Internet telephony over mobile phones is on the way but don't expect many commercial offerings until operators have made a key network technology enhancement, probably toward the end of 2007 or later in most parts of the world, according to a senior executive with Lucent.The problem with providing VoIP service over mobile handsets today is the uplink, which is too slow to support quality voice calls, according to Lucent Chief Marketing Officer John Giere.To increase uplink speeds, operators of GSM networks, which dominate Europe and many parts of Asia and Latin America, will need to upgrade their networks with High Speed Uplink Packet Access ( HSUPA) technology, he said."HSUPA will give operators the bi-directional capability they need to run real VoIP," Giere said in an interview last week at the Cebit trade show in Hanover, Germany.However, the Lucent executive doesn't expect the high-speed technology, which is currently being standardized, to become commercially available until the latter part of 2007 or early 2008. Operators are presently busy rolling out the downlink counterpart High Speed Downlink Packet Access (HSDPA).How that timing fits into VoIP-over-mobile plans of Skype and the Hutchison 3 Group (Hutchison 3G) is unclear.At the 3GSM World Congress in Barcelona last month, the two companies announced a partnership to provide the world's first commercial VoIP service for mobile phones. The companies aim to begin offering service in select markets as early as this year, said Christian Salbaing, managing director of European telecommunications at Hutchison 3G, in an earlier interview.Though Hutchison operates an IP-based network, it has not rolled out HUSPA.In addition to HSUPA, operators planning mobile VoIP services will need to "flatten" their networks by reducing the number of components and using IP wherever possible, according to Giere. "The number of network components you have also contributes to network latency, which is a big issue with VoIP," he said.Most GSM operators today have legacy circuit-switched networks, which tend to slow the flow of IP traffic because of their numerous network components and conversion processes, according to Giere.In response to the need to reduce network components, Lucent has introduced a new base station system that collapses a series of network architecture layers into one component, according to Giere.Lucent is also collaborating with Samsung in a project aimed at developing Session Initiated Protocol (SIP) client software, which is essential for offering VoIP for mobile handsets, he said.Until now, mobile operators have largely dodged the great VoIP debate, trying to squeeze every possible cent of their largely amortized circuit-switched networks before investing in yet another new technology.But should they be interested in VoIP? "Absolutely," said Giere. "Efficiency is one reason; operators can significantly increase their bandwidth utilization with VoIP. Applications are another; an IP environment is all about creating a rich set of applications."Another reason, especially for those operators that are net payers of international roaming services, is the ability to use VoIP to undercut high intra-carrier network usage fees.