VoLTE and RCS: Getting it Right

P A R T

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ContentsVoLTE and RCS Ramp Up 3

Down to the Device 4Working with Chipsets 5

Working with RCS 5

Validating VoLTE and RCS Applications 5

VoLTE and VoWi-Fi 6 7

Hiding the Seams 8

Interoperability 9Fragmentation Issues Challenge VoLTE Interoperability 10

Test Plans will Help 11

More Essentials: Interconnections and Roaming 12

What Makes or Breaks the VoLTE User Experience 13 14

Paradigm Shift 15

Handoffs and Handsets 16

Create More Variables 16

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VoLTE and RCS Ramp Up

The global mobile industry has committed to VoLTE as the technology of choice to provide voice and RCS to deliver multimedia services on LTE. VoLTE and RCS deployments are gaining momentum and dozens of operators are launching commercial services in 2015. Dozens more will help accelerate the rollout into 2016 and beyond.

VoLTE has significant implications for the mobile ecosystem because it will introduce fundamental changes in the mobile service environment and the user experience. With VoLTE, operators will finally have the capability to shed their legacy circuit-switched networks and consolidate all of their voice, video and messaging services on IP. They’ll be able to offer high-definition voice, conversational video and other features to better compete with over-the-top providers. They’ll also gain significant cost efficiencies and a welcome opportunity to free up 2G and 3G spectrum for their LTE networks. The industry must succeed with VoLTE and RCS because it will enable the most essential services delivered on

LTE beyond high-speed mobile data. But there’s much more to a successful launch than the initial rollout and as services are established, companies must focus making sure it delivers what it promises.

To get it right, operators must meet several challenges. Above all, they must ensure their VoLTE services are well-received by customers. They need to maintain customer loyalty and attract new customers who use the services if they want to gain full benefit of VoLTE’s operational and spectral benefits. Many factors can influence the market’s acceptance. Devices must interoperate and calls must work across networks. Customers must be able to roam with consistent services and they need the capability to have seamless handoffs between VoLTE and Voice-over-Wi-Fi services.

This e-book discusses all of these challenges, and more. It also explains how developers can create compelling RCS and VoLTE applications, native to the device, to intrigue and engage the customer base.

VoLTE and RCS Ramp Up

Down to the Device

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“VoLTE has huge implications. Once you’re doing voice, video and SMS in the IP domain, those data flows are more like data applica-tions than they ever were before,” said Peter Rysavy, president of Rysavy Research. “The ability to integrate voice and video messag-ing into other apps opens the door for mas-sive innovation that can occur.”

VoLTE, when offered with conversational vid-eo, gives mobile operators an essential tool to offer applications that rival—and poten-tially outperform—over-the-top (OTT) options such as Apple’s FaceTime and Microsoft’s Skype. The creation of these new services requires extensive software development at the chipset, device and infrastructure levels.

This article focuses on software that is em-bedded as native solutions and integrated with vital device functions to create these new capabilities. If done well, the embedded software plays a tangible role in this new competitive environment.

Ian Maclean Vice President of Strategy at Mavenir Systems

“ If you make these things native and easy to use and reduce the number of clicks to get to an app, people are going to use the services.”

Embedding VoLTE software does require a learning curve. Device developers must have expertise not only in phone manufac-turing and design, they must now learn how to add these new software capabilities with standards they haven’t used before. They need to implement new software stacks and media engines and provide security, quality of service (QoS) assurance and support. The features must interoperate, pass conform-ance and operator certification tests.

“It requires a lot of development and a lot of expertise and knowledge in IMS and VoLTE to implement it correctly,” said Sagi Subocki, head of products for the developer tools business unit at Spirent Communications.

As the mobile industry brings voice over LTE (VoLTE) to market, service providers have an opportunity to build customer services that were simply not possible in the circuit switched environment. Companies will be able to take mobile services beyond the traditional restrictions of voice and text. They’ll have a chance to create innovative features that can better engage customers and, they hope, attract new users to their networks.

