STAMFORD, USA: Mobile portal voice over Internet protocol (VoIP) offered by third-party application-based providers poses a huge and direct challenge to the $692.6 billion global mobile voice market, according to Gartner, Inc.

Gartner predicts that over time traditional network-based mobile carriers face the real prospect of losing a major slice of their voice traffic and revenue to new non-infrastructure players that use VoIP.

However, Gartner said that despite this significant potential, conditions for the rapid expansion in the use of mobile VoIP are not yet right and are not likely to become right for at least five years and perhaps as long as eight years.

"Mass-scale adoption of end-to-end mobile VoIP calling will not happen until fourth-generation (4G) networks are fully implemented in 2017," said Tole Hart, research director at Gartner. "Once the basic market conditions are in place, transition to mobile portal VoIP should be fairly rapid because of the inherent convenience and end-user cost savings. In 10 years time we expect that 30 percent of mobile voice traffic will be carried out through third-party mobile portals, such as Google, Facebook, MySpace and Yahoo, which will adopt wireless VoIP service as a voice option to their current communications hub."

A number of third parties, such as Skype, Truphone and fring, which carry VoIP traffic using a mobile phone, have cropped up in the past couple of years, offering access to voice services via Wi-Fi and/or the carriers' wireless voice networks.

This has been the most efficient way to offer the service to date because of the inconsistencies of voice services over third-generation (3G) data networks. However, with the advent of 4G networks (WiMAX and Long Term Evolution [LTE]), and increased use of smartphones with open operating systems, it is conceivable, perhaps even inevitable, that wireless voice services will be run completely over VoIP.

"Ten years from now, more than half of mobile voice traffic will be carried end-to-end using VoIP," said Akshay Sharma, research director at Gartner. "Carriers will adopt voice services because of the increased capacity and reduced cost of delivering voice over 4G networks. Third parties will adopt a voice option for their communications hub."

Gartner analysts warned that there will also be a number of factors that will inhibit the adoption of third-party, end-to-end VoIP services, including the delay in rolling out 4G networks because of current economic conditions and also the general plan to put 4G only in the main cities and build out from there. Nevertheless, in five to 10 years time, as 4G networks become common, mobile VoIP services will have a strong impact on the communications market.

Competing with mobile portal VoIP will be wireless carriers that offer circuit and VoIP voice and data services, and resellers and mobile virtual network operators (MVNOs) that also offer services off the carrier networks.

Gartner expects this opening of the VoIP channels to spawn a number of voice services from companies that offer voice services to communities using voice as a communications link. This means that the biggest competitors to mobile VoIP may be text messaging and e-mail, as people may prefer to use these types of communication because of their non-intrusive, less emotional and less time-consuming nature.

Although the impact of the technology shift will be gradual as 4G networks roll out, Gartner advises carriers to start thinking now about how the transition will occur and how they might cooperate and partner with other types of service providers. Third-party providers, such as Google and Yahoo, should look to offer voice services today using the carriers' networks and Wi-Fi to leverage their portfolio of services. Mobile social communities, such as Facebook and MySpace, which benefit from messaging traffic as it keeps eyeballs on their sites, should also have a voice option.