It's no secret: Sprint, the No. 3 cellular carrier in the United States, has gone through some major changes over the past year or so, which includes the acquisition of Nextel, an upgrade to next-generation technology, and a huge WiMax project. If you're a subscriber, the changes likely have affected you in some way, whether it's network performance or customer support. But based on my conversations with Sprint last week, it sounds like good things are to come.First of all, it's important to address the concerns of former Nextel subscribers. The demand is down for Sprint's integrated Digital Enhanced Network, or iDEN, which it inherited when it acquired Nextel in 2005, as I reported in a story on Monday that analyzes Sprint's business model and strategy. Reports show that there aren't nearly as many cell sites for iDEN as there are for Sprint's CDMA network. That means Nextel subscribers have had to deal with spotty coverage around the country. Here's what Sprint is doing to solve the problem:

Last week Sprint upgraded its Evolution Data Optimized, or EV-DO, network from Revision 0 to Revision A in Miami, Portland, Ore., and Puerto Rico. The upgrade started in October and has been completed in 24 U.S. locations up to date. Here's what it means to subscribers:

Juggling a major network upgrade and a WiMax rollout isn't easy. But at least Sprint has set its priorities for the year. They include continuing to invest in its networks, simplifying the business, enhancing customer service, and improving distribution channels. Now we've got to see if it delivers on the promise.