola, Nokia, Samsung, Sierra Wireless and Sony Ericsson. The devices support GSM/GPRS, work on multiple spectrum bands and are available in a wide variety of price points and feature sets.

For operators, the key benefits of EDGE include:

• Spectral efficiency and flexibility: EDGE lets operators quickly launch 3G services within their existing spectrum. As a narrowband technology that uses 200 kHz channels, EDGE doesn’t require a large block of spectrum, so it’s easily deployed in today's most widely used bands, including 850, 900, 1800 and 1900 MHz. The ability to deploy EDGE within existing spectrum without a new 3G license means that an operator can launch 3G services faster in more markets and at a lower cost than if it were necessary to buy additional spectrum.

• Ease of upgrade: EDGE uses the same TDMA frame structure, logic channel and 200 kHz carrier bandwidth as today's GSM networks. As a result, deploying EDGE doesn't require a major re-engineering of cell plans. If an operator's radio infrastructure is less than seven years old – as is the case for most GSM operators in the Americas – then upgrading to EDGE usually requires only new software and channel cards for cell sites. As a result, upgrading all of the cell sites in a major city takes only a few weeks, allowing operators to launch EDGE services quickly. The relatively low cost of the EDGE upgrade also means that operators can price their advanced services much more competitively than if the upgrade required replacing major elements of the radio or packet core infrastructure.

• Voice capacity: Although EDGE is a data technology, it also helps boost the number of voice calls that a network can handle simultaneously by sending data up to 150% more efficiently than GPRS. With EDGE transmitting more data into the same amount of bandwidth, the voice-coding or “vocoder” technology in the GSM voice network can be upgraded to a version that increases voice capacity 15-20%.

• Compatibility: EDGE is compatible with other technologies in the GSM migration path to 3G, so when customers with multi-mode phones and PC card modems move out of EDGE coverage, they're automatically switched to GPRS networks, depending the data services they use. EDGE also re-uses the packet core network infrastructure deployed for GPRS, making upgrade costs incremental rather than monumental.

• Coverage: EDGE signals also are more robust than GPRS signals, so they cover a significantly larger geographic area. As a result, EDGE customers encounter fewer coverage holes, so they’re less likely to churn. Robust signals also mean that when upgrading their radio infrastructure to EDGE, operators don’t necessarily have to add more cell sites just to ensure good coverage and a good user experience. Those savings can be passed on to customers, or they can be used to help fund upgrades to UMTS/HSDPA/HSUPA.

• Cost-efficiency: Based on more than four years of commercial deployments, the cost to upgrade to EDGE from GSM/GPRS is about $1-$2 per POP. This low figure is due to the fact that the upgrade only requires relatively simple software and hardware modifications.

• Global cost structure: EDGE services are available from more than 263 networks in 131 countries, as of December 2007. This market size translates into high volumes of EDGE infrastructure and user devices, and one rule of business is that higher volumes drive down the cost of network infrastructure and user devices. As a result, EDGE is ideal for operators in price-sensitive markets such as Latin America.

• Service quality: EDGE includes sophisticated quality-of-service (QoS) mechanisms that give operators more control, ensuring that each application or customer gets the right amount of bandwidth. (In fact, EDGE uses the same QoS mechanisms as UMTS.) QoS is key for a service that targets enterprise customers, and it helps retain customers while reducing the need for cut-rate pricing to attract customers to replace those who have churned.

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How is EDGE deployed?

All next-generation wireless networks have three main components:

• The radio infrastructure, which includes the cell sites.

• The packet core infrastructure, which handles only the packet-data traffic.

• The circuit-switched infrastructure, which includes the mobile switching centers (MSCs) and handles circuit-switched voice traffic. Eventually, as wireless networks evolve to an all-IP architecture, voice will also be packetized and travel over the packet core, and the circuit-switched infrastructure will be phased out.

All current-generation wireless networks, regardless of technology, have circuit-switched infrastructure. The packet core is deployed when an operator migrates to GPRS, which is the first step toward 3G. Because EDGE is an upgrade to GPRS, it leverages the investments in the packet core and circuit-switched infrastructure by re-using them. The majority of the changes to deploy EDGE are in the radio infrastructure, where software and hardware are added at each cell site.

This approach to migration benefits customers because their EDGE devices will work on GPRS networks, and vice versa, because of the forward and backward compatibility between the two technologies.

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How does a GSM operator deploy EDGE?

Most GSM operators deploy GPRS before upgrading to EDGE. The GPRS upgrade lays the foundation for EDGE by adding the packet core infrastructure, which EDGE re-uses.

If a GSM radio infrastructure is less than seven years old – as is the case for most GSM networks in the Americas are – it usually can be upgraded from GPRS to EDGE with software and channel cards. If the operator has older GSM radio infrastructure and chooses to replace it during the GPRS upgrade, the EDGE upgrade is still simple and cost effective because most GSM/GPRS radio equipment sold this decade is already designed to support EDGE.

With EDGE, the circuit-switched infrastructure continues to handle only voice calls. No changes are necessary.

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How does an analog or TDMA operator deploy EDGE?

Analog and TDMA operators that have chosen the GSM-based migration path to 3G begin by deploying a GSM/GPRS network in parallel with their existing network. Doing so allows them to continue generating revenue from their existing customers while signing up new customers for GSM/GPRS. Depending on their business plan, they could choose to deploy EDGE at the same time as their GSM/GPRS deployment. Or they could deploy GSM/GPRS/EDGE in only some places, such as major cities, and then add EDGE software to the rest of their GSM/GPRS footprint as market conditions and business plans dictate.

