LTE/EPC: Lack of service ownership poses challenges on road to LTE

Layer123’s recent LTE/EPC & Converged Mobile Backhaul conference highlighted some of the innovation going on to make fast and spectrally-efficient networks a reality. But the services that will run on the networks add extra challenges, writes Siân Harris

Mobile devices are becoming increasingly important in the day-to-day lives of their users. The provision of information and services on mobile devices are hot topics in many industries. All this sounds good news for mobile operators and the vendors who serve them but there are challenges, as discussions at Layer123’s recent LTE/EPC & Converged Mobile Backhaul conference in London revealed.

One of the biggest challenges is that mobile operators no longer own the services that mobile users access. Applications and services are provided by a wide range of developers and often designed without taking into account the capabilities of the networks they run on, as Phil Tilley, EMEA head of IP portfolio strategy for Alcatel-Lucent, observed in a lunchtime roundtable session at the event.

This can lead to the problem of signalling storms – bursts of signalling that can cripple networks. And this problem has increased as new smartphones have emerged. “New devices can impact the performance of a network. It is important to work with device manufacturers,” Tilley explained.

He noted that much of the signalling from new smartphones such as the iPhone4 happen automatically as a result of location-based services rather than because of any user interaction.

There has been a dramatic increase in signalling because applications are developed by people who don’t really care about the network,” agreed Frank Lupke, head of Packet Core sales, West Europe for Nokia Siemens Networks. “This affects the number of simultaneous users. Networks weren’t really designed with signal storms in mind but the 4G packet core will have to deal with huge increases in gateway signalling.”

He noted the importance of efficiency in this, and addressing issues like content optimization, especially as much of the content shared in the future is expected to be video.

“Signalling storms is not something that the industry saw coming. In the past it was all about data,” observed Dina Bartels, marketing manager – network security for Nokia Nokia Siemens Networks in a panel discussion. “It is very important to be prepared and flexible for the future.”

Fortunately, both operators and vendors are considering these issues carefully. “Signalling issues will not go away. Testing is important- starting in the labs of the vendors, observed Karl Grabner of JDSU in a panel discussion on the topic. 

Understanding the traffic

There was also general consensus about the importance of analytics to help with this. “Signalling can be detrimental even to the livelihood of a network. In essence, networks over the coming years will have to assume that signalling will be there and so need to cope with it,” argued Jan Vandenhoudt, senior product manager for Alcatel-Lucent in the panel discussion. “If a network provider wants to be on top of the problem there is a need for better understanding of the issue.”

Matz Hedman, director, mobile internet solutions, Tellabs, observed that today’s networks exist in silos: transport, radio and applications. “You need to know the network and synergies between the layers. Analytics on all layers is the only way to get an end-to-end view,” he said. “Operators have to understand who’s going on the network and what they are doing. I speculate that usage patterns with smartphones today will be similar to the 4G experience.”

However, Tilley of Alcatel-Lucent noted that there is a challenge about how much you can monitor what happens in a network without upsetting subscribers.

The problem of lack of ownership by the network operators goes beyond applications. Voice services are increasingly also becoming a commodity. As Matt Stagg, senior manager of network strategy at Everything Everywhere, noted, “We no longer run the services. If Apple launches a new device we all want it to work on our services, and that includes voice. And, with voice, our competitors aren’t actually O2, Vodafone and 3. They are the likes of Google Talk and Skype.”

Lupke of Nokia Siemens Networks echoed the concern about the risk from other providers of voice services: “Voice is still a service. If you enable Skype to have the same quality as you offer for voice then you could lose customers to Skype. Don’t give that area away to the Googles and Skypes,” he argued.

There are other challenges for voice too in the move to 4G. The specifications for LTE do not include a circuit-switched component. In the LTE networks that have already been rolled out, operators tend to fall back to the circuit-switched components of 2G and 3G for voice. But as more LTE networks are rolled out and uptake of them grows, there is a need for a more long-term solution.

“Circuit-switched fallback will impact the legacy networks as new interfaces will have to be developed,” noted Rémi Thomas, director of the LTE EPC program, France Telecom-Orange. “Voice-over-IP (VoIP) is the only solution to support voice over LTE/EPC.”

There are issues with this, however, with quality of service management and features. “For VoIP you need a guaranteed bit rate,” he explained.

Town and country

Rural broadband was another hot topic at the conference, with operators proposing ways to meet the UK government’s rural broadband targets as part of their LTE plans.

“The industry needs to work together to tackle the issue of rural broadband for the last 10% very hard-to-reach areas. Two or three thousand premises in the UK really don’t receive broadband at all, said Dave Axam, director of managed services business development for BT Wholesale.

At the conference, he and Simon Belmont, senior solutions architect of Everything Everywhere, described a trial that their two companies have being doing together using LTE at 800MHz to deliver broadband in a rural part of Cornwall. The trial demonstrates a sharing model to provide both pseudo fixed and wireless for rural broadband. The two operators shared their radio access and backhaul and routed the different traffic through two different EPCs to enable the operators to each control their own users’ experience.

“We believe that this is a very good model of how to do other rural areas. Even four miles away from the site users see speeds of five times that of 3G,” commented Belmont.

The challenge of delivering broadband to rural areas includes the issue of spectrum. “For rural, you need low frequency for penetration and distance,” he said. “This trial shows that 800MHz really does work for rural areas and we’re working with Ofcom because they are interested in this.”

One of the reasons that Cornwall was chosen for the Everything Everywhere LTE trial was that this area had already completed its migration to digital TV, which meant that the 800MHz band is now available. The same is not true for all regions of the UK.

Hanpal Mann, founder, chairman and CEO of Clear Mobitel, which intends to participate in upcoming spectrum auction in UK, said, “The 800MHz spectrum release in UK very important. We hope that 900MHz will also be refarmed for rural. There has to be a spectrum audit; organizations can’t be sitting on spectrum and not doing anything with it.”

At the other extreme – dense urban areas – spectrum availability is also an issue. “Smartphones drive the need for new spectrum and LTE,” said Paul Ceely, head of network strategy at Everything Everywhere. “We don’t want to be investing in 2G anymore; we want to be investing in new technology but we need the spectrum.”

The UK is expected to auction spectrum for LTE at the end of 2012 in the 800MHz and 2.6GHz. The clearance of other uses in these and other spectrum bands is eagerly awaited as LTE brings the demand for many bands on devices. According to Thomas of France Telecom-Orange, all LTE devices need at least four bands for GSM/EDGE and three bands for UMTS/HSDPA, in addition to at least four bands for LTE to cover the high-capacity needs of urban areas, longer-range spectrum for rural areas and roaming.

Once these issues are resolved, operators hope to be able to roll out faster, more spectrally-efficient networks – and to make money from them.

“We want to launch LTE first time right,” noted Thomas. “Once we no longer have a spectrum issue
we can choose when to launch and optimize the radio to ensure quality of service.”

And, as Alcatel-Lucent’s Phil Tilley pointed out, “I don’t think anyone in this conference room has any control on the apps and content. This is either an opportunity that we can reap rewards from or massive challenge. We need to control the controllables.”


Humberto J. La Roche, Director - Wireless Architecture, Juniper Networks, examines the practicalities of implementing VoLTE in a greenfield and an established network. Find out more about the influence of network architecture on QoS. First webcast live in December 2011

NOW available to view on-demand.


Mobile operators need to get their LTE networks up and running. However, the decisions that they make today on core network (EPC) and backhaul architecture, offload strategy and convergence - functional, architecture, services and boxes, will have a substantial impact on the scalability, performance, business success and cost of their networks now and in the future.


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