Nokia Siemens Networks is hoping more operators will start using QoS to offer differentiated mobile broadband services. But the technology will be a hard sell, because proving users are getting their money's worth will be difficult, Richard Webb, directing analyst at Infonetics, said.

Today, operators are looking for new ways to charge for mobile data, and using QoS is one alternative. Nokia Siemens sees the technology mainly being used when mobile networks are congested, it said in a blog post on Monday.

In Finland, telecom operator Elisa is already using QoS to give subscribers who are willing to pay for more bandwidth when the radio path is congested, it said on Nokia Siemens' website.

QoS can also be used to provide a more fine grained bandwidth throttling when a user has surpassed the monthly data quota. When that happens the user's priority is dropped to a lower class, resulting in a slower connection when the network is overloaded, rather than throttling the traffic all the time, Nokia Siemens wrote.

At the same time, Nokia Siemens underlines that QoS does not replace the need for having good capacity and coverage.

More operators are now looking at using QoS to differentiate their offerings. Egyptian operator Etisalat Misr has successfully tested products from Huawei and Ericsson over HSDPA (High-Speed Download Packet Access), industry organization GSA (Global mobile Suppliers Association) said on Sunday. During the test users were divided into three types: gold, silver and bronze.

But, in general, operators seem to be moving forward with caution when it comes to packaging these features as services.

"I would think its because so few have really figured what their long-term data strategy is. It doesn't seem so clear when you speak to [operators] about it," said Webb.

If the operators go down the QoS route, the challenge will be to justify and explain premium price plans, and then deliver on what they have promised, according to Webb. It is difficult for operators to benchmark the differences, because the speed in a mobile network depends on so many factors, he said.

"You also run the risk of losing the casual subscriber that doesn't want to understand all that stuff," said Webb.

Getting it right is important, because as operators gradually move to 4G they have to be able to position those networks as an improvement over their 3G counterparts, according to Webb.

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