Editor’s Note: Welcome to our weekly Reality Check column. We’ve gathered a group of visionaries and veterans in the mobile industry to give their insights into the marketplace.
With 18 LTE networks now in commercial service around the world, LTE handsets will surely be unveiled at the Mobile World Congress in Barcelona next week. As with any handset, consumers will expect to be able to pick up a LTE phone and ring anyone they like. But, before they press the green button to connect the call, an LTE phone will be able to display real-time status information about the person they are about to contact. That’s because, underneath the bonnet, LTE phones are going to make voice calls using a completely different technology to their predecessors.
LTE networks are designed to carry all traffic, including voice calls, using Internet protocol, rather than the dedicated circuit-switched technology that underpins mobile voice services today. In the past 12 months, the mobile industry has made great strides towards the adoption of a common approach to implementing IP-based voice calls over LTE networks. This is critical. A single global approach will make it straightforward for voice calls to travel across different networks and will enable international roaming, while also encouraging the development of a large ecosystem of competing equipment manufacturers, giving consumers greater choice of handsets.
Formally launched at the 2010 edition of the Congress, the GSMA’s Voice over LTE initiative to create a common approach based on IP multimedia subsystem technology has won the support of the vast majority of the world’s leading mobile operators and equipment vendors.
There has also been major progress on the technical front. Contrary to some reports, the IMS-based protocol work on VoLTE has largely been completed. In April 2010, the GSMA published the User-Network Interface definition for VoLTE (the interface between the handset and the network), while the Network-Network Interface definition (to allow one network to connect to another) was published in June 2010. These two documents enable handset and network equipment manufacturers to develop VoLTE interfaces and implementations.
During 2010, several vendors demonstrated VoLTE services on laptops. The GSMA, for example, hosted a demonstration in conjunction with Hong Kong operator CSL and China-based equipment supplier ZTE Corp. at the Mobile Asia Congress in November 2010. But the real proof point will be handsets making VoLTE calls, something we are likely to see demonstrated at the Mobile World Congress next week.
While VoLTE is clearly about voice, the use of IMS as the underlying engine means that operators will be able to move beyond offering “plain old telephony” into a much richer suite of person-to-person communication capabilities. The use of IMS allows two devices establishing a communications session to see each other’s capabilities, meaning high-definition voice services, for example, can be implemented from day one.
Moreover, IMS allows information on presence and device capability, as well as instant messages, to be exchanged between different networks, devices and operating systems. So, real-time information about the person that you are trying to contact will be available on the device in your hand. You will be able to tell immediately if someone is available and the best way to contact them.
So what? Isn’t all of this available today via other means? Yes, but only if you happen to be a part of the same “community” as the person you are contacting, be that the same VoIP provider, instant messaging service or operator. With a globally-implemented IMS-based service, this information would be available to you for anyone on your contact list, regardless of their operator or service provider.
Prior to the launch of VoLTE, there were at least five competing alternative approaches to providing voice calls over LTE networks. This kind of fragmentation would have undermined the interoperability and reliability that are the longstanding hallmarks of GSM-based communications. If voice calls are implemented using different protocols, they can’t necessarily connect across networks, or they may require the deployment of expensive interworking equipment that can introduce delays, affecting the quality of the call.
Furthermore, people may find they can’t make LTE-based voice calls while travelling abroad because the network they are roaming on supports a different voice implementation to that of the customer’s home network. That’s why nearly every LTE operator will move to VoLTE over time, even though they may use interim solutions, such as falling back on 2G and 3G networks for voice calls, in the short-term.
In any case, telecoms companies’ in-house voice services will likely face intensifying competition from third-party VoIP providers. One of the challenges that all operators, fixed or mobile, will face in the coming years is how to safeguard their position as the voice provider of choice. A common voice over LTE implementation is key to ensuring callers continue to have a good experience of operator-provided telephony. A rock solid voice service that offers all the flexibility the customer has today, enhanced with status information and other functionality, is the best way to compete with VoIP providers.
Dan Warren joined the GSM Association (GSMA) in 2007 as Director of Technology with a particular focus on helping the Association drive forward standards and technologies including High Speed Packet Access (HSPA) mobile broadband, Long Term Evolution (LTE) standards and IP Multimedia Subsystem (IMS) as well as providing internal technical consultancy to GSMA’s Projects and Working Groups. Prior to joining the GSMA, Dan worked for Vodafone and Nortel. Dan has a degree in Mathematics and a PhD in Applied Mathematics.