Down to the Device

CHAPTER 1

Developing embedded devices with VoLTE and RCS

By Peggy Albright

Down to the Device

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Working with Chipsets

Because VoLTE is based on IMS, it must have appropriate client functionality installed on customer devices. Ambitious device manufacturers that have significant R&D resources, silicon processing as well as device production capabilities might develop their VoLTE expertise and capabilities in house so they can apply differentiating, advanced services to their own product lines.

Some device manufacturers, however, build their VoLTE capabilities by using chipsets, provided by their silicon vendors, which already include the IMS client stack. This is also convenient for manufacturers because many chipset companies are offering toolkits and terminal APIs with their chips to facilitate VoLTE application development by their customers and partners.

There are variations in chipsets from vendor to vendor. Not all chipsets offer all VoLTE capabilities. Some offer voice and messaging, while others offer voice, messaging as well as video. Some chipsets provide more flexibility for customization than others.

Manufacturers also use software development kits (SDKs) from the vendor community to facilitate IMS, VoLTE or RCS development for chipsets and devices. Depending on the solution used, SDKs can be used to launch customizable voice, video and messaging features that are carrier grade and standards compliant and configured to interoperate with other similar services. The conveniences mean that the manufacturer doesn’t need to develop in-house expertise or perform complex integrations, which can help shorten time to market.

Working with RCS

Validating VoLTE and RCS Applications

Rich Communications Services (RCS) uses VoLTE as a foundation and adds conversational video, video sharing, presence, buddy lists, messaging, geolocation and other capabilities on top of the VoLTE foundation to create advanced multimedia features in a device.

Maclean envisions that these types of features could be used, for example, to evolve the dialer function on a device so that it provides a new user experience based on presence and that works across devices, operating systems and networks. For this application, an embedded client could work with an intelligent server to support conversational messaging features and messaging delivery verification.

RCS is typically not embedded in chipsets. Developers will need to perform the integration work to add the capabilities into chips and devices or adopt a commercial SDK to use when performing this work. As with VoLTE, these services, when properly implemented, will add interoperable, carrier-grade features.

Testing is often one of the most time-consuming phases of the software development life cycle. For VoLTE and RCS, developers need to perform tests to make sure their services and applications will work on carrier networks according to the standards specifications, pass standards conformance tests and operator-specific certification processes. Specialized testing tools that can emulate carrier-realistic end-to-end environments in the lab help developers iron out any issues during product development.

Sagi Subocki Head of Products for the Developer Tools Business UnitSpirent Communications

“ You hope to get to the operator’s testing phase with a product that is as mature as possible.”

VoLTE and VoWi-Fi

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So said FCC Chairman Tom Wheeler last year as he explained the commission’s decision to free up another 100 MHz of spectrum for Wi-Fi. The extra spectrum is good news for mobile operators that use Wi-Fi to offload data traffic and, increasingly, voice too.

“There’s definitely a lot of interest in VoWi-Fi,” said Michael Thelander, CEO and founder of Signals Research Group. “A lot of that was driven by the iPhone and Apple. When they announced support for IMS-based VoWi-Fi, operators started embracing that as a service they wanted to support.”

Some operators like VoWi-Fi as a relatively low-cost opportunity to try their hand at IP calling.

“That’s another reason why so many smaller operators are looking at VoWi-Fi: It’s a chance to have a commercial offering that’s VoIP based,” said Ray Vinson, product manager at Interop Technologies. “It kind of sticks their toes in the water before they go to a full VoLTE solution.”

VoLTE and VoWi-FiCHAPTER 2

Licensed and unlicensed spectrum are more complementary than competitive. They’re less oil and vinegar and more peanut butter and jelly.

Bridging the GapBy Tim Kridel

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VoLTE and VoWi-Fi

VoWi-Fi can also be another tool for targeting the enterprise market. One example is businesses where employees use their mobile as their primary phone, sometimes to the point that their employers question the capex and opex of providing them with deskphones. VoWi-Fi provides operators with a way to serve that market segment without the expense of adding capacity at nearby cell sites or deploying in-building solutions such as distributed antenna system (DAS) technologies.

