LTE World panel: Operators need to 'radically simplify' LTE network core

It's imperative that the telecom industry simplify the LTE network to accommodate future data growth and emerging services, according to speakers at the LTE World Summit 2015 going on this week in Amsterdam, reports.

"Complexity is your enemy," said Pieter Veenstra, lead solutions architect and product manager at NetNumber, who discussed the need to consolidate the control plane, according to the report. "We're looking at a paradigm shift towards a centralized signaling and routing model, where applications can be added on request. Operators need to radically simplify the network core, and that's what we're working on."

He also highlighted the importance of orchestration to future network services. "It's not just in the network itself, it's also in the OSS and BSS," he said. "When different functions are in different parts of the network and data centers; and when they're combined into one platform, the OSS and BSS needs to be simplified because of the orchestration process.

"We're looking at all of this, NFV included, to help manage VoLTE as well as the Internet of Things and M2M. Additional authentication elements are required to expand services to non-LTE accesses to support VoWi, M2M and IoT," Veenstra was quoted as saying.

Bill Welch, senior product manager at Sonus, noted how much pressure operators are under from the media to ensure constant connection, and that NFV will help. "There's ever increasing LTE growth, and driving diameter growth with policy and mobility," he said. "VoLTE and video broadcast are the big new use-cases, but we have to maintain legacy--we're still seeing growth in 2G and 3G in some markets."

"Let's not forget, it's real media-worthy when there's an outage or a signaling storm, so there are some significant operator challenges in this space right now," he said.

In another session, the incumbent Dutch operator KPN talked about the networking battles it has had in bringing VoLTE services and roaming to market.  

Wendy Ooms, a senior architect of voice and mobile signaling at KPN, said operators can expect a boom in signaling traffic when VoLTE comes into the picture. "On various interfaces you'll be seeing at least a two-fold growth in signaling traffic, because of VoLTE, and its need to have multiple bearers of voice and video per call," she said. "All of this traffic will be doubled again on the Diameter Routing Agent."

Ooms said the operator ran a pilot with 100 participants, both international and external customers, who received a VoLTE-ready phone to test VoLTE on its live network, which covers 98.2 percent of the population. "We mainly focused on the voice aspect of VoLTE, with limited use of ViLTE [Video over LTE]. Customers used a shared IMS mobile and fixed infrastructure, and we utilized DRA in all diameter interfaces."

Ooms warned the audience that even slightly altering IMS registration times could cause an SIP storm, and identified Wi-Fi as a potential solution, according to the report. "SIP signaling can have a massive effect of the load on the mobile network if you're not doing it right," she said. "During our trial, someone changed the IMS registration time from 50 minutes to 5 minutes, and the load generated absolutely exploded. SIP registration storms can occur on mobile when users lose their connection, and multiple users come flooding back when the service becomes available again. Wi-Fi could be a solution to integrate with VoLTE if one user is somewhere 4G doesn't reach."

In the U.S., a recent benchmarking test by network testing firm P3 communications showed that operators' VoLTE implementations were leading to significant improvements in voice quality over legacy circuit-switched voice.

Verizon (NYSE: VZ) and T-Mobile US (NYSE:TMUS) offer VoLTE nationwide, while AT&T (NYSE: T) is still rolling it out market by market and offers VoLTE in all or part of 23 states. U.S. Cellular (NYSE:USM) is planning three VoLTE trial markets for launch later this year, though customers will not be able to sign up for the service. Sprint (NYSE: S) has said it will eventually launch VoLTE but has not given a timeframe for it.

The P3 test showed that Verizon led the way in terms of call quality. The testing also showed that while VoLTE is delivering on its promise of faster call set-up times and improved HD voice quality, carriers still have plenty of work ahead to optimize their LTE networks and provide the VoLTE-to-VoLTE calling between carriers and deliver on international VoLTE roaming.

For more:
- see these two separate articles

Related articles:
Report: Verizon, AT&T and T-Mobile show significant voice quality improvements in test of VoLTE networks
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AT&T: 2015 will be the year of mass market VoLTE
Verizon exec: VoLTE on track for 2014 rollout