TDMA operators have the option of deploying a GSM/GPRS/EDGE overlay alongside their TDMA networks at 850 MHz and/or 1900 MHz. Analog operators have the option of deploying a GSM/GPRS/EDGE overlay alongside their 850 MHz networks. Signals travel farther at lower frequencies, so an 850 MHz EDGE deployment is particularly attractive because of the excellent propagation characteristics: fewer cell sites covering large areas, thus reducing the number of sites necessary to cover a market with 3G. This makes EDGE particularly favorable for rural areas.

One frequent concern, particularly for operator with networks already at capacity, is whether there is enough spectrum to deploy a second network, especially when additional spectrum is expensive or unavailable. The solution is first to switch the existing network to a more efficient frequency re-use pattern, which frees up between 50-90% spectrum capacity. This additional capacity can then be used for the GSM/GPRS/EDGE network. GSM/GPRS also is much more spectrally efficient, so it can support at least seven times more voice calls than analog and nearly twice as many as TDMA in the same amount of spectrum.

Although EDGE is a data technology, it also helps boost the number of voice calls that a network can handle simultaneously by sending data more efficiently than GPRS. With EDGE transmitting more data into the same amount of bandwidth, the voice-coding or “vocoder” technology in the GSM voice network can be upgraded to a version that’s increases voice capacity 15-20%.

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How much do operators spend to deploy EDGE?

The answer depends on factors such as the age and manufacturer of the operator’s infrastructure. Based on more than three years of commercial deployments, the cost to upgrade to EDGE from GSM/GPRS is about $1-$2 per POP. This low figure is due to the fact that the upgrade only requires relatively simple software and hardware modifications.

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Is EDGE a 3G technology?

Yes. The International Telecommunication Union (ITU), which sets telecom standards for worldwide use, approved EDGE as a 3G standard in July 2000. However, many people consider EDGE to be a 2.5G technology similar to CDMA20001x, and the later evolution to UMTS as the third generation (3G) of GSM technology.

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Is EDGE a global technology?

Yes. EDGE services are available in more than 131 countries as of December 2007.

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Does EDGE affect voice capacity?

Yes. Although EDGE is a data technology, it also helps boost the number of voice calls that a network can handle simultaneously by sending data up to 150% more efficiently than GPRS. With EDGE transmitting more data into the same amount of bandwidth, the voice-coding or “vocoder” technology in the GSM voice network can be upgraded to a version that’s increases voice capacity 15-20%.

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Which companies offer EDGE products?

More than 500 models of EDGE handsets, modems and other devices are currently available from all leading manufacturers such as including HTC, LG, Motorola, Nokia, Samsung, Sierra Wireless and Sony Ericsson. EDGE network equipment is available from most GSM infrastructure vendors.

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Is EDGE compatible with UMTS?

Yes. In fact, there are 159 operators with commercial EDGE-UMTS networks as of December 2007 because this enables a very good business strategy. The benefits of an operator utilizing this dual-technology strategy include:

• An operator initially deploys UMTS only in major cities. When its UMTS customers travel outside of UMTS coverage, their devices are automatically switched to an EDGE network.

• An operator deploys UMTS only in cities and suburbs, while deploying EDGE in rural areas. When UMTS customers travel to rural areas, their devices automatically switch to EDGE. When EDGE customers travel to cities, their devices will work on the UMTS networks, so they can continue to use their EDGE-based 3G services.

Most UMTS devices today also support EDGE technology which enables international roaming with a fall back from UMTS to EDGE in those areas which do not yet offer UMTS or HSPA service.

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Why deploy EDGE when UMTS is already available?

There are at least four reasons:

• Greater 3G coverage: EDGE complements UMTS just as GPRS complements EDGE. One major advantage of the GSM-based evolutionary path to 3G is that customers are automatically switched between networks, depending on factors such as coverage. Most device vendors include EDGE in their UMTS handsets and modems, so customers who move out of UMTS coverage are automatically switched to an EDGE network, ensuring continuous 3G service.

• Flexibility: EDGE gives operators the flexibility to launch 3G in stages. For example, operators such as PEOPLES (Hong Kong) and Rogers Wireless (Canada) launched EDGE in heavily traveled intercity corridors and densely populated areas before expanding EDGE coverage into other areas. Other operators launched EDGE in cities and then added UMTS in major urban areas while expanding EDGE into rural areas. This approach to 3G is cost-effective because deployment costs for UMTS are higher, so it makes sense to keep the initial UMTS launch in areas with the largest pool of potential customers, while EDGE provides 3G in smaller cities and rural areas.

• Cost: Operators can make a business case for deploying EDGE because with upgrades as low as $1-$2 per customer, they can begin offering 3G service quickly. EDGE isn't a wasteful interim step: EDGE and UMTS both re-use the packet core infrastructure deployed for GPRS.

• Performance: Not all wireless data applications require the speeds delivered by UMTS, so routing each application over the appropriate network makes the best possible use of spectrum. Studies by 3G Americas have indicated that spectral efficiency for EDGE is ideal for data rates below 100 Kbps, while a UMTS network is preferred for spectral efficiency for data rates above 100 Kbps.

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