Operators Cast Doubts On GPRS

Early networks are performing poorly when handling standard Internet applications

February 20, 2002

5 Min Read
Operators Cast Doubts On GPRS

CANNES, France – 3GSM World Congress – Some thorny questions concerning General Packet Radio Service (GPRS) technology were raised by a couple of executives of major service providers in a technical session on Monday here at the 3GSM World Congress.

The service providers – the U.K.’s One2One and Australia’s Telstra Corp. – are rolling out GPRS in their networks. And they don’t appear to be happy bunnies. They say the technology makes it tough to handle Internet applications efficiently. They also say performance can be disappointing, making it unsuitable for handling higher-bandwidth applications.

To make matters worse, handsets capable of supporting those higher-bandwidth applications may be slow to arrive, judging from non-committal remarks made by developers of handset operating systems at the 3GSM show.

The most worrying issue is that GPRS doesn’t appear to work well with standard Internet connections. Simply put, “TCP does not like GPRS,” according to Matthew Stroud, senior engineer in the strategy group for switch network engineering at One2One.

GPRS networks do things like prioritizing voice calls ahead of data transfers, which results in variations in the available bandwidth. Meanwhile, the Internet transmission control prototype expects regular network acknowledgement, which it does not get from GPRS. This results in what those in the know call a “bursty flow” of packets, rather than the preferred smooth, continuous connection.

This is a waste of bandwidth, which, as Stroud points out, is particularly vexing for European carriers, which have laid out huge sums for third-generation network licenses. To them, every drop of bandwidth is sacred.

Stroud says One2One has been experimenting with various techniques, which he wouldn’t name, to solve these GPRS problems. “We haven’t found any solution that solves them all.”

Greg Drayton, general manager of mobile network engineering at Telstra, may be laughing up his sleeve at his European counterparts for paying so much for 3G licenses, since his government charges a pittance in comparison.

However, Drayton still questions the role of GPRS for multimedia applications. GPRS does not reach the data transfer speeds needed for many multimedia applications, he contends, and Telstra’s service has only been achieving an average speed of 20 kbit/s.

This could mean different types of services being offered in urban and rural areas when 3G systems are rolled out. A user will likely be able to access fancy, animated, interactive mapping applications in big cities but not when on the road, roaming on GPRS. “I think GPRS has progressed, but it’s not the answer,” Drayton says.

In spite of these reservations, the 3rd Generation Partnership Project (3GPP), an industry body that issues technical specifications for 3G networks, is using GPRS as the underlying transport for multimedia data in Release 5 of its UMTS (universal mobile telecommunications system) spec, which is due to be “frozen” next month.

Stephen Hayes, chairman of the core network working group at 3GPP, acknowledges that GPRS may have shortcomings. Speaking to Unstrung at the show, he said that GPRS tunneling would enable operators to set bandwidth requirements, though he concedes that the GPRS radio interface could still prove to be a bottleneck: “It may turn out that you will not be able to deploy some of the richer applications without W-CDMA” (wideband-CDMA, a faster 3G air interface).

In fact, the 3GPP Release 5 specification calls for a lot of additional features on the handset side, which might hold back the rollout of advanced applications. In particular, the specification requires support for Session Initiation Protocol (SIP) – an IP telephony signaling protocol developed by the Internet Engineering Task Force (IETF) – as well as IPv6.

One big player in the handset operating system market is being cagey as to when it will release software supporting IPv6. Symbian Ltd. announced on Tuesday that the latest version of its EPOC smartphone operating system will support IPv6. However, the company – which was founded by Ericsson AB (Nasdaq: ERICY), Motorola Inc. (NYSE: MOT), Nokia Corp. (NYSE: NOK), Psion PLC,and others – wouldn’t say when this operating system is likely to arrive on the market, merely that more information about version 7 will be available at the Symbian developers’ conference in London in April.

A looming presence in this market, Microsoft Corp. (Nasdaq: MSFT), has also said that it will work on a mobile client for IPv6, although it has not put a time frame to this effort yet. At Cannes, the company announced a partnership with Intel Corp. (Nasdaq: INTC). The “Wintel” alliance will work together to produce reference designs for mobile device makers, using Intel’s Xscale embedded processors and Microsoft’s Pocket PC and Smartphone operating systems.

Most vendors agree that it is crucial to have the handset and network capabilities in order to offer services that will appeal to enterprise customers and consumers.

“The carriers say, ’We’ve got GPRS now,’ and the public says, ‘so what?’ ” Stroud says. “Phones don’t offer any interesting experiences at the moment – it just looks like WAP that’s a bit faster.” Vendors should, according to Stroud, look to the success of the I-mode wireless data service offered by NTT DoCoMo in Japan, that has seen such fantastic growth because of its well thought-out applications.

Telstra’s Drayton believes the multimedia messaging service (MMS) – the extension of the SMS text messaging system that will allow mobile phone users to transmit color images – could prove an attractive application. “I think the introduction of MMS will make a big difference,” he says.

MMS is expected to be available this year. Ericsson, Nokia, Motorola, Siemens AG (NYSE: SI; Frankfurt: SIE), Logica, CMG, Comverse Ltd., and handset joint venture Sony Ericsson Mobile Communications said that they will work to develop systems that will allow interoperability between MMS-enabled handsets and servers from different vendors – clearly a key requirement if network operators are to offer nationwide MMS services.

— Dan Jones, Senior Editor, Unstrung

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