By Wang Yongde
Carriers usually develop VoLTE in four distinct stages – a complex process, one that requires a great deal of engineering and re-engineering, and yet worthwhile, as VoLTE represents a path to the future, not just a fancier way of delivering voice.
Never before have people been able to communicate with one another so freely and conveniently. With the increasing penetration of broadband, maturing social media, and the proliferation of powerful yet cheap multimedia devices, the Internet has become a major medium for both consumer and business communications. In addition, advertisers, vendors of fast-moving consumer goods (FMCGs), and social networks use the Internet to connect with consumers. Enterprises can use the Internet to cultivate user loyalty, allocate and supervise work, and coordinate with suppliers and partners based in different areas.
This represents two major changes to the ICT industry. First, the model of communication has changed. One-to-one bidirectional voice and messaging communications are being replaced by many-to-many coordinated, multimedia communications. Second, the dominant power in the ICT industry is shifting, from carriers to open Internet platform vendors, due to the opening of standards and various technological advancements.
Despite currently dominating one-to-one communications, carriers are now increasingly challenged by newcomers who use open platforms to meet fast-changing and varied customer needs. According to Juniper, voice revenue will drop 2% annually for the foreseeable future. Carriers must find ways to secure their position in an ever-changing industry if new growth opportunities are to be seized.
New value through LTE
LTE can greatly improve the mobile service experience, create new value, and even enable new business models and ecosystems. In the LTE era, traditional voice and messaging services will transform into rich media services that feature half-second connection times, crystal clear A/V performance, and instant messaging/sharing/transfer. Carriers can now provide enterprise customers with fixed-mobile convergence (FMC) and multi-terminal coordination services. In the future, an all-IP Internet will integrate third-party applications with ease. Carriers will be able to open their network capabilities to third-party developers to launch innovative services jointly (and share the profit) through communication as a service (CaaS).
Evolution of mobile voice
LTE deployment and a maturing terminal ecosystem have prompted global carriers to evolve their mobile voice services in the following steps.
Step 1: LTE hotspots give rise to pre-VoLTE
Initial LTE deployments are usually for hotspot offload; circuit-switched fallback (CSFB) is a must for such scenarios. However, CSFB typically has a call delay of seven to twelve seconds, and sometimes longer. It also requires legacy upgrade, which most carriers are no longer willing to do on a large scale. Flash CSFB and CSFB proxy solutions can help.
Step 2: Widespread LTE coverage leads to VoLTE
When LTE is deployed throughout a large and/or highly-populated area, commercial VoLTE becomes viable. VoLTE provides a superior user experience, and improves spectrum utilization as well. Compared with mobile softswitch (MSX) architecture, which has only two network elements (NEs), VoLTE architecture, based on the IP-multimedia subsystem (IMS), is much more complex, with over 40 NEs and 60+ interfaces. Its deployment requires not just an IMS network, but reconstruction or building of a CS network and evolved packet core (EPC), along with LTE, IMS, and PCC.
LTE and 3G networks must be transformed to support enhanced single-radio voice call continuity (eSRVCC) and robust header compression (ROHC), which reduce the handover delay and improve the network performance. With the EPC and CS network upgraded and transformed to coordinate with IMS (so that call continuity is ensured), user data management is integrated, and service experience is consistent on multiple networks. A Diameter-based signaling network must be introduced, with the unified policy and charging controller (UPCC) upgraded to support QoS control. The IP bearer network must also be transformed to support IPv6, with the charging and BSS/OSS upgraded along with it to support VoLTE service provisioning. Legacy service inheritance and terminal interoperability testing must also be accounted for during VoLTE deployment. Carriers around the world seek to simplify this process. Therefore, ICT vendors need to provide not just E2E technical solutions, but also corresponding integration services and support to help carriers tackle this challenge.
Step 3: NFV-based VoLTE
During this stage, LTE and other wireless broadband technologies such as high-speed packet access (HSPA) form a seamless wireless network. VoLTE is on its way to being a major voice service, and traditional CS networks will eventually be replaced, but the latter will not happen for quite some time, time enough for all network infrastructures to move to the cloud. With hardware decoupled from software, resources can be scheduled on demand, with service expansion and contraction automated. With their open, automated nature, these networks will be more dynamic, efficient, and scalable. Service provisioning times will be shortened and innovation will be accelerated. As LTE goes mainstream, DT, Vodafone, and Telefónica are all deploying virtual IMS-based VoLTE as the first step towards cloudification.
Rich communications experiences
In an all-IP LTE era, carriers must offer amazing services to attract end users. There is an initiative in the industry to integrate VoLTE, rich communications suite (RCS), and RCS-e features into all LTE chips so that innovative multimedia services can be offered through phone address books, without the need to install related apps; these include instant message/picture/video sharing, file transfer, and SNS integration. Users will also be able to use phone numbers for new communication services, without applying new IDs and rebuilding their communication context, and enjoy all relevant communications services, and be reached by all manner of terminal or soft client.
The enterprise market offers carriers a great opportunity to increase revenues. Gartner shows that communications expenditure accounted for nearly 40% (USD1.5 trillion) of all enterprise IT expenditures worldwide, and carriers such as BT, AT&T, Vodafone, and TATA are all trying to provide hosted UC solutions.
Hosted UC is a cloud-based synergy solution for SOHOs and enterprises of all sizes. To enhance work coordination and cut cost, enterprises need a unified UC platform that provides a single interface for coordinated work, while supporting instant messaging, voice and video call, and convergent conferencing. As a whole, this solution enhances an enterprise's cross-regional communications, information collection & switching, and overall work efficiency.
By opening communications capabilities to third parties as a service (CaaS), telcos can achieve their ultimate goal – communication monetization. The key is to allow third parties to explore carriers' rich communications capabilities at both the network and terminal sides, in a simple and intuitive manner.
On the network (upstream) side, open application platform interfaces (APIs) can empower third-party applications with carrier-level capabilities relating to voice, video, instant messaging, and file sharing. These capabilities will improve partners' application and service quality, creating value for both partners.
For the terminal (downstream) side, open software development kits (SDKs) can endow terminal devices, and even items like glasses and shoes, with communications capabilities, turning machines and things into network nodes. Communications will expand from people-to-people to include people-to-thing and thing-to-thing communications.
Commercialization of VoLTE is on the way
During their 2012 and 2013 LTE deployments, carriers started or completed their CS network upgrades to support CSFB. In South Korea and the U.S., VoLTE commercialization began in earnest. In May 2014, the process went global. On May 15, HKT launched seamless VoLTE service, with Hutchison Global Communications announcing the commercial use of VoLTE on the same day. On May 21, Singtel launched full VoLTE. The next day, T-Mobile in the U.S. also launched VoLTE. On May 23, AT&T did the same.
According to GSMA estimates, in the next 12 months, over 20 carriers will deploy VoLTE, including China Mobile, the world's largest mobile operator. Accordingly, handset support is rapidly accelerating as all major players scramble to launch VoLTE-enabled phones like the VoLTE-ready Huawei Ascend P7, already released in the third quarter of this year.