Are mobile operators offering their own over-the-top (OTT) technologies? Third-party OTT apps have been riding on operator data networks since 2007. Operators didn’t mind initially for non-voice and video OTT apps that created a demand for overall data usage, increasing their revenue. But as demand increased and OTT apps started offering voice services, operators came up with their own OTT—a cool platform known as RCS (Rich Communication Suite).

VoIP OTT Clients

Try searching for Voice over Internet Protocol (VoIP) apps on Android or iOS, and you’ll find hundreds. All provide free service with their own proprietary end-to-end solutions that don’t interoperate with each other. There’s also no guarantee of any quality of service (QoS) because the OTT service providers don’t control the network, device, or environment. As for the network, these apps have access to a data-only, non-QoS bearer that doesn’t differentiate between any real-time applications, file/image/video downloads, audio/video streaming, or Internet browsing.

Mobile devices such as smart phones and tablets have different screen sizes, video resolutions, acoustics, and even microphone and speaker locations, making it more challenging for real-time applications to provide a seamless experience across all devices. In addition, no single application meets all user requirements. Users must keep hopping between multiple applications to get access to even basic services such as contacts, presence, voice, video, instant messaging, and SMS/MMS.

OOTT (Operators-Over-The-Top) Clients

Operators have taken the OTT challenge so seriously that they ended up formalizing their own OTT in the form of a GSMA RCS client standard. RCS includes enriched calling with file/image/video share during the call, enriched messaging, 1:1 chat/group chat, interworking with SMS/MMS, enhanced address book, social presence information, and many more features including geo-location.

Real-Time Voice And Video

Initial versions of RCS were launched with voice and video calling over Wi-Fi, but the ultimate goal per the latest RCS 5.0/5.1 standards is to support the GSMA Voice over LTE (VoLTE), Voice over HSPA (VoHSPA), and Video over LTE standards. VoLTE and Video over LTE are fully embedded and integrated with the native dialer/application. VoLTE supports wideband HD voice, and early measurements have shown that VoLTE provides superior quality voice than the circuit-switched voice.

When integrated with VoLTE, RCS will be offered as a native application, improving the user experience. And unlike OTT apps that run the software video and consume more power, embedded RCS integrates with hardware video accelerators to reduce power as well as support HD video and multi-party voice and video conferencing (see the figure).

RCS Offers Turnkey Solution

Integrating with VoLTE, operators now have a complete solution (real-time Video and VoIP (V.VoIP) + rich communication features), further enhancing the user experience. Both RCS and VoLTE use the same IMS network to offer their respective services, improving cost efficiency and reducing time-to-market.

Operators have complete control over the network, devices, and environment, leveraging them by providing all of the user desired features such as:

  • Multiple device support: Users can set personalized profiles across multiple devices where presence notification and updates are sent to all devices provisioned under the same user account.
  • Multiple network support: All the RCS services can be offered across the wireless networks (3G/4G/Wi-Fi) irrespective of the geographic location—home, enterprise, or on the road.
  • Seamless handoff: Seamless handoff is very critical for real-time voice and video applications. The GSMA IR.92 standard for VoLTE supports single-radio voice call continuity (SRVCC) for seamless voice handoff between LTE and cellular networks while the third-party OTT applications will drop the calls when migrating from one network to the other.
  • Guaranteed QoS: Since operators own the spectrum and bandwidth, they have the liberty to allocate dedicated bandwidth for real-time voice and video calls as per the GSMA IR.92 standard. Third-party apps don’t have this advantage.
  • High level of integration: By tightly integrating the RCS and VoLTE stack with LTE modem and audio/network drivers, the overall latency is very low and significantly improves the user experience.
  • Low power: Because of the very predictive and periodic nature of V.VoIP packets, the system can be switched off even during the active call state using techniques such as connected state discontinuous reception, increasing the battery life.
  • Widely interoperable: One of the key advantages is that RCS and VoLTE are standards-compliant and driven by operators. There is a high level of interoperability between RCS clients running on U.S. mobile operators’ networks and devices and European/Asian networks.

RCS: Operator’s Super-app

RCS is a super-app integrating non-real-time applications such as file share, image share, geo-location, and chat with real-time voice and video applications. It fully exploits smart-phone platforms loaded with multiple-gigahertz processors, high-resolution cameras, larger screens, and multiple interfaces.

While initial RCS versions are OTT clients, the next wave of mobile devices will have them pre-loaded and ultimately integrated with the native dialer so they provide a seamless unified user experience. In addition, the platform exposes the application programming interfaces (APIs) that allow integration with applications such as social networking and gaming applications, making it more appealing to all generations of users.

The net result is that we’re now seeing a reverse trend of third-party OTT providers copying the RCS features. Overall, RCS has emerged as a winner as it is gaining acceptance worldwide from mobile operators’ subscribers.