Q&A: GPRS

What is GPRS?

How fast is GPRS?

Which companies offer GPRS products?

For users, what are the main benefits of GPRS?

How does a GSM operator deploy GPRS?

How does an analog or TDMA operator deploy GPRS?

What factors determine the cost of deploying GPRS in an existing network?

How does GPRS compare to other 2.5G technologies?

Where is GPRS available?

What is GPRS?

General Packet Radio Service (GPRS) is a packet-data technology that allows GSM operators to launch advanced data services, such as Multimedia Messaging Service (MMS) and fast Internet access. As a result, GPRS provides operators with the ability to use data to drive additional revenue and compete on services rather than price alone. GPRS is often called a "2.5G" technology because it is a GSM operator's first step toward third generation (3G).

GPRS builds on two of the world’s most widely used platforms: GSM and Internet Protocol (IP), the universal standard that is the foundation of the Internet. By using IP, GPRS avoids the problems that come with using a wireless-only networking standard that requires proprietary equipment. By using an open, fully standardized technology, GPRS is ideal for providing wireless access to other IP-based networks, such as corporate LANs and ISPs. Another advantage of the GPRS IP foundation is that operators and their partners can develop and launch advanced data services much more quickly and less expensively by leveraging the wide availability of IP expertise and off-the-shelf IP equipment.

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How fast is GPRS?

GPRS supports download data rates of up to 115 kbps, with average speeds of 40-50 kbps, which is comparable to other 2.5G technologies, such as CDMA2000 1X. GPRS’ speeds are fast enough for applications such as Multimedia Messaging Service (MMS) and a Web browsing experience comparable to a wired dial-up modem.

GPRS also allows customers to maintain a data session while answering a phone call, which is a unique and exclusive feature to GSM. GPRS provides an "always-on" data connection, so users do not have to log on each time they want data access. The packet architecture also means that users only pay for the data itself rather than for the airtime used to establish a connection and download data.

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For users, what are the main benefits of GPRS?

GPRS is a packet-based technology, which means that data is divided into packets and transmitted in short bursts over an IP network. This design is much more efficient than circuit-switched networks, resulting in reduced network operating costs. The packet design benefits users in three primary ways:

• The reduced network operating costs can be passed on to users in the form of lower data charges.

• GPRS provides an "always-on" connection, so users do not have to log on each time they want data access.

• Users pay only for the data itself rather than for the airtime used to establish a connection and airtime downloading data.

As the most widely supported packet-data wireless technology in the world, GPRS supports seamless roaming in more than 180 countries, providing users with access to their data services when traveling. When users travel to areas that have not yet been upgraded to GPRS, they still can access many data services via circuit-switched GSM.

With peak data rates of up to 115 kbps, and average speeds of 40-50 kbps, GPRS is faster than circuit-switched data (CSD) and Cellular Digital Packet Data (CDPD). GPRS carries a far larger data payload than Short Message Service (SMS), where each message is limited to about 160 characters, depending on language. This combination of speed and capacity makes GPRS an ideal medium or "bearer" for services such as Wireless Application Protocol (WAP) and Multimedia Messaging Service (MMS).

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Which companies offer GPRS products?

The large, global operator and user adoption of GPRS has created a customer base that has attracted dozens of device manufacturers. As a result, hundreds of models of GPRS phones and PC card modems are currently available from dozens of manufacturers. GPRS phones are available at a wide variety of price points and feature sets, including smartphones for business users and sub-$30 models for developing markets.

GPRS network infrastructure is available from leading vendors such as Alcatel-Lucent, Motorola, Nokia Siemens, and Nortel.

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How does a GSM operator deploy GPRS?

All next-generation wireless networks, regardless of technology, 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 also will be packetized and travel over the packet core, and the circuit-switched infrastructure will be phased out.

If a GSM radio infrastructure is less than seven years old, it usually can be upgraded to GPRS with software and additional channel cards. Many GSM networks in the Americas are less than seven years old, which means that the time and cost to add GPRS is much lower than if the radio infrastructure had to be replaced.

