Sprint Nextel will begin a US$4 billion to $5 billion project to upgrade its mobile network in 2011, with improvements focused on improving network speed and reducing operating costs, the company said Monday.The Network Vision project, expected to last between three and five years, will concentrate on improving network coverage and on deploying multimodal equipment that works in all three spectrum bands -- 800MHz, 1.9GHz and 2.5GHz -- that Sprint uses now, company officials said. The multimodal equipment will allow Sprint to reduce the footprint at its cell tower sites and operate them in a more environmentally friendly manner, officials said.The project will also help Sprint reduce the number of its cell sites by a third, including a phase-out of its integrated digital enhanced network (iDEN) sites, and will include repurposing some 800MHz spectrum for Sprint's CDMA-based service in an effort to improve coverage, officials said.Sprint expects $10 billion to $11 billion in savings from the project, including reduced roaming and backhaul costs, said Steve Elfman , Sprint's president of network operations and wholesale.Sprint announced contracts for hardware, software and services with Alcatel-Lucent, Ericsson and Samsung as part of the project. "We are eager to begin deployment with these world-class partners, and look forward to both the customer-experience and financial benefits this program will bring," Elfman said during a press conference.The project allows Sprint to "future proof" its network that allows the company to roll out new technologies such as long term evolution (LTE), said Dan Hays, a director in the services, electronics and software business group at consulting firm PRTM. "That's the primary objective of this," he said.Sprint's current CDMA network is starting to age, Hays added. "Like anything electronic, things start to break as they get older," he said. "One of the reasons ... is to ensure you replace and upgrade cell sites before they start to develop problems."The project's efforts to reduce the number of cell sites and reduce the equipment footprint at cell sites will be important to the company's bottom line, Hays added. "They will also make their sites greener and more energy efficient by having more up-to-date equipment," he said.Grant Gross covers technology and telecom policy in the U.S. government for The IDG News Service. Follow Grant on Twitter at GrantGross. Grant's e-mail address is firstname.lastname@example.org.