But for VoWi-Fi to be a viable alternative for those customers, they need the ability to start a call in the office on Wi-Fi and then seamlessly switch to LTE as they walk out the door. Ditto for consumers who want to use VoWi-Fi at home or as a way to minimize roaming charges when they’re traveling abroad.

Some operators, such as Swisscom, offer seamless data handoffs between cellular and Wi-Fi. But so far, no commercial services do the same with VoLTE and VoWi-Fi. That should change over the next year or so.

“I think you’re going to see a lot of VoWi-Fi launches, especially in the next couple of quarters. Then you’ll see the VoLTE launches later.”

Ray Vinson Product ManagerInterop Technologies

“ There are some Tier 1s planning on launching both VoWi-Fi and VoLTE this year, so there’s a lot of testing going on.”

VoLTE and VoWi-Fi

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Hiding the Seams

Seamlessness is influenced by the owner of the Wi-Fi network. For example, some mobile operators own public Wi-Fi networks, so they have control over those hotspots’ abilities to provide seamless handoffs and good Wi-Fi calling experience.

They need to use Wi-Fi “as one more RAN that they consider trusted and can be managed by the network elements,” he said.

Mobile operators have little or no control over hotspots owned by a business partner or the customers themselves, such as an office WLAN. So if an operator is concerned about the customer experience on Wi-Fi, it could limit handoffs from VoLTE only to hotspots it owns.

Hotspot operators and aggregators want people to use their networks, and quality is one way to convince them to pay for access versus using free alternatives. Vinson said he has been using T-Mobile’s VoWi-Fi service for about six months, and his experience shows that 802.11 doesn’t have to feel like a step down.

“Most of the time I don’t even know what I’m using,” Vinson said. “I have to look at the phone to see that I’m using VoWi-Fi. Ultimately that’s what operators want. It has to be a good call quality experience to be able to do that.”

Boingo already monitors its hotspot partners to make sure they’re providing the quality-of-service (QoS) that its retail and wholesale customers want. Those that don’t meet that requirement are dropped from its directory. If more hotspot operators and aggregators provide QoS service-level agreements, it would help ensure that Wi-Fi calling doesn’t seem like a step down in terms of customer experience.

“One of the nice features of VoLTE is you give it guaranteed lane on the freeway, so to speak,” Thelander said. “It’s dedicated, and no matter what other traffic is there, your call gets priority. On Wi-Fi, there are some crude mechanisms that would give certain traffic some priority, but it’s not nearly to the same degree that you get on LTE.”

Regardless of who owns the hotspot, operators don’t want the handoffs to be noticeable. They don’t want big variations in call quality, for example.

“We have testing solutions that allow the device manufacturer to test the performance of Wi-Fi calling and VoLTE-to-Wi-Fi offloading,” said Saul Einbinder, vice president of marketing at Spirent Communications. “As part of that [VoLTE-to-VoWi-Fi] transition, for example, the device side has to make sure it negotiates properly with the far end. The codec selection might have to change during the call.”

Vendors also are developing tools that enable operators to track handoffs so they know how to charge accordingly. That task can be complex. “How are you going

to charge if you’re roaming, and you have one minute over LTE and two minutes over Wi-Fi?” Rodrigues asked.

On the plus side, some of the interoperability framework is already in place.

“The nice thing is that from a network perspective, it’s a lot of the same systems,” Vinson said. “You’re still using a telecommunications application server (TAS), the VoIP technology, the same codecs, especially the codec for HD Voice.”

That infrastructure can help ensure that VoLTE-to-Wi-Fi handoffs provide a better user experience than when the cellular service is circuit-switched.