The biggest part of deploying GPRS is adding a packet core, which is the infrastructure that handles data traffic and enables services such as Virtual Private Networks (VPNs). It includes equipment such as Gateway GPRS Support Nodes (GGSNs) and Serving GPRS Support Nodes (SGSNs). However, the GPRS packet core is re-used when an operator deploys EDGE and/or UMTS/HSDPA; thus the equipment becomes a cost-effective, long-term investment.

The circuit-switched infrastructure continues to handle only voice calls, so no changes are necessary when upgrading to GPRS.

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How does an analog or TDMA operator deploy GPRS?

Analog and TDMA operators have a couple of options for deploying GPRS. The most common and practical approach is to deploy a GSM/GPRS network in parallel with their existing network. This approach allows the operator to continue generating revenue from its existing AMPS/TDMA customers while signing up new GPRS customers.

In each cell site, GSM/GPRS radios can be deployed alongside the existing analog or TDMA radios. In some cases, the old and new radios can share the same antennas, further reducing the cost of deployment. As in a GSM network that's being upgraded to GPRS, a packet core also is added.

One frequent operator concern, particularly for those in Latin America, is whether they have enough spectrum to operate a second network, especially when additional spectrum is expensive or unavailable. A common solution is to first switch the existing network to a more efficient frequency re-use pattern, which frees up 50-90% of spectrum capacity. This additional capacity then can be used for the GSM/GPRS network. Depending upon how much capacity is freed up and how much the GSM/GPRS network needs, some capacity also could be used to improve the quality of service (QoS) on the existing network by reducing blocked and dropped calls.

Another attraction is that GSM/GPRS is much more spectrally efficient, reducing the long-term need for additional spectrum. For example, within the same amount of spectrum, GSM can support at least seven times more voice calls than analog, and nearly twice as many voice calls as TDMA. When an operator does not have to buy additional spectrum, its overhead costs are reduced, improving its competitive position.

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What is the average cost of deploying GPRS in an existing GSM network?

The cost varies significantly by the size, age and design of the existing network. For example, if the operator's existing radio infrastructure can be upgraded to GPRS, as is the case with most networks in the Americas, the cost is relatively minimal. In networks that are older than seven years, the radio infrastructure may not be upgradeable, which increases the cost of deploying GPRS.

The biggest cost is for the packet core infrastructure, which becomes an important long-term investment because it’s re-used when the operator deploys EDGE and/or UMTS/HSPA.

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How does GPRS compare to other 2.5G technologies?

There are three key areas to consider when comparing one 2.5G technology to another: data rates, effect on voice capacity and cost structure.

• Data rates: GPRS has peak data rates of up to 115 kbps, and average speeds of 40-50 kbps, which provides an experience similar to a dial-up modem. These speeds and experiences are comparable to what users typically encounter with CDMA2000 1X.

• Voice capacity: Adding high-speed data shouldn't come at the expense of voice capacity. Fortunately, GPRS deployment is also an opportunity to deploy a new type of voice coder or "vocoder," which turns voice into digital signals before they pass across the wireless network. A GSM network using this vocoder, called Adaptive Multi-rate (AMR), can handle twice as many simultaneous voice calls as a network that uses the old vocoder. A CDMA2000 1X network has only slightly more voice capacity than a GSM/GPRS network with AMR.

• Cost structure: As of September 2007, 452 operators in 182 countries have launched GPRS, making it the most widely supported packet-data wireless technology in the world. That translates into large volumes of network infrastructure and user devices, which drive down costs. For operators, those savings mean that with GSM, they can price their devices and services more competitively than with any other wireless technology. GSM's market share also attracts vendors and application developers, whose innovative content, services and devices help operators attract and retain customers.

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Where is GPRS available?

As September 2007, 452 operators in 182 countries have launched GPRS according to Informa’s World Cellular Data Metrics.

Like GSM, GPRS supports seamless roaming, allowing users access to their home data services when traveling. No other 2G or 2.5G wireless technology offers roaming as extensive and seamless as GSM/GPRS.

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