Managing wireless data limits

With 3G wireless broadband subscriptions forecast to exceed global DSL connections by as early as 2010, mobile carriers are slowly coming round to the realisation that the finite resources of the wireless last mile could pose some serious problems going forward.

However Alcatel-Lucent is intent on bringing this problem to the fore, and not least because the careworn vendor is touting a Bell Labs developed platform, incubated by the Alcatel-Lucent Ventures unit, as the “first in a new product category”.

Telecoms.com recently met with Michael Schabel, general manager of Alcatel-Lucent Ventures, who said the wireless traffic management platform was designed to address the blind spot in mobile networks that occurred when transmitting data traffic. In the near future, Schabel said this blind spot, could lead to severe network degradation, including brownouts.

“Carriers still charge for calls by the minute but the industry is moving towards a data-oriented infrastructure and flat rate calling,” Schabel said. “Wireless network design is based on a model that counts on users and devices being mostly off the network because the resources are finite.” Schabel said that from a historical “data is data” perspective, all applications have the same impact on the network and cost per bit, but in wireless data networks, every IP application has a significantly different network impact and cost per bit.

Data traffic management, or traffic shaping as it’s known, has got a lot of bad press in the fixed line world, after it emerged that carriers were using the technology to throttle the bandwidth on certain packet types, such as VoIP or peer to peer. However, the technique, as applied by Alcatel-Lucent’s 9900 Wireless Network Guardian (WNG), promises to ensure smooth running of a wireless network.

In the wireless last mile however, all users share the link and there are limited signalling resources for channel allocation, finite channels at the base station, and finite bandwidth per channel. Schabel makes the point that the congestion is not in the data layer, but says that low data volume users can use a lot of airtime because of their chatty nature.

Email capable devices, like a BlackBerry, cause on average, ten times the signalling load as mobile phones or 3G datacards used for web browsing, because the device is constantly polling the network to check for email.

An email device consuming 1MB of data consumes 2 hours of airtime because it generates 1500 signalling events, while at the other end of the spectrum, a P2P application consuming 1MB of data would only hog 30 seconds of airtime as it creates just 0.3 signalling events by comparison.

Carriers also need to be aware of malware infected or malfunctioning devices consuming disproportionate amounts of signalling resources.

“In the fixed line world you can have the net neutrality argument because the network and the data are separate,” said Schabel, “But this problem exists in all wireless networks as a result of sharing spectrum.”

Alcatel-Lucent claims operators have a blind side and are in need of expertise from the IP world to help fix it, because existing radio management tools are blind to packet data and IP network management and packet inspection tools are blind to the cellular access network.

The vendor claims its WNG appliance, which is application agnostic and granular at a subscriber level, enables operators to determine which subscribers, servers, and applications are the most significant contributors of non-value-add traffic and load on the network, and can determine the network ‘cost’ to support any given application.

“It’s the ultimate state engine and anomaly behavioural engine,” said Schabel, “You’re building the network to cope with application growth.”

And other players have acknowledged the problem within the last few days. At the CeBIT trade show in Hannover, Germany, this month the Next Generation Mobile Networks Alliance (NGMN) said future technologies like LTE and WiMAX still had some way to go.

NGMN Alliance member and CTO of Vodafone Germany, Hartmut Kremling, said, “Increasing network traffic load beyond petabytes per month and the demand for high data rates indicate a clear need for a step-change in spectrum and network technology. Spectrum – the blood of our industry – is a scarce resource. Sufficient spectrum allocation and efficient use is therefore essential for NGMN. The performance of LTE / Mobile WiMAX is getting closer to the NGMN requirements; however, there is still a way to go.”

How advanced network technologies and architectures contribute to resolve the challenges of next generation mobile broadband, was the emphasis of the CeBit speech from Matthias Reiss, head of LTE radio at Nokia Siemens Networks. “Reduced network cost per Megabyte is a clear prerequisite for maintaining the profitability of mobile broadband networks,” Reiss said. “LTE/SAE offers an evolutionary network migration path enabling investment protection for operators and low network cost per Megabyte by flat architectures, optimized backhaul transmission, high spectral efficiency, and a scalable bandwidth. We are enthusiastic as “LTE live on Air” field trials carried out in Berlin have shown very encouraging performance results for LTE including the feasibility to deploy it on existing 3G sites.”

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