WebRTC and VoLTE

by iago.soto | WebRTC (Web-based real time communication) has been explained before in this blog and other marketing materials from Quobis. As a technology designed to bring real-time multimedia capabilities to browsers, it has lots of potential use cases for telcos. At Quobis, we’ve been focusing on WebRTC interconnection to IMS/NGN and other telco implementations, trying to create an element, our Sippo WAC, that makes possible to deal with the complexity of a WebRTC deployment in a telco network.

During the last years telcos were investing on LTE (Long-Term Evolution) as the 4G technology. Through different standardization bodies (3GPP and GSMA) a standard for voice transmission over data channel is available. In VoLTE (Voice over LTE) the objective is to transfer voice calls over the LTE data network instead of using common voice networks.

So we have WebRTC that makes possible to use browsers to send peer-to-peer (as OTT) voice on the data channel and VoLTE that allows something similar but using the telco assets. Let’s explore if they compete or not.

    • Devices.

While WebRTC works in any device that can run a browser (tablets, PCs, etc), VoLTE is only supported on modern smartphones (iPhone 6 or 6s, latest Samsung Galaxy mobiles, etc). In iOS WebRTC is not supported on browsers, so you need to install native or hybrid WebRTC applications to have a similar functionality. Despite this, we can say that WebRTC works in more devices than VoLTE as you can install free WebRTC-enabled browsers in almost all the devices.

    • Coverage.

In the case of WebRTC, as in any OTT service, it depends on internet/data connectivity. In the case VoLTE the limitation is LTE availability (and service activation by the telco). Today, most of the voice over LTE networks are still rolling-out worldwide. Despite this, it’s important to mention that VoLTE forces telcos to offer QoS for voice (traffic priority to mail, web surfing, etc.), while WebRTC depends on general QoS and it’s not possible to give priority to this traffic.

    • Infrastructure.

WebRTC does not define anything for signalling, standards are open and lots of open/free implementations are available. VoLTE implementations are quite closed instead, as they depend on a specific implementation by the telco (protocols defined, not many network equipment vendors available, etc.) and vendors expect to get revenues after years and years of tests. This means a high investment by comparison with WebRTC.

    • Quality of experience.

WebRTC makes possible to build lots of user scenarios but VoLTE has two important advantages. First, telcos can control the bandwidth available and offer a better service for voice over LTE by comparison by a pure internet service (like WebRTC). Second, the standard codec for VoLTE allows to offer HD Voice (up to 7000Hz) with less than 1ms in the bandsplitting filter. WebRTC supports variable-rate codec Opus (with a similar frequency range) but depends on network quality and the transcoding capabilities of the webRTC gateway to have something similar.

So lots of analysts refer the opportunity of VoLTE as being part of the subscriber package and used for basic voice (even video, that will be discussed in a future post) calls, whereas WebRTC can be used for value-added services like creating their own over-the-top voice service or to integrate voice/data into web experiences of the customers.

WebRTC openness and flexibility makes possible to add new calls and revenue streams to telcos (easy to adopt by users, easy to motivate developers to add voice capabilities to web services, etc), but WebRTC is by nature vendor-less and even telco-ness (only internet is needed to access services) so telcos must decide how to manage the investments and efforts on WebRTC and VoLTE.

Combining WebRTC and VoLTE in telcos

As stated before, telcos will use VoLTE for their standard packages while WebRTC could help to build customer-demanded solutions, specially in the enterprise domain or in those companies with a huge presence in the web. As we were discussing in our recent webinar “use cases of WebRTC for telcos” (slides and video availables in our website and youtube account), other telco services like yellow pages could benefit of WebRTC.

But now we are going to focus on how WebRTC can help to extend traditional VoLTE services.
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While VoLTE works in some of the most modern smartphones, lots of user devices are out of this possibility. Today customers are using different devices (PC, laptops, tablets, etc) that are not natively connecting to the mobile telco networks (i.e. mobile tethering). It’s important to mention that more than 90% of the tablets are only supporting WiFi, so they will not connect to LTE infrastructure.

Telcos are willing to extend the current VoLTE services to these devices, so WebRTC could be the best technology to enable this. Using WebRTC you can emulate really easy and fast the same behaviour as the VoLTE (including video) use case, assuming only the limitations of non-prioritizing the WebRTC traffic.

This is just one of the points to take into consideration about the benefits of the coexistence of WebRTC and VoLTE on telco strategy.