“Call setup for VoLTE and VoWi-Fi is much faster than with circuit switched,” Vinson said. “Some of those inbound handover issues with authentication will be taken care of with VoLTE because it’s using the same call setup methodology for Wi-Fi as it is for VoLTE. I think it’s going to fix a lot of the issues we’re dealing with today.”

Tiago RodriguesProgram DirectorWireless Broadband Alliance

“ The major issue operators must face is the need to integrate Wi-Fi as part of the core infrastructure of their cell site.”

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Interoperability

Interoperability CHAPTER 3

But launching a new service doesn’t guarantee market acceptance or success. To facilitate wide-scale adoption and fully exploit VoLTE’s benefits, devices must interoperate, calls must work across networks and customers must be able to roam with consistent services.

“Operators certainly accept that interoperability will be essential, having learned that lesson from GSM and SMS, for example, but this is extremely complex,” said Caroline Gabriel, research director at Rethink Technology Research.

“It’s not just about connecting different operators’ VoLTE calls, but layering the services that will make VoLTE attractive on top, such as conferencing and video chat, making those interoperate too, and also allowing for fallback to 3G when no 4G is available.”

The industry is tackling these issues and 2015 could become the year in which important strides are made. AT&T and Verizon Wireless are providing impetus with their commitment to enable VoLTE-to-VoLTE connections between their customers in 2015. Their experience, and an operator community that is motivated to build interoperability test strategies, could help build momentum. Nagging challenges, such as debates over VoLTE roaming architectures, could hinder growth, however.

Mobile operators are finally ramping up their voice over LTE (VoLTE) deployments. They’ll use the technology to offer high-definition voice calling and enriched services, like FaceTime, to their customers. Internally, operators will gain spectral efficiencies and important opportunities to free up 2G and 3G spectrum to support LTE coverage.

A Must-Have for Strong Market Growth

By Peggy Albright

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Interoperability

Fragmentation Issues Challenge VoLTE Interoperability

The telecom industry needs standards to facilitate interoperability and this is also the case with VoLTE. Led by the GSMA, operators are using common technology implementations that are based on 3GPP specifications and leverage IMS infrastructure to provide carrier-grade voice over LTE (VoLTE); conversational video over LTE (ViLTE) and rich communications services (RCS). GSMA is continuing to refine the standards to improve interoperability and make VoLTE more robust.

“We very much value the experience we have today in mobile telephony, and what we had with GSM and 3G, where you can have device portability and the ability to swap SIMs so you’re not bound to a particular operator network. That’s what we’d like to do going forward.”

The telecom industry usually provides leeway in how specifications are used so companies can differentiate their offerings or configure their deployments to meet their own network requirements. For VoLTE, this flexibility has been vexing.

Even when a VoLTE device passes conformance testing to ensure compliance with the standards, its ability to interoperate with other VoLTE devices is not guaranteed. Variable client software settings, differing software versions, processor technologies, parameters established in the core network, and LTE frequency bands can all create product incompatibilities.

The issues have created a “high degree of lack of interoperability between devices, even between devices from the same manufacturer,” said Emil Olbrich, vice president of networks at Signals Research Group.

Furthermore, VoLTE devices have more responsibility for facilitating interoperability compared to devices that operate on circuit switched networks. To enable a VoLTE-to-VoLTE voice call, for example, the devices must establish a handshake and make sure they’re using the same voice codec, quality-of-service (QoS) bearer and other features. RCS will place similar responsibilities on devices.

“We’re finding that conference calling, presence, and other advanced features all require device-to-device interoperability,” said Sue Ahimovic, product marketing manager, Wireless at Spirent Communications.

David HuttonDirector of TechnologyGSMA

“ We think that any device should work on anybody’s network.”

Interoperability

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Test Plans will Help

Interoperability will gain importance and complexity as more operators deploy VoLTE and as more devices come to market. Better and more pervasive interoperability testing will be needed to enable the market’s growth.

“Leading carriers are very motivated to create extensive test plans and require them of OEMs and the ecosystem,” said Ahimovic. “They recognize these things need to be tested and are coming on board quickly.”

Operators can perform the testing themselves, require their partners to perform specified tests early in the product development cycle to identify potential issues, and specify device-to-device testing methodologies that can be done in the lab or on a live network, suggested Saul Einbinder, vice president of marketing at Spirent.

This year GSMA is hosting interoperability test events with leading operators and vendors to test device interoperability within and across networks. The GSMA will use findings from the events to define test cases companies can to accelerate the introduction of interoperable devices and networks.

Olbrich believes that the industry would also benefit from an open, dedicated test environment that can accurately represent carriers’ networks and provide a process for evaluating test devices against each network. The environment would make it easier for companies to test dozens or hundreds of devices operating against each other on multiple networks.

“If the test industry can do that, this problem gets mitigated quickly, because now you have a common platform to test against and you have a high degree of certainty that devices are interoperable,” he said.

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Interoperability

More Essentials: Interconnections and Roaming

To help the industry advance VoLTE beyond siloed services on individual networks, operators must also have IP interconnection agreements with one an-other so their respective customers can call each other and enjoy consistent end-to-end HD voice calls. The GSMA expects to see IP interconnected networks in the second half of 2015.

Operators will also need to forge agree-ments with international partners to extend their geographic coverage, and IP exchanges will facilitate these IP intercon-nections.

Finally, operators must offer roaming capabilities so customers can enjoy their VoLTE services and the VoLTE user expe-rience even when they travel to another country.

“Today we can go around the world and our 2G and 3G services work great. We must do that for VoLTE as well,” said Ed Elkin, head of marketing for communica-tions and collaboration at Alcatel-Lucent.

Roaming is currently inhibited by both technical and architectural issues. For

example, various parameter settings defined in the IMS core network and the VoLTE client can vary from carrier to car-rier, which can prevent a device from one carrier registering on another network, creates roaming issues.

The industry also needs to settle on an architectural model for roaming. The op-tions include the current default model, “local breakout” (LBO), and an alternative home routing option (S8 HR).

The GSMA is testing both roaming alter-natives with leading operators in the U.S., China, Japan and Korea.

Ed ElkinHead of Marketing for Communications and CollaborationAlcatel-Lucent

“ Roaming is a core value. It has to work great.”

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What Makes or Breaks the VoLTE User Experience

What Makes or Breaks the VoLTE User Experience

CHAPTER 4

If mobile calling is dead, killed off by SMS, Facebook and other data services, the numbers say otherwise. Americans, for example, talked 2.62 trillion minutes in 2013, up from 2.3 trillion in 2012, according to CTIA.

By Tim Kridel

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What Makes or Breaks the VoLTE User Experience

And three years from now, voice will still be about 45 to 48 percent of total mobile service revenue, he predicts.

Those numbers highlight one reason why it’s critical for mobile operators to ensure that their VoLTE services provide a user experience that’s at least as good as the circuit-switched services VoLTE replaces. Other rea-sons include the following:

� It’s cheaper for operators to keep customers than to replace them. In Nokia Solutions and Networks’ annual surveys regarding acquisition and retention, call quality is one of the top loyalty factors worldwide and No. 1 in the U.S.

� Consistently reliable, high-quality calling experiences encourage consumers and businesspeople to drop their wireline services and shift that spending to mobile.

� When VoLTE works well, operators can scuttle the overhead of their 3G/2G networks and refarm that spectrum.

Stéphane TéralHead of Marketing for Principal Analyst for Mobile Infrastructure and Carrier EconomicsInfonetics Research

“ Voice is a half-a-trillion-dollar business.”

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What Makes or Breaks the VoLTE User Experience

But ensuring a great VoLTE user experience is easier said than done. One indication is that opera-tors, when issuing press releases about their VoLTE launches, won’t discuss how they’re measuring and maximizing call quality.

“There’s a lot of hesitancy on the part of operators,” said Michael Thelander, CEO and founder of Signals Research Group (SRG). “They’re really sensitive to the quality of their networks. If your LTE coverage isn’t perfect, you’re going to have problems.”

Virtually all VoLTE rollouts have been in select markets rather than across an operator’s entire foot-print. That’s partly because LTE itself is still relatively new for most operators, so they’re still optimiz-ing their networks on a market-by-market basis. For example, it takes time to ferret out all of the things causing packet loss, which is a common reason for poor VoLTE call quality.

“That’s mostly due to IP connectiv-ity and configuration issues [in] the access network, the backhaul and the core,” said Jeff Atkins, director of marketing at Spirent Communi-cations.

And even if an operator has spent a few years optimizing its LTE network, it still has to do another round of tweaking when it layers on VoLTE.

“Basically it doesn’t work right out of the box,” Atkins said. “When you turn it on in the network, substan-tial optimization needs to be done before VoLTE outperforms legacy and OTT services.”

The people doing this work come from a circuit-switched world, where IP is used only for data. VoLTE is the first time they’ve had to use IP for voice-related tasks such as call setup and signaling.

That learning curve compounds the challenge of addressing end-to-end delay, which is the

aggregate of delays that have accumulated at various points in the network and the device. Also known as one-way conversational delay, it becomes noticeable to customers when it reaches the point where callers start talking over each other.

To measure end-to-end delay, op-erators need devices on both ends of a VoLTE session. “That’s one of the areas we’ve been working on,” Atkins said. “We have a new capability that lets you do highly accurate end-to-end delay meas-urements.”

By collecting IP information at the device and then correlating that with user experience data, opera-tors can understand the relation-ship between the two. These foren-sic insights are useful for tweaking the network to minimize IP-related problems that would undermine future VoLTE calls.

Paradigm Shift

Jeff AtkinsDirector of MarketingSpirent Communications

“ Substantial optimization needs to be done before VoLTE outperforms legacy and OTT services.”

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What Makes or Breaks the VoLTE User Experience

“Once that packet goes into somebody else’s network, that QoS setting can be changed,” said Ray Vinson, product manager at Interop Technologies, a vendor whose products include VoLTE platforms.

Furthermore, operators don’t directly con-trol the quality of the mics and speakers in the customer’s handset or headset. But operators can ask handset vendors to make changes to their firmware and VoLTE client, both of which play a major role in call quality. In fact, even when two different vendors’ phones use the same supplier’s audio com-ponents, chipsets and reference designs, there often are still big differences in call quality.

“Even with all that commonality, when opera-tors evaluate those devices on their network, they see wildly different performance levels and different levels of experience,” Atkins said. “The call-setup time or speech quality will be significantly different. So they’re trying to get an apples-to-apples comparison of those devices before they get launched and then work with the manufacturers to tweak their designs to make sure they all have the acceptable levels.”

He added: “We often find that changes that need to be made are just at the software and firmware level. The manufacturers are often able to make very small changes in the firmware or other places and in a matter of days, release a device that offers some level of improvement.”

When operators get VoLTE right—from the network through the handset—the service shines in ways that customers can’t over-look. For example, in summer 2014, Sig-nals Research Group tested a commercial VoLTE network against a circuit-switched 3G network and Skype’s high-definition voice service. The VoLTE network provided meas-urably higher call quality than both, and it set up calls twice as fast as the circuit-switched network.

Handoffs and HandsetsCreate More Variables

Some factors are beyond the operator’s control. For example, it’s futile to try to use policy to enforce quality of service (QoS) when VoLTE calls traverse multiple networks.

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© 2015 Spirent Communications, Inc. All of the company names and/or brand names and/or product names and/or logos referred to in this document, in particular the name “Spirent” and its logo device, are either registered trademarks or trademarks pending registration in accordance with relevant national laws. All rights reserved. Specifications subject to change without notice. Rev. A 04/15

For more information on VoLTE & RCS: http://www.spirent.com/Solutions/Volte

Get Part 1 of this eBook series Every twist and turn, tired and tested: VoLTE testing explained