The goal of the initiative, called One Voice, is to ensure widespread adoption of LTE and to avoid fragmentation on technical issues, according to a statement.

For mobile subscribers the agreement improves the chance of phones working in different parts of the world.

Voice is too important to have unresolved and expect operators to move forward with LTE, according to Richard Webb, directing analyst at market research company Infonetics.

"Voice is still where most of the money comes from for operators. [The agreement] is what needed to happen," said Webb.

AT&T, Orange, Telefónica, TeliaSonera, Verizon Wireless, Vodafone, Alcatel-Lucent, Ericsson, Nokia Siemens Networks, Nokia, Samsung Electronics and Sony Ericsson are all involved in the agreement. The list of participants is impressive, but, for example, Chinese infrastructure, handset and modem vendor Huawei is missing.

The participants have developed a technical profile for LTE voice and SMS services. The profile is based on IMS (IP Multimedia Subsystem) and defines a set of features that can be used to offer compatible services.

At first, LTE will be used to offer data services, and existing networks will be used to carry voice and SMS, which works just fine. But running a number of networks using different technologies will in the long run add costs that operators can ill afford, according to Bengt Nordström, CEO at market research company Northstream.

The first mobile phones with support for LTE are expected to arrive in 2011, but voice in LTE networks will start to take off in a major way in 2012 or 2013, according to Nordström.

Fifteen commercial LTE based networks are expected to be launched by the end of next year and focus on offering faster mobile broadband, and in 2012 33 networks are expected to be in service, according to industry organization Global mobile Suppliers Association.