Sprint Nextel launched what it’s calling Sprint Wireless Integration, a product that extends enterprise customers’ premises-based PBX features and functionality to their mobile phones.

Sprint Wireless Integration features include providing users with one phone number that simultaneously rings both the desk phone and mobile phone, along with one converged enterprise voicemail inbox. It also extends PBX features like conferencing and call forwarding to the mobile phone so users can get all the functionality of their desk phone even while away from the office.

The service is enabled by Avaya’s “Extension to Cellular” technology, combined with Sprint’s migration to an IP Multimedia Subsystem (IMS) architecture.

Separately, Sprint Nextel continues to upgrade both the Sprint PCS Nationwide Network and the Nextel National Network. The company said it invested $107 million through the third quarter of 2006 to expand coverage and network capacity throughout Kansas. The company is upgrading to EV-DO Revision A